MICROZONING of EARTHQUAKE HAZARD in ISRAEL Project 3
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MICROZONING OF EARTHQUAKE HAZARD IN ISRAEL Project 3 SITE EFFECT AND SEISMIC HAZARD ASSESSMENT FOR PETAH TIKVA, HOD HASHARON AND ROSH HAAYIN TOWNS: CONTINUATION OF MEASUREMENT IN THE HASHEFELA AREA November, 2006 Report No 569/237/06 Principal Investigator Dr. Y. Zaslavsky Collaborators: Galina Ataev, Marina Gorstein, Dr. Rami Hofstetter, Michael Kalmanovich, Dagmara Giller, Ilana Dan, Nahum Perelman, Tatyana Aksinenko, Vadim Giller, Ion Livshits and Alexander Shvartsburg Submitted to: Earth Sciences Research Administration National Ministry of Infrastructures and The Ministry of Absorption 1 CONTENTS LIST OF FIGURES ........................................................................................................................ 2 LIST OF TABLES .......................................................................................................................... 3 ABSTRACT .................................................................................................................................... 5 1. INTRODUCTION ...................................................................................................................... 7 2. APPLICATION OF AMBIENT NOISE MEASUREMENTS FOR ESTIMATING SITE EFFECT .......................................................................................................................................... 9 3. GEOLOGY ............................................................................................................................... 11 4. DATA ACQUISITION, FIELD WORK AND PROCESSING ............................................... 20 5. RESULTS ................................................................................................................................. 23 5.1. Variations of Fourier spectra and H/V ratio shape obtained from ambient noise recordings throughout the study area and its correlation with geological structure .............................................. 23 5.2. Stability of measurements ............................................................................................................. 27 5.3. Distribution of the fundamental frequency and its associated amplitude ..................................... 31 5.4. Developing of S-wave velocity model .......................................................................................... 34 5.5. Reconstruction of subsurface structure ......................................................................................... 42 5.5.1. Profile AA ................................................................................................................... 42 5.5.2. Profile BB ................................................................................................................... 44 5.5.3. Profile CC ................................................................................................................... 49 6. SEISMIC MICROZONATION IN TERMS OF UNIFORM HAZARD ACCELERATION SPECTRA ..................................................................................................................................... 52 7. DISCUSSION ........................................................................................................................... 57 8. CONCLUSIONS ...................................................................................................................... 61 ACKNOWLEDGEMENT ............................................................................................................ 63 REFERENCES ............................................................................................................................. 64 Appendix A. Table A1.Well data in the study area ...................................................................... 71 2 LIST OF FIGURES Figure 1. Geological map of the study area (scale 1:50,000). .......................................................13 Figure 2. Schematic geological cross section along profile indicated in Fig. 1. ............................14 Figure 3. Fragment of the structural map of Top Judea Gr. in the study area. ..............................15 Figure 4. Isopach map of Hashefela and lower Saqiye Groups in the study area. Numbers indicate well number as given in Appendix 1. ...............................................................................16 Figure 5. Isopach map of clay (Yafo Fm.) in the study area. ........................................................16 Figure 6. Isopach map of calcareous sandstone (Kurkar) in the study area ..................................17 Figure 7. Isopach map of loose sediments (Rehovot Fm., the Kurkar Group) and alluvium in the study area .......................................................................................................................................17 Figure 8. Geological division of the study area .............................................................................18 Figure 9. Map showing location of the measuring point in the study area ....................................22 Figure 10. (a) Average Fourier spectra of horizontal (blue line) and vertical (red line) components of motion obtained at points 501 and 312; (b) H/V spectral ratios. The shaded area represents the frequency range of resonance motion. Points positions are indicated in Fig. 9. ....24 Figure 11. (a) Examples of average Fourier spectra and (b) H/V spectral ratios for points 152, 166 and 253. ...................................................................................................................................25 Figure 12. (a) Examples of average Fourier spectra and (b) individual and average H/V spectral ratios for points 457and 107. .........................................................................................................26 Figure 13. (a) Examples of average Fourier spectra and (b) H/V spectral ratios for point 466 located at the Coastal Plain ............................................................................................................27 Figure 14. Comparison of horizontal-to-vertical spectral ratio from ambient noise observed at point 420 in different month: (a) Individual H/V ratios; (b) average spectral ratios. ....................28 Figure 15. Comparison of horizontal-to-vertical spectral ratio from ambient noise observed at point 253 in different month: (a) average spectra Fourier for three component of motions; (b) average spectral ratios. ...................................................................................................................29 Figure 16. Comparison of horizontal-to-vertical spectral ratio from ambient noise observed at point 262 in different month: (a) individual H/V ratios; (b) average spectral ratios. ....................30 Figure 17. Comparison of horizontal-to-vertical spectral ratio from ambient noise observed at point 329 in different month: (a) average spectra Fourier for two components (NS and EW) of horizontal and vertical (V) components of motions; (b) individual and average spectral ratios. ..30 Figure 18. Comparison stability of horizontal-to-vertical spectral ratio from ambient noise observed at point 81 in different month: (a) average spectra Fourier for three component of motions; (b) average spectral ratios. ..............................................................................................31 Figure 19. Distribution of the fundamental frequency...................................................................33 Figure 20. Distribution of the amplitude associated with fundamental frequency. For legend see Fig. 19. ...........................................................................................................................................34 Figure 21. (a) – Lithological cross section of well 70; (b) - comparison between H/V spectral ratio obtained at well 70 (red line) and analytical transfer functions calculated using well data and velocities from refraction line RL-3. The black line corresponds to the model, in which the reflector located at a depth of 12 m has Vs=1900 m/sec; the blue line corresponds to the soil column model from Table 5. ..........................................................................................................36 Figure 22. Lithological section for well 61 and analytical transfer function for well 61 compared with H/V spectral ratio obtained at this well. ................................................................................37 3 Figure 23. Lithological cross section of well 111; (b) - comparison between H/V spectral ratio (red line) and analytical transfer functions calculated using well 111 and refraction survey data (black line). ....................................................................................................................................38 Figure 24. (a) - lithological section of Pt2 well with the Top Judea Gr. indicated by the red line; (b) - comparison between H/V spectral ratio obtained at well location (red line); trial analytical transfer functions corresponding to the reflector – Top Judea Gr. (blue line) and optimal transfer function (black line); (c) the suggested lithologial section corresponding to the reflector – dolomite of the Judea Gr. ...............................................................................................................39 Figure 25. Comparison between H/V spectral ratio obtained at Givat Hashlosha and Neve Yaraq wells (red lines); trial analytical transfer functions corresponding to the 1D model from Givat Hashlosha