AN ABSTRACT OF TI-fE THESIS OF
BrvndIs Brandsdóttir for the degree of Master of Science in Geophysics presented on October 3. 1986. Title: Precise Measurements of Coda Buildup and Decay Rates of Western Pacific P. P0.ani0Phases and their Relevance to Lithospheric Scattering. Redacted for Privacy
Abstract approved: Wi1li.m H. Menke
Empirical functions were used to fit band-passed P, P0, andS0coda envelopes of 93 earthquakes. The data sets consisted of earthquake data from the western and northwestern Pacific recorded by arrays of several stations and included both hydrophone and geophone recordings on analog and digital instruments. Prior to the fitting each earthquake was band-passed into six frequency bands, each an octave wide, with a total range in frequency from 0.8 50 Hz. The falloff rate was measured individually for each band. These analytical results were then compared to predictions of theoretical models. The study showed that P, P0, andS0average falloff rates vary systematically with frequency, where the lowest frequencies most commonly have the minimum falloff rates and the middle frequencies have the maximum falloff rates. The variation in falloff between earthquakes is large, with the trends only becoming apparent upon averaging many measurements. A strong increase in falloff rates at about 3 Hz may be associated with a decrease in the amount of scatterers with scale lengths of about one half the wavelength of a 3 Hz compress ional wave, which is about 1.3 km. Falloff rates were seen to decrease with epicentral range. The falloff rates of the Northwest Pacific Basin data set, with an epicentral range of 8 - 210 are 20 30% higher than those of the Wake data set that has an epicentral range of 20 35°. The fact that both the data sets have raypaths through the Cretaceous and Jurassic Northwest Pacific lithosphere indicates that the difference in observed falloff rates may be due to increased scattering with length of propagation path. The scattering that produces the coda is thus not concentrated in the source region but distributed along the propagation path. Falloff rates were seen to decrease with increasing age of crust. TheP0and S0falloff rates at 10 Hz are about 50% lower for the Pacific Northwest Basin than for the Philippine Sea. The difference may be due to the different average age of the lithosphere in these two geographical areas. The Pacific Northwest Basin crust is of Cretaceous and Jurassic age whereas the Philippine crust is of Tertiary age. Average apparentP0velocities recorded by the Northwest Pacific Basin and Wake arrays are higher than recorded from the Philippine Sea. Oceanic crust thickens with age, and presuming that thinner (younger) crust has less heterogeneities than thicker (more hydrothermally altered?) crust we can explain the higher falloff values in the Philippine Sea as due to fewer heterogeneities and less scattering. Earthquakes with 100 300 km deep hypocenters have systematically lower Po falloff values than shallow (< 100 km deep) earthquakes. The effect is seen in outer trench/inner trench EQs recorded by the Wake array, where the inner trench (deeper) EQs have lower falloff values than the outer (shallower) EQs. This difference indicates that significant scattering is occuring within (or near) the deeply buried part of the subducting plate. There is some indication (though it is not statistically significant because of uncertainties in the earthquake location) that rays that travel obliquely up (or along) the slap have lower falloff than those that travel straight up (or through) the slab. Significant difference was found in average falloff rates ofP0versus S, between falloff measurements made on geophone data and hydrophone data. The P01S0falloff ratio for the geophone data is 1.7 - 2.0 which is consistent with the rate of falloff being dominated by frictional attenuation. TheP0/S0falloff ratio for the hydrophone data is 0.81.1, a factor of two lower than for the geophone measurements. As the geophone and hydrophone data have similar apparent velocities the difference in their falloff ratios cannot be ascribed to a different quality factor ratios. The difference is most likely due to conversion of shear waves at or below the sea floor. The average falloff rates are inversely related to the quality factor (Q) where y= 2itf/Q. At 10Hz our falloff rates give Q = 1250 which is a reasonable number for a compressional wave quality factor in rock. However the fact that the falloff rates are fairly consistent in the frequency range 5 30 Hz but vary with propagation distance suggest that attenuation cannot be the only phenomenon determining the decay of the coda. Other factors, such as reverberations in the water column, may play an important part in the coda formation as well. A systematic variation in the position of the maximum of the coda with frequency was observed for the Philippine Sea events. The peak in the low-frequency (0.83.1 Hz) coda occured 60- 100 s after the peak of the high-frequency (50100 Hz) coda. This 'reverse-dispersion' may be due to a correlation between attenuation and velocity in the lithosphere where the low-frequency coda will then contain mostly crustal rays, which have propagated at lower speeds. Precise Measurements of Coda Buildup and Decay Rates of Western Pacific P,P0andS0Phases and their Relevance to Lithospheric Scattering.
by
Bryndis Brandsdóttir
A THESIS submitted to Oregon State University
in partial fulfillment of the requirements for the degree of
Master of Science
Completed October 3, 1986 Commencement June 1987 Redacted for Privacy
Assistant Professr 6f Geophysics in charge of major Redacted for Privacy
Dean of College of Oceanography
Redacted for Privacy
Dean of
Date thesis is presentedOctober 3. 1986
Typed by BrvndIs Brandsdóttir ACKNOWLEDGEMENTS
This thesis is a result of a joyful, although sometimes frustrating, cooperation between a theoretical seismologist (W. H. Menke) and an observational seismologist (author) who, before this study, had never considered looking past the first arrival of P and S phases. So I would like to thank my major professor, William H. Menke, for teaching me how to look 'beond the observational world' and do a little math. My other professors Dale Bibee and Martin Fisk I thank good reviews. The data used in this study was generously supplied by L. D. Bibee (OSU), N. Frazer, C. McCreery, and D. Walker (hG). To my fellow students, may you have a good time now and good Vitas in the future whether at OSU or in Florida, New Orleans, The Netherlands, France, Mexico, Taiwan, and Kópavogur. I thank Sarah Hoffman and Dallas Abbott for editing this thesis. This research was supported by the National Science Foundation under grant No. OCE - 8417959. TABLE OF CONTENTS
INTRODUCTION 1
DATA ACQUISiTION 16 The data sets 16 The OSU OBS experiments 16 The OSU analog OBS 18 The digital Wake array 21
DATA PROCESSING 24 Steps in data processing 24 Step 1. Bandpassing the signal 24 Step 2. Forming band-limited envelopes 28 Step 3. Fitting an empirical function to the band-limited envelope 28
TECTONTC SE1TING OF THE PHILIPPINE SEA 34
PHILIPPINE SEAP0 I) FALLOFF MEASUREMENTS 36 South Mindanao Molucca Sea region 45 Philippine, Taiwan and Ryukyu trenches 53
EVENTS RECORDED BY THE WAKE ARRAY 61
WAKE P, "oL' "oH' AND SOH FALLOFF MEASUREMENTS 64 Mariana, Bonin, and Izu trenches 69 Japan trench 74 Kuril trench 77
PACIFIC NORTHWEST BASIN FALLOFF MEASUREMENTS 89 CONCLUSIONS 99
BIBLIOGRAPHY 103
APPENDiX 1 109
APPENDIX 2 113
APPENDIX 3 130 LIST OF FIGURES
Figure Page 1. Seismogram of a Kuril trench earthquake (EQ7) recorded by an 2 instrument in the Pacific Northwest Basin 2. Seismogram of a Kamchatka earthquake (EQ47) recorded by an 3 instrument in the Pacific Northwest Basin 3. Seismogram of a Izu trench earthquake (EQ27) recorded by an 4 instrument in the Pacific Northwest Basin 4. Seismogram of the Mussau trench earthquake (EQ1 886) recorded 5 by the Wake array 5. Seismogram of a Sea of Okhotsk earthquake (EQ 2556) recorded 6 by the Wake array 6. Seismogram of a Sea of Okhotsk earthquake (EQ 2492) recorded 7 by the Wake array 7. Two proposed propagation models forP0andS0phases 11 8. Location map of the study area 15 9. Location map of the Philippine Sea 17 10. Location map of the northern part of the Pacific Northwest Basin 19 11. Frequency response of the OSU analog OBS 20 12. Location map of the southern part of the Pacific Northwest Basin 22 13. Frequency response of Wake array hydrophones 23 14. Frequency domain tapers used in bandpassing theP0/S0seismograms 25 15. Comparison of Cosine and Gaussian bandpass filtered and rectified 26 seismograms 16. Comparison between two Gaussian bandpass filtered arid rectified 27 seismograms 17. Test of the bandpassing and fitting algorithms 29 16. The Poisson distribution, Pn(x) 30 19. Apparent velocity at the onset ofP0and S phases versus range for the37 vertical component of the Philippine data set 20. Apparent velocity at the onset ofP0andS0phases versus distance 38 for the horizontal component of the Philippine data set 21. Apparent velocity at the onset ofP0andS0phases versus earthquake 39 depth for the vertical component of the Philippine data set 22. Falloff rate as a function of frequency for the Philippine data set 41 23. Falloff rate as a function of frequency for typical P,P0andS0phases 42 24. Bandpassed and rectified seismograms for two Mañana earthquakes 43 25. Falloff rate as a function of frequency for two Mañana earthquakes 44 26. Tectonic map and a seismic profile of the Molucca Sea 46 27. Two puplished tectonic models of the Molucca Sea 47 28. Tectonic model of the Molucca Sea proposed in this study 48 29. Bandpassed and rectified seismograms for three Molucca Sea 50 earthquakes, (193, 194, and 126) 30. Bandpassed and rectified seismograms for three Molucca Sea 51 earthquakes, (243, 338 and 428) 31. Example of dispersion inP0coda of a Philippine Sea earthquake 52 32. Falloff rate as a function of frequency for three Molucca Sea earth- 54 quakes (193, 194, and 243) 33. Bandpassed and rectified seismograms for three Philippine trench 55 earthquakes, (168, 232, and 297) 34. Bandpassed and rectified seismograms for three Luzon Taiwan 56 earthquakes, (166, 249, and 293) 35. Bandpassed and rectified seismograms for two Taiwan Okinawa 57 trough earthquakes, (152 and 282) 36. Bandpassed and rectified seismograms for three northeast Ryukyu 58 trench earthquakes, (239, 278, and 334) 37, Falloff rate as a function of frequency for Mariana, Molucca Sea and 59 Philippine trench earthquakes 38. Falloff rate as a function of frequency for Taiwan and Ryukyu trench 60 earthquakes 39. Bandpassed and rectified seismogram for a Wake recorded 62 earthquake (EQ 1398) showing P,oH'and SOH phases 40. Bandpassed and rectified seismogram for a Wake recorded 63 earthquake (EQ 1578) showing voL' 'oH' and S0H phases 41. Apparent velocity at the onset of P,oL' 1'oH'and S0H phases versus65 range for the Wake data set 42. Apparent velocity at the onset of P, voL' 'oH' and S0H phases versus 66 earthquake depth for the Wake data set 43. Falloff rate as a function of frequency for P andoLphases of 67 the Wake data set 44. Falloff rate as a function of frequency for and S0H phases of 68 the Wake data set 45. Falloff rate as a function of frequency for Mañana outer trench 70 earthquakes (1886, 1893, 663, and 3057) 46. Falloff rate as a function of frequency for Mañana and Bonin inner 71 trench earthquakes (3120, 659, 3067, 1578, 2262, and 3213) 47. Falloff rate as a function of frequency for Izu outer trench earthquakes 72 (1494, 1801, 1802, 611, 3054, 3055, 3058, 3061, and 3248) 48. Falloff rate as a function of frequency for Izu inner trench earthquakes 73 (1850, 2144, 2495, 2242, and 2238) 49. Falloff rate as a function of frequency for Kyushu Japan outer trench 75 earthquakes (2911, 1518, 1451, 715, 1272, and 1806) 50. Falloff rate as a function of frequency for a Japan inner trench 76 earthquake (2261)
51. Apparent velocity at the onset ofvoL'oE1'and SOH phases versus78 range for the Kuril trench data set 52. Apparent velocity at the onset of ', 'oL'oH'and S0H phases versus79 earthquake depth for the Kuril trench data set 53. Falloff rate as a function of frequency for the Kuril trench data set 80 54. Falloff rate as a function of frequency for Japan - Kuril outer trench 81 earthquakes (1201, 2283, 984, and 1407) 55. Falloff rate as a function of frequency for S-Kuril outer trench 82 earthquakes (3237, 2321, 1261, 896, and 717) 56. Falloff rate as a function of frequency for N-Kuril outer trench 83 earthquakes (96, 710, 2307, and 1528) 57. Falloff rate as a function of frequency for Kuril outer trench 84 earthquakes (993 and 2001) 58. Falloff rate as a function of frequency for Kuril Kamchatska outer 85 trench earthquakes (867, 2884, 1481, and 2340) 59. Falloff rate as a function of frequency for Japan Kuril inner trench 87 earthquakes (791, 1856, and 2246) 60. Falloff rate as a function of frequency for Kuril inner trench 88 (Sea of Okhotsk) earthquakes (319, 2477, 2492, 2566, and 2645) 61. Apparent velocity at the onset ofP0andS0phases versus distance 90 for the Pacific Northwest Basin data set 62. Falloff rate as a function of frequency for all Pacific Northwest Basin 91 earthquakes recorded by the vertical geophone component 63. Falloff rate as a function of frequency for all Pacific Northwest Basin 92 earthquakes recorded by hydrophones 64. Falloff rate as a function of frequency for Pacific Northwest Basin 93 earthquakes 7, 9, 10, 11, and 13 on the vertical geophone component 65. Falloff rate as a function of frequency for Philippine Sea earthquakes 94 with epicentral distance <100 66. Falloff rate as a function of frequency for Pacific Northwest Basin 95 earthquakes 7, 9, 10, 11, and 13 on the vertical geophone component at station 3 67. Falloff rate as a function of frequency for Pacific Northwest Basin 96 earthquakes 7, 9, 11, and 13 on the hydrophone at station 3 68. Falloff rate as a function of frequency for Pacific Northwest Basin 97 earthquake 27 recorded on stations 3 and 14 69. Falloff rate as a function of frequency for Wake earthquakes with 98 epicentral distance between 20° and 22° PRECISE MEASUREMENTS OF CODA BUILDUP AND DECAY RATES OF WESTERN PACIFIC P,P0AND S PHASES AND THEIR RELE VANCE TO LITHOSPHERIC SCATTERING
INTRODUCTION:
Since their identification by Linehan (1940),P0andS0phases (also called high-frequency and long-rangenand S phases) have intrigued seismologists studying the propagation of waves through the oceanic lithosphere. The main characteristics ofP0andS0phases (o for oceanic) are their relatively high frequency, their efficient transmission, the typically gradual buildup, and the long duration of their coda (Figures 1, 2, 3, and 4). The P amplitudes are generally smaller thanP0 amplitudes (Figures 3 and 4). However, some earthquakes (EQs) have smallerP0 than P amplitudes (Figure 5) or no visibleP0and phases (Figure 6). The same relationship applies toP0versusS0amplitude ratios. S phases have been observed which have amplitudes larger thanP0phases (Figures 1, 2, and 3) as well as those having equal or smaller amplitudes thanP0phases. These different amplitude ratios have been attributed to regional effects (Fedotov, 1963; Oliver and Isacks, 1967; Molnar and Oliver, 1969; Mitronovas et al., 1969; Walker, 1977a) whereP0and especiallyS0energy is absorbed in areas of high attenuation, such as at plate boundaries or hot spots. They could also be related to source excitation effects where the source mechanism generates no shear waves. Furthermore, hydrophone data are likely to have higherP0/S0amplitude ratios than geophone data from the same events (Figures 1, 2, 3, 4, and 5) because shear waves do not couple well to the compressional waves recorded by hydrophones. One of the reasons whyP0and S have been of interest to seismologists is that they may be able to provide some information about the structure of the oceanic crust and upper mantle. Other available data, such as marine refraction surveys, are PNW-7
P0 So
HY
iftlllhIftr '--
1 mtnute
IllII III IIIIICLIII II Ill III I 1111111 III I!! III 1, I LIII1111111111
Figure 1. Typical Po/So seismograms of a Kuril trench earthquake (EQ 7)recorded by an instrument in the Pacific Northwest Basin (distance 8°). Thethree channels shown are the hydrophone (HY, top), horizontal geophone (H, middle) andvertical geophone (V, bottom). Note that the H component is clipped, that is, thesignal is too strong for the instrument to record. The HY channelhas noise arriving just before the onset of theP0phase and 2 minutes after the onset of theS0phase. The onset of each phase is labeled on the seismogram. PNW-47 P0 So H V .._,._p!._ 1 minute I I I I 1 I III II II I I Figureformatinstrument 2. asPo/Soii Figure in the seismogram 1.Pacific Northwest of a Basin (distance III III Iii III IJI III Kamchatka earthquakeIlk (EQ 47) recorded by an liii 11111 11°). This Figure has the same liii 11111 PNW-27 PPo So
1 minute LI IL I III I III I 111111 III 11111 III III 11111 111111 1111 LIII III 111111 II I 111111 11111 I 11111111111 IltillI 111111 11111 I IIIIIIIIIIILIIII III 111111 Figureformatinstrument 3. asPo/So Figure in theseismogram 1.Pacific Northwest of an Izu Basin (distance 21 trench earthquake (EQ 27) recorded by an o) This Figure has the same W- 401886 PP0 So 20 1IU, .**w, 76 V .4. :t £. r VrFrIIIJf 1flU Li Wi_LL ,.VJr.i-1I; V '*VU - V L_J*VVVJIV N . ir-- rL I1t iIiIU1VWUr L. V 3U1,L 1mUV.flL V VLVU4 t - _ ! T. .mVVVL. .V:VVV V TJ1tJI,fl1 VVV V: VV V r VV V 4Ittr1us*r.ii.-V VV V -auwr,t - LII IIIIIIIIII III 11111111111 UUIU2ULLI 111111 II I hal IhIII II II III theFigure Wakehydrophone 4. hydrophone identification array. Numbers number. on Hydrophones the left at the 10, beginning 11, 20, 21of andeach 40 signal are are P0/S0II seismogram of the Mussau trench earthquake (EQ 1886) recorded by is labeledphases,located onbothin thethe the SOFARseismogram. P and channel, Note 71-76 the amplitude near the ocean ratio betweenbottom. The the P,onset P0, ofand each the phase S0 phase amplitudes are smaller than the P0 amplitude. S0 (Ji -2566 P P0 So *LU.JLfl *tTI
p trtiP.1i1: r* 1 1 minute rr. - iii liii 11111111 lii LIII liii liii iii I II I Iii lii! U liii! Iltil liii III Liii PtheFigure phase Wake 5. amplitude hydrophone is larger array. than This that Figure of the has the same format as Figure 4. Here, the P0/S0 seismogram of a Sea of Okhotsk earthquake (EQ 2566) recorded by P0 phase. 7
P
75
Figure 6.P0/S0seismogram of another Sea of Okhotsk earthquake (EQ 2492) recorded by the Wake hydrophone array. This Figure has thesame format as Figure 4. No Po andS0phases are visible. restricted to very shallow (<10 km) depths or, in the case of surface wave dispersion data, to very large scale features (>50 km wavelength).P0and S0, being high frequency phases, may be able to constrain kilometer scale features. An important characteristic of theP0andS0phases is the unusually long duration of their coda compared to other body wave phases. Their coda can be several minutes long (hundreds of oscillations), and most often theP0coda extends into the S0coda even at large epicentral distances (>20 degrees). The coda most frequently has a gradual buildup to a maximum amplitude that may last for several up to tens of seconds (Figures 1 to 5). TheP0and S, coda amplitudes have been observed to vary with frequency (Asada and Shimamura, 1976; Ouchi, 1981; Menke and Chen, 1984; Butler, 1985; Novelo-Casanova and Butler, 1986). Walker et al. (1983) concluded from composite spectra that the P wave amplitudes decrease faster with frequency than theP0wave amplitudes and that theS0phases decreased slightly faster than theP0 phases. However, due to large deviations between different earthquake spectra, the differences betweenP0andS0spectral falloffs observed in the composite spectra are highly questionable. Currently available quantitative data onP0andS0phases are limited to phase velocities of the onset of the coda and primitive spectral analyses (Press and Ewing, 1955; Shurbet, 1962; Herrin and Taggart, 1962; Walker, 1965; Bath, 1966; Fedotov, 1968; Molnar and Oliver, 1969; Walker and Sutton, 1971; Sutton and Walker, 1972; Hart and Press, 1973; Huestis et aL, 1973; Asada and Shimamura, 1976; Walker, 1977 a; Stephens and Isacks, 1977; Mantovani, 1977; Walker et al., 1978; Sutton et al., 1978; Talandier and Bouchon, 1979; McCreery, 1981; Ouchi, 1981; Walker et al., 1983; Ouchi, 1983). Most of these studies were done on small data sets (see upper part of Table 1) using single station observations and regression analyses on X/T observations from different stations (where X is a range measured along a great circle on the earth's surface and T is the travel time). Single station observations on apparent phase velocities (X/T) cannot be compared primarily because of the different tectonic settings for different raypaths.Anisotropies, observed in nonarray experiments (Talandier and Bouchon, 1977), are caused by heterogeneities in the oceanic and upper mantle structure of different regions. Array measurements OBSERVER YEAR NO OF EQ RANGE AGE Po RANGE TYP Po NO OF EQ RANGE AGE So RANGE TYP So STUDY AREA ShurbetHerrin&T.Press&E. 196419621955 10 53 13-3069-79 8.07-8.347.98-8.24 7.6-8.37.7-8.2 7.8 1015 5 52-12513-30 4.55-4.634.34-4.634.2-4.7 4.58 various4.5 areas BermudaUSABermuda FedotovOliverBAthWalker & I. 1966196519681967 24 5 31.5-35.1 17-32 8.13-8.258.21-8.31 8.26 8.48.1 3328 21.6-41.4 17-32 4.66-4.78 4.754.724.65 TongaPacificRussia Hait&PressSutton&W.Walker&S.Molnar&O. 1973197219711969 62 0-30 8.25-8.31 8.28 >130 4060 4 7.6-20.6 0-306-351-27 4.74-4.804.75-4.834.64-4.68 4.774.794.664.57 variousKamchatkaNPacific - Pacific areas Stephens&I.Huestis&aI.Huestis&al.Hart&Press 19771973 0-50> my. 50 m.y. 2030 35-4014-34 8-271-27 >1500-50 m.y.m.y 4.75-4.874.69-4.754.56-4.604.70-4.72 4.724.584.71 NIndiaN-Atlantic - Atlantic4.7 W - Australia WalkerTalandier&B. 1977a 19811977 45 3-168-30>30 60-130 m.y. >130 m.y 7.90-8.127.92-7.988.28-8.388.38-8.66 8.017.958.338.52 3-168-30>308-30 60-130 m.y. >130 m.y 4.64-4.724.74-4.804.63-4.77 4.77 NW - Pacific4.7 NW - Pacific C&S - Pacific OBSERVER McCreery ButlerOuchi YEAR NO OF EQ 198519831981 1114 4 RANGE 17-359-184-13 <30 m.y.150 my. AGE Po RANGE 7.91-7.967.23-7.47 8.1-8.3 TYP Po NO OF EQ 7.967.35 10 RANGE 17-35 AGE So RANGE 150 4.53-4.61 TYP So STUDY AREA 4.57 NW-Pacific Cocos Plate Japan 10
(shown in lower part of Table 1) have been made by McCreery (1981), Ouchi (1983), and Butler (1985). Unfortunately, these array studies were also done on small data sets so their results are limited to small areas and are sometimes highly questionable (Ouchi, 1983; Butler, 1985). No systematic polarization studies onP0andS0phases are available, but authors have commented on their chaotic particle motion (Bath, 1966). P0andS0phase velocities have been found to depend on: 1) tectonic setting and epicentral depth (Fedotov, 1963; Oliver and Isacks, 1967; Utsu and Okada, 1968; Molnar and Oliver, 1969; Mitronovas et al., 1969; Huestis et al., 1973; Walker, 1977 a; Talandier and Bouchon, 1979; McCreery, 1981); 2) range interval (Fedotov, 1968; Walker and Sutton, 1971; Sutton and Walker, 1972; Walker 1977 a,b); and 3) lithospheric age and cooling (Hart and Press, 1973; Asada and Shimamura, 1976; Walker, 1977 a; McCreery, 1981; Black and Braile, 1982),P0 and S phase velocities have been used as constraints on petrological models of the upper mantle (Hart and Press, 1973; Fuchs and Schulz, 1976). The large amplitudes ofP0andS0phases as well as their nearly range-independent phase velocity and low attenuation have prompted past investigators to conclude that they are guided waves. The type, location, and shape of their waveguide are not clearly defined or understood. Several modes of propagation have been proposed; for example: 1) Transmission by whispering gallery propagation in the mantle by multiple grazing reflections from the MOHO discontinuity (Press and Ewing, 1955; Menke and Richards, 1980) (Figure 7, top); 2) Transmission in a layer of increasing velocity directly below the MOHO and above the LVZ (Shurbet, 1964; Stephens and Isacks, 1977); 3) Transmission through a minimum velocity channel (LVZ) slightly below the MOHO (Shurbet, 1962; Walker, 1965; Sutton and Walker, 1972) (Figure 7, bottom). Crust
Mantle
LVZ
Mantle
A.
______,' Crust
Mantle
44 I ::::\.'T:z.z:::: LVZ
Mantle
Figure 7. Two models for the proposed propagation paths ofP0andS0. A) Propagation by whispering gallery modes at the crust-mantle boundary. B) Propagation through a mantle low-velocity zone. Iy
In addition, the following questions have been debated:
1. Is there more than one waveguide involved (Molnar and Oliver, 1969; Mantovani et al., 1977; Walker, 1977a, b)? 2. Is the high frequency nature ofP0andS0phases a result of the tunneling of low frequency waves by thin high velocity layers in the lower lithosphere (Fuchs and Schulz, 1976; Ouchi, 1981)? 3. Perhaps the waveguide is not present, and the coda is simply created by reverberations in a very simple lithospheric structure (Gettrust and Frasier, 1981; Sereno and Orcutt, 1985)? 4. How do the crust, sediments, and water column affect the coda production? Are reverberations in those layers important in building the coda (Gettrust and Frasier, 1981; SerenoandOrcutt, 1985)? 5. Are the scatterers that cause the coda layers in the crust (Gettrust and Frasier, 1981; Sereno and Orcutt, 1985) or random irregularities in the crust or mantle (Menke and Richards, 1983; Sato, 1984)?
One reason that these questions have not yet been definitely answered is that, although theP0andS0phases have received considerable attention from seismologists, very little quantitative data has been published. The models that have been attempted lack good data against which they can be tested. The lack of data is due largely to the fact that digital signal analyses are required to understand this phase, and until recently, most recordings of it were analog paper records. The fact thatP0and are composed of reverberating coda has made them very difficult to study. It has proven impossible to model the waves in a 'wiggle-by-wiggle' way that is commonly done today with simpler, long period seismograms. An alternative is to model the coda statistically, that is, to match only the gross shape of the coda. Recent work on other kinds of coda-dominated waves (notably local EQs), when combined with theoretical models of coda generation, have demonstrated that this technique can produce interesting results (Toksöz et al., 1974; 13
Aki and Chouet, 1975; Menke and Richards, 1980; Gettrust and Frazer, 1981; Richards and Menke, 1983; Menke and Richards, 1983; Menke and Chen, 1984; Sato, 1984; Sereno and Orcutt, 1985). The approach is to recognize that the coda is a product of two competing phenomena in the earth: Scattering of waves from heterogeneities in the earth, which tends to lengthen the travel time of the waves and produce long coda, and: Attenuation of waves by frictional absorption which tends to preferentially absorb waves, that have travelled an extra distance, and reduce the coda. Both scattering and attenuation are known to be frequency dependent phenomena. The amount of scattering is controlled by the amount of heterogeneities in the earths structure at scale lengths comparable to the wavelength of the seismic waves. Attenuation often causes waves to loose energy at a rate proportional to exp(-2itft/Q) wherefis frequency, t, travel time, and Q, the quality factor. Thus by measuring the shape of the coda in different frequency bands it may be possible to recover information about the scale length of heterogeneities in the earth and about the magnitude of the attenuation. Both of these parameters are of considerable geophysical interest, since they may be related to the type of lithospheric formation and its current thermal state. Aki and Chouet (1975) studying shear wave coda of local EQs demonstrated that they could recover both the attenuation and degree of heterogeneity along their raypaths. However, their work was greatly simplified by the geometry of local EQs where the overall seismic structure is simple, the raypaths of the waves forming the coda short, and largely known. This is not the case withP0andS0phases so we cannot hope to apply Aid and Chouet's (1975) simple formulas to the coda falloff measurements made in this study. Instead, our approach will be more ad hoc. We use empirically chosen functions to describe the shape of the coda, functions that do not have much theoretical justification except that they vary with frequency and contain a term that exponentially decays with time as is suggested by the attenuation rule. It is our expectation that, when compared to similar measurements derived from synthetic P0andS0seismograms (for instance, those of Gettrust and Frazer, 1981; Sato, 1984; Sereno and Orcutt, 1985), our measurements will help constrain the lithospheric structures that form theP0/S0'waveguide'. 14
The purpose of this study is to quantitatively describe the shape of the coda for different frequency bands by fitting empirical functions to the coda envelope in each band, using a large (-100) EQ data set recorded on hydrophones and geophones in the NW Pacific (Figure 8). These analytical results can then be compared to the predictions of theoretical models. Furthermore any variations in coda falloff values can be related to variables such as epicentral range, tectonic setting, age of the crust, depth of focus, and apparent raypaths. The data consist of EQs from the western and northwestern Pacific recorded by arrays of several stations and includes both hydrophone and geophone recordings on analog and digital instruments. This study concentrates on theP0andS0coda, and especially on its decay rate, because the coda is very sensitive to the type of scatterers, to their size and shape, and because measurements of coda buildup and decay are independent of the response of the recording instrument and of the seismic source (Aki and Chouet, 1975). We therefore can use existing data, some of which is only poorly calibrated, to make high quality measurements of the properties of the coda. 15
Figure 8. Location map of all earthquakes (circles and hexagons) and the three recording arrays (triangles) used in this study. Each array operated during different time intervals. Earthquakes denoted by circles were recorded by the Wake hydrophones; those denoted by hexagons were recorded on the OSU OBSs. 16
DATA ACQUISITION: The data sets:
Three data sets were used in this study. Two sets were recorded by OSU ocean bottom seismometers (OBS) during an experiment in the Philippine Sea in February and March, 1981, and during the Deep Sea Drilling Project (DSDP) Leg 88 in the Northwest Pacific Basin in September, 1982. The OSU data sets were made available to this study by L. D. Bibee. The third data set contained 106 selected EQs recorded by the Wake hydrophone array from September, 1982, to January, 1985. The Wake data were made available by N. Frazer, C. McCreery, and D. Walker at the Hawaii Institute of Geophysics (HIG). The EQ locations were obtained from the Preliminary Determination of Epicenters-Earthquake Data Report (PDE-EDR) monthly reports. They are listed in Appendix 1. The PDE-EDR locations are sufficiently accurate to be used in this study because the size of our geometrical array is very large compared to hypocentral location errors.
The OSU OBS experiments:
The Philippine Sea data were recorded in a three phase experiment during February and March, 1981. The experiment was conducted by Oregon State University in cooperation with the Scripps Institute of Geophysics and Planetary Physics (IGPP). The objective of this project was to determine compressional and shear wave velocities as well as attenuation at depth in the Philippine Sea (Goodman, 1983). During the first phase of this experiment, seven ocean bottom seismometers were deployed in a line, about 500 km in length, striking NW SE in the West Philippine Basin (Figures 8 and 9). Due to inoperative satellite navigation, only five OBSs (stations A, B, D, E, and G) were recovered at the end of the first phase. During the second phase, data were collected by three instruments, stations AA, BB, and EE (Figure 9). In the third phase, five OBSs were deployed, and four were recovered (stations BBB, DDD, EEE, and FFF). The Philippine Sea stations have a location error of about 500 m. For further description of the Philippine Sea refraction 17
3 239 266w 278
I\.25°I
URDAMETA '-.'z PLATEAU 0 J2 , I PHIL I P P I N E
1501
2ega
CELEBES MERCATOR PROJECTION g 0194 ii ; SCALE AT EQUATOR BASIN 38 1:6.442.194
? 428 ALNAHERA 24 j1300 11350 11400
Figure 9. Location map for the Philippine Sea data set. Earthquakes (circles) and stations (triangles) are numbered and further described in Appendix 1. IL,]
survey, the reader is referred to Goodman (1983). The second data set was recorded in September, 1982, during DSDP Leg 88, in the NW Pacific Basin, near 160°W and 44°N, using two OSU OBSs and a digital ocean sub-bottom seismometer (OSS) developed by Hawaii Institute of Geophysics (HIG). Figures 8 and 10 show the location of the NW Pacific Basin array. The location error for each station is about 250 m. Only data from the two OSU OBSs, were used in this study. One of the objectives of the NW Pacific Basin project was to obtain information on the crustal structure of the 110 m.y. old crust in the Northwest Pacific Basin. For further description of the project the reader is referred to Bee, (1984).
The OSU analog OBS:
The OSU ocean bottom seismometer is a four-channel, analog instrument consisting of horizontal and vertical geophones with a natural frequency of 3 Hz and of a pressure-compensated hydrophone with a flat frequency response between 1 and 30 Hz. The fourth data channel is the time signal. The OBS clocks are corrected by using the Universal Time Code (UTC), transmitted from stations on land. The OSU OBS frequency range is 2 30 Hz. After filtering, the data is converted into the digital domain at a rate of 100 samples per second, resulting in a Nyquist frequency of 50 Hz, twice that of the high frequency setting of the anti-alias filter. Signals between 2 25 Hz are thus fairly well recovered, with little aliasing noise from higher frequencies. The data reduction converts the raw data into the standardized ROSE format decribed by LaTraille et al. (1982). Figure 11 shows different response curves for the OSU OBS system. The response is approximately flat from 518 Hz with a highpass slope of approximately 6 dB/octave and a lowpass slope of approximately 16 dB/octave. The 40 Hz noise is due to the recorder motor. The dynamic range of the seismometer is about 40dB, which equals approximately 1.8 units of magnitude being recorded without distortion. For further information on the OSU OBS instrumentation, refer to Goodman (1983) and Solano (1984). 19
DEPTH 0 10-leO km 148 0 4 0300-500 1398 >500 O q. 2645 2566 :J 50°N t1 1: .000
tk P.O2492 'p I'j_c "4
1 PAC-NW AT' 00 0 ARRAyZ
791034W. 12011 400 J
3000
/ 150° E 160°
Figure 10. Location map for the Pacific Northwest Array and earthquakes recorded by that array (circles with crosses) and the Wake array (circles). Each earthquake is numbered and further decribed in Appendix 1. 20
RESPONSE OF OSU ANALOG 085 1010 7
i09 6 108 5
4
106
1 o
iO
102 2
101
101 101 FREQUENCY (HERTZ)
Figure 11. Adapted from Solano (1984). Frequency response of the OSU analog OBS. Curve 1) Geophone response to velocity. Curve 2) Hydrophone response to pressure. Curve 3) Electronics response. Curve 4) Geophone plus electronics response to velocity. Curve 5) Hydrophone plus electronics response to pressure. Curve 6) Geophone plus electronics response to displacement. Curve 7) Hydrophone plus electronics response to displacement. 21
The digital WAKE array:
Tn August, 1982, a continuous digital data collection system was installed on Wake island in the northwest Pacific (Figures 8 and 12) in order to record seismic signals from a nearby array of hydrophones. The array consists of six ocean bottom hydrophones (OBH) and five "doubled" sound fixing and ranging (SOFAR) channel hydrophones. Figure 13 shows the estimated response of the Wake system hydrophones. The system has a dynamic range of 96 dB, so that events ranging from at least mb = 4.0 to mb = 8.0 are recorded without distortion. For further description of the WAKE recording and processing system, the reader is referred to McCreery (no year). 22
LI
2144_ 3061 3058 3248 . i91,
30 2242
1494
WAKE 4 ARRAY AA 15789 A 0 3057 15°N
DEPTH 0-lOOkm Qloo-300 0300-500 .>500
1886 135°E 150° 165°
Figure 12. Location map for the southern part of the Pacific Northwest Array earthquakes (circles with crosses) and the Wakearray data (circles) and stations (triangles). Each earthquake is numbered and further decribed in Appendix 1. 23
6O
4o '3 z20 ,, , I- -J , /
I- ' , ' , zLU 020 0 I- >LU
-6O
0.1 0.2 0.5 1.0 2 5 10 20 50 FREQUENCY (Hz)
Figure 13. Response curve for the Wake hydrophone array. Pressure compensation hole closed (dashed line). Pressure compensation hole open (solid line). 24
DATA PROCESSING:
The purpose of this study was to fit simple empirical curves to selected phases of data in order to characterize their shape and thus evaluate their falloff rates. Each EQ was filtered into six frequency bands, and the measured falloff rates for P,P0and S0phases in these bands were compared for a total of 93 EQs.
Steps in Data Processing:
Step 1. Bandpassing the signal. Before bandpassing each data channel, its mean was removed, and it was padded with zeroes to a total of 65536 points. Each data channel was then bandpassed into six frequency bands using a standard Fast Fourier Transform (FFT), tapering the transform to remove unwanted frequencies, and then applying an inverse FFT. The bands were chosen to be about one octave wide, with the highest band being between 0.5 f andn'where fis the Nyquist frequency. We tested two filters, one based on cosine functions and the other on gaussian curves (Figure 14). The cosine filter we use has overlapping pass-bands. Consequently, considerable energy spreads between the frequency bands of a channel, especially at the higher frequency bands where the tapers are broader (Figure 15). The gaussian filter we use does not taper into adjacent frequency bands, since we truncate it at the edges of each octave band. We investigated several values for the variance of the gaussian filter. A higher variance creates a broader "gaussian bell" resulting in a slight increase in frequency domain amplitude which is transmitted to the bandpassed time series (Figure 16). Our experiments indicated that the gaussian filter, with a variance chosen such that its amplitude was 0.9 at the edge of the pass-band (that is, almost a box-car), was most appropriate for our purposes. 25
0 25 50 Frequency. Hz
50 0 25
Frequency. Hz
Figure 14. Frequency domain tapers used in bandpassing theP0/S0seismograms. Top) Cosine taper. Bottom) Gaussian Taper. After initial experimentation, the Gaussian taper was exclusively used to compute falloff values. 26 the into the thebottom. column, filtered for bands rectified with at Middle ratios bands. L and bands, Hz) 0.1. Cosine noice adjacent value column, from frequency filtered (0.78-1.56 Left signal-to lowest lowest cutoff 0.9. better energy and bandpass octave-widepass with a ii andthe value give spreads highest gaussian different top, cutoff values taper the and are the seismogram a cutoff cosine in --lw1I,--1 Iw!,Ii I,Ii ii.iiiI cosine rows at with the seen .1 Hz) filtered that best of Gaussian different is (25-50 seismogram Note This The Gaussian Higher u. Comparison data. band. filtered IL 15. frequency column, ii.iii1 filtered "ii I1ii 111,11 "Ii I1I Figure seismograms. highest Right Gaussian seismogram. bandpassed the 27
S.
S.
S.
I p p I I I 4 d ii
Figure 16. Comparison between two Gaussian bandpass filtered and rectified seismograms, with two different cutoffs of the Gaussian, 0.1 (dashed) and 0.9 (solid). Note that the 0.9 cutoff gives a higher amplitude signal, but that the shapes of the envelopes are similar. [PT.] re.]
Step 2. Forming Band-limited Envelopes. The band-limited time series were then squared and summed over either 128 point intervals (for the 100 Hz OSU data) or 102.4 point intervals (for the 80 Hz Wake data). This created six band-limited envelopes, each an octave wide, in the frequency range 0.7850 Hz. (OSU) and 0.62 40 Hz. (Wake), with a sampling interval of 1.28 seconds. The shape of the band-limited envelope is a measure of the energy in the various bands. The summation has the effect of smoothing out small time scale (that is <1.28s) variations in the envelope. However, we have made careful tests that demonstrate that the bandpassing and summing process does not affect any of the features on scales greater than 1.28 seconds. In particular, the smoothing does not effect the decay rate of the envelopes (Figure 17). The Wake version of the bandpassing program (WAKEROSEBD) is listed in Appendix 2.
Step 3. Fitting an empirical function to the band-limited envelope. The band-limited envelope data were windowed (parts of the data were selected) by hand-picking the desired phases on a high-resolution graphics terminal. The windowed data were then fitted using a modified version of the Poisson distribution. The Poisson distribution is a discrete distribution on the integers of n:
'ne(B'/n!) n=0,1,2, (1)
where B is a fixed positive number called the parameter of the Poisson distribution. In our analyses,
B= where t is the time after the beginning of the phase and y is a positive constant hereafter called the falloff. Figure 18 shows the Poisson distribution for n = 0, 1, 2, 3, and 4. As n increases the distribution becomes longer-tailed. We modify this distribution -o IMPULSE2.OWT-PO COLCO.IMPULSE2.OUTT-PO I1 FREO FREQ AGAINSTAGAINST COL COL 5 GAMMA 5 GAMMA O3000+OO - IMPULSE2.OUTT-POIMPIJLSE2.OUTI-PO COL I FREOFHEO AGAINST COL 34 ASIGUAA O.2500E.00 O.2000E+OO 0.15005.00 PIPt If_ P0 __ - 0.I000E+00 AAA_ ti' 0.5000E.01 _-_- 0.00005+00 p p o NotedecayingrectifiedFigure that spikes.the17. seismograms, falloffTest Right) of is the constant Falloff bandpassingwhere with asthe function originalfrequency. and fitting offunction frequency algorithms. consisted (circles) Left) of and Bandpassed icr error bars. and a set of exponentially N)
31
slightly by requiring that it have area, A. Because:
I eY tT' dt= F(n+1) / =n! / n = 0,1,2 ..... Jo
the normalized formula is:
Pn(Y,t) = Ay1tne in! (2)
This formula is a reasonable one because its shape changes for each n, and by fitting various n's of the formula to the data, one can iteratively approximate the shape of each phase envelope. We do not claim that the true shape of the coda falloff is a Poisson distribution, only that the distribution is a reasonably good approximation to the shape of the coda envelopes. The fitting process used a combination of a nonlinear least squares procedure for the parameters, A and y (Menke, 1984), and an exhaustive search for the best parameter, n. In other words, different A's ands were determined for n = 0,1,2,3..., with those values which minimized the error being chosen as the best fitting ones. The fitting program (WAKEFALLOFF) for the Wake data is listed in Appendix 2. The area, A, is un-normalized in that we have not tried to remove source/receiver effects. As an result, A becomes useless, except when comparing ratios between several phases in same band. We also estimated the standard error for the parameters A and y. The least-squares fitting subroutine estimates the variance (d2) of the bandlimited envelopes timeseries, d, as;
= (d -dpre)2/(N2)
where d is the observed data, dpre the predicted data, and the summation takes place over the N samples in the portion of the band-limited envelope being fitted. 32
We then define the normal equation matrix:
(aP/a) (aP/A) A B [GTG] (P/A) (P/y) (aP/A) (P/y) [ ]
The standard error in the area, A, and the falloff, 'y, are given by the following equations, = ad[A /(AD BC)]1t2 and
cY=rad[D/(ADBC)IV2
The time interval of the fit for each EQ was determined by handpicking the beginning and end of each phase. The same interval was then used to fit all spectral envelopes of that particular EQ. The phase interval had to be handpicked due to variations in apparent phase velocities (XIT) in the data. The handpicking subroutine also calculated the apparent velocity of each pick. Averaging (over 1.28 s intervals) of the data increases the error in calculated apparent velocities. This error decreases with increased travel time (T) and is therefore larger (0.20.3 s) for theP0phases than for theS0phases (0.10.2 s). In comparing theoretical fits to the data, one observes that most often the fit integral is equal to 90% or more of the data function integral (A). To be used in the fmal data processing, the fits had to include at least 90% of the data envelope and had to be satisfactory in the eye of the analyser; in other words, had to follow the eye-fitted falloff of the data reasonably well. We observed that signal-to-noise ratios varied greatly for different EQs and also between different instruments recording the same EQ. The best signal-to-noise ratios are in the two middle frequencies for all instruments, i.e. at 2.510 Hz for the Wake data and at 3 12.5 for the OSU OBS data. Noise in the highest frequencies is often generated by explosive devices, such as airguns and sparkers, operated in the vicinity of the instruments during their time of recording. High frequency noise is also generated by the biggest inhabitants of the recording area, the great whales. Often the "whale pulses" alternate between the two highest frequencies, 10 20 Hz and 20 - 40 Hz. 33
The noise in the two lowest frequency bands of the spectra is primarily caused by seafloor microseismic activity. Recent studies on seafloor microseismicity by Webb and Cox (1986) show close agreement between the theory of microseismic generation and observations of changing wind wave field, where changes in wind energy are directly related to the magnitude of the noise level in the lowest frequency bands. The horizontal component of the seafloor noise has significiantly higher noise level than the vertical component (Figures 1, 2, and 3). To compensate for this, the horizontal OBS geophone has a lower magnification than the vertical OBS geophone. Still, most of the recorded horizontal phases are clipped. The clipping is caused by a signal too strong for the instrument to record. Why the amplitude of the signal recorded on the horizontal component is many times greater than of the signal recorded on the vertical component is not clearly understood. It could be caused by coupling and orientation differences, with respect to the seafloor, between the two components. 34
TECTONIC SETTING OF THE PHILIPPINE SEA:
The Philippine Sea is one of several western Pacific marginal seas, some of the others being the Sea of Okhotsk, the Sea of Japan and the East China Sea (Figure 8). Marginal seas are isolated ocean basins found at the margins between continents and major ocean basins. Numerous seismic studies have revealed crustal and mantle velocities similar to that of the major oceans. Three hypotheses on the origin of marginal seas have been developed. One suggests that marginal basins represent older oceanic crust trapped as a result of the initiation of intraplate subduction or from the relative motion of trench boundaries (Uyeda and Ben-Avraham, 1972). Alternative models for explaining the structural history of marginal sea basins propose that they are formed by extension behind an island arc (Karig, 1971) or by retreating subduction where the Philippine plate's eastern trench system has progressively migrated over the subducting Pacific plate (Kanamori, 1977). The Philippine plate is juxtaposed between the Asian continent and the NW Pacific (Figure 8). The plate is bordered by active trenches and is composed of several distinctly defined basins. The Philippine Basin (Figures 8 and 9) is considered to be the largest and deepest marginal basin in the world, and compared to ocean floor of similar age (early Eocene), it is anomalously deep by as much as 1000 m. This anomaly may in part be an isostatic response to crustal and/or upper mantle anomalies (Goodman, 1983). The NW SE trending Central Basin ridge divides the Philippine Basin. The N S trending Kyushu - Palau ridge separates the Philippine Basin from the Parece Vela Basin. Goodman (1983), in a detailed refraction study on the crustal and upper mantle structure in the Philippine Basin, found the oceanic layer (layer 3) in the basin to be abnormally thin by about 2000 m, compared to average crustal thicknesses. The crust was shown to be thinner in the eastern part of the basin. Typical upper mantle velocities (at 4 km depth) were found to be around 8 km/s. Crustal thinning towards the east is believed to be consistent with the Kyushu Palau ridge being a remnant transform fault connecting the Central Basin ridge with the subducted Kula Pacific ridge, as proposed in the model of Uyeda and Ben-Avraham 35
(Goodman, 1983). The presence of symmetric magnetic anomalies having strikes roughly parallel to the Central Basin ridge (Louden, 1976) also supports this model, but N NE spreading is not in agreement with the retreating subduction model. Katsumata and Sykes (1969) studied the seismicity of the Philippine plate boundary. They found that the western boundaries of the plate from the Philippines to Japan and the Mañana trenches, are fairly well defined whereas the southern boundaries have shallower and more diffuse seismic zones. They did not detect any events from the Kyushu - Palau ridge, from the Central Basin ridge, or from the rest of the Philippine plate. Seismic cross-sections of the Izu, Bonin, and Mañana trenches have been used to delineate the dip, vertical extension, and subduction mechanism of the Pacific slab (Katsumata and Sykes, 1969; Samowitz and Forsyth, 1981; Roecker, 1985; Creager and Jordan, 1986). According to the Plate-Tectonic map of the Circum-Pacific Region (1981), maximum EQ focal depths are 200 300 km along the eastern border of the Philippine plate (Molocca Sea Phillippine trench Taiwan Ryukyu trenches). On the western border, focal depths greater than 600 km are observed along the Izu, Bonin, and Mañana trenches south to about 15°N. South of 15°N, the seismic zone extends only to 200 km depth and becomes progressively shallower towards the Yap trench. Seismicity in the Yap and Palau trenches is low, and focal depths are less than 70 km. 36
PHILIPPINE SEAP0AND FALLOFF MEASUREMENTS:
Figure 9 shows the location of EQs recorded by the Philippine array during the refraction survey in 1981. The EQs and their measured falloff rates are listed in Appendix 3A. The dataset consists of 21 EQs which all occur in the shallow seismic regions of the Philippine plate (< 200 km depth). One EQ (35) has an intraplate epicenter just south of the Ryukyu trench. The epicentral distance of these EQs ranges from 5 to 18 degrees. Plots of apparentP0andS0velocities (X/T) versus distance for the vertical (Figure 19) and horizontal (Figure 20) components indicate averageP0and S0velocities of 8.06 ± 0.04 km/s and 4.69 ± 0.02 kmls, respectively. TheP0 apparent velocities (APVELs) range from 7.6 to 8.6 kmls, whereas theS0APVELs have a smaller range from 4.4 to 5.0 km/s. This smaller range is most likely due to increasing accuracy in APVEL calculations with increasing timespan on the seismogram. Because of higher noise amplitude on the horizontal component, fewer APVEL measurements could be made on that component, but they show a similar velocity range. Frequently, the vertical component of a given EQ has a slightly higher APVEL than the horizontal component (see Appendix 3A). Plotting APVEL versus depth (Figure 21) shows a cluster of EQs at 33 km depth having a totalP0velocity span from 7.6 to 8.6 km/s. As hypocenter location is often hindered by unsufficient station coverage in the epicentral area of an EQ, a normal depth of 33 km is chosen for the EQ location. The Phiffippine EQs that have a normal depth of 33 km have greater hypocentral errors, resulting in greater inaccuracies in their APVEL determinations. EQs 35 and 152, which have an epicentral distance of less than 9 degrees, have higher APVELs, up to 8.6 kmls, whereas EQs 194, 338, 428, 232, 166, and 239 have lower than average APVEL on one or more stations. Only EQ 35 has a normalized depth at 33 km. Apart from these EQs, APVEL measurements give fairly constantP0andS0 phase velocities both with range and depth to 160 km for the Philippine plate. Falloff values for the Philippine data set showed considerable variations for individual EQs both within the same band and between different frequency bands. Average falloff values on the vertical component for the Philippine Sea show little 37
9.0000 - Phi lippine Sea, Po velocity versus distance vertical component, all EQs
8.6000 * x
x xx x x 8.2000 - xx Xxx x X % X> XX I) xx o x x 7.8000 x x x x) 7.4000 - 7.0000 I 4.0000 6.8000 9.6000 12.400 15.200 18.000 distance, deg 6.0000 - Philippine Sea, So velocity versus distance vertical component, all EQs 5.6000 - 0, E 5.2000 - 4-' --4 () 0 4.8000 ,- 0 000 a) o0 o % 0% 0 00 00 00 4.4000 - 0 4.0000 I I 4.0000 6.8000 9.6000 12.400 15.200 18.000 distance, deg Figure 19. Apparent velocity ofP0andS0onset versus distance for the vertical component of the Philippine Sea data set. Top)P0phase. Bottom)S0phase. Philippine Sea, Po velocity versus distance Q. 0000 8.6000 S E 8.2000 4) 0 7.8000 a) 7. 4000 7. 0000 4.0000 6.8000 9.6000 12.400 15.200 18.000 distance, deg Philippine Sea, So velocity versus distance horizontal component, all EQs on all stations 15. 6000 (0 5.2000 .1.) 0 4.8000 0 00 0 4.4000 0 4.0000 L_ 4. 0000 6.8000 9.6000 12.400 15.200 18.000 distance, deg Figure 20. Apparent velocity ofP0andS0onset versus distance for the horizontal component of the Philippine Sea data set. Top)P0phase. Bottom)S0phase. 39 9.0000 - P0 velocity versus depths all EQs on all stations 8.6000 - x U) x - x 8.2000 x X .lJ >° 7.4000 - 7.0000 I 0.0000 40.000 80.000 120.00 160.00 200.00 depth, km 6.0000 P0 velocity versus depth, all EQs (U) on all stations 5.6000 - Ci) E 5.2000 4.8000 o 0 4.4000 - 4.0000 I 0.0000 40.000 80.000 120.00 160.00 200.00 depth, km Figure 21. Apparent velocity ofP0andS0onset versus earthquake depth for the Philippine Sea data set. Top) P0. Bottom) S0. 40 variation between different frequency bands (Figure 22). It is much smaller than the falloff variation within the same band. Although the averaging smears out individual characteristics, we see that the average falloffs are significiantly lower in the two lowest frequency bands. The average falloff for theS0phase is considerably higher than for theP0phase especially in the lowest two bands. Comparing averageP0and S0falloffs indicates that theS0decay rate is twice the rate of theP0decay. This effect could also be due to the fact that many EQs completely lack low frequencyS0energy. An overall effect is, that whereasP0falloff values seem to decrease with increasing frequency,S0falloffs remain fairly constant. In the bandpassed data,S0phases have more peaked coda shape butP0phases have more gradually shaped coda in the highest bands. A typical P, P0, andS0falloff curve with standard error bars is shown in Figure 23. TheP0falloff (shown for EQ 297) is low in the lowest two bands, highest in the middle bands, and slowly decreases in the two highest bands. As mentioned earlier the individual EQ falloff pattern shows greater deviations between frequency bands than is seen in the average pattern. The individual pattern is governed by regional effects at the EQ source and along each raypath, as different frequencies are scattered and attenuated by different structures. The effect of depth can be seen by comparing two EQs (277 and 279) located in the same area at different depths. Band-passed and squared seismograms and their theoretical fits are shown in Figure 24. EQ 277 has a focal depth of 27 km and a smaller-than-average APVEL (7.98.0 km/s (P0) and 4.6 km/s (S0)), whereas EQ 279 has a focal depth of 93 km and higher-than-average APVEL ( 8.3 - 8.5 km/s and 4.8 km/s). TheP01S0amplitude ratio is much higher for 279, as hardly anyS0phase is associated with the deeper EQ, while the shallower EQ has someS0energy in all bands. Comparing the same bands shows that both EQs have similar buildup rates, but the lower frequency bands have a more gradualP0phase buildup than the higher bands. As a result, the maximum amplitude of theP0phase (reflecting the group velocity) shows a dispersion effect where the group velocity increases with increasing frequency. Most of the Philippine Sea EQs exhibit this dispersion effect. Figure 25 shows a plot of absolute falloff values versus frequency for the verticalP0and S phases of EQs 277 and 279. The 41 1.2000 Philippine (U) data, So fal 10ff versus frequency 0.96000 0 0 0 0 o 0.72000 8 0 8 0 00 0 0 0.48000 0 8 00 0.24000 0 8 0.0000 0C I 2J 0.0000 8.0000 16.000 24.000 32.000 40.000 frequency, Hz Figure 22. Falloff rate of the P0 and S0 bandpasses and rectified seismogramsas a function of frequency. Top) P0 measurements (crosses), mean (middle solid line) and icr standard errors of the mean (outer lines). Bottom) S0 measurements (crosses), mean (middle solid line), and icr standard errors of the mean (outer lines). Note the large scatter in values. Nevertheless a trend is detectable, with the falloff of the lowest frequencies being the lowest. 1.0 1.0 0 0.5 0 0.5 So P0 0.0 0.0 0 frequency, Hz 20 40 0 frequency, Hz 20 40 Figure 23. Falloff rate as a function of frequency for typical P, P0, and S0 waves. 43 i I a a a a a a a a a a a a a a I I I I I I Lu I I I I I I a a a a a a a liii iii a a a a a a a rr. Iirw-JPi.1111111 Figure 24. Bandpassed and rectified seismograms for two earthquakes with similar locations but different depths. The figure has the same format as Figure 15. Left) EQ 277 with a depth of 27 km. Right) EQ 279 with a depth of 93 km. Note that theS0 phase is more prominent in the shallower earthquake. 44 Figure 25. Falloff as a function of frequency for the two earthquakes in Figure 24. Top)P0phase. Bottom)S0phase. 45 P0falloff values are similar for both EQs except in band 3 (2.55Hz) where the shallower EQ has significiantly more energy and lower falloff. Comparing theS0 falloffs, the shallower EQ has some energy in the lowest band (0.61.2Hz) and in the two highest bands (>10Hz), whereas the deeper EQ has no detectableS0energy in these bands. Both the horizontal (H) and hydrophone (HY) components have considerably lower signal-to-noise ratios than the vertical (V). Their signal-to-noise ratios are best in the two middle frequency bands. Where measureable, V, H and HY falloff rates have similar trends. South Mindanao - Molucca Sea region: The Molucca Sea is situated at the junction of the Eurasian, Indian Australian, Pacific, and Philippine plates. Figure 26 (adapted from Hamilton, 1979) shows a map of the tectonic features of this area along with the seismic profile of Hatherton and Dickinson (1969). Tectonic features in the area strike roughly N S and consist of alternating ridges and troughs (Figures 9 and 26). A seismic profile (Figure 26) compiled by Hatherton and Dickinson (1969) revealed two oppositely dipping seismic zones, interpreted to represent the subduction of two slabs, one towards NW and one towards SE (Figure 27). The slabs subduct beneath the Sangihe (W) and Halmahera (E) volcanic arcs (ridges) and connect in the Molucca Sea. A tectonic model (Figure 27) by Silver and Moore (1978) shows the Molucca Sea to be a collision complex between the two slabs. The convexly-facing Sangihe and Halmahera volcanic arcs are separated by about 250 km at their closest points. Recent focal solution studies from EQs in the upper part of subducting slabs show normal faulting, indicating the existence of extensional forces in the upper part of the slab. These focal solutions and the fact that the Molucca slabs are subducting in opposite directions suggests that the overlying region must be extensional rather than coffisional. Figure 28 presents a tectonic model of the Molluca Sea which incorporates extension rather than collision. The following factssupportthis model: 1) The south end of the Philippine slab subducting underneath the eastern border of 46 92 TECIONICS OF THE INDONESIAN REGION A * * MINIWIAD EXPLANATiON - F * A.00ICoO 0 bodiWoVoICflo T,.o.of OObdoeIoo -. - t No.0 of no.fioge woeg. - Aaio. --;---;/ X PHILIPPINE _.a.._A. s.:;:b.4fSflowin / , I - / dIr.dioo of .sfatiw / / L SEA t'E.45:E/ ,,' ----=0 // ,/' 4, K1ANG / ____7/______/ / / II " / !#--L / ii / " / -; &' i i Ii PfllH N Ii,,/- / ' / I -. 400. ,_f N -..-..... ). To.nd.o 000 o. o -. GUINEA SULAWFSI I______0 1 200 300 KILOMEIERS WNW ES- Sangitie P,niection of Projection of U) U.: I- LU a -J z I I- 0. aLU Figure 26. Top) Thctonic map of the Molucca Sea region, adapted from Hamilton (1979). Bottom) The seismic profile by Hatherton and Dickinson (1969). 47 (I, w Lii 0 z I w0 c3 NW SE Sangihe Arc Halmahera Arc l90 Kilometers Collision Complex Figure 27. Tectonic models of the Molucca Sea region. Top) Hatherton and Dickinson (1969) interpretation of the seismic data. Bottom) Model of Silver and Moore (1978). coHision extension collision 0.4 cm/year .- Sangihe plate Molucca sea Halmahera plate 7-,# Pacific plate Figure 28. The tectonic model of the Molucca Sea region proposed in this study. 49 the Halmahera plate is not very active. This can be interpreted to indicate that the thrust (convergence) from the Pacific plate in that area is small. 2) The absolute eastward motion of the Eurasian plate in the Celebes Sea is very small, 0.4 cm/year, also indicating a slow convergance from the Eurasian plate. 3) No recent island arc traces are obvious on each concave side of the Sangihe and Halmahera island arcs indicating that if those island arcs are colliding, their rate of converging is very slow. 4) The Molucca Sea is underlain by an extremely large gravity low indicating missing crustal volumes resulting from extension. This is incompatible with compression which would increase crustal volume in the area. The tectonic model in Figure 28 shows the Molucca Sea as an extensional area of a unique kind, a kind of a passive rift valley. Six EQs were recorded with epicenters in the South Mindanao Molucca Sea region (Figure 9, EQs 126, 193, 194, 243, 338, and 428; at depths 230, 140, 155, 153, 34, and 34 1cm, respectively). Figures 29 and 30 show bandpassed and squared seismograms along with theoretical fits for those EQs recorded on stations EE (126, 193, 194, and 243) and DDD (338 and 428). All these EQs have either abnormally small or no S phases, making measuredS0falloff values inaccurate. Two of these EQs (126, depth 2301cm, and 193, depth 1401cm) have epicenters in the Sangihe arc and two (194, depth 155 1cm, and 243, depth 153 1cm) have epicenters in the Halmahera arc. Unfortunately, event 126 occurred during a period of high microseismic activity so no reliable falloff measurements could be made on that EQ. EQ 193 has a partiy splitP0phase. This effect is not visible on the other EQs in the Molucca Sea. All EQs in this area show the same dispersion effect as the Mariana EQs where the higher frequencies peak early while the lower frequencies are more spread Out. This dispersion effect occurs on all three components of an EQ (Figure 31) and is most lilcely caused by different frequencies having a different modes of propagation in the lithosphere. The Molucca sea EQs haveP0APVELs ranging from 7.6 to 8.2 1cm/s. APVELs for EQs 338, 194, and 428 are markedly lower than those of 193 and 243 (Figure 19, see Appendix 3). The lower velocities of EQs 338 and 428 can possibly be explained by their shallow origin, but this is not the case for EQ 194, 50 I I I I I a a a a a a a I I I I I I I I I I I I I I I I I I I I I I I I I I a a a a a a a a a a a a a a a a a a a a aaaaaaaaaaaaaaaaaaaa I I I I I I I I I I I I I I I I I I I I I a a a a a a a a a a a a a a a a a a a a a I I I I I I I Iii Iii I 11111: a a a a a a a a a a a a a a Figure 29. Bandpassed and rectified seismograms for three Molucca Sea earthquakes. The figure has the same format as Figure 15. Left) EQ 193. Middle) EQ 194. Right) EQ 126. 51 &aaa! a a a a a a a a a a a a a a LL I I I I I I I I I I I I I I I I I I I a a a a a a a a a a a a a a aamaa Iii III I Iii Iii I I11111 - a a a a a a a Figure 30. Bandpassed and rectified seismograms for three Molucca Seaearthquakes. The figure has the same format as Figure 15. Left) EQ 243. Middle) EQ338. Right) EQ 428. VERTICAL HORIZONTAL HYDROPHONE z 12.5-25 25-50 wU- 6.2-12.5 1.56-3.13.1-6.2 APPARENT VELOCITY 0.78-1.56 7.69 5.82 7.65 5.98 7.65 5.76 forFigureverticalbandpassed EQ 31.338). (left), Example Note and horizontal thatrectified of thedispersion coda(middle), seismograms. maximum in and hydrophone This occurs effect later (right).is in visible the lower in all frequencies three components, of the P0 coda from Philippine Sea EQs (here shown r',)01 53 which has anomalously lowP0velocity both with respect to distance and depth. Figure 32 shows recordedP0falloffs of the Molucca Sea EQs (EQs 193, 194, and 243) on instruments 3 (station EE), 12 (BB), and 14 (AA). Each EQ exhibits the same falloff pattern on all three stations, which indicates that their coda generation is not dominated by near-receiver structures, or that the structure of the crust-upper-mantle in the receiver region is fairly homogeneous. Comparing the falloff pattern for individual EQs, EQ 194 has higher falloff rates (decays more rapidly) in bands 4 and 5. Raypaths for EQs 193, 243, and 428 cross the complicated tectonic structure of the Molucca Sea. The lack ofS0energy for all these EQs may be an indication that all their raypaths have crossed regions of high S absorption, but the data are not sufficient to determine where those regions are. Also, the lack ofS0energy could be an source excitation effect, that is, no shear phases where generated at the source. Philippine, Taiwan and Ryukyu trenches: Squared and bandpassed seismograms and their fits for EQs from the Philippine trench, N Luzon, Taiwan, and Ryukyu trench are shown in Figures 33 36. With respect toP0/S0amplitude ratios, the Philippine data set can be divided into two groups. The first group includes all EQs from the Marianas, Molucca Sea, and Philippines (Figures 24, 29,30, 33, and 34), and the second group includes the Taiwan Ryukyu EQs (Figures 34- 36). The Taiwan Ryukyu EQs (249, 293, 152, 282, 266, 239, 278, and 334) all have clearS0phases making theirP0/S0amplitude ratios much lower than those for all recorded EQs from the Philippine and Mañana trenches as well as those from the Molucca Sea. This is reflected in the falloff rates. All Philippine SeaP0falloff values are similar but S falloff values are higher in the Taiwan to Ryukyu regions (Figures 37) than in the Mañana trench Molucca Sea Philippine trench EQs (Figure 38). Although the southwestern part of the Okinawa trough is presently undergoing a crustal extension with normal faulting, rifling, and magmatic intrusions (Lee et al., 1980), clearS0phases were observed for all EQs originating in that area. 54 PoH vertical falloffs, instrument 3 o 25000 EQs 193,194, 243 o20000 0.15000 AL -_---- 0.10000 /'<243 '<194 - 193 I 00000 I 0.0000 8.0000 '5.00 24.000 32.000 40.000 frequency, Hz 025000 . PoH vertical falloffs, instrument 12 EQs 193,194, 243 0.20000 0.150 0.100 'x194 0.050000 -/ 243 00000 I I 0.0000 8.0000 16.000 24.000 32.000 40.000 frequency, Hz vertical falloffs, instrument 14 0.25 0 Y° EQs 193,194, 243 0.20000 )(194 0.050000 3 I 0.0000 8.0000 16.000 24.000 32.000 40.000 Figure 32. Falloff as a function of frequency for the three Molucca Sea earthquakes shown in Figures 29 and 30. Top) oH falloff on station EE, EQs 193, 194, and 243. Middle) oH falloff on station BB, EQs 194, and 243. Bottom)oH falloff on station AA, EQs 193, 194, and 243. a a Middle) Figure a a I II I earthquakes. 33. a a Iii 11 EQ 232. The aa a Ii II IiI II Bandpassed a a Right)EQ figure has and a 1111111 a Ii a I I I 297. the rectified a I C same a II I C format a C liii as seismograms a II1I C II Figure 15. thefor a I 1111111 11111 1111111 C I mma a I EQLeft) three a ii :! a Iii 168. Philippine a iIiI iLk a trench a III 1111111 1111111 a liii a 1111111 I Ii LL 55 56 I i i iLL I I I Iii I I I I I I I I LLAJLI I I I I I I I I I I I I I I I I I I I I I I I I I 1 I I I I I I I 1111111 I I I I I I I I I I I I I I Figure 34. Bandpassed and rectified seismograms for the three Luzon-Taiwan earthquakes. The figure has the same format as Figure 15. Left) EQ 166. Middle) EQ 249. Right) EQ 293. 57 LIJ ii a a a a a a a a a a a a a a LJL aaaaaaaI I I I I I i I I I a a a a a I I I I I I I a a a a a a a fr. Iii Iii I iiiiil a a a a a a a Figure 35. Bandpassed and rectified seismograms for two Taiwan Okinawa trough earthquakes. The figure has the same format as Figure 15. Left) EQ 152. Right) EQ 282. I.I I I I i a a iii a a a a a I I I I I I I I I I I I I I i a LI a a a a a a 1111111 I I a Cf a a a a a a I I I iii iii a a a a a a a a a a a a a a a a a a a a a ii I Iii I I I a a a a a a a uulIJ 11111 1111111 a a a a a a a a a a a a a a Iii" Figure 36. Bandpassed and rectified seismograms for three northeast Ryukyu trench earthquakes. The figure has the same format as Figure 15. Left) EQ 239. Middle) EQ 278. Right) EQ 334. 59 PoH fal lof Is, Mariana-Ilolucca-Phi I ippine EQs 0.60000 0.48000 0.36000 t4. 0 0.24000 10.12000 ISW,ISIIIS"1 8.0000 16.000 24.000 32.000 40.000 frequency, Hz Figure 37. Falloff rate versus frequency for the Mariana, Molucca Sea and Philippine trench earthquakes recorded by the Philippine array. Top)P0phases (crosses). Bottom)S0phases (crosses). The standard error of the mean is denoted with solid lines. 60 0.60000 - PoHfafloff3 0.48000 - -1 0.36000 - x 4-4 4-4 X o x -4 0.24000 -x x 0.0000 8.0000 16.000 24.000 32.000 40.000 Frequency, Hz faIIoffsTaiwanRyukyu EQS 1.2000 SoH 0.96000 0 0 0 -1 0.72000 - 8 0 0 0 4-4 o 0 -4 0 -4 0 0.48000 0.24000 a 0 o 0.0000 I I 0.0000 8.0000 16.000 24.000 32.000 40.000 - frequency, Hz Figure 38. Falloff rate versus frequency for the Taiwan and Ryukyu trench earthquakes recorded by the Philippine array. Top)P0phases (crosses). Bottom)S0 phases (crosses). The standard error of the mean is denoted with solid lines. 61 EVENTS RECORDED BY THE WAKE ARRAY: A total of 60 EQs recorded by the digital Wake hydrophone array were used in this study. The epicenters of these EQs and their depth interval are shown in Figures 10 and 12. All of these EQs originate at convergent boundaries between the Pacific, Philippine, and Eurasian plates, northward along the Mariana trench and the Bonin, Izu, Japan, and Kuril trench system to the Kamchatka peninsula. The overall hypocentral pattern given by these EQs is consistent with the seismicity pattern of their areas, as described by Katsumata and Sykes (1969) and by the Plate-Tectonic map of the Circum-Pacific Region (1981). The Wake array is situated in the vicinity of Wake Island on the oldest part of the Pacific plate. Seismic rays travelling from the Mariana, Bonin, and Izu trench areas have paths solely across the Jurassic platform whereas rays from the Japan and Kuril and Kamchatka trenches first cross the Cretaceous northern part of the plate before entering the Jurassic basin. The Philippine plate is Tertiary in age. Wake array raypaths thus transect older crust than the Philippine Sea raypaths. There are large variations seen in the P, P0, and amplitude ratios of the Wake recorded EQs. Some EQs clearly exhibit all three phases (P, P0, and while others either have an unclear P phase, consisting of a few water columii reverberations or no P phase at all. Still other EQs have a clear P phase but unclear or non-existent P0andS0phases. All EQs which completely lackP0andS0phases originate at depths greater than 300 km. The reverberations seen in the P phase coda are consistent in traveltime with water column reverberations. Similar but much more diffuse reverberations can be seen in theP0andocoda. Bandpassed and rectified seismograms revealed no dispersion effect like that observed for the Philippine data set, where the APVEL of the high amplitude part of the coda seemed to increase with frequency. On the other hand, the Wake data frequently exhibited an effect where a low frequencyP0phase (termedoLphase, Figure 39) was seen to arrive earlier than the higher frequencyP0phase (PoH, Figure 40). The low frequency phase is most prominent in the lowest three frequency bands and hardly seen in the higher bands. 62 W-1398 time Figure 39. Bandpassed and rectified seismogram for Wake array EQ 1398. The P phase arrives about 100 seconds before the oH phase and has an apparent velocity of 9.94 km/s. 63 W 1578 time Figure 40. Bandpassed and rectified seismogram for Wake array EQ 1578. TheoL phasehas an apparent velocity of about 8.7 kmls. 64 WAKE P, voL' 'oH' ANDS0FALLOFF MEASUREMENTS: Figure 41 shows apparent 1, 'aoL' P011, and S0H bottom hydrophone velocities of the Wake data set plotted versus range. Each EQ was recorded by at least eight hydrophones, five sitting on the ocean bottom and 3 in the SOFAR channel. All measured SOFAR (stations 10, 11, 20, 2 land 40) apparent velocities and falloffs are listed in Appendix 3. The accuracy of the SOFAR falloff measurements is significiantly reduced by attenuation and spreading properties in the water colunm. Therefore, they are not included in this study. Distinguishing between P andoL phases was often difficult for epicentral distances of less than 25 degrees. No successful measurements could be made on subsequent S0L velocities due to their vague appearance in the coda. Average APVELs for the Wake dataset recorded by bottom hydrophones were found to equal 8.75 ± 0.05 km/s (voL phase), 8.19 ± 0.02 km/s (oH phase), and 4.79 ± 0.02 kmls (SOH phase). These average velocities are significiantly higher than those previously reported from the Philippine Sea.oHAPVELs were found to range from 7.0 km/s (EQs 443 and 993) to 9.2 km/s (EQ 1886).oHand SOH phases were recorded from EQs having hypocenters down to depths of 450 - 500 km (Figure 42), but those phases were too vague to produce reliable falloff measurements. The large variation in measured APVELs at depths of 20- 30 km could be due to inaccurate hypocentral locations for those EQs. Figures 43 and 44 show average falloffs for the complete Wake dataset. The ratio of P/POH falloffs is approximately 4:1 for the three lowest frequency bands, but the falloff ratio, POH/SOH, is about 1:1. The P falloff average peaks in band 3 (3.126.25 Hz) whereas bothoHand SOH falloffs peak in band 4 (6.25 - 12.5 Hz). Due to the vast epicentral coverage of the Wake data, EQs their falloff analyses were divided into three main areas: 1) The Mariana, Bonin, and Izu trenches. 2) The Japan trench to 40° north. 3) The Kuril trench. 65 13.000 - P (*)PoL(o) andPaM 11.800 CO * 10.600 - 0 9.4000 - 00 > * 4' * o 1x 'q5j 8.2000 - 0 Xa9 x I 7.0000 I 33.600 38.000 16.000 20.400 24.800 - 29.200 distance, deg SoH Co) versus range, Wake 7* stations 7.0000 6.2000 8 0 CO 5.4000 '? 0 e 4.6000 0 -4 a a 3.8000 3.0000 I 16.000 20.400 24.800 29.200 33.600 38.000 distance, deg Figure 41. Apparent velocity versus range for the sea floor hydrophones of the Wake array. Top) P phases (stars), oL phases (circles), phases (crosses). Bottom) S0H phases (circles). Figure 42. Apparent velocity versus depth for the sea floor hydrophones of the Wake array. Top) P phases (stars), oL phases (circles), oH phases (crosses). Bottom) S0H phase (circles). 67 2. 0000 1.6000 1.2000 0.80000 0. 40000 0. 0000 0 6.4 12.8 19.2 25.6 32 frequency, Hz PoL fat loffs, Woke data, all 7* stations 0. 50000 0.40000 0.30000 0.20000 '- 0.10000 0.0000 0 6.4 12.8 19.2 25.6 32 frequency, Hz Figure 43. Falloff rate versus frequency for the sea floor hydrophones of the Wake array. Top) P phases (crosses). Bottom) oL phases (crosses). The standard error of the mean are denoted with solid lines. 0.50000 rPoH falloffs, Wake dataall 7* stations 0.40000 IX Ix L 0.30000_l x Ix x I x x X x x 0.20000 -. I0.10000 I.w.I.I.I. 0 6.4 12.8 19.2 25.6 32 frequency, Hz 0. 50000 0.30000 . 0.20000 L.II.I.IaI.] 0 6.4 12.8 19.2 25.6 32 frequency, Hz Figure 44. Falloff rate versus frequency for the sea floor hydrophones of the Wake array. Top) oH phases (crosses). Bottom) SOH phases (circles). The standard error of the mean are denoted with solid lines. [*] Mariana, Bonin, and Izu trenches: The Mariana and Bonin trenches data includes EQs 1893, 663, 3120, 659, 3067, 3057, 443, 1578, 2262, and 3213 along with EQ 1886 in the Mussau trench. Those eleven EQs were divided into two subsets: Inner and outer trench EQs. The inner trench EQs have a deeper origin, and their epicenters strike along the Mañana island arc. They have APVELs 8.27 ± 0.01 km/s (POH) and 4.70 ± 0.01 kmls (S0H) while the outer trench EQs show more APVEL variations. Outer trench EQs 663, 3057, and 3067 have similar APVELs. EQs 443 and 1886 are the two extremes of the whole dataset with respect to APVELs. EQ 443 has an epicenter unusually far out on the convex side of the trench compared to its depth of 600 km. Its APVELs are abnormally low, 9.7 km/s (P) and 7 km/s (P011). TheoHphase for EQ 443 is very vague, and it has no detectable S0H phase. If it is located correctly EQ 1886 represents the other extreme, having extremely high (9.2 kmls) oH and S0H (4.9 kmls) phase APVELs at Wake. Also, EQ 1893 has a high S0H APVEL of about Skmis. oHfalloff values for the outer trench EQs (Figure 45, top) are considerably higher than those for the inner trench EQs (Figure 46, top). However, their S0H falloff values are similar (Figures 45 and 46, bottom). The outer trenchoRfalloff averages are higher than the average of the whole Wake dataset, but the inner trench oHfalloff averages are lower than the total average. The SOH falloff values are about the same for both the inner and outer trench falloff averages, and those values are the same as the total average. The increase in the average oEI falloff value from band 2 to band 1 is caused by contamination of theoHphase by theoLphase at the lowest frequencies. The Izu trench data covers EQs 1494, 1801, 1802, 611, 3054, 3055, 3058, 3061, and 3248 (outer trench EQs, Figure 47), and EQs 2238, 2242, 2495, 1850, and 2144 (inner trench EQs, Figure 48). The outer trench EQs have P, 1'oL'oH'and S011 average APVELs of 8.74 ± 0.04 kmls, 8.89 ± 0.03 km/s, 8.25 ± 0.01 kmls, and 4.71 ± 0.01 kmls, respectively. The P andoL aresimiliar because these two 70 0.25000 0.20000 0.15000 0 0.10000 '; 0. 050000 0.0000 0 6.4 12.8 19.2 25.6 32 frequency, Hz 0.25000 0.20000 0.15000 4.1 4.1 0 0.10000 4-4 0. 050000 0. 0000 0 6.4 12.8 19.2 25.5 32 frequency, Hz Figure 45. Falloff rate versus frequency for the sea floor hydrophones of the Wake array (outer trench Mariana earthquakes). Top) oH phases (crosses). Bottom) SOH phases (circles). The standard error of the mean are denoted with solid lines. 71 1578, 2262 50000 0000 50000 o0oo 0000 000 0 6.4 12.8 19.2 25.6 32 fxequxscy, Hz PoH fat Ioffs, EQs 3120, 659, 3067, 1578, 2262 arsd 3213 0.25000 0.20000 0.15000 0. 10000 0.050000 0. 0000 0 6.4 52.8 19.2 25.6 32 frequency, Hz SoH fat loffs, EQs 3120, 659, 3067,1578, and 3213 0.25000 0.20000 0. 15000 0.10000 0.050000 0.0000 0 6.4 12.8 19.2 25.6 32 fxequency, Hz Figure 46. Falloff rate versus fruency for the sea floor hydrophones of theWake array (inner liench Mariana and Bonin earthquakes). Top) Pphases (crosses). Middle) oH phases (crossses). Bottom) S0H phases (circles). The standard error of the mean are denoted with solid lines. 72 X PoH fat toffs 0.25000 EQs 1494,1801,1802, 611, 3054, 3055, 3058, 3061, 3248 [ x 0.20000 - x 0.15000 - - x 'C x 'C 0.10000 -. - 0.050000 f] 0.0000 I 0 6.4 12.8 19.2 25.6 32 frequency,Hz 0.25000 - S0H fat 101 fs 0 EQs 1494, 1801,1802, 611, 3054, 3055, 3058, 3061, 3248 0.20000 - 0 0. 15000 , 0 0 :::::: 0.0000 -t 0 6.4 12.8 19.2 25.5 32 frequency,Hz Figure 47. Falloff rate versus frequency for the sea floor hydrophones of the Wake anay (outer trench Izu earthquakes). Top)oHphases (crosses). Bottom) S0H phases (circles). The standard error of the mean are denoted with solid lines. 73 P falloffs. EQs 1850. 2144. 2495. 2242. 2238 2.0000 1.6000 1.2000 0.80000 0.40000 0.0000 0 6.4 12.8 19.2 25.6 32 frequency, Hz PoH falloffs, EQs 1850, 2238, 2242. 2495 0.25000 0.20000 0. 15000 0. 10000 0.050000 0.0000 0 6.4 12.8 19.2 25.6 32 frequency, Hz 0.25000 SoH fal loffs, EQS 1850, 2144, 2495, 2242, 2238 0.20000 0. 15000 . 0 ° 0. 10000 0 o 08-.-...... 0.050000 0.0000 I I I 6.4 12.8 19.2 25.6 32 frequency, Hz Figure 48. Falloff rate versus frequency for the sea floor hydrophones of the Wake array (inner trench Izu earthquakes). Top) P phases (Crosses). Middle) oH phases (Crosses). Bottom) S0H phases (circles). The standard error of the mean are denoted with solid lines. 74 phases are still merged for these EQs. The inner trench EQs have higher average P and APVELs of 10.89 ±0.16 km/s and 9.13 ± 0.03 km/s whereas theiroHand S0H APVELs are 8.15 ± 0.05 km/s and 4.65 ± 0.01 kmls. These inner trenchoH and S0H APVEL values are significiantly lower than the outer trench values. The POH average falloffs for the Izu outer trench are considerably lower than those found on the Mariana outer trench. Also, the inner Izu trenchoHfalloff values are higher than the Mañana and Bonin inner trench values. Average SOH falloff values for both the inner and outer trench are similar to those found for the Mañana and Bonin trenches. The Izu inner trench and SOH falloff values have a greater standard deviations from the mean than the inner Mañana and Bonin values. The Izu innertrench S0H phases recorded at Wake are smaller than those from the Mañana and Bonin trenches, indicating a greater absorption along their raypaths. Japan trench: This dataset includes EQs 1451, 715, 1272, and 1806, all shallow EQs, located at the outer strike of the Japan trench. It also includes one deep EQ with an epicenter in the Japan Sea and EQs 1518 and 2911, with epicenters on the western coast of Kyushu. Only the P phases were detected from EQs 1518 and 2911. Average P, voL'oH'and 5oH APVELs of the four outer trench EQs are 9.29 ± 0.11 kmls, 9.12 ± 0.04 km/s, 8.20 ± 0.03 km/s, and 4.69 ± 0.01 kmls, respectively. Figure 49 shows the P falloffs for EQs 2911 and 1518 (Kyushu EQs), as well as the oH and SOH falloffs for the Japan outer trench EQs (1451, 715, 1272, and 1806). TheoHfalloff values for EQ 2261 are lower (Figure 50) than for the outer trench EQs. Overall, theoHfalloff values for the Japan outer trench are lower than those for the Mañana trench but are similar to the Izu outer trench falloffs. The 5oH falloffs for the Japan outer trench EQs are higher in the highest four frequency bands than both the Mañana and Izu outer trench falloffs. 75 0.30000 0.40000 0. 30000 0.200001 0.10000 0.0000 0 6.4 12.9 19.2 25.6 22 fz.quy.Hz 0.25000 Pill f.lIoffs EQi l4Sl 7l5 I272 1106 0.20000 0.11000 K xx * 0.I0000 N :: 0. 6.4 12.1 19.2 25.6 32 ffiqu,Hi 0.20000 0.20000 0.11000 0. I I 0.000000 0.0000 0 6.4 12.9 11.2 5.6 22 trequesey,Hi PIgers 49.Filloffrate venus frequency for die tea floor hydiophones of the Wake anay (outer Wench Japan earthquakes). Top) P wave (crosses). Middle) P phases (crosses).Bo00in)S phases (circles). The itandard error oldie sst denoted with solid tines. PnU fII iff Ffl 22 I 0.25000 0.20000 '1 0.15000 0.10000 0.050000 0.0000 0 6.4 12.8 19.2 25.6 32 frequy, Hz 0.25000 SaH faIIoff. E02261 0.20000 'I 0.15000 0. 10000 0.050000 0.0000 0 6.4 12.8 19.2 25.6 32 fraqncj. Hz Figure 50. FaIlofi rate versus frequency for tlsea floor hydrophones of the Wake array (inner uench Japan earthquake). Top) P phases (crosses). Middle) "oH phases (crosses). Bottom) SOH phases (circles). The standard error of the mean are denoted with solid lines. 77 Kuril trench: Average apparent"'3oL' 'oH' and S0H velocities for all Kuril EQs (all EQs on Figure 10) recorded by the Wake ocean bottom hydrophones were found to be 9.68 ± 0.09 kmls, 8.62 ± 0.09 kmls, 8.13 ± 0.02 kmls, and 4.85 ± 0.03 km/s, respectivly (Figure 51). TheseoLand 1'oH APVELs are significiantly lower than for the entire Wake data set, but the S011 APVEL is higher. Average APVELs for all Kuril EQs with epicentral depths less than 100 km are not significiantly different from the average of all Kuril EQs. EQs 993, 2001, 2246, and 319 have lower than averageoLand 'oH APVELs. EQs 2001, 2321, and 2246 have lower than average S0H APVELs, but EQs 3237, 2283, 2884, and 2340 have unusually high S011 APVELs. APVELs are plotted against depth on Figure 52. Again, there are large variations at the normal (fixed) depth of about 30 km. Falloffs for all Kuril EQs are shown in Figure 53. The P011 average falloff values for the Kuril EQs are higher than those of the entire Wake data set, but the S0H falloff averages are about the same. Figures 54 58 are falloff plots for all Kuril EQs with depths less than 100 km. Average falloffs for both P011 and S0H phases from the Hokkaido EQs (Figure 54), at the junction between the Japan and Kuril trenches, are lower and more diffuse than the average falloffs for EQs north of Hokkaido (Figures 55 and 57). Average "oH APVELs and average falloffs are similar for all EQs in frequency bands 2 6 (excluding EQs 993 and 2001, Figure 57) along the Kuril trench (Figures 55 and 56). For Kamchatka they are slightly higher (Figure 58). However, S011 APVELs and average S011 falloff values are more variable. The average falloff values in frequency band one (0.781.56 Hz) and five (12.520 Hz) have the greatest variability. Higher average falloff values in the lowest frequency band are most likely due to contamination by the P andoLphases whose coda often stretch into theoHcoda in the lowest frequency bands. EQs 993 and 2001 have anomalously low P011 and S011 APVELs. Their P011 falloff average (Figure 57) is higher than that of the other shallow Kuril EQs. EQs 2001, 993, and 1201 are the only shallow Kuril EQs which have clear P phases. P phase contamination is clearly seen in the lowest band of the oH falloff for EQs 993 and 2001, and these EQs have I 13.000 PoLCo),PoH(x) versus rag., all KurlI EQs 11.800 - 'I, a ''' * 10.600 * >, lIwI* 9.4000 - -I 0 000 S 00 00 8 '0x 8.2000 . SC X)Soc 7.0000 26.000 28.000 30.000 32.000 34.000 36.000 distance,deg 0 0 6.0000 Soil versus range, all Kuri IEQs 00 5.5000 o8o 0 a 5.2000 . - d'B' 0 >, 4J 0 4.8000 00 8o 0 4.4000 - 0 4.0000 - 26.000 28.000 30.000 32.000 34.000 36.000 distance, deg Figure 51. Apparent velocity veraus range for all Kuril earthquakes recorded by the sea floor hydrophones of the Wake array. Top) P phases (stars),oLphases (circles), POR phases (crosses). Bottom) S0H phases (circles). 79 i.000 p(*), PoL(o) and PoH(x) versus depth for all Kuri IEQs 11.800 - * * 10.600 . * * * S U S * I * 8.2000 x K a I K e 7.0000 I I I 0.0000 120.00 240.00 360.00 480.00 600.00 depth, 1 6.0000 SoHversus depth for all Kur ii EQs 0 5.6000 0 0) - 5.2000 ' §9 4.8000 a 4.4000 0 4.0000 1 I I 0.0000 120.00 240.00 360.00 480.00 600.00 depth, k Figure 52. Apparent velocity versus depth for all Kuiil earthquakes recorded bythe sea floor hydrophones of the Wake array. Top) P phases (stars),oLphases (circles),oHphases (crosses). Bottom) SoH phases (circles). * PoH falloffs for all Ki.ril EQs 0. 25000 I.I.i.i.i.] 0. 15000 0.10000 0.050000 0.0000 0 6.4 12.8 19.2 25.6 32 freqtncy, Hz 0.25000 0.20000 0.15000 0. 10000 0.050000 '1 0 6.4 12.8 19.2 25.6 32 ftequcy. Hz Figure 53. Failoff rate venus frequency for all Kuril eazthquakes recorded by the sea floor hydrophones of the Wake array. Top) P011 phases (crosses). Bottom) S0H phases (cirtles). The standard error of the mean are denoted with solid lines. hiL.I P fat I..tf Ca t 0.25000 o 20000 0. 19000 0. 10000 0.050000 0.0000 0 6.4 *2.6 19.2 25.6 32 fxsquestcy, Hz 25000 19000 Z 100001 050000 xx 0 6.4 12.6 19.2 25.6 32 fiuquey, Hz 0.25000 0.20000 0.15000 0.10J 0.050000 0.0000 0 6.4 12.6 19.2 25.6 32 faquaitcy. Hz Pljuze 54. Palloff rate vs. frequency foi shallow Hokkaido enibquakea at the junction of the Japan and Kuni uenchea recorded by the aea floor hy&çhones of the Wake may. Top) P wave (crosses). Middle) P wave (crosses). Bottom) S (cutles). Thi s*sialszd enor of the imsu atu denoted th solid lines. Ff 2237 2321 1281 R06717 0.25000 PH fnIInffc 0.20000 0.15000 0.10000 0.050000 0.0000 0 6.4 12.8 19.2 25.6 32 fieqncy, Hz 0.25000 ii i2iRQ 717' 0.20000 0. 15000 0.10000 0.050000 0.0000 0 6.4 12.S 19.2 25.6 32 ft.qncy Hz Figure 55. FaIloff rate vs. frequency for south Kuril uench earthquakes recorded by the sea floor hydrophones of the Wake array. Top) oH wave (crosses). Bottom) S0H (circles). The standard error of the mean are denoted with solid lines. P.J.1 f,IIff r..- rn QA 1fl 0.25000 I* 0.20000 0.15000 0.10000 0.050000 0.0000 0 6.4 12.8 19.2 25.6 32 freqncy, Hz 0.25000 0.20000 0.15000 0. 10000 0.050000 0.0000 0 6.4 12.8 19.2 25.6 32 freqy, Hz Figuie 56. FaIloff rate vsus frequency for north Kuril Dench earthquakes recorded by the sea floor hydrophones of the Wake array. Top)oHphases (crosses). Bottom) S0H phases (circles). The standard enor of the mean are denoted with solid lines. P feIloffs for EQo 993. 2001 1.0000 0.90000 0.60000 0400001 0.20000 0.0000 0 6.4 12.S 10.2 25.9 32 fioqossey. Ho PO14 feII.fV.for E 993. 2001 0.20000 0.20000 0.15000 0.l0000I 0.050000 0.0000 0 6.4 *2.5 19.2 25.0 32 faqsesey. Hz SaM fat off. for EQ. 993. 2001 0.20000 0.20000 0.15000 ! 0.10000 0.050000 0.0000 0 0.4 12.5 19.2 25.0 32 ffiqxy,H* Plgiiic 57. Fsflo1T ate vesni froquency for i mIddle Kuril Ounch eatthquakes .dsd by the floor hyopiIones o( the Woke onoy. Top) P phases (crosies). Middle) P phases (crosses). Bouoin) Sg phases (cbtles). The stsndsid error the en e denoted with solid Ilees. 1.0000 o.10000 0.e0000 o.20000 o.0000 6.4 12.1 19.2 25.6 32 fr.qney. Hz P.14 (.11.11. far £ 56?. 23*4. 14*1. 2340 ois000 0.20000 o.is000! 0.050000 0.0000 0 6.4 12.1 19.2 25.6 32 faquexy, Ha ScSI 1.11.1 1* far LOS 16?, 2114, 14SI, 2340 0.20000 0.15000 0000 0.000000 0.0000 0(0 6.4 12.1 19.2 25.6 32 HI P1131e 5*. PsIIolT rate vusus frequency for Ksuil to Kchatka earthquakes iecded by the sea floor hydrophones of the Wake array. Top) P phases (ciosses). MIdde) Pgj phases (crosses). Bottotn) S phases (cities). The standard error of die meue ale doted with solid lines. falloff value characteristics more related to deeper (inner trench, Figures 59 and 60) EQs. Because they both have normal (fixed) depths, it is likely that they have deeper origins, as indicated by their falloff values. Thus the falloff values indicate the the epicenters for these EQs were inaccurately determined. Five EQs with epicenters in the Sea of Okhotsk (2492, 319, 2477, 2645, and 2566) were recorded. Each of these EQs has different " "i "oH' and S0H APVEL characteristics. They all had clear P phases and two (319 and 2566) hadoL phases as well. These PoL average APVELs were abnormally low, 7.6 ± 0.01 km/s (319) and 8.21 ± 0.04 kmls (2566). Only one (2566) had a clearoHphase with a low phase API/EL of 7.96 ± 0.01 km/s. Two (EQs 2566 and 2654) had visible S0H phases, both with a high SOH API/EL average of 4.88 ± 0.01 km/s. The average falloff values for the Okhotsk EQs are shown in Figure 60. Their average falloff values are lower and more constant between frequency bands than those of the shallower (outer trench) EQs. zj P fIItf fn a* L0000 o.0000 o0000 o40000 0.20000 o .eeee 32 0 6.4 12.1 19.2 25.3 frsqcncy. Hz o25000 0.20000 0. tS000 0.10000 0.000000 0.0000 0 0.4 12.6 11.2 25.6 32 trequswy,Hz o.000 0.20000 0. '000 0.000000 0.0000 0 6.4 12.1 19.2 25.6 32 fr.qusnc, Ha Plpti 39. PsJloft rile venus frequency for deeper Hokkaldo earthquakes at the juardos of the Japan and Xu,il venches recorded by the floor bydropbcmes o(thc Wake army. Top) P phases (crosses). Middle) Pphases (crosses). Bottom) phases (circles). The standard error of the scan sit denoted with solid lines. I.'. [s1s $0000 0. 60000 '0.60000 0.40000 0.20000 0.0000 0 6.4 12.6 $9.2 23.6 32 fJMusary, Ha 0.25000 r P.H ?.IIof?a £02566. 0.20000 0.15000 0.10000 0.000000 0.0000 06.412119225. 32 Hz 0.20000 0.15000 0.10000 0.050000 22 0 6.4 12.6 19.2 25.6 0sqyHs PIgure 60. Palloff rate vusus fseqae,.., fix Sea of Okbotsk earthquakes iecorded by the sea floor hy*opbones of the Wike array. Top) P phases (asacs). Middle) phases (circles). The standard mmix of the mean oHPhh165(crosses). Boacan) S me denosad with solid lines. PACIFIC NORTHWEST BASIN FALLOFF MEASUREMENTS: Twelve EQs, with epicentral range 822°, were recorded at the Pacific Northwest Basin seismic array by two OSU OBS's (Figures 10 and 12). Their averageP0andS0APVELs, on the vertical component, are 8.35 ± 0.06 km/s and 4.69 ± 0.04 km/s respectively (Figure 61). This averageP0APVEL is higher than for both other data sets whereas the averageS0APVEL is equal to that found for the Philippine Sea data set. AverageP0falloffs, as measured by the vertical geophone and hydrophone, are similar to one another (Figures 62 and 63, top), but the average S, falloffs for the Pacific Northwest Basin data are significiantly higher on the vertical component than on the hydrophone (Figures 62 and 63, bottom). The average hydrophoneP0falloffs (Figure 63) are similar to the average WakeP0falloffs (Figure 44) in the first four bands (up to about 15 Hz) and slightly higher than the WakeP0falloffs in the highest two bands. AverageS0falloffs are significiantly higher on the Pacific Northwest Basin hydrophones than the Wake hydrophones. EQs 7,9, 10, 11, and 13 all occurred within the same area in the southern part of the Kurile trench at epicentral distance of about 8°. The S0/P0ratios, for these EQs, on the hydrophone and vertical component at station 3, are 1.3 - 1.4 and 1.52.2 respectively, in the two middle frequencies. Their averageP0andS0falloffs are lower than for Philippine EQs at the same range (Figures 64 and 65) and their falloff average ratios between the vertical component and the hydrophone (Figures 66 and 67) on station 3 (P0vIP0hy and S0v/S0hyin the two middle frequencies are 1.41.5 and 1.62.5 respectively. EQ 27 (Figure 3) has the greatest epicentral distance (21°) and depth of EQs recorded at the Pacific Northwest Basin array. Its hypocenter is at a depth of 155 km in the Izu subduction zone. The P0vIP0hy and S0v/S0hy ratios for EQ 27 are 2.1 2.8 and 1.4 - 1.6 in the middle two frequencies. Its vertical component falloff values are exceptionally low (Figure 68) which can best be seen by comparing it to the average falloff rate of Wake recorded EQs at epicentral distances of 20 - 22° (Figure 69). The P0v/P0hy and S0v/S0hy ratios for EQ 27 are 2.1 -2.8 and 1.4- 1.6. PoH velocity versus range, all PHIl EQs - vertical 9.0000 ! 8.6000 8.2000 X ?.8000 X 0 -4 a 7.4000 7.0000 I I 8.0000 10.800 13.600 16.400 19.200 22.000 disnce, deg Figure 61. Apparent velocity of theP0phase andS0phase onset versus distance for the vertical component of the Northwest Pacific Basin data set. Top)P0phases. Bottom)S0phases. 0.50000 0.40000 0.30000 0.20000 0.10000 0.0000 0.0000 8.0000 16.000 24.000 32.000 40.000 fxeqcy. Hz SoH falleff, all PNU EQs - vertical 0.50000 0 0. 40000 0.30000 .! 0.20000 0.10000 0 8 0 8 8 8 0.0000 I 0.0000 8.0000 16.000 24.000 32.000 40.000 fteqency, Hz Figuz 62. FaIIoff rate versus frequency for all Northwest Pacific Basin earthquakes recorded by the vertical geophone component. Top)P0phases (crosses). Bottom) S0phases (circles). The standard error of the mean are denoted with solid lines. 92 0.50000 r Po falloff, all P4 EQs - hgdrophan. 0.40000 0.30000 0.20000 x 0.1o00D I I I I 0.0000 I 0.0000 8.0000 16.000 24.000 32.000 40.000 fzeqency, Hz 0.50000 - So fol loff, allPNW EQs - hVdrophon. 0.40000 - 0 0.30000 0 -I 0.20000 ::0.0000 8.0000 16.000 24.000 32.000 40.000 Hz Figure 63. Falloff rate versus frequency for all Northwest Pacific Basin earthquakes recorded by hydrophones. Top) P phases (crosses). Bottom)S0phases (circles). The standard error of the mean are denoted with solid lines. 93 0.50000 r PoH folloffs, EQs 7,0,10,11,13, v.rtieai eo 0.40000 0.30000-II- 0.20000 L x x ( x 0. 10000 x x 0.0000 I J 0.0000 8.0000 16.000 24.000 32.000 40.000 fxeqiexY, Hz o.s0000 SoH falloffs, EQs 7,0,10,11,13, vrtical co*p 0 0.40000 0 0 0.3000C. - o 0 0.20000 :- P0.10000 .08 098 0.0000 1 I I I 0.0000 8.0000 16.000 24.000 32.000 40.000 freqy,Hz Figure 64. Falloff rate versus frequency for Northwest Pacific Basin earthquakes 7, 9, 10, 11, and 13, recorded by the vertical geophone component. Top)P0phases (crosses). Bottom)S0phases (circles). The standard error of the mean axe denoted with solid lines. 94 x Phil EQs, 152, 156, 168, 232, 277, 279, 297, cl0degr..s 0.50000 0.40000 ix x I x 0.30000 . -I 0.20000 x x x 0.10000 * Ix x 0.0000 I I I 0.0000 8.0000 16.000 24.000 32.000 40.000 frequency, Hz So falloffs, Phil EQs, 152,1 168, 232, 277, 279, 297,"<10d.- 0.50000 0 o 0 0 0 0 ( 0.40000 0 0 ::::I 0O S 0 0 0 0 0 0 0 0 0. 10000 o 0 B 0.0000 ' I I p 0.0000 8.0000 16. 000 24. 000 32.000 40. 000 freqDcy, Hz Figure 65. Falloff rate venus frequency for all Philippine Sea earthquakes that have epicena1 distance less than 100, recorded by the vertical geophonecomponent. Top)P0phases (crosses). Bottom)S0phases (circles). The standard error of the mean are denoted with solid lines. 95 0.50000 p falloffs, EQS 7,9,10,11,13, vertIcal coep, statIon 3 0.40000 - 0.30000 . - X 0.20000 0. 10000 XX X 0.0000 I 0.0000 8.0000 16.000 24.000 32.000 40.000 ureql3enCy, Hz 0.50000 SoH falloffs, EQs 7,9, 10,11, 13, vertical cow, statIon 3 0 0.40000 0 0 0.30000. o 0.20000 8 8 0.10000 .00 a 0 00 I I I 0.0000 8.0000 16.000 24.000 32.000 40.000 faquy, Hz Figure 66. Fallofi rate versus frequency for Northwest Pacific Basin earthquakes 7, 9,10,11, and 13, recorded by the vertical geophone component at station 3. Top) P0phases (crosses). Bottom)S0phases (circles). The standard error of the mean are denoted with solid lines. 0.50000 r PoH faIloffs1 EQs7,9,11,13, hydrophon., statIon 3 0.40000 0.30000 0.20000 0.0000 I I 0.0000 8.0000 16.000 24.000 32.000 40.000 xeqry, Hz 0.50000 r SoH falloffs, EQS 7,9,11,13, hydrophont, station 3 0.40000 0.30000 0.20000 0. 10000 0 0 0.0000 0.0000 8.0000 16.000 24.000 32.000 40.000 faqxy, Hz Figure 67. Falloff rate versus frequency for Northwest Pacific Basin earthquakes 7, 9, 10, 11, and 13, recorded by the hydrophone at station 3. Top)P0phases (crosses). Bottom)S0phases (circles). The standard error of the mean are denoted with solid lines. 0.50000 Po falloff, EQ 27, statIons 3 and 14 0.40000 030000. 0.20000 - 0.10000 - 0.0000 I I I I 0.0000 8.0000 16.000 24.000 32.000 40.000 fxeqxcy, Hz 0.50000 - So falloff, EQ 27, stations 3 and 14 0.40000 - 0 30000 . - 0.20000 - 0. 10000 - 0 -8- 0.0000 I 1 I I 0.0000 8.0000 16.000 24.000 32.000 40.000 freq1ncy, Hz Figure 68. Fafloff rate versus frequency for Northwest Pacific Basinearthquake 27 (Figure 3) recorded at stations 3 and 14. Top)P0phases (crosses). Bottom) S0phases (circles). The standard error of the mean are denoted with solid lines. o.50000 o.40000 0.30000 - 0.20000 0. 10000 0.0000 0 6.4 12.8 19.2 25.6 32 fzeqncy, Hz 0.50000 SoH fall of f for Uak. dat. ra.fl- 0.40000 0.30000 0.20000 0. 10000 0.0000 6.4 12.8 19.2 25.6 32 fzeqexy, Hz Figure 69. Fafloff rate versus frequency for Wake earthquakes with epicentral distance from 20 to Top)P0phases (csses). Bottom)S0phases (circles). The standard enr of the mean are denoted with solid lines. CONCLUSIONS: We undertook a study of coda falloff rates of 93 Northwest Pacific Basin and Philippine Sea earthquakes recorded on analog and digital instruments. The P,P0and S0coda falloff rates exhibit a systematic pattern, dependent on frequency, epicentral range, depth of focus, and age of raypath. 1. TheP0andS0falloff rates are significantly lower than that of the P wave. The ''1'oH falloff ratio for earthquakes recorded by the Wake hydrophone array is approximately 4.0. This high ratio emphasizes the different propagation nature of these two phases. 2. Both theP0andS0falloff rates vary systematically with frequency. The lowest frequencies (0.83.1 Hz) have the minimum decay rate for both theP0andS0phases (unless they are contaminated by low frequency P and S phases which can occur over shorter ranges). The highestP0average falloff rates occur in the mid-frequency range, 3.1 - 12.5 Hz, with the position of the maximum varying somewhat from earthquake to earthquake. Average falloff rates are most difficult to measure in the highest frequency bands (12.5 50 Hz) because the signal/noise ratio is lowest there. Where measurable, they give average falloff rates that are intermediate between those of the lowest and middle frequencies. The variation in falloff between earthquakes is very large, with the trends only becoming apparent after averaging many measurements. The strong increase in falloff rates at about 3 Hz may be associated with a decrease in the number of scatterers having scale lengths of about one half the wavelength of a 3 Hz compressional wave, that is, about 1.3 km. 3. There is a significant difference in fafloff rates ofP0and S in measurements made with geophones. TheS0/P0falloff ratio for earthquakes recorded by geophones is 1.7 - 2.0. This falloff ratio is consistent with the rate of falloff of the coda being 100 dominated by frictional attenuation. An attenuating medium that has all its losses confmed to shear and none to pure compressionas is typically the case for rocks has higher shear wave attenuation than compressional wave attenuation, with the ratio of quality factors being Q1/Qp4 = 3a2/42 (Aki and Richards, 1980). Here cx and 13are the two wave speeds and the quality factor, Q, is the fractional loss of energy per wavelength. Average apparent velocities (XIT) for theP0andS0waves are 8.1 km/s and 4.7 km/s, respectively. Therefore, 3cc2/4132 = 2.23, predicting a falloff rate of 2.23, close to the observed amount. If we ascribe all the coda decay to attenuation, then we can estimate the amount of attenuation using the rule exp (-yt) = exp (-2irft/Q). For our Wake data the average falloff(ny)forP0phases is approximately 0.05us,at f= 10 Hz. Substituting this information into the attenuation formula we get Q 1250, which is a reasonable number for the compressional wave quality factor in rocks. However, the fact that the falloff rate is fairly constant in the frequency range 5 30 Hz but varies strongly with propagation distance, both of which contradict the rule exp (-2itftlQ), suggests that attenuation cannot be the only phenomenon determining the falloff rate of the coda. A completely different explanation for the observedS0/P0falloff ratio involves the presence of the water colunm. Since only compressional waves propagate in liquids, it is possible that the lowerP0falloff rates are caused by reverberations of compressional waves in the relatively low velocity (1.5 km/s) water column. 4. There are low falloff rates forS0in measurements made with hvdrophones. The SOHIPOH falloff ratio for earthquakes recorded by the Wake hydrophone array is 0.81.1, a factor of two lower than the geophone measurements. Average apparent velocities forP0and S phases recorded by the Wake array are 8.2 kmis and 4.8 kmls, respectively. Thus 3a2/4132 = 2.19, so the difference cannot be ascribed to a different Q1/Qp The difference in ratios is most likely due to differences in the manner in which geophones and hydrophones record theS0phase. Hydrophones are pressure sensitive devices located in the water column a few meters above the ocean bottom so, unlike the geophones, they do not measure shear waves directly. Instead hydrophones measure compressional waves in the water that result from conversion of 101 shear waves at or below the sea-floor. This conversion process is complex, and depends upon the angle of incidence of the rays that comprise theS0phase. The angle of incidence probably decreases with time into the coda, leading to different falloff rates as measured by the different types of instruments. This conclusion is indirectly supported by the observation that the amplitude of theS0phase observed with hydrophones often increases with frequency more strongly than the amplitude ofP0 (see, for instance, Figures 39 and 40), which is also most easily explained by (in this case) a frequency-dependent wave-conversion process. £._F0falloff rates decrease with epicentral range. The average falloff rates of the Northwest Pacific Basin data set, with ranges of 8 - 21°, are 20 30% higher than those of the Wake data set, with ranges of 20 35°. The fact that both the data sets have raypaths trough the Cretaceous and Jurassic Northwest Pacific lithosphere indicates that the difference in observed falloff rates may be due to increased scattering with length of propagation path. The scattering that produces the coda is thus not concentrated in the source region but distributed along the propagation path. A decrease in falloff with range has also been noted by Menke and Chen (1984), who studied forward scattering in plane layers and foundy ocx312, wherex is epicentral range. Thex312 dependence would implya ratio of about 4 for the Pacific Northwest Basin and Wake data sets, higher than what is observed. 6. Earthquakes with 100 300 km deep hvpocenters have systematically lowerP0 fallpff values than shallow (< 100 km deep) earthquakes. The effect is seen in outer trenchlinner trench EQs recorded by the Wake array, where the inner trench (deeper) EQ have lower falloff values than the outer (shallower) EQs. This difference indicates that significant scattering is occuring within (or near) the deeply buried part of the subducting plate. There is some indication (though it is not statistically significant because of uncertainties in earthquake location) that rays that travel obliquely up the slap have lower falloff than those that travel straight up the slab. 102 7. The falloff rates of bothP0and S measured in the Philippine Sea and Pacific Northwest Basin (both with epicentral ranges of about 8 - 12 deg) are significantly different. TheP0falloff rate for Band 4 (10Hz) is 0.143 ± 0.013 1/s for the Philippine Sea, whereas it is 0.096 ± 0.0111/s for the Pacific Northwest Basin. Likewise theS0falloff rate for Band 4 (10 Hz) is 0.302 ± 0.033 1/s for the Philippine Sea, whereas it is 0.220 ± 0.035 1/s for the Pacific Northwest Basin. The difference may be due to the different average ages of the lithospheres in these two geographical areas. The Pacific Northwest Basin crust is of Cretaceous and Jurassic age whereas the Philippine crust is of Tertiary age. Average apparentP0velocities recorded by the Northwest Pacific Basin and Wake arrays are higher than recorded from the Philippine Sea. Oceanic crust thickens with age, and presuming that thinner (younger) crust has less heterogeneities than thicker (more hydothermally altered?) crust we can explain the higher falloff values in the Philippine Sea as due to fewer heterogeneities and less scattering. 8. There is a systematic variation in the position of the maximum of the coda with frequency for the Philippine Sea events. The peak in the low-frequency (0.8 - 3.1 Hz) coda occurs 60- 100 s after the peak of the high-frequency (50100 Hz) coda. This 'reverse-dispersion' may be due to a correlation between attenuation and velocity in the lithosphere (that is, a high-attenuation, low-velocity crust and a low-attenuation, high-velocity mantle). The low-frequency coda will then contain mostly crustal rays, which have propagated at lower speeds. 103 BIBLIOGRAPHY: Aki, K., and B. Chouet, Origin of coda waves: Source, attenuation, and scattering effects, J. Geophys. Res., 80, 3322 3342, 1975. Aid, K., and P. G. Richards, Quantitative Seismology: Theory and results, Volume 1, 557pp, 1980. Asada, T., and H. Shimamura, Observation of earthquakes and explosions at the bottom of the western Pacific: Structure of oceanic lithosphere revealed by Longshot experiment, in; The geophysics of the Pacific Ocean Basin; Geophys. Monogr. Ser., 19, 135153, 1976 Bath, M., Propagation of 5n and l'ntO teleseismic distances, P. and Appl. Geophysics, 64, 1930, 1966. Bee, M., A comparison of seismic properties of young and mature oceanic crust, Ph.D. Thesis, Oregon State University, 183 pp, 1984. Black, P.R., and L.W. Braile, P velocity and cooling of the continental lithosphere, J. Geophys. Res., 87, 10.55710.568, 1982. Butler, R., Anisotropic propagation of P and S waves in the western Pacific lithosphere, J. Geophys. J. R. astr. Soc., 81, 89- 101, 1985. Creager, K. C. and T. H. Jordan, Slab penetration into the lower mantle beneath the Mañana and other island arcs of the Northwest Pacific, J. Geophys. Res., 91, 35733589, 1986. Fedotov, S. A., The absorption of transverse seismic waves in the upper mantle and energy classification of near earthquakes of intermediate focal depth, IZV. Geophys. Ser., 829 - 849, 1963. Fedotov, S. A., and L. B. Slavina, An estimate of the longitudinal-wave velocities in the upper mantle under the northwestern part of the Pacific Ocean and Kamchatka, IZV. Earth Physics, 2, 831, 1968. Fuchs, K., and K. Schulz, Tunneling of low-frequency waves through the subcrustal lithosphere, J. Geophys., 42, 175190, 1976. 1 04 Gettrust, J. F., and L.N. Frazer, A computer model study of the propagation of the long-range Pn phase, Geophys. Res. Lett., 8, 749 752, 1981. Goodman, D., Seismic refraction survey of crustal and upper mantle structures in the west Philippine basin, M.S. Thesis, Oregon State University, l22pp, 1983. Hamilton, W., Tectonics of the Indonesian region, U. S. Geol.Surve.Prof. Pap., 1078, 345 pp, 1979. Hart, R.S., and F. Press, S velocities and the composition of the lithosphere in the regionalized Atlantic, J. Geoph. Res., 78, 407 411, 1973. Hatherton, T., and W. R. Dickinson, The relationship between andesitic volcanism and seismicity in Indonesia, the Lesser Antilles, and other island arcs, J. Geoph. Res., 74, 53015310, 1969. Herrin, E., and J. Taggart, Regional variations in P velocity and their effect on the location of epicenters, Bull. Seism. Soc. of Am., 52, 10371046, 1962. Huestis, S., P. Molnar, and J. Oliver, Regional S velocities and shear velocity in the upper mantle, Bull. Seism. Soc. Am., 63, 469 475, 1973. Kanamori, H., Seismic and aseismic slip along subduction zones and their tectonic implications, in; Island arcs, deep sea trenches and back-arc basins, Maurice Ewing Ser., 1, 163174, 1977. Karig, D. B., Origin and development of marginal basins in the western Pacific, J. Geoph. Res., 76, 2542 2561, 1971. Katsumata, M., and L.R. Sykes, Seismicity and tectonics of the western Pacific: Izu - MarianaCaroline and Ryukyu Taiwan regions, J. Geoph. Res., 75, 5923 5948, 1969. LaTraille, S.L., J.F. Gettrust, and M.E. Simpson, The ROSE seismic data storage and exchange facility, J. Geoph. Res., 87, 83598363, 1982. Lee, C. S., G. G. Shor, Jr., L. D. Bibee, R. S. Lu, and T. W. C. Wide, Okinawa trough: Origin of a back-arc basin, Marine Geology, 35, 219 241, 1980. Linehan, D., Earthquakes in the West Indian Region, Trans. Am. Geophys. Union, 21, 229-232, 1940. 105 Louden, K. E., Magnetic anomalies in the West Philippine Basin, in; The geophysics of the Pacific Ocean Basin and its Margin, Geophys. Monogr. Ser., 19, 253267, 1976. Mantovani, E., F. Schwab, H. Liao, and L. Knopff, Teleseismic Sn: a guided wave in the mantle, Geophys. J. R. Astr. Soc., 51, 709 - 726, 1977. McCreery, C.S., High-frequency 1n 5n phases recorded by ocean bottom seismometers on the Cocos plate, Geophys. Res. Lett., 8, 489 - 492, 1981. McCreery, C.S., The continuous digital data collection system for the Wake Island hydrophones, HIG report, 25 pp, no date. Menke, W.H., and P.G. Richards, Crust mantle whispering gallery phases: A deterministic model of teleseismicnwave propagation, J. Geophys. Res., 85,5416-5422,1980. Menke, W.H., and P.G. Richards, The horizontal propagation of P waves through scattering media: analog model studies relevant to long range P propagation, Bull. Seism. Soc. Am., 73, 125 - 142, 1983. Menke, W. H., and R. Chen, Numerical studies of the coda falloff rate of multiply- scattered waves in randomly layered media, Bull. Seism. Soc. Am., 74, 16051621, 1984. Menke, W. H., Geophysical data analyses: Discrete inverse theory, 26Opp, 1984. Mitronovas, W., B. Isacks, and W. Seeber, Earthquake locations and seismic wave propagation in the upper 250 km of the Tonga island arc, Bull. Seism. Soc. Am., 59, 1115- 1135, 1969. Molnar, P., and J. Oliver, Lateral variations of attenuation in the upper mantle and discontinuities in the lithosphere, J. Geophys. Res., 74, 26482682, 1969. Novelo-Casanova, D. A., and R. Butler, High-frequency seismic coda and scattering in the northwest Pacific, Bull. Seism. Soc. Am., 76, 617 626, 1986. Oliver, J., and B. Isacks, Deep earthquake zones: Anomalous structures in the upper mantle, and the lithosphere, J. Geophys, Res., 72, 4259- 4275, 1967. Ouchi, J., Spectral studies of high frequency P and S phases observed by OBS's in the Mañana Basin, J. Phys. Earth, 29, 305326, 1981. ir Ouchi, T., S. Nagumo, J. Kasahara, and S. Koresawa, Separation of high-frequency P phases and mantle refracted P phases at distances between 6° and 18° in the western Pacific by ocean bottom seismograph array, Geoph. Res. Lett., 10, 10691072, 1983. Press, F., and M.Ewing, Waves with P and Sn velocity at great distances, Proc. Nail. Acad. Sci. U.s., 41, 24 27, 1955. Richards, P. G., and W. H. Menke, The apparent attenuation of a scattering medium, Bull. Seism. Soc. Am., 73, 10051021, 1983. Roecker, S. W., Velocity structure iii the Izu-Bonin seismic zone and the depth of the Olivine-Spinel transition in the slab, J. Geophys. Res., 90, 77717794, 1985. Samowitz, I. R., and D. W. Forsyth, Double seismic zone in the Mariana island arc, .1. Geophys. Res., 86, 7013 7021, 1981. Sato, H., Attenuation and envelope formation of three-component seismograms of small local earthquakes in randomly inhomogeneous lithosphere J. Geophys. Res., 89, 12211241, 1984. Sereno, T.J., and J.A. Orcutt, Synthesis of realistic oceanic P wave trains, J. Geophys. Res., 90, 12.75512.776, 1985. Shimamura, H., Anisotropy in the oceanic lithosphere of the northwestern Pacific Basin, Geophys. J. R. astr. Soc., 76, 253260, 1984. Shurbet, D.H., The high frequency P and S phases from the West Indies, Bull. Seism. Soc Am., 52, 957 - 962, 1962. Shurbet, D. H., The high frequency S phase and the structure of the upper mantle, J. Geophys. Res., 69, 2065 2070, 1964. Silver, E. A., and J. C. Moore, The Molucca Sea collision zone, Indonesia, J. Geophys. Res, 83, 1681 - 1691, 1978. Solano-Borrego, A.E., Crustal structure and seismicity of the Gorda Ridge, Ph.D. thesis, Oregon State University,185 pp, 1984. Stephens, C., and B.L. Isacks, Toward an understanding of Sn: Normal modes of Love waves in an oceanic structure, Bull. Seism. Soc. Am., 67, 69 - 78, 1977. 107 Sutton,G.H., and D.A. Walker, Oceanic mantle phases recorded on seismographs in the northwestern Pacific at distances between 7° and 40°, Bull. Seism. Soc. Am., 62, 631655, 1972. Sutton, G.H., C.S. McCreery, F.K. Duennebier, and D.A. Walker, Spectral analysis of high frequencyn'S phases recorded on ocean bottom seismographs, Geophys. Res. Lett., 5, 745747, 1978. Talandier, J., and M. Bouchon, Propagation of high frequencynwaves at great distances in the central and south Pacific and its implications for the structure of the lower lithosphere, J. Geophys. Res., 84, 5613 5619, 1979. Toksöz, M.N., A.M. Dainty, S.C. Solomon, and K.R. Anderson, Structure of the moon, Reviews of Geophysics and Space Physics, 12, 539 567, 1974. Utsu, T., and H. Okada, Anomalies in seismic wave velocity and attenuation associated with a deep earthquake zone (II), J. Fac. Sci. Hokkaido Univ. Japan Ser., VII, Vol. III, 6584, 1968. Uyeda, S., and Z. Ben-Avraham, Origin and development of the Philippine Sea, Nature, 240, 176 - 178, 1972. Walker, D.A., A study of the northwestern Pacific upper mantle, Bull. Seism. Soc. Am., 55, 925 - 939, 1965. Walker, D.A., and G.H. Sutton, Oceanic mantle phases recorded on hydrophones in the northwestern Pacific at distances between 9° and 40°, Bull. Seism. Soc. Am., 61, 65-78, 1971. Walker, D.A., High-frequency P and Sn phases recorded in the Western Pacific, J. Geophys. Res., 82, 3350 3360, 1977a. Walker, D.A., High-frequency P phases observed in the Pacific at great distances, Science, 197, 257 259, 1977b. Walker, D.A., C.S. McCreery, G.H. Sutton, and F.K. Duennebier, Spectral analysis of high-frequency P and 5n phases observed at great distances in the western Pacific, Science, 199, 13331335, 1978. Walker, D.A., High-frequency P, S velocities: some comparisons for the western, central, and south Pacific, Geophys. Res. Lett., 8, 207 - 209, 1981. iiii:i Walker, D. A., C. S. McCreery, and G.H. Sutton, Spectral characteristics of high-frequency P, S phases in the western Pacific, J.Geophys. Res., 88, 4289 - 4298, 1983. Webb, S.C., and C.S. Cox, Observations and modeling of seafloor microseisms, J.Geophys. Res., 91, 7343 7358, 1986. APPENDICES 109 APPENDIX 1 110 PHILIPPINE SEA STATIONS station id position name number lat, deg long, deg A 12 16.945133.454 B 14 16.964133.397 D 13 17.550131.463 E 01 17.939130.136 G 03 18.240129.083 AA 14 17.333131.917 BB 12 17.567131.450 EE 03 16.927132.233 BBB 05 16.655133.262 DDD03 17.395132.057 EEE 12 17.767130.875 FFF 14 18.017130.127 PACIFIC NW BASIN STATIONS station id position number lat, deg long, deg 03 43.894159.809 14 43.931159.864 WAKE ARRAY STATIONS station id position number lat, deg long, deg 71 20.4123 166.4298 72 20.3162 166.2620 73 20.5416 166.2555 74 20.6010 166.5051 75 20.4104 166.6428 76 20.2305 166.47 11 10 19.2702 166.6185 11 19.2687 166.6173 20 17.9275 167.4993 21 17.9275 167.4993 40 19.4105 165.8559 41 19.4105 165.8559 PHILIPPINE EARTHQUAKE LOCATIONS EQ # date time position depth, magnitude yr day mon hrmmsec lat, deg long, deg km 35 8102070350 19.59 22. 144127.128 033.0 5.3 126 8102091906 54.00 05.681125.232 230.1 4.7 152 8102101511 23.09 23.889123.386041.3 5.2 166 8102122333 37.46 19.162121.206046.0 4.7 168 8102131108 34.39 09.563126.588 045.0 5.6 191 810214041 03.75 02.564125.815 140.5 5.1 194 8102140731 33.69 03.333128.128 154.9 5.6 232 8102172033 25.31 09.686126.272 063.0 0.00 239 8102181548 10.69 29.328130.216 034.0 5.4 243 8102191333 23.32 00.759127.400 153.4 4.7 249 8102202009 09.92 22.918121.448 026.0 5.4 266 8102240645 09.67 28.314129.410 043.0 5.6 277 8102251619 03.75 11.280140.291 027.0 5.4 278 8102251626 13.85 28.333130.804 033.0 5.3 279 8102251841 26.62 11.198140.352 093.4 4.6 282 8102270227 33.30 24.608121.848 070.6 4.7 293 8103021213 45.34 22.894121.453 023.5 5.5 297 8103050636 36.77 09.399126.357 051.1 4.5 334 8103161228 29.6229.333129.358 033.0 5.1 338 8103161755 28.24 01.985129.488 033.5 5.4 428 8103202331 43.20 00.453126.185 033.64.6 PACIFIC NW BASIN EARTHQUAKES EQ# date time position depth, magnitude yr day mon hrmm sec lat, deglong, deg km 7 8209030132 04.80 43.710148.920010.1 6.0 9 8209030340 15.10 43.700148.750010.1 5.8 10 8209030411 57.64 43.774 148.471033.0 5.4 11 8209030806 41.24 43.724148.479033.0 5.1 12 8209030828 39.40 43.480 148.560016.3 5.7 13 8209031004 43.72 43.743 148.558033.0 5.0 25 8209060037 59.22 44.020148.283033.0 4.9 27 8209060147 06.70 29.180140.650155.6 6.5 34 8209071551 23.94 41.827142.707057.5 4.9 42 8209091249 09.22 43.314 146.738051.6 4.6 43 8209091425 36.29 38.567 141.910067.9 0.0 47 8209101020 37.65 55.178 161.698033.0 5.0 112 WAKE ARRAY EARThQUAKE LOCATIONS EQ # date time position depth, magnitude yr day mon hrmmsec lat, deg long, deg km 96 8209260109 28.51 50.053 158.798 044.0 5.5 319 8211270955 38.94 50.205147.727 622.0 5.6 443 8212270132 57.68 19.013 144.995 600.0 5.3 611 8301302245 41.56 33.407140.812 063.1 5.7 659 8302130635 30.00 13.837144.935 105.0 5.7 663 8302140023 19.42 10.504140.924 039.0 5.8 710 8302260711 01.9 48.87 155.73 045.4 6.0 715 8302271214 20.77 35.869139.916 078.3 5.9 717 8302280544 24.45 44.161 148.058 042.0 5.8 791 8303171959 28.83 41.817140.650 134.4 5.4 867 8304041904 20.64 52.931 159.858 038.0 6.0 896 8304111534 55.49 44.290147.751 097.0 5.1 984 8304301403 49.23 41.473 143.764 030.4 6.5 993 8305011810 40.39 46.353 153.453 024.0 6.1 1201 8306210625 27.35 41.346139.099 009.9 6.7 1261 8306301339 04.04 44.043 147.837 042.4 5.6 1272 8307012203 42.10 36.935 141.115 051.7 5.5 1398 8307242307 30.97 53.930158.372 180.4 6.1 1407 8307281506 44.76 41.970142.654 062.8 5.5 1451 8308080347 57.10 35.498 139.069 024.8 5.9 1481 8308171055 54.13 55.867 161.287 062.6 6.6 1494 8308201308 32.56 27.904 141.793 040.8 5.7 1518 8308252023 33.32 33.509 131.484 126.4 6.1 1528 8308281130 14.59 46.177151.514 074.9 5.5 1578 8309141125 00.90 18.104145.770 158.5 6.0 1801 8311151735 08.4 31.11 142.09017.4 5.6 1802 8311151803 58.77 31.196 141.809 025.8 5.5 1806 8311161044 06.54 37.353 141.618 042.7 5.5 1850 8311292059 50.85 32.598140.003 136.7 5.6 1856 8311300256 47.28 41.790142.772 056.9 5.8 1886 8312081318 00.2 03.50 149.16023.9 5.9 1893 8312110913 49.23 08.137137.239 023.9 6.2 2001 8401042240 44.2 45.27 151.67010.8 6.2 2144 8402130940 26.10 34.275139.998 115.0 5.2 2238 8403051100 59.88 28.726139.252 460.4 5.1 2242 8403060217 21.26 29.384138.935 457.4 6.2 2246 8403061455 16.55 42.570142.840 103.3 5.5 2261 8403112222 25.75 38.392135.482 351.0 5.3 2262 8403120234 17.99 22.286143.110 187.5 5.2 2283 8403161710 46.57 42.931 145.484 049.1 5.5 2307 8403210244 24.35 49.176 155.385 040.5 6.0 2321 8403240944 02.60 44.117148.192 044.4 6.1 2340 8403262312 35.23 56.012 163.019 031.6 5.6 2477 8404200631 10.63 50.120148.745 582.0 6.0 2492 8404232140 35.51 47.450146.692 414.1 6.0 2495 8404240411 35.2 30.81 138.46394.8 6.1 2566 8405151515 53.35 50.982153.735 281.8 4.9 2645 8406041836 05.80 51.244 150.770 498.9 5.2 2884 8407271251 10.50 52.997161.257 033.0 5.7 2911 8408061906 38.36 32.386131.945 046.2 6.3 3054 8409181702 46.5 34.11 141.37 035.0 6.6 3055 8409190120 55.86 33.933141.333 043.2 5.7 3057 8409201919 23.04 16.784 147.166 044.6 5.7 3058 8409202153 55.25 33.975 14 1.554 032.7 5.7 3061 8409210929 53.48 34.003141.507 040.2 5.9 3067 8409221810 35.54 13.822145.378 098.0 5.9 3120 8410232228 59.86 13.714 144.917 122.7 5.4 3213 8412040743 23.16 22.609 143.334 121.5 5.8 3237 8412172357 01.2 44.17 149.63 035.8 5.9 3248 8412281037 59.3 56.24 163.8 021.5 6.2 113 APPENDIX 2 171j WVNDOad uaas01aNvA 1119LNI '(L)vw (1)NrrI .IaJJV1vH3 I 'b SSVd O8.JaI3V1VID mod /SAViNV/N0WW0D '(0000L)A '(0000L)H (0000)x 'IvaN A *1 aia aYZLL sanias 'IVaN H *1 AdOD dO dWLL saivas MV'INA0 RLIA& SJ1 Na[1{flOd *1 WN0dSNVLL XTIdNOD (000cc)H 113NH'IVAIflOH ((T)H3'CI)H) 'IVaN N *1 AdOD dO IIHI IJWLL saniac N1V1NUAO l{LTM SIT 1fflNfl0d .1 ?fl{0dSNVLL xa'ldwoD (000cc)x 3JNTIvAIIIOa ((1)Ni(I)'I) aoaLM '(oI)Id '(oi)z1 (oi)c +/ ADNanbaNd SddOLu)J 'IvaN 'ddOMD ZVTWIS iIHSNI$ LLdXIV11H NvIssnvo)'I)ainI ((ssvdciNvfl TIVD )iiaio Cc 1nd1no,3.'I)au a-IL1 Aosv)'thavai in1 TIVD )LvuNdo '9 'mod '1 (nim )ir OaN1aI C NifiIL ANvO)'i)aLDIM Nd0 V1DaN ((T11d dOIS cia dl 'i)aii CcnJsN ((ou).'1)avaN .LSM ((oiA'ikivau IAIII (L.1aNNvH3.J.'I)aLnL& C(oII).'I)avaN 1131 ''i)a1nIM 'NOW 'AWl '[H 'MW 'Das ((,,uNoDasrrm (,(oIIL)'Ikivar WI=r(J)Ku) dNVSN = 9E9 0000LN 10N NflN I TIVD )siusi 'Ls 'JAm 'HDI 'KU 'dINVSN 'A 'N 'ON 'NaN ' 'Nffl 'JSN 'NVILN (IUI *1 uvaN YLYcI 01 AVfl[V A HJDNTLJ,'I)aLnIA dO :yjyu C(oix', Nvw oNuw1s)'T)aLnIA XUUNI (.(oir JSN sn1vis,)'1)au CUv)'Duvai O )& OaO ( dOJS 115 N=NTRAN DO lI=1,NST-1 /ZEROBEGINNTNGOFDATA Y(I)=0.O CONTINUE DO 3 I=Ni-I, 65536 Y(J)=O.0 I ZERO END OF DATA CON1INIJE DO 54531=1,65536 /* COPY DATA TO H H(I) = Y(1) 5453 CONTINUE CALL RFFF (H, 65536) I FOURIER TRANSfORM WRITE (1, RFFF CALLED")') F1(1)=81932-1 F2(1)=163852-1 F3(I)=8 1923-i-I F1(2)=4O972-I P2(2)4193*2-i F3(2)=4O963+1 F1(3)=20492-i P2(3)4097*2I F3(3)=20483+1 Fi(4)=1025*2I F2(4)=2049*2-I F3(4)=1024*3+1 F1(5)=513*2-1 F2(S)=1025*2-I F3(5)=S123+I F1(6)=2572-1 F2(6)=5132-i F3(6)=2563-1 WRrrE(1, 'C'WHAT DOyou wrTHE CUTOFF LEVEL TO BE?)) READ(I, *) CUTOFF WRITE(1,'C'CUTOFV ',E13.5y) CUTOFF DO 1101 J=1,6 /LOOPOVER BANDS I STANDARD DEVIATION OF GAUSSIAN SIGMA2 = -0.5 '(PLOAT(Pi(J)-F3(J))2) / ALOG(CUTOFF) WRITE(1,'('TrERATION ",14)') I WRITE(1,'('FREQUENCY CUTOFFS ',3I10)) Fl (J),F2(J),F3(J) WRrFE(1,'("SIGMA ',E13.5)') SQRT(SIGMA2) DO 411=1,32769 / COPY FOURIER TRANSFORM TO H CK(1) = CH(1) 41 CONTINUE DO 511=1, P1(J) 1* ZERO OUT TO START OF BAND CK(i)=0.0 51 CONTINUE 1* APPLY GAUSSIAN TAPER lUCK =P2(J) 116 DO 61 IFl(J), F3(J) TEMP = EXP(.0.5FLOAT(I-F3(J))2ISIGMA2) CK(1) = TEMPCK(I) CK(K1U() = CKUcK)1 KKK=KKK-1 61 CONTINUE DO 81 I=F2(J), 32769 I ZERO PAST END OF BAND CK(I)=0.0 81 CONTINUE CALL RFFI( K, 65536) I INVERSE FOURIER TRANSFORM DO 91 1=1,65536 I NORMALIZATION OF DOUBLE FF K(I)K(I) / 32768. 91 CONTINUE Is CORRECF BECAUSE OF DIGITATION RATE 80 (WAKE) /5ROSE DATA HAS DIG1TATION RATE 100 /5WE WANT THE SAME SAMPLING RATE FOR BOTH I DATASETS FOR EASIER COMPARISON DO 991=4,639 IP(NSUM.EQ.102)THEN NSUM = 103 ELSE IP(NSUMEQ.103)THEN NSUM= 102 END IP 1 COMPUTE POWER IN BAND IC=1 DO 101 1=1, 65536=NSUM, NSUM SUM = 0.0 DO 111 L=I,NSUM SUM = SUM+K(I+L-1)552 111 COJE TABLE(IC,8-J)=SUM IC=IC+1 101 (X)NIINUE 99 CONTINUE 1101 CONTINUE /5END DO FOR GAUSSIAN BANDPASSER ITYPE=1 /* INTERPOLATED DATASET SAMP= 1.28 DMIN=0.0 NROW = 639 NCOL 7 WRITEçITFLE,(ItOSEBD: INST ",15," EVT ",J5," ICR ",I5y) & INST,IEVT,ICH COLNAM(I)=TIME' COU'1AM(2)='BAND 1' COLNAM(3)='BAND 2' COLNAM(4)=BAND 3' COLNAM(5)=EAND 4' COLNAM(6)='BAND 5' COLNAMC7)='BAND 6' CALL PUTDAT( 6, HEAD, TABLE, MROW, MCOL, lEER) CALL CLSDAT( 6) CLOSE(UNIT=5) STOP END 117 PROGRAM WAKEFALLOFF COMMON/ARRAYS/ DAT(639,l0), X(639), Y(639,7) COMMON/ARRAYS/ E(639,7), NN(7), A(7), GAMMA(7), ERR(7) COMMON/KLIJGE' LASEN, LASTCOL, IPS, ERRPLOT(2,0:I0,7) DIMENSION YMIN(12), YMAX(12), MAXROW(12), MINROW(12) DIMENSION APVEL(639),SIGMAA(7), SIGMAG(7) INTEGER IX, IY, NN INTEGER MAXROW, MINROW, X, Y INTEGER POA, POB, SOA, SOB, SAROW, SBROW, PAROW, PBROW REAL RANGE, APVEL, SIGMAA, SIGMAG REAL DAT, TABLE, YMIN, YMAX, XMIN, XMAX, NENTRY REAL E, A, GAMMA, ERR character8O fin, fout, STRING, STRIN, OLDTITLE, EQ INTEGER ISTA, IEQ, IBP CHARACIER1 Q, C Sinsert Menke>regtab>head.f77 DATA NFNTRYI0.0I, MROW/6391, MCOLJIO/ CALL PAGE CALL SET'DIA( 20,80,3500,1) CALL DIAENA( .TRUE.) CALL DIAVIS( TRUE) CALL DIACLE write(I, '("ENTER STATION NUMBER")') read(1,'(15)') ISTA IBP =9 write(1, '("ENTER EVENT NUMBER")') read(1, '(15y) IEQ WRJTE(FIN, ç'W",15,'Q",34,"G",I2".REG"y) & ISTA, IEQ, JBP CALL DEBLANK(FTh4) WR1TE(FOUT, çW",J5,'I4,"G",I2'.OUT"Y) & ISTA, IEQ, IBP CALL DEBLANK(10U1') I OPEN INPUT FILE, READ DAT, CLOSE INPUT FILE call opadat( 5, fin, 0, ielr) if (ierr.ne.0) then write(1,'("cant open"1A80)') fin stop end if call gctdat( 5, head, DAT, mrow, mcol, ierr) if (ierr.ne.0) then write(1, '("cant read input")') stop end if OLDTFLE 1TILE call clsdat( 5) I OPEN OUTPUT FILE call opndat( 6, foul, 1, ierr) if (ierr.ne.0) then write(1,'('cant open"1A80)') foul stop end if 118 / GET TIlE ETATION COORDINATES CALL GETSTA(ISTA, STLAT, S'fl.ON) 1* GET THE EARTHQUAKE LOCA1ION CALL GFIEQLOC(IEQIDATE,IHRMN,SEC,ELAT, & ELONG,DEP,MAG,JHRMN,TSEC) I FIND THE RANGE CALL DIETAZ(ELAT,ELONG, STLAT, ETLON, XDEG, AZ, AZJNV) I TRANSFER RANGE IN DEG TO KM 1* FIND TRAVEL TIME RANGE=XDEG 111.2 TFSEC=TSEC-SEC rr = U + TTSEC / DAT IN ARRAY DAT(I,J) /*DAT(I,1)flME JDAT(I,2)-BAND I,ETC. I APPARENT VELOCITY IN ARREY APVELO DO 1914,NROW APVEL(1) =0.0 19 CONTINUE 1* COLUMN ONE IS INTERPOLATED AND CONTAINS CUM SAMPL /* INTERVAL I TRANSLATE SAMPL INTERVAL TO TIME DO 201=1,NROW APVEL(I) = RANGFI(IT+DAT(1,1)) 20 CONTINUE /* FIND MIN AND MAX VALUE FOR EACH FREQ BAND XMIN=DAT(I,I) XMAX=DAT(NROW,I) ISTART=I IFINISH=NROW DO 21 J=2, NCOL YMIN(J)=DAT(ISTART,J) YMAX(J)=DAT(ISTARTM MAXROW(J)=ISTART MINROW(J)=ISTART DO 22 I$START,IFINISH IF (DAT(U).GT.YMAX(J))THEN YMAX(J)=DAT(I,J) MAXROW(J)=I ELSEIF (DAT(I,J)LT.YMIN(J))THEN YMIN(J)=DAT(I,J) MINROW(J)=I END IF 22 CONTINUE 21 CONTINUE 119 /5BUILD X(I) ANT) Y(I,J) BEFORE PLOTI'ING ON TECTRONTCS DO 30I1,NROW XVAL DO 31 J=2,NCOL DO 32I=1,NROW YVAL=(DAT(I,1)-YMIN(J))/(YMAX(J)-YMIN(J))-0.5 Y(J,J) = (I0005YVAL) + (370J) 32 CONTINUE 31 CONTINUE / PLOTI]NG LOOP i PROGRAM PLOTS BANDPASSED, SQUARED, EQ.TIME SERIES I FROM REGTAR FILES 1 LOWEST COLUMN NO = LOWEST FREQ. BAND CALL PAGE DO 40 J=2,NCOL CALL DRAWXY(X,Y(I,J),NROW,0,0) 40 CONTINUE 1* DETERMINE VELOCITY LOCATIONS /V 7.6, 5.0,4.5,3.0 DO 531 I=1,NROW IF (APVEL(1).LE.7.6)T}LEN POA = I WRITE( STRING, (P5.2)) APVEL(I) WRITE( STRIN, (14)) POA GOTO 532/i BREAK LOOP END IF 531 CONTINUE 532 CONTINUE IXIPIX(PLOAT(POA)54096.0/NROW) CALL UNESEG( IX, 1, DC, 3000) CALL ANOTAT( DC-SO, 3050, STRING, 2,0.0,0.0) CALL ANOTAT( IX-30, 3000, STRIN, 2,0.0,0.0) DO 535 I=1,NROW IF (APVE.L(1).LE.5.0)TI-LEN FOB = I WRITE( STRIN, (14)) FOB WRITE( STRING, (P52)) APVEL(I) GOTO 536/f BREAK LOOP END IF 535 CONTINUE 536 CONTINUE IX IFIX(FLOAT(POB)4096.0/NROW) CALL LINESEG( DC, 1, DC, 3000) CALL ANOTAT( DC-SO, 3000, STEIN, 2,0.0,0.0) CALL ANOTAT( DC-30, 3050, STRING, 2,0.0, 0.0) DO 537 I=I,NROW IF (APVEL(1).LE.4.5)THEN SOA = I WRJTE( STRING, (P5.2)) APVEL(I) WR1TE( STEIN, (14)') SOA GOTO 538/i BREAK LOOP END IF 537 CONTINUE 538 CON11NUE xi = oIl.uo96op+(vOs)1voTd)xidi TWD )oasar'ri 'xi 'i 'xi Cocos TIYD )lvJ,oNv 'oc-xi 'ococ 'oNnas 'z '0.0 Coo 'rIvD )1v.LoNv 'oc-xi '000 'Nnas 'z 'oo Coo 051 A&oxN'I=I65c di 1.aiuC0sar(Dmjdv) 005 = I )aLDIA& 'ONOU,S ((zci). CIYiaAdv )au 'NDLLS (vj) fibs oioo ovc / svaia dOOT IN di 65c aflNLUlo3 oi'c anNLLlIoD xi = Co/o96oI'+Caos)ivo'ia)xidi TIVD )oasar'.iri 'xi 'l 'xi (000 T1VD )LvloNv 'os-xi 'ocoS 'DNNLS 'z 'oo Coo TWD ),w.LoNv 'O5-xi '000 'r.znas 'Z '00 (00 xoIa,)'l)aLraJ £XV.LS (,C,ddo TIVD )A.xxrd '3 'XI 'Al (0 !O1d )xiij Co96ov/1voi.Coo.i)1vo1d )aInIM 'oNnas (Czci), Co1aMv )ai,nEM 'NflflS (vT), C MO1d TTVD 'xT)oasaNrl 'I 'xi (000s TWD )J.v.LoNv 'oc-xI 'ocos 'ot.znis 'z 'oo Coo TIVD )AvIoNv 'os-xi '0005 'NDUS 'z 'oo Coo )(JliL)'l)aLnLA LXV.LS dO (Cod TWD )AxxDId '3 'XI 'Al (0 = )xiii vo+C&oiLvo1d (0960 )aLnI 'oNDus (zcA ( (MowdYTaMv )aLnL 'NDUS ((vT), MXVd TIVD )oasaNn 'xi 'i 'xi (0005 TIVD )lvloNv 'os-xi 'ocos 'oznLis 'z 'oo Coo TIVD )Lvi.oNv 'os-xi '000s 'nas 'z 'oo (00 ii,)'i)ai.ni&& (INH dO ((od TIVD )AxxDII '3 'XI 'Al (0 = )xitfl 'xliLVO1d+CAOIN)1VOld (0960 )ainA& 'ONDUS ((zcd), Co)mAIv )auIM 'r.iniis (Ct'i), Moiad TIVD )osNr1 'xi i 'xi' (000s TWD )lvJ.oNv 'os-xi 'ococ 'ONDLLS 'z 'oo Coo TIVD )1vJ.oNv 'os-xi '0005 'rinus 'z '00 (00 )loId.J'1)aLnL LIV1S dO CC,os TiVD )AxXDIJ 'D 'XI 'Al (0 AO)1VS )xJdI )in[A 'oNruS (.(tsA (Moivs)twiv )aLnL 'inijs (t'i) C oivs TIVD )oasri 'xi 'I 'xi (000c TWD )Lvj.oNv 'os-xi 'ocos 'onu.s 'z 'oo (00 TIVD )lvloNv 'oc-xi 'ocos 'tiras 'Z (0000 )Dui'l)aLnIA& IN do (Cos TIVD )Aioold ' 'XI 'Ai (0 o1as )xldI IN).lvo'u x.LvousC&&o (0960 )ami 'o.znu.s (zc.i), C (oias)1aAIv )aLni 'NDUS ((t'i) os -rivD )oasairi 'xi 'I 'xi (0005 TIYD )J.vloNv 'os-xi 'oco 'oNnas 'z 'oo Coo TIvc )IvJoNv 'o-xi '000 'NflU.S 'z '00 (00 TIVD )vvIu (arnLL LL dWVSI SZT si AdOD Viva 0JI a AaxUV ocr 09 AtOLMff1I ocr 19 iODN11 (r'r)a = (il)iva 19 afINLLMOD 09 anNIINOD +1 dOOl 1HAO 1H)flIVdS viva )DliL.)'flaInLM iX3N 1)PLVdS IO 1111 ö ol (Luxa ocr L99 000rl=NJIdI TWD )AxxId xi u Co = )xiai (096op/Cx1)1vou(moEN)1voia NHLCbbaD)dI 0100 L9 )IVa'dfl+I dOcri asia 9+SIaT ocr 999 ai'si='i (s'i)a = AI1NN (9"r)a = ALLMaN = 999 HI1NLLNOD UN di L99 aflNUNOD L9 anNLLM0D ' 0c1X ZV ANIZV iX8oNO1,'rXc8aLV1a1)aLn[At 'JVLLS Sd sd,NO'US,,'1X'c U .LV1U DNO1il 'IV'US N0115 ocr ccc Z1=N NaHJflOwx)di oaivjsX1)aLnEM a CCaAv = AOdNSN OIVd NILL(zba)r)d1aSIa oLvJs,J,r)aLnL s (,aAv SN = AtOLVS aN = MOIflS diaNa AOIM AOLN 10DM 10DM SdI = VIIODJS 10DM TIVD (O1rI'0V}0IS I)aLnt LDVth. wo CLLJd ocr 1E6 IODNZf ocr Z6 HN'SNI (fI)A (TjAA.O(JOj) + s0L) (1 Zr6 arINLLMOD TIVD +5(J5N)X)AXAWQ (Jo(i T6 I1MLNOD 122 NROWSAVE=NROW NCOLSAVE=NCOL /*PUT DECAY RATES INTO FOUR TABLES /*EACH TABLE CONTAINS ONE SLOPE INTERVAL ICOLUMN 1: CENTER FREQUENCY OF BAND /$COLUMN 2: NN /*COLUMN 3: AREA /*COLUMN 4: SIGMAA /$COLUMN 5: GAMMA /*COLUMN 6: SIGMAG /*COLUMN 7: ERROR IF(K.EQ.1)THEN/*POCASE*I ISET UP THE HEADER OF THE FIRST OUTPUT TABLE nrow=6 neal=7 itype=0/ OR 1 FOR INTERPOLATED TABLE TITLE=OLDTfl'LE(1:60)// P0 PHASE' EXTRA(I)=PAROW EXTRA(2)=APVEL(PAROW) EXTRA(3)=PEROW EXTRA(4)=APVEL(PBROW) COLNAM(1)=PREQ COLNAM(2)='NN' COLNAM(3)='A' COLNAM(4)='SIGMAA COLNAM(5) 'GAMMA' COLNAM(6)='SIGMAG COLNAM(7)=ERR' /*SET UP THE FIRST OUTPUT TABLE IOVERWRiTE THE DAT ARREY DAT(6,I)=30.0 DAT(5,1)=15.0 DAT(4,1)= 07.5 DAT(3,I)=03.75 DAT(2,I)=01.87 DAT(l,I)=00.93 DO 100 I=I,NROW DAT(I,2) =NN(I+1) DAT(I,3)=A(I-i-1) DAT(I,4)=SIGMAA(I+I) DAT(I,5)=GAMMA(I-i-1) DAT(I,6)=SIGMAG(I+1) DAT(I,7) =ERR(II) 100 CONTINUE /*WRITE THE FIRET OUTPUT TABLE call putdat( 6, head, DAT, mrow, meal, ieff) if(ierr.ne.0) then write(1 ,('cant write 1st table")') stop END IF ELSEIF(K.EQ.2)THBN /*5111 UP THE HEADER OF IRE SECOND OUTPUT TABLE ow =6 neal=7 itype0IOR I FOR INTERPOLATED TABLE TITLE=OLDT1TLE(1:60)I/'SO PHASE' 123 EXTRA(1) SAROW EXTRAC2) =APVEL(SAROW) EXTRA(3)SBROW EXTRA(4) = APVEL(SBROW) COLNAM(1)FREQ COLNAM(2)=NN' COLNAM(3)='A COLNAM(4)=SIGMAA COLNAM(5)=GAMMA COLNAM(6)=SIGMAG COLNAMC7)=ERR' /*SET UP ThE SECOND OUTPUT TABLE DAT(6,1)=30.0 DAT(5,l)=15.0 DAT(4,1)=07.5 DAT(3,1)03.75 DATC2,1)=01.87 DAT(1,l)=00.93 DO 101 I=lNROW DAT(I,2) =NN(I+1) DAT(I,3)=A(I+1) DAT(1,4)SIGMAA(I1) DAT(1,5)=GAMMA(I+1) DAT(1,6)SIGMAG(I+1) DAT(I,7) =ERR(I+1) 101 CONFINUE 1*WRITE ThE SECOND OUTPUT TABLE call putdat( 6, head, DAT, mrow, mcol, ierr) if(ierr.ne.0) then write(1 ,'(cant write 1st table")) atop END IF END IF NROW=NROWSAVE NCOL=NCOLSAVE 555 CONTINUE CALL CLSDAT(6) CLOSE (UN1T=9) CLOSE (UNIT=10) wRrrE(1,(" THIS IS',X2,A80y)FIN WR1TE(1,("MAKE A HARD COPY AND HIT RErURNy) READ(1,(Aly)Q CALL PAGE CALL PLOTERROR atop end 124 SUBROUTINE LINESEG(X1,YI,X2,Y2) INTEGER X1,Y1,X2,Y2 DIMENSION IX(2), IY(2) IX(1) = Xl IX(2) = X2 JY(I)=YI IY(2) = Y2 CALL DRAWXY( IX, IY, 2,0,0) SUBROUTINE DEBLANK(S) CHARACrER80 S,T 1=0 T=S 5=,, DO 111 1=1,80 IF( T(1:I).NE.' ') TI-lEN J=J+ I S(J:J)=T(I:I) END IF 111 WNDNUB flSjPI SUBROUTINE GETSTA(ISTA, STLAT, STLON) INTEGER ISTA REAL STLAT, SUON OPEN(UN1T=9, FILE='STATIONS) REWIND(IJN1T=9) DO 11=1,90 READ(9, '(15,2F10.5y, ERR=I00, END= 102) & KSTA,STLAT$ThON IF (KSTA .EQ. ISTA)TIIEN RSTURN END IF CONTINUE CALL DIAVIS( .FALSE.) CALL DIAENA( FALSE.) 100 WRiTE (1,'(READ ERROR IN STATION FILE, LINE,I5y)I STOP 102 WRITE (I,'('CANT FIND STATION"y) STOP END UNLLu1O1Rf1S '1vIU'DasNwIllrHLvUrbm)Do1baJao ' (3as1'Ntiii1'OVIdaa'ON0'iU tUOLNt 'visi 'bar 'aLVcII 'NDll N1H1 1VII1 'DUS 'IV'TH 'ONOIH 'dHG 'OVW DaSI 0SttHJDVIVHJ ba 'ol=nNn)NadO (3o'Iba=aIu (oI=11Nn)nct&au ocr 01I'11Z 'cLLd'vrzd'z9d'v6dzLd'cr8rc1)'o1)avau ' rn=nia 'Das'NwIa1vca'bH3I(zoI=aNa I' DvidaoDN0'lHLV1a UI! DHsL'N dl ba ba NWU(baI NflJ iNH dl Z Hf1NLINO3 001 au uva),'1) ronia NI awnbI{urva 'ami I(,(cIaNrI dOIS zoi aur .LNVD,),'1) (INLJ (CHIVnbHLYa dOIS HNLLfl01RflS Jul 'VVOIS'V'NVSL'I0DN'aN'SN1N'E) ' (10t0VT'OIS'VINNVO *1 HNILtI01ffflS 0(101 V ISYTI aUVnbS Jul 01 V IV100VSIHS *1 IU-LL aNimOaans STIVD HSflOH +1 oowsius=a aunariww (f'I)Iva *1 MONN *1 ONINNIOHflSN !tOI +1 JSVTHN 0E *1 DIdNVS=dNVSI 'IvAIaLNI .1 arrwA=NN dO N WO1d) (9011 aarrua ./ V = VaiV HGNfl HAflD (i)ivjriaa uairuai *1 VVNOIS = HDNVDLVA NI 'V UaNULLH( .1 vtwvo = '(z)iviiact INHNOdXH HIflVA IUN1ELLH .1 DVI0IS = DNVDIVA Nt 'VWPZVO UHN1JfLLH *1 H = 1OO1 NVHN bs '1O1fH cia1aLau *1 roiai = UODIO[IH cIHNflLa NOISNHWII '(z'659)o (6E9)&wa '(L'69)alloIsiawIa '(o1:&dv '(01:O)VV0 (o1:ohiooju NOISNHtHI '(619)1u (619)d.L NOISNHNIU '(L)VVIOIS '(L)OVIOIS (z'69)do N0ISNHU '(L)V '(L)NN '(L)vwv'wo (L)r /H0fD(/NOVZNOD 'tasv'i 'roaLsv'i 'sir (L'ot:o'z)JcmnIua lVwa 'S1NWL 'dNINU '0 'xa 'Od 'H 'dH 'dY 'dYVS1 dL iVaU 'dY}NIVO 'V 'VWJ'VO ita 'IOflIE 'NThH .LDVdN iVai 'dO 'VVNOIS OVIOIS 1VH( AINN 1OaLNI '1N 'SN 'aN cJN NN toniai NXVW = 9 NLSV1 NXVN ALLN3M = 00 i)aini NLJ,' ((cwJJd IODN3N'SN1N (IN ISNHN 1 NflN dO SJMOdVIV(1 NI o 126 DO 100 ICOL=2,NCOL I LOOP OVER COLUMNS (BANDS) DO 101 INO,MAXN /* LOOP OVER VALUES OF N /* SET SPARKER DATA TO NENTRY = 0.0 I ARREY EP(NP) EXCLUDES SPARKER DATA NP = 0 DO 102 IROW=NSNE IP( E(IROW,ICOL).NRNENTRY) THEN NP=NP+ I TP(NP)=TSAMPFLOAT(IROW-NS) EP(NP)=E(IROWJCOL) END IF 102 CONTINUE ETOTAL=O.0 GAMPP 0.1 APPO.0 DO 15 IROW=NS,NE I' ESTIM. AREA UNDER CURVE APP APP+TSAMPE(1ROW,ICOL) ETOTAL = ETOTAL + E(IROW,ICOL)2 15 CONTINUE ETOTAL = SQRT( ETOTAL/ FLOAT(NE-NS+1-2)) AP(IN) APP GAMl.1AP(IN)=GAMPP NFACF = FACIORIAL(IN) DO 16 IT=1,100 / IThRATIONS USING NONLIN. LSQ. DO 17 I=1,NP TMINTS=TP(I) IF( (IN.EQ.0) AND. (I.EQ.1) ) THEN POWER =1 ELSE POWER = TMINTS1N END IF EX=EXP(-GAMMAP(IN)4TMINTS) P0 = AP(IN)tGAMMAP(IN)(IN+1) & /NFACPIPOWER*EX EMINP(I)=EP(I)-PO G(I,1)=PO/AP(IN) G(T,2)=AP(IN)*POWERJNPACF*((IN+I) & *G&4AP(IN)**IN+(.ThENTS)+GAMMAP(IN)**(IN+1))+EX GP(I,1) = 0(1,1) GP(I,2) = G(I,2) 17 CONTINUE ITRIAG =0 CALLHOUSE(GEMINP,NP,639,2,2,ERROR(IN),1 .OE-6,IERROR,ITRIAG) 1* EMINP IS DESTROYED DURING THE HOUSE CALL AND I REPLACED BY THE SOLUTION VECTOR (2) I HOUSE RETURNES RMS ERROR 127 DELA = EMINP(1) DELG = EMINP(2) SIZE = SQRT( (DELAJAPP)**2 + (DELG/OAMPP)*S2) JF(IT.LT.30)THEN TVALUE = 0.15 ELSE TVALUE=0.30 END IF IF( SIZE.GT. TVALUE ) ThEN SCALE = TVALUE I SIZE DELA EL SCALE DELG = DELG * SCALE END IF AP(IN)AP(1N) + DELA GAMMAP(IN)=GAMMAP(IN) + DELG IF( GAMMAP(IN).LT.0.0) GAMMAP(N)=0.0 IF( SIZE .LT.1.E-4 ) GOTO 301 /BREAK LOOP*/ 16 CONTINUE J'END ITERATION LOOP/ 301 cDN11NUE /* DETERMINE ThE EX? AND AREA OF WITH SMALLEST ERROR /* FOR EACH IN ERRPLOT( IPS, IN, ICOL) = ERROR(IN) I ETOTAL 101 CONTINUE /PND OF N LOOP*/ EMIN ERROR(0) NN(ICOL) = 0 A(ICOL) A.P(0) GAMMA(ICOL) = GAMMAP) ERR(ICOL) ERROR(0) DO 21 J=1,MAXN IF( EMIN.GT.ERROR(J) )THEN NN(ICOL)J A(ICOL)AP(J) GAMMA(ICOL) GAMMAP(J) ERR(ICOL) = ERROR(J) EMIN = ERROR(J) ENDIF 21 CONTINUE 128 I OVERWRITEDATA WITH CURVE FOR BEST N ITHE CURVE IS THEN SUMPERIMPOSED ON THE DATA PLOT DO 25 14,ND IF( E(I+NS-I,ICOL) NE. 0.0)THEN IN=NN(ICOL) NFAC FACFORIAL(IN) TMINTS TSAMPFLOAT( I-I) IF( (IN.EQ.0) .AND. (I.EQ.I))TI-lEN POWER =1 ELSE POWER=TM1NTSIN END IF EX=EXP(-oAMMA(ICOL)TMlNTS) E(I+NS-I,JCOL)=A(ICOL)*GAMMA(ICOL)(IN+l) & /NFACFPOWEREX END IF 25 CONTINUE /GPTGP IS A 22 MATRIX, CONTAINING SUMS I'SUMA GF'I'GP(l,l) 1*SUMS=GPTGP(1,2)=GPTGP(2,l) ISUMD=GPTGP(2,2) SUMA=0.0 SUMB =0.0 SUMD=0.0 DO 255 I=I,ND SUMA=SUMA +OP(I,I)2 SUMS=SUMS OP(I,I)GP(I,2) SUMD SUMD +GP(I,2)"2 255CON1'INUE ICOV(MODEL PARAM)=(COV(DATA)2)(GPTGPI) DETER=I/((SUMA*SUMD)(SUMB**2)) SIGMAA(ICOL)=SQRT(DETER*SUMD)*ERR(ICOL) SIGMAG(ICOL)=SQRT(DETER+SUMA)4ERR(ICOL) ERR(ICOL)=ERR(ICOL)/ETOTAL 100 CONTINUE /END OF COLUMN LOOP/ RETURN END REAL FUNCFION FACIORIAL(1) IF( LEQ.0)THEN FACTORIAL=1.0 ELSEIF(I.EQ.I )THEN FACTORIAL=1.0 ELSE FACFORIAL=I DO 20 K=1,I-I FACrORIAL=FACIORIAL*FLOAT(IK) 20 (DNDNUE END IF RETURN END 129 SUBROUTINE PLOThR1OR I THIS SUBROUTINE PLOTS ERROR AGAINST N R)R EACH BAND COMMONIKLUGFJ LASTN, LASTCOL, II'S, ERRPLOT(2,0:I0,7) DIMENSION X(0:l0), Y(0:I0) INTEGER X, Y, XO, YO LENGTH = 400.0 LTICK = 400.0 I (LASTN+l) CALL PAGE DO 500 K=1, 2 /* LOOP OVER P AND S DO 300 ICOL=2, LASTCOL /* LOOP OVER COLUMNS XO = 100 + 500(ICOL-2) YO = 100 + 1000(K.I) CALL LINESEG( 0+XO, 0+YO, 400+XO, 0+YO) CALL LINESEG( 0+XO, 0+YO, 0+XO, 400+YO) DO 2001=0, LASTN XCI) IFIX(I400.0/(LASTN+1)) + XO Y(I) = !FIX( 400.0 $ERRPLOT(KICOL)) + YO 200 CONTINUE CALL DRAWXY(X,Y,LASTN+1 ,0,0) 300 CONTINUE 500 CONTINUE 130 APPENDIX 3 131 APPENDIX 3A: PHILIPPINE SEA and PACIFIC NW BASIN DATA Tables of measured apparent velocities and falloff values. Explanation of columns: column 1-EQNO Earthquake number column 2-STA Station number column 3-DIST Epicentral distance, deg column 4-DEPTH Hypocenter depth, km column 5-PoHJSoHratio of PoH to SoH apparent velocities column 6-PoL-arr apparent velocity of oneset of PoL, kmls column 7-PoH-arr apparent velocity of oneset of Poll, km/s column 8-SoH-arr apparent velocity of oneset of SoH, km/s column 9-Poll- 1.17PoH Falloff rates, 1/s for band 1, 1.17 Hz column 1O-PoH2.34Poll Falloff rates, 1/s for band 2, 2.34 Hz column 1 1-PoH4.68PoH Falloff rates, 1/s for band 3, 4.68 Hz column 12-PoH9.37PoH Falloff rates, 1/s for band 4, 9.37 Hz column 13-PoH18.7Poll Falloff rates, 1/s for band 5, 18.7 Hz column 14-PoH37.5Poll Falloff rates, 1/s for band 6, 37.5 Hz column 15-SoH1.17SoH Falloff rates, 1/s for band 1, 1.17 Hz column 16-SoH2.34SoH Falloff rates, 1/s for band 2, 2.34 Hz column 17-SoH4.68SoH Falloff rates, 1/s for band 3, 4.68 Hz column 18-SoH9.37SoH Falloff rates, 1/s for band 4, 9.37 Hz column 19-SoH18.7SoH Falloff rates, 1/s for band 5, 18.7 Hz column 20-SoH37.5SoH Falloff rates, 1/s for band 6, 37.5 Hz I-EQNO 35 2-STA 121 3.DIST 7.893 4-DEPTH 5-PdH/SoH 33 1.8029 6-PoL-arr 7-PoIl-arr 8.6 8-Sd-air 4.17 9-Poll-Ill I0-Po02.34 ll-PoH4.68 12-PoH9.37 13-PoH18.70.0323 l4-PoH31.5 15-SoHj.17 16-SoH2.34 ll-SoH4.68 18-SoH9.31 19-SoHI8.7 20-SoH37.5 0.0397 0.037 35 132131123122 7.8936.126 33 1.66921.7672 8.228.358.83 8.5 5.294.81 0.01320.012 0.04560.18830.04140.0341 0.03430.029 0.03460.0082 0.04020.0637 0.00050.0094 0.0352 0.03450.0633 0.06360.43020.0599 0.03520.53650.0079 0.04330.37630.0144 0.04680.02110.068 35 142141 1211 5.0495.049 7.84 33 1.78131.79291.7817 8.558.57 4.864.784.81 4.8 0.1479 0.18820.0826 0.10140.0916 0.06540.103 0.06120.0592 0.0069 0.001 0.38450.0375 0.50940.14140.0806 0.28880.15740.0587 0.8004 0.2360.098 1.16760.1775 0.094 0.34370.11050.0059 152 35 121 323113 9.8217.7385.049 41.3 33 8.238.258.72 4.694.754.78 0.2418 0.09310.0926 0.29880.13120.1065 0.18630.17040.0975 0.23960.14110.1545 0.1238 0.68180.53980.4523 0.57770.4292 0.275 0.68080.2512 1.0750.794 0.885 166152 142141122 31 9.82110.7213.3110.31 41.3 46 8.038.35 4.614.714.73 0.0754 0.09110.0723 0.068 0.202 0.3548 0.89320.10590.6624 0.09520.67440.7384 0.359 0.4219 0.348 168166 141121 3231 10.3389.1519.856 4546 8.128.087.98 4.794.974.564.55 0.2164 0.08010.08820.241 0.33170.01270.3211 0.15580.07570.16060.1614 0.22830.01240.15340.1889 0.2434 0.2338 0.20820.00410.79240.7261 0.26190.13310.20960.4871 0.06760.08290.18450.2154 0.14320.03090.1339 0.0794 168 142141122121 9.253 9.3 45 7.957.957.88 4.794.974.67 4.7 0.1411 0.17230.22880.101 0.32460.32380.23430.14070.2435 0.26330.11670.11640.4113 0.567 0.06060.53080.25910.1751 0.05210.0121 0.12123 0.11550.0848 0.12280.07240.89120.48710.0923 0.48430.21060.1061 194193 141121 31 14.09815.85315.90315.609 93 154.9140.5140.5 7.658.03 4.664.64 4.5 0.0671 0.09260.11170.1037 0.14960.15870.1612 0.12990.0439 0.073 0.15720.04840.0544 0.0655 0.1136 0.06880.2389 0.26690.08910.2748 0.19090.09180.1601 0.06880.02330.6294 194 141122121 32 14.40114.51614.098 154.9 7.687.477.61 7.6 4.584.49 0.0049 0.024 0.05430.03710.0311 0.08420.09850.0929 0.062 0.10480.03830.12340.0993 0.0974 0.198 0.01410.1036 0.001 0.07270.08250.1524 0.13170.08010.1802 0.06870.33310.1112 232194 121142 3231 14.4019.3099.243 154.9 63 7.737.927.37 8 4.714.584.77 0.0707 0.41610.48780.0339 0.06670.89660.0418 0.068 0.14950.2362 0.0978 0.0581 0.2481 0.1539 0.3019 239232 121142141 31 13.76212.4829.374 3463 7.338.127.757.82 4.514.744.684.72 0.1946 0.20050.2965 0.14630.04060.14680.2364 0.12330.05880.16450.4536 0.05790.04480.3139 0.37490.10210.0014 0.33060.17240.07760.3596 0.42080.23860.18480.1281 9.235 0.23010.31890.4061 (1319 2432.43239 121141 3231 17.17116.57612.041 153.4 34 8.098.018.06 8.1 4.75 0.0874 0.05620.05930.0703 0.12140.46890.13060.1159 0.04050.09990.0536 0.0459 0.0528 0.5852 0.7157 0.14 249243 121141 3231 11.76117.05910.79 153.4 26 8.068.148.17 4.644.684.60 0.0363 0.29360.14920.0675 0.17470.16820.08990.0937 0.14890.07960.16580.0387 0.09820.0256 0.2401 0.4449 0.50250.4134 0.06310.5032 0.6982 0.1053 266 122121 3231 11.628 10.86 43 7.978.04 7.97.9 4.714.73 0.04410.1694 0.0732 0.101 0.32890.18710.193 0.19290.13270.1071 0.10950.00270.0972 0.204 0.01790.0615 0.00080.0314 0.13860.15060.24840.0721 0.16220.48140.18330.3782 0.50880.67550.57270.2834 0.69940.48360.2711 0.243 0.4472 0.541 277 333231 9.6211086 2727 7.98 7.9 4.62 4.6 0.1661 0.32330.0938 0.25760.07810.16(80.1454 0.10910.410.23160.3509 17 0.02190.00970.1152 0.0944 0.4979 0.1421 0.73820.1956 0.164 0.44170.44060.6095 0.00150.2171 0.1688 (.0.) I. p Cf1 0PP 0 0 ! ! ! 0 0 0 0 000 000 S 2 0 p p p p 0 000OO -J-J-Z® 134 p !1 o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - O O 'O0 0 o 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 '6 1J ! 0 00 00 0 00 0 0 000 0 00 p !. ! d d d dd dd od d dd ,'f oddodo ddr '6'6 do66 oo600 0000000000000000 .-,-O% 135 APPENDIX 3B: WAKE DATA Tables of measured apparent velocities and falloff values. Explanation of columns: column 1- EQNO Earthquake number column 2-STA Station number column 3-DIST epicentral distance, deg column 4-DEPTh hypocentral depth, km column 5-Parr P wave apparent velocity, km/s column 6-PoL-arr PoL wave apparent velocity, km/s column 7-PoH-arr PoH wave apparent velocity, kmls column 8-SoL-arr SoL wave apparent velocity, km/s column 9-SoH-arr SoH wave apparent velocity, kmls column iO-PO.93 P wave Falloff, its, for band 1, 0.93 Hz column ii-Pi.87 P wave Falloff, its, for band 2, 1.87 Hz column 12-P3.75 P wave Falloff, its, for band 3, 3.75 Hz column 13-P7.5 P wave Falloff, its, for band 4, 7.5 Hz column 14-P15 P wave Fajioff, its, for band 5, 15 Hz column 15-P30 P wave Falloff,us,for band 6, 30 Hz column 16-PoLO.93PoL wave Falloff, its, for band i, 0.93 Hz column 17-PoL1.87PoL wave Falloff, its, for band 2, i.87 Hz column 18-PoL3.75PoL wave Falloff, its, for band 3, 3.75 Hz column 19-PoHO.93PoH wave Falloff, its, for band 1, 0.93 Hz column 20-PoH1.87PoH wave Falloff, its, for band 2, 1.87 Hz column 21-PoH3.75PoH wave Falloff, its, for band 3, 3.75 Hz column22-PoH7.5 PoHwave Falloff,its, for band 4, 7.5 Hz column 23-PoH15 PoH wave Falloff, ifs, for band 5, 15 Hz column 24-PoH3O PoH wave Falloff, ifs, for band 6, 30 Hz column 25-SoLO.93SoL wave Falloff, its, for band i, 0.93 Hz column 26-SoL1.87SoL wave Falloff, its, for band 2, 1.87 Hz column 27-SoHO.93SoH wave Falloff, its, for band 1, 0.93 Hz column 28-SoH1.87SoH wave Falloff, its, for band 2, i.87 Hz column 29-SoH3.75Soil wave Falloff, its, for band 3, 3.75 Hz column 30-SoH7.5 Soil wave Falloff, its, for band 4, 7.5 Hz column 31-SoH15 Soil wave Falloff,us,for band 5, 15 Hz column 32-SoH3O SoH wave Falloff, its, for band 6, 30 Hz 1- EQNO 2-STA 3-DIST 4-DEPTH 5-Parr 6-PoL-arr 7-PoH-arr 8-S0L-arr 9-SoH-arr 10-P0.93 11-P1.87 12-P3.75 13-P7.5 14-P15 15-P30 16-P0LO.93 96 75717374 30.22930.19230.03830.019 44 8.268.398.298.28 4.714.734.11 4.7 319 96 74737671 33.22233.07433.04130.377 622 44 10.7810.7710.68 7.587.59 7.6 8.2 5.685.67 4.72 0.0718 0.223 0.4831 0.401 0.06190.1106 0.197 0.05260.1589 0.0024 0.0036 443319 73207675 35.89233.40433.299 600622 10.9510.7610.77 9.74 7.597.66 7.6 7 6.03 0.22780.5771 0.191 0.53650.66350.01620.0915 0.20410.0697 0.5810.261 0.22160.3258 0.15 0.0011 443 75747671 20.42820.26720.22820.066 20.3 600 9.729.639.759.76 8.587.67 7.077.17 0.17220.24740.0998 0.289 0.11390.26150.28250.0816 0.19210.14210.0803 0.257 0.16510.1117 0.068 611 76717473 26.30926.17326.12425.966 63.1 8.328.35 8.3 4.724.734.75 659611 40201075 20.79128.45526.98226.338 63.1 105 8.238.278.31 4.694.72 659 71761073 21.5452121.46721.419 .539 105 8.278.268.248.18 4.674.69 4.7 663659 73207574 26.33122.07521.738 21.66 105 39 8.188.228.17 8.2 4.724.674.69 663 75747176 26.63626.57226.44626.428 39 9.029.01 8.218.228.24 4.684.694.67 710663 71737420 29.66429.49926.774 45.4 39 9.289.269.238.96 8.198.228.17 4.68 4.7 715710 74737675 27.81127.66729.84829.715 78.345.4 9.149.069.279.29 8.258.248.25 8.3 4.714.724.69 4.7 17-PoLI.87 18-P0L3.75 19-POHO.93 20-PoHI.87 21-PoH3.75 0.02570.056700328 22-P0H7.5 0.02760.05380.1142 23-PoH1S 0.0568 0.044 24-PoH3O 25-SoLO.93 26-SoLI.870.0006 27-SoHO.93 28-SoH1.87 29-SoH3.75 0.03780.07550.0544 30-SoH7.5 0.0605 31-SoHI5 0.0473 32-SoH3O 0.0005 0.0308 0.03440.0351 0.05760.0588 0.06150.0431 0.5847 0.218 0.0506 0.059 0.05710.0682 0.27090.2215 0.3 147 0.07 0.09 0.01670.03930.07210.0975 0.09110.08370.0407 0.07830.05710.0478 0.098 0.12660.0921 0.0930.085 0.13030.09880.10050.0327 0.00050.12180.0806 0.00070.00050.04820.0445 0.04560.04650.0937 0.065 0.08540.13980.10320.0972 0.09150.04910.05360.0018 0.0005 0.00280.2613 0.07370.0385 0.073 0.04 0.02440.07960.05190.1108 0.00040.07290.06090.1165 0.00030.1117 0.0768 0.05480.0345 0.03970.1042 0.05030.0592 0.0595 0.0289 0.04 0.045 1 0.03590.02630.06370.0256 0.03470.07080.0064 0.0186 0.04690.11060.0424 0.04350.22760.0418 0.04710.16520.0681 0.05490.12760.0862 0.04790.0756 0.01380.0289 0.05660.01160.03610.0288 0.04460.03010.0048 0.04290.02950.03840.0314 0.07750.0469 0.046 0.03510.03350.0718 0.06540.06730.08060.0762 0.08330.0868 0.085 0.08 0.0449 0.03080.02050.1298 0.0559 0.151 0.10010.10620.0753 0.09250.0996 0.055 0.0048 0.06350.06750.0725 0.03570.04570.0562 0.07670.1077 0.079 0.06070.05790.0358 0.03590.0146 0.03830.0798 0.05090.0165 0.077 0.07670.08290.04450.0562 0.11940.05520.09080.0933 0.11670.1168 0.12070.0354 0.10930.04820.03750.0843 0.12560.05140.04570.0537 0.00990.0116 0.014 0.05950.06810.0261 0.06530.07220.0402 0.09320.0891 0.052 0.03970.1935 0.0680.086 0.03680.1586 0.0280.005 0.08570.1218 0.106 0.09930.09330.1052 0.14320.0458 0.12050.04070.0476 0.05320.06880.0876 0.06550.0919 0.1 0.1305 0.064 0.07490.0609 0.068 0.10350.10610.0947 0.09960.08850.1317 1- EQNO 2-STA 3-DIST 4-DEPTH 5-Parr 6-P0L,arr 7-POH-arr 8-SoL-arr 9-SoH-arr 10-P0.93 11-P1.87 12-P3.75 13-P7.5 14-P15 15-P30 16-P0LO.93 715 20757671 30.24828.03128.01927.875 78.3 9.348.989.21 9.2 8.288.278.26 8.1 4.72 0.0515 717 75717473 28.28827.999 28.1928.06 42 9.139.179.12 8.278.268.24 8.3 4.724.774.744.75 791717 71747376 30.39830.29328.368 134.4 42 9.599.559.12 8.248.218.26 4.734.754.76 4.7 867791 73747675 32.70732.67830.62630.496 30.66 134.4 38 9.169.55 8.188.178.248.23 4.714.78 4.7 896867 73767571 33.03932.83332.855 9738 8.058.178.15 8.1 4.694.684.86 896 76757174 28.60628.52828.42928.29928.238 97 8.198.118.248.23 4.714.674.734.724.69 984 75717473 28.45728.35128.256 28.58 30.4 9.079.178.91 8.188.258.178.19 4.674.714.68 993984 71747376 27.97327.79828.624 27.82 30.4 2424 9.049.188.98 7.197.187.678.16 4.67 0.16380.0806 0.2048 993993 40767510 29.10528.74428.15728.042 24 8.96 9 7.056.296.83 0.07250.0588 0.0107 0.09730.0932 0.10260.1095 0.00030.0004 1201993 71747320 31.17831.08530.973 30.64 9.9 24 9.269.249.279.28 5.418.32 8.4 0.13380.21180.19070.0558 0.22470.05170.0041 0.11 0.06210.12640.2109 12611201 73207675 28.00733.70631.33831.313 42.4 9.9 9.439.289.27 8.317.958.76 4.77 0.11810.18520.0865 0.38180.1252 0.137 0.43510.12670.2088 0.0042 0.0034 0.0005 0.)-I 17-PoL1.87 18-P0L3.75 19-P0HO.93 20-PoHI.87 21-PoH3.75 0.01790.0209 0.0587 0.033 0.06430.1083 22-PoH7.5 0.08280.0626 23-PoH15 0.00030.0028 24-P0H3O 25-SoLO.93 26-SoLI.870.0003 27-SoH0.93 28-SoH1.87 29-SoH3.75 0.04960.0279 0.0367 0.039 0.11010.0776 30-S0H7.S 0.15730.1257 31-S0H15 0.0079 32-SoH3O 0.00440.0009 0.1015 0.01640.00040.0301 0.02 0.03140.05180.10640.0515 0.07460.06150.07590.1161 0.06620.06460.0683 0.0003 0.02790.0337 0.03950.0715 0.05440.0712 0.082 0.08520.04440.1183 0.04160.0032 0.00040.0032 0.01050.00020.0112 0.05650.05970.0355 0.04270.06720.03950.0346 0.0374 0.0660.043 0.00250.00030.0011 0.00020.0011 0.0483 0.096 0.03350.03710.0567 0.06170.07350.04090.0723 0.12830.09950.0819 0.00050.04190.0255 0.00030.00050.0004 0.0316 0.06890.08950.04730.0941 0.07730.04530.0861 0.106 0.02560.04680.07040.0317 0.18610.06580.13970.1093 0.03810.1022 0.07180.03750.06440.0451 0.08960.05030.0954 0.0005 0.00060.0562 0.02770.0688 0.0760.053 0.0435 0.04170.0676 0.06310.06320.1175 0.0486 0.08360.08390.0630.0654 8 0.0398 0.0564 0.04710.03780.03850.0391 0.03710.07220.0393 0.05450.04520.05140.01 14 0.05550.06540.0628 0.0542 0.0403 0.0345 0.04 0.07350.0883 0.04 0.08470.0769 0.085 0.04 0.0006 0.04730.04550.0507 0.06530.06540.04180.0579 0.00190.0242 0.002 0.23580.0562 0.25690.15380.26090.0631 0.20820.08590.2396 0.0005 0.22950.0053 0.06470.10920.22030.1104 0.25020.26430.1479 0.117 0.24540.1027 0.043 0.0005 0.0694 0.0631 0.09220.0506 0.0598 0.0896 0.038 0.0404 0.0551 0.0006 0.0006 0.0442 0.0651 0.0704 1- EQNO 2-STA 3-1)1ST 4-DEPTH 5-Parr 6-P0L-arr 7-PoH-arr 8-S0L-arr 9-SoH-arr 10-P0.93 14-P15 16-PoLO.93 1261 75717274 28.29828.19928.20628.069 42.4 8.729.049.08 9.1 8.288.33 4.784.764.73 11-P1.87 12-13.75 13-P7.5 15-P30 12721261 72747376 27.74727.44927.31528.376 51.742.4 8.958.949.079.14 8.178.228.28 4.674.694.73 1272 20767571 29.95427.67327.67227.552 51.7 9.249.119.149.13 8.148.188.12 8.1 4.634.684.67 139813981272 71747321 34.02433.84933.87329.954 180.4 51.7 9.929.949.28 8.248.258.19 4.734.634.65 0.10540.2241 0.07110.2796 0.11470.0976 0.00480.0088 0.00060.0029 1407139814071398 767475 29.57929.30834.20934.056 180.4 62.8 9.94 9.9 8.138.248.218.27 4.734.684.754.74 0.34910.13110.1502 0.25680.19010.5158 0.1583 0.1580.198 0.29920.08840.1519 0.00090.0013 0.001 148114511451 737476 35.46928.47928.278 35.43 62.624.8 9.69 8.158.07 8 4.724.674.62 14941481 73767571 23.45535.79535.63135.611 40.862.6 9.729.749.73 8.7 8.288.148.198.068.22 4.714.744.724.73 0.2191 0.03530.1277 0.21270.03620.1017 0.323 0.03950.00050.00730.0447 0.0023 0.0008 1494 75767174 23.76323.65623.648 23.84 40.840.8 8.778.788.748.73 8.248.258.28 4.684.694.74 4.7 15181494 72732010 33.51533.39725.62724.285 126.4 40.8 9.748.768.75 8.188.27 4.634.69 0.18330.3977 0.28950.2871 0.28630.2751 0.0885 0.001 0.001 1518 75767174 33.77733.72833.603 33.57 126.4 9.729.73 0.12350.24420.10120.0423 0.10260.26420.27580.1934 0.25570.14230.26640.2716 0.00080.00160.0006 0.003 0.00170.0007 0.00070.00060.0014 1528 72717473 28.49228.46228.31528.281 74.9 9.269.259.248.61 8.418.468.44 4.744.794.77 4.8 17-PoL1.87 18-P0L3.75 19-PoHO.93 20-PoH1.87 21-PoH3.75 22-P0H73 23-P0H15 24-P0H3O 25-S0LO.93 26-S0L1.87 27-SH0.93 28-SoH1.87 29-SoH3.75 30-SoH7.5 31-SoHI5 32-SoH3O 0.01120.0144 0.024 0.03090.07450.03590.0457 0.06540.06520.07580.0443 0.06170.0537 0.0360.109 0.0004 0.00150.0011 0.003 0.04050.07450.02930.0338 0.07580.03820.0428 0.048 0.05240.07540.0793 0.109 0.04520.0454 0.01550.01240.0409 0.07990.06110.0425 0.05560.05340.04490.0729 0.03890.06510.05170.0701 0.00490.02960.00040.0352 0.07870.05110.0523 0.00520.06930.0404 0.027 0.14030.05960.10660.0394 0.09730.11320.0827 0.099 0.06470.07270.10320.0483 0.0004 0.00940.03760.00650.0059 0.03260.09370.0594 0.08610.0617 0.08 0.05510.0748 0.069 0.03690.0004 0.036 0.03860.0286 0.07010.03590.0239 0.0862 0.1970.173 0.21040.11340.1137 0.09210.12610.0586 0.05310.0183 0.023 0.00040.04280.0441 0.04170.06110.0666 0.03170.04430.0303 0.00110.00040.0006 0.0003 0.02810.0024 0.00220.0488 0.05220.06010.0618 0.12720.0619 0.06980.0005 0.0009 0.04220.01580.0547 0.00780.04050.1108 0.08950.04450.06880.0433 0.04490.04520.0422 0.04070.03070.00110.0017 0.00050.00940.0582 0.03240.03910.0702 0.006 0.12090.09310.0674 0.093 0.21420.1468 0.156 0.14480.05430.1064 0.0016 0.07230.0323 0.037 0.03980.07580.04240.0795 0.04070.0636 0.04930.08450.05770.1936 0.1385 0.00910.0203 0.00370.0325 0.08720.09470.0583 0.07660.10060.0396 0.03560.0407 0.0245 0.014 0.02910.06050.0885 0.08470.07970.0309 0.08870.11390.0408 0.0490.0861 1 0.01540.0082 0.015 0.01810.07240.0317 0.03830.08190.18140.0885 0.18920.10620.1526 0.03790.0873 0.00030.0004 0.01240.1399 0.0090.061 0.09340.0082 0.03 8 0.08220.06410.0754 0.04 0.05360.13710.0819 0.0409 0.05 0.0005 0.05580.17350.0159 0.04070.0655 0.034 0.04020.07970.0549 0.07430.21970.06530.0434 0.06550.04920.09160.0356 0.0004 0.00610.0536 0.00710.02830.0541 0.03370.03990.0404 0.03670.06490.0426 0.04520.04040.0458 0.043 0.00050.0004 0.01910.0246 0.05090.01350.0106 0.08230.0437 0.055 0.06370.05830.0885 0.00330.0547 0.00050.00030.0013 0.03780.0004 0.028 0.0389 0.041 0.05020.05220.0348 0.05770.05460.0452 0.039 0.00050.00410.0504 0.00040.0014 0.0007 0.02420.00030.0592 0.00690.0101 0.05920.07610.03310.0219 0.03730.02890.0616 0.022 0.0017 0.00110.00040.0712 0.03480.05250.0392 0.027 0.03540.03920.0413 0.036 0.10770.06420.08360.0908 0.03460.0348 2-STA 3-DIST 4-DFPTH 5-Parr 6-PoL-arr 7-PoH-arr 8-S0L-arr 9-SoH-arr 10-P0.93 11-P1.87 12-P3.75 13-P7.5 14-P15 15-P30 16-P0LO.93 1-EQNO 15781528 71737675 19.63919.48428.64428.539 158.5 74.9 8.659.319.17 8.268.238.378.31 4.714.994.76 4.7 0.1538 0.458 0.0013 1578 75107476 19.83919.78519.72119.669 158.5 8.71 8.7 8.238.268.288.21 4.744.714.624.69 0.6782 0.613 0.509 0.0019 0.0022 0.0023 18011578 71747320 24.28524.11420.666 24.32 158.5 17.4 8.758.438.688.69 8.188.178.25 4.574.634.674.73 0.7041 0.7443 0.6802 180118021801 74207576 24.54126.50624.49324.447 25.817.4 9.078.818.718.73 8.138.248.19 8.2 4.824.684.58 18861806 20767410 22.988 27.5427.31 23.942.7 8.75 9.83 9.189.158.148.15 4.69 0.7635 1886 75717376 23.16423.93123.78523.75423.692 23.9 9.89 9.199.269.129.22 4.914.944.92 0.2101 18931886 76737410 30.72130.63230.55823.965 23.9 8.698.588.62 8.198.118.279.21 5.125.095.134.92 0.4782 1893 20757471 30.99930.93230.87230.743 23.9 8.748.588.628.56 8.398.198.168.17 4.815.135.055.14 0.41920.38990.2054 2001 75717473 27.70627.62627.48127.444 10.8 9.839.849.82 8.01 8 7.847.797.77 4.384.414.36 4.4 0.17480.20680.3482 0.13550.29830.30850.1628 0.30880.61030.30120.2323 0.14270.19520.1137 0.316 0.01720.1163 0.075 0.00370.00090.0131 0.2174 21442001 73207610 26.93130.29728.74427.808 10.8 115 11.6110.0910.039.86 8.288.198.06 7.93 7.8 4.39 0.35650.32161.1805 0.328 0.30620.08520.30081.2498 0.65010.38930.06271.0011 0.91870.2293 0.178 0.05480.00120.0184 0.00120.00080.0006 2144 75767174 27.30227.27727.13927.086 115 11.5411.5311.56 7.42 0.34240.2926 0.3480.339 0.17460.27520.30320.7962 0.16210.27830.3328 0.241 0.21050.11360.13260.6774 17-P0L1.87 18-P0L3.75 19-P0HO.93 20-Pofll.87 21-Po113.75 0.0336 0.0399 0.032 22-PoH7.5 0.04280.0468 23-PoHI5 0.0392 24-P0H3O 25-S0LO.93 26-SoLI.870.0027 27-S0HO.93 28-SoH1.87 29-SoH3.75 0.0004 0.03020.0083 0.0381 0.068 30-S0H7.5 0.12450.1434 31-S0HI5 0.04950.0778 32-SoH3O 0.0031 0.03630.03490.0601 0.11450.0246 0.03420.03140.0325 0.03690.05750.0541 0.05540.05520.0479 0.02310.02410.0014 0.04010.13440.0392 0.053 0.05510.0614 0.029 0.04790.05740.05870.0854 0.07790.06950.0684 0.07220.06390.0673 0.03640.03250.0282 0.07470.08520.0863 0.035 0.01360.0326 0.01020.03330.0341 0.045 0.04560.03140.04470.0564 0.04160.05360.04060.0544 0.00110.02650.00040.0218 0.05050.04450.0412 0.04590.04740.08130.0352 0.07940.07490.0919 0.06070.0615 0.0880.066 0.09560.04070.09090.0503 0.00290.03280.0394 0.00670.01510.13070.0505 0.01740.02820.03090.0311 0.06460.02740.0816 0.058 0.11230.04690.08070.0408 0.02090.00430.0017 0.00080.0003 0.0005 0.04090.00050.0006 0.04960.05250.0005 0.06480.00510.05250.0432 0.00060.0005 0.0005 0.02080.0227 0.06 0.06730.02820.0498 0.034 0.05350.09230.04060.0501 0.10180.09750.1255 0.00210.00040.0227 0.0003 0.00050.00160.0006 0.0005 0.0040.005 0.07620.00060.0342 0.05570.05810.0374 0.05270.0058 0.04080.10260.0342 0.19980.09560.0314 0.276 0.16430.18890.28540.0613 0.00050.00040.1728 0.00030.0006 0.0442 0.04420.1347 0.04440.0522 0.0004 0.06460.01320.0576 0.03980.0227 0.13860.1267 0.1370.156 0.18690.16170.17830.1791 0.14420.15090.06580.0608 0.00030.00170.0004 0.00060.00070.0075 0.00060.0008 0.08530.04910.03980.0402 0.04780.05310.04610.0579 0.0007 0.065 0.00070.0008 0.197 0.03790.0522 0.0214 0.0390.123 0.15480.19260.0.0971 1401 0.17680.15940.19240.2142 0.06530.07760.0005 0.167 0.00040.0006 0.00070.0049 0.0007 0.03980.0431 0.04460.04510.0612 0.0447 0.0081 0.01220.0537 0.03810.00820.0283 0.27670.0809 0.136 0.31750.16040.1464 0.12830.0731 0.0003 0.0006 0.00050.0017 0.02680.04710.0663 0.00060.04470.0683 0.0537 0.11540.08420.0561 0.03090.0405 0.01 0.03150.06820.0464 0.03610.06690.0641 0.04090.07380.0413 0.00030.00170.0016 0.003 0.00760.04090.06570.0386 0.03470.03520.0422 0.05060.04670.0566 0.09750.04910.0394 0.03230.04410.0335 0.0005 0.11910.04020.2174 0.54 0.03640.03220.00940.0376 0.07170.11250.05020.0627 0.06890.07850.06050.0683 0.00030.03030.04550.1166 0.0003 0.002 0.049 0.0797 0.03 0.0338 0.039 0.07840.0729 0.03830.0384 0.0009 0.3294 0.2353 0.7221 0.1205 (-i) 4-DEPTH 5-Parr 6-PoL-arr 7-PoH-air 8-S0L-arr 9-SoH-arr 10-P0.93 11-P1.87 12-P3.75 13-P7.5 14-P15 15-P30 16-PoLO.93 1- EQNO 22382144 2-STA 732010 3-DIST 26.01129.44727.964 25.82 460.4 115 11.4911.55 8.22 4.644.65 0.08070.0872 1.0827 0.9015 0.8796 2238 7174207576 28.00926.28526.13126.022 460.4 8.148.238.29 4.634.65 2242 40717473 26.42426.39526.236 457.4 10.0510.0910.03 10.1 0.26290.1629 0.211 0.32360.29640.23570.2728 0.33070.2991 0.345 0.14110.1593 0.116 0.00120.00130.00730.0014 0.00110.0014 2242 107576 27.09926.62126.55126.439 457.4 10.1510.3410.0310.09 0.33030.0803 1.37640.27180.30030.1205 1.33750.0832 0.0767 0.00090.0082 0.00170.01220.00430.00080.0046 22462242 7571747320 29.69429.58629.49328.46429.815 103.3 9.689.729.649.65 7.917.957.927.94 7.747.767.787.73 4.574.624.61 0.20220.50270.3143 0.24590.49350.54660.5714 0.50850.30910.27570.2837 0.10720.51850.2071 0.234 0.00630.0011 0.00850.00050.0011 0.35070.09170.1361 2246 20407610 32.28930.71630.18629.862 103.3 10.0410.05 9.849.73 8.128.278.087.97 7.917.79 8 0.60790.19030.38460.5718 0.23940.56720.54620.2776 0.63410.28090.27750.1083 0.40790.12920.4633 0.074 0.00110.0009 0.0011 0.50290.13570.1484 2261 76717473 32.30732.09231.952 32.16 351 9.259.249.72 8.158.168.14 4.874.864.84 2261 20407510 34.55933.04232.41332.313 351 10.06 9.379.349.83 8.198.258.08 8 4.784.885.03 4.9 2262 74717340 21.83821.79721.61621.445 187.5 11.6911.7411.7111.48 8.348.298.338.16 0.19740.2829 0.187 0.05430.20550.10520.0531 0.11560.20750.11260.1401 0.13980.10760.1372 0.0008 22832262 73757610 22.17921.99521.865 28.32 187.5 49.1 11.94 8.8211.7 8.348.448.36 8.3 5.2 0.3745 0.08060.1983 0.30340.1048 0.15160.2425 0.0011 0.0011 22832283 76757174 28.68928.62928.61728.399 49.1 8.879.088.828.78 8.288.218.32 8.2 5.225.23 5.2 17-P0LI.87 18-PoL3.75 19-P0HO.93 20-P0HI.87 21-P0H3.75 0.0547 22-PoH7.5 0.0702 23-PoH15 24-P0H3O 25-SoLO.93 26-S0L1.87 27-S0HO.93 28-S0HI.87 29-S0H3.75 0.0681 30-SoH7.5 0.0757 31-SoHI5 32-So1130 0.04840.06920.05670.0773 0.063 0.04720.06840.0723 0.0860.109 0.10470.06010.0806 0.089 0.10.07450.0831 173 0.101 0.04310.0667 0.09170.03670.0347 0.00770.00820.0358 0.02180.02130.0212 0.08380.04930.0405 0.07390.03380.0411 0.00090.00050.0013 0.35590.1187 0.039 0.00840.0068 0.006 0.00050.00560.0234 0.00050.0254 0.041 0.0005 0.03350.13570.14840.3507 0.00680.04790.02980.0059 0.032 0.02090.01790.01780.0197 0.04070.06020.0426 0.035 0.02680.03930.0674 0.0490.057 0.00030.00020.0016 0.04140.01490.01230.5029 0.02410.0193 0.029 0.05140.08660.0574 0.049 0.06690.05090.07210.04430.0584 0.00120.02420.0014 0.00030.0009 0.12890.0549 0.06490.14240.06470.0283 0.10170.07170.05140.0816 0.11110.12030.05660.0712 0.07380.04180.10110.0409 0.00030.00060.0004 0.0121 0.0274 0.04980.02880.08480.0734 0.03320.07120.0544 0.211 0.00060.02530.0294 0.00110.0003 0.03010.0852 0.05890.04710.07840.0484 0.07470.08670.1035 0.00060.07870.13260.0825 0.00060.00040.0014 0.05040.01890.0531 0.05750.00220.02890.0332 0.07040.15940.03270.0734 0.09650.0717 0.076 0.00160.2342 0.0012 0.0126 0.09260.0346 0.03710.08420.0941 0.0.03790.0617 01 83 0.0004 0.0018 0.0381 0.048 0.0154 0.0034 0.02050.0209 0.02960.02780.04360.0482 0.0251 0.00230.0003 0.0071 0.0076 0.04670.03810.04730.0441 0.06180.08890.0834 0.078 0.039 0.00040.0006 01-j 1- EQNO 23072283 2-STA 731040 3-DIST 29.56729.066 4-DEPTH 40.549.1 5-Parr 9.218.99 6-P0L-arr 7-P0H-arr 8.158.688.39 8-S0L-arr 9-S0H-arr 5.435.34 10-P0.93 11-P1.87 12-P3.75 13-P7.5 14-P15 15-P30 16-PoL0.93 2307 76757174 30.21530.08330.03129.86729.865 40.5 8.9 8.9 8.198.15 8.2 4.814.834.85 23212307 71747340 28.09627.96527.90530.867 44.440.5 9.249.01 8.9 9.249.01 8.9 8.168.238.278.43 4.584.564.67 4.9 2321 40767510 29.18128.72528.27328.193 44.4 9.13 9.1 9.13 8.79.1 8.248.628.46 8.3 4.774.694.59 2340 7675717374 35.65235.63835.50135.455 31.6 8.898.658.67 8.128.098.16 8.1 5.195.145.225.18 24772340 74734010 32.61936.78336.60535.821 31.6582582 11.64 11.6 9.139.19 8.46 5.38 5.4 0.12530.1046 1.89161.5867 24472477 40767571 33.54132.98132.87232.79832.649 582 11.9211.6711.7311.65 0.12590.1658 0.2030.143 0.0.3037 135717941.8937 24922447 71747310 32.36932.23231.18233.923 414.1 582 10.6510.6910.7112.01 0.21190.2215 0.181 0.10410.35450.09250.1082 2.010.05611.53591.5797 22 0.0.29810.2292 1899 0.0059 0.0012 2492 40767510 32.46932.03632.54832.459 414.1 11.1610.9610.7510.72 0.22240.21010.27570.2678 0.11640.350.28660.6606 11 0.06082.01120.0.2535 1167 0.23480.18040.2825 0.826 0.0083 0.00110.0016 24952492 71747320 27.19534.03426.991 27.17 394.8414.1 11.0211.0710.88 11.1 8.258.198.13 0.10860.29980.03911.1149 0.26480.81271.2073 0.34051. 13 88 0.0840.039 0.29210.9257 0.006 0.0085 0.0009 2495 75764010 27.37327.31527.206 27.9 394.8 10.6211.0411.0211.08 8.418.228.17 8.2 0.30190.2956 0.25350.8098 0.08050.0.16840.3421 1721 0.07240.6854 0.118 0.00370.0015 0.00090.0037 17-POLI.87 18-PoL3.75 19-PoHO.93 20-PoH1.87 21-P0H3.75 0.0179 0.0037 0.0197 22-PoH7.5 0.0481 23-PoHj5 24-PoH3O 25-S0LO.93 26-SoLI.87 27-SOHO.93 28-SoH1.87 29-SoH3.75 30-S0H7.5 31-SoH15 32-S0H3O 0.03280.0329 0.02710.03720.02380.0176 0.03780.03380.0205 0.068 0.0246 0.00030.0004 0.0052 0.00040.0077 0.04590.03740.0451 0.05480.04910.0846 0.0422 0.00060.00230.0007 0.02470.03260.06170.0875 0.06040.03760.05530.0836 0.04580.07550.0668 0.068 0.05950.00050.00040.0082 0.07 0.09720.03860.03040.00040.0005 0.05020.07460.03730.0353 0.0363 0.0120.043 0.04430.15650.05050.0361 0.06940.12170.07380.0476 0.12270.06860.07850.0765 0.000400003 0.0061 0.048 0.00050.0367 0.04580.08310.04410.0712 0.09720.09340.04360.06530.0606 0.00130.0006 0.01440.05820.0359 0.03 0.02980.04930.0365 0.10680.02970.03290.0475 0.132 0.05810.12860.0785 0.03070.0617 0.00030.0273 0.05150.05120.0006 0.06240.05770.05530.0669 0.08910.0622 0.108 0.0668 0.064 0.05710.04170.06190.0303 0.02990.04290.06540.0655 0.02980.12710.08910.1115 0.05820.12450.12860.15560.0684 0.03130.13210.05040.0351 0.0007 0.02610.00240.0003 0.05230.06690.06070.03140.0315 0.06440.05260.06390.07090.0964 0.09190.08040.0862 0.0870.074 0.06950.06160.04410.05030.0431 0.0003 0.0003 0.0003 0.03920.0343 0.02940.0003 0.02030.0003 0.03980.0003 0.03430.07520.03920.0596 0.037 0.04590.0324 0.00350.0004 -a 1- EQNO 2-STA 3-DIST 4-DEPTH 5-Parr 6-PcjL-arr 7-PoH-arr 8-S0L-arr 9-SoH-arr 10-P0.93 11-P1.87 12-P3.75 13-P7.5 14-P15 15-P30 16-PoLO.93 25662495 71747320 32.10531.94231.93829.299 281.8394.8 10.91 9.679.599.65 8.178.228.35 7.987.947.99 4.884.854.84 0.24630.51860.8901 0.262 0.42540.72611.4351 0.178 0.30630.28521.1139 0.27010.29840.07950.0013 0.00250.0013 0.002 0.17570.1268 0.249 2566 40767510 33.24832.93332.159 32.29 281.8 10.05 9.889.699.62 8.719.048.198.13 8.318.197.947.93 5.034.834.84 5 0.34260.51610.1989 0.26 0.28320.72570.33270.1291 0.28860.28490.22050.6355 0.29390.29780.2196 0.379 0.00110.00490.00120.0008 0.0011 0.001 0.40540.29930.0496 0.274 26452566 71747320 33.13832.98232.96534.755 498.9281.8 9.429.489.85 9.5 8.15 4.894.91 0.6886 0.33410.25270.9226 0.16891.73981.1631 0.11660.3202 0.0046 0.0011 2645 40767510 34.27433.92633.32233.202 498.9 9.699.499.45 5.054.954.93 0.25120.01960.1787 0.16870.08730.7952 0.121 2884 75717374 32.79232.626 32.7732.59 33 8.228.298.28 5.595.545.565.49 2884 407610 33.91833.71132.954 33 8.768.36 8.68.4 5.815.685.55 2911 4071747320 32.98232.96932.94332.76435.336 46.2 9.649.63 0.23410.18450.29740.2109 0.24460.12240.2945 0.123 0.22030.1963 0.2180.153 0.0499 0.0008 0.0006 2911 20757610 35.07333.67633.14633.089 46.2 9.739.919.869.64 8.49 0.35110.08030.2565 0.211 0.31090.29420.09850.1714 0.07920.19820.06330.1181 0.00450.0007 0.00080.0038 0.00070.0008 3054 76717473 26.17626.03625.98125.828 35 9.049.039.018.99 8.318.288.26 8.3 4.734.754.74 0.3161 3054 20407510 28.36126.22126.197 26.87 35 9.179.069.029.05 8.228.268.248.32 4.684.754.73 0.4602 3055 76717473 26.12825.98925.93525.781 43.2 8.938.718.87 8.7 8.288.248.258.32 4.74 4.74.8 -J 17-PoL1.87 18-P0L3.75 19-PoHO.93 20-P0H1.87 21-PoH3.75 0.0162 0.0233 22-PoH7.5 0.0231 23-PoHI5 0.0323 24-P0H3O 25-S0LO.93 26-SoL1.87 27-SoHO.93 28-S0H1.87 29-SoH3.75 0.072 0.0428 0.0301 30-SoH7.5 0.0355 31-S0H1S 0.0323 32-SOH3O 0.07270.21940.0644 0.02790.0212 0.02740.0401 0.0110.018 0.03010.02830.0285 0.02350.0404 0.0250.026 0.02410.02590.02280.0218 0.0203 0.03230.11850.09590.1134 0.02320.09690.0378 0.05230.04960.04980.0539 0.02840.04750.0534 0.081 0.03510.03550.02740.0555 0.0013 0.01630.0401 0.03020.02350.0285 0.03270.02360.0404 0.00030.03360.0218 0.0002 0.11340.0796 0.00050.00750.0384 0.03870.03120.0536 0.07930.03650.0527 0.03460.0561 0.00050.00310.02960.0042 0.04030.03130.0006 0.033 0.08050.057 1 0.0386 0.16150.18960.1619 0.05780.04630.0646 0.06370.07650.0673 0.10590.06650.1126 0.00630.00210.0487 0.0393 0.05040.04750.03740.0454 0.08580.06480.04830.0388 0.04280.16150.28270.1269 0.162 0.04290.04540.06460.07780.0415 0.09080.06270.07660.0804 0.058 0.00680.06460.11150.0638 0.069 0.0029 0.00040.04910.02790.0356 0.00510.0287 0.04 0.03490.04290.0425 0.03570.08420.0622 0.0787 0.0421 0.0125 0.2046 0.1653 0.02270.01340.04530.0137 0.04620.06160.02610.0436 0.07850.09230.07010.1036 0.12830.10870.07680.0659 0.10910.12110.0668 0.103 0.00040.00120.0014 0.03380.03120.08810.2395 0.04720.03880.04140.0421 0.10310.05650.08090.0717 0.09020.11860.0859 0.118 0.14310.12320.0883 0.085 0.00040.00120.03180.0027 0.7902 0.692 0.02050.0465 0.0790.064 0.04890.06040.05320.0779 0.05410.10150.03480.0538 0.09460.09450.07340.0737 0.10640.09870.03590.1221 0.00140.01970.0008 0.03030.06160.0871 0.06260.04840.14720.0373 0.05580.08160.03470.0982 0.06470.07490.03860.1061 0.04920.0328 0.089 0.03510.00040.0023 0.02660.07110.13690.0139 0.00450.04360.05360.0298 0.04610.06860.06450.0297 0.11580.04850.11530.0342 0.00030.0004 0.18810.0003 0.0540.058 0.00280.00490.0031 0.003 0.04160.04450.07810.0292 0.05880.04750.08570.0647 0.02940.0006 (.0 1- EQNO 30573055 2-STA 7510 3-DIST 17.95826.81826.151 4-DEPTH 44.643.2 5-Parr 6-PoL-arr 9.038.54 7-Poll-air 8.348.35 8-S0L-arr 9-SoH-arr 4.734.744.67 10-P0.93 11-P1.87 12-P3.75 13-P7.5 14-P15 15-P30 16-PoLO 93 3057 7671734010 18.64418.62518.61118.467 44.6446 8.358.388.37 4.754.744.734.72 30583057 73207574 25.63319.44318.80818.707 44.632.744.6 8.82 8.8 8.228.368.378.33 8.2 4.724.764.73 3058 7576717410 26.67326.00225.786 25.9825.84 32.7 8.938.878.89 8.9 8.098.238.228.24 4.69 4.7 306130583061 71747320 25.88825.83328.163 25.68 40.232.7 9.048.96 8.9 8.278.258.238.09 4.714.734.72 30673061 73407576 21.02920.38726.04926.027 40.2 98 8.548.988.94 8.6 8.218.188.268.28 4.71 4.7 3067 74717610 2121.14821.062 .265 21.14 98 8.688.658.648.69 8.098.268.078.19 4.69 4.7 31203067 76732075 21.59821.66121 .341 21.48 122.7 98 8.738.768.578.61 8.238.268.248.07 4.754.724.73 47 3120 75747110 21.72121.60521.52121.798 122.7 8.738.748.54 8.278.288.31 4.754.724.73 32133120 71727320 21.59621.45821.41322.121 121.5122.7 8.758.748.78 8.6 8.298.258.338.35 4.734.694.724.71 0.4256 3213 75767411 21.99321.79321.66621.634 121.5121.5 8.718.638.738.65 8.268.218.27 8.3 4.754.694734.71 -a01 IC) 19000 66c0o 6LFO 66800 60000 LC000 £W10 90800 8L90O 900 6'0OZ600Z8c0Oc060o £99006800t'L00i'61'00 8Z00cct'ooM'OOZlt'OO i'8008I'001100019Z00 i'8Z00 6Z0016Z00wcooL00 i'E001LOoc9COOt100 6cz0o86t00i'ZIOOZ8Z00 Z1O06i'8r0£t90011100 t'OOOO 81.000 i'oo 9L9(10Z6i'ooL1900£0600 ct-coozocoo991'OO11'90018110 6600t'i'60O6t'ooczoo i'9000ZOtO0Lcco0coo £1000 zzzoo 0000 9cEo061'OZO68t'oO61E0OJtI'OO 69t-00£I'EOO81600zcoo9Z0O 61100c8900cccooLi'ZOO 98000£9O0Z8100 £1000 690080900lt-E00 t'E800pt'oo6Z1V0£IVO 8010£t-ZZOLt't-OO 8Lc0oEZOIO£LLO0 zcoo 1.1000£9000 c000o Z000£0000L100 cc600Tzcoo£9coo M'coot'OI'OO16000 t-1100i'IOOO6t00LECO0 9co0088000 £0000 cocoo68coo8600L6Z00 90800Z9600t'1800891.00 99i'OOL9900L880019900 SIEO0£t-006co10L8Z00 6t'LOO91200Z8EO0 £cZO0L6ZO0ILZO0 12Z0089Z00t'OOO18Z008000 SOZO0ZIZO0£t'ZOO10t-00 8810061000LZO0 Z0t'OOct-cooZIEO096000i'tcio £EL00 1.0600c60099600801U0 9cLoo99800L6IFOLt'ôOO c6c009900P120069900 L6t'OOLEt'OOP6E00czzoo cLcO0izcooIEO0 £0000t0000 t'i'OOOi'czoo£00006SE006SZ00 £00001t'Zooit'oOo£CZO0 zcioo£0000P91001Z0069100 800009czoo9Z00 1zoo 68c00180001S800 iccoo £0800E06(T0690F0ggcoo IcPO0Lc9oo9CLO0£6E00101.00 1100081-00t'ct'oo L6000t'OOOOicoo c89oo8cP1088010 cc9ooc9cooZc800 ZP00SL000Z6L009Z00 t6000601001-0008100 cc000 1000 6E00cotro161.00 P9t'Oo661-00 1-1.000ZZZOO 1-0000c000o £0000£t'OOO £890061800IZLO0 99oo6090.05t'SOO t'ciooZcEOOLSZO0 It-zoo8L000Zi'600 c0000c000oIccoo t'cBoo9Z60096800 Zt-L0091-COOcLO01-tOO 91-E00£i'tOOL1tO0ci000 c00001-0000 £0000 Z8L0061.006Z6006900WUO 1-600icLo'o1090081900 coo 919009cco0czcoo£1E00 'coo ccoo9110061.000 900001000 P1600600101810 8LZI06c11090800cczio1L800 £8800601-006L110ZOLO0 ZZ800910001800616F0 680009L1-008c1101-0000 ci000 8E900S9Z001ç8C0 ZçL1Ocoiio£9910LZ800 9scooZ1901200 1i'900i'LOIO1-L6Z086ç00 8Z1-008Zc00cccoo c000o191'OO 89600LSOOzzcioL9ZI0 Z80O6LEZOcccoo19600 12600Z80O8cLI010800 t900zciioZZLZ0801-00 51010£8coO81-coo 1-0000£6L00 1-090099110i'8ZZ0£10£9010 61-101-8016c0018110 99c0091010£01.106cL0081-010 ct-coo8C1'OOL6coo9c1-o0 69000£L1ZOZ8600ZLC0o 1.1000 OcHOS-ZE 900009000.0cz9o0 cmos-Ic Z6LO0cLHOS-Oc88000 911-009c1-oo881Z0cLdllos-6z L81H05-8Z c6oHos-Lz L81I°S-9t £6010S-cZ OdH°d-1-Z ZL9I06c1'OOo 50000t'ocoo 1-0000 1-0000ZZLO0£0000cIH°d-cz 99010Z6Z0 cLHOd-zZ 1.1.9006ccoo1-L10SLcHOd-IZ cOcio98600L8H1°d-OZ £60HOd61 çLIod-81 L811°c1L1 61.1.00c8LO0 1- EQNO 2-STA 3-DIST 4-DEVFH 5-Parr 6-PoL-arr 7-PoH-arr 8-SoL-arr 9-SoH-arr 10-P0.93 11-P1.87 12-P3.75 13-P7.5 14-P15 15-P30 16-PoLO.93 3213 73212010 27.32323.13221.993 121.5 35.8 8.71 8.4 8.388.33 8.4 4.724.746.05 4.7 3237 75717476 27.60327.51127.378 27.69 35.8 8.19 5.825.956.11 32483237 40732010 25.68830.17428.608 28.17 41.135.8 8.28 4.674.715.415.61 32483248 76757174 26.08526.05725.89525.841 41.1 8.218.258.26 8.3 4.724.674.714.73 18503248 71747320 26.46126.29628.217 136.741.1 9.059.22 8.158.16 4.694.63 18561850 73207576 26.67226.68326.503 28.73 136.7 56.9 8.769.329.099.159.18 8.168.188.17 4.714.674.644.68 1856 76757174 29.39729.35429.12629.028 29.23 56.9 9.299.048.95 8.248.238.27 8.3 4.694.744.71 4.7 0, 17-PoLl .87 18-PoL3.75 19-PoHO.93 20-PoH1 .87 21-PoH3.75 0.0141 0.0488 0.008 22-PoH7.5 0.045 23-P0H15 0.0094 24-P0H3O 25-SoLO.93 26-SoLI.87 27-SoHO.93 28-S0HI.87 29-SoH3.75 0.0686 0.1086 0.1259 30-S0H7.5 0.1358 31-SoH15 0.0067 32-S0H3O 0.07320.0087 0.15330.2397 0.05320.0564 0.0076 0.0135 0.0427 0.12470.08510.0991 0.098 0.13090.09220.1112 0.129 0.14360.11260.04870.0535 0.08630.07820.00050.0035 0.24270.0004 0.22670.10980.11530.1819 0.10730.13480.14020.1813 0.02640.12940.1318 0.185 0.23660.05960.0512 0.00040.2396 0.07230.0622 0.07270.0581 0.2049 0.06740.04820.22930.1091 0.04440.05370.22590.1325 0.12320.0378 0.0004 0.05320.03910.03450.0718 0.07490.07230.0434 0.06540.00850.0392 0.04690.06940.0462 0.03770.0024 0.07 0.04670.08340.07680.0451 0.06760.08430.08530.0754 0.1043 0.03480.0447 0.0070.077 0.04120.07730.03240.0438 0.08680.07990.0632 0.0445 0.0616 0.03980.06610.0615 0.11170.07650.0856 0.03580.05870.1254 0.00050.047 1 0.002 0.0049 0.04210.0378 004740.0811 0.0404 0.0575 0.015 0.04590.06380.04440.0556 0.06650.04060.0396 0.071 0.07190.05080.04030.0733 0.00050.0028 0.00050.02820.0039 0.04240.03390.0406 0.07 0.06540.05040.04230.0508 (31