Thermal IR for Geology

Home , Bitterwater Creek

FIG. 1. Index (nap showing major physiographic features and approximate location of areas described and illustrated in this report.

EDWARDW. WOLFE* U.S. Geological Survey Flagstaff, Ariz. 86001 Thermal IR for Geology

An evaluation for Caliente and Temblor Ranges in Southern California compares pre-dawn and post-dawn imagery and a conventional photograph.

(Abstract on next page)

in the Caliente Range, and unpublished maps by both T. W. Dibblee and G. Vedder HERMAL INFRARED IMAGERY, recording J. radiation from 8 to 13 micrometers in were used to evaluate the imagery in the T Temblor Range. wavelength, was flown by NASA on June 18, 1965, in the Carrizo Plain of southern Calif- Figure 2 is a generalized geologic map of ornia. A line approximately normal to the re- the area in which imagery was studied in gional geologic structure was selected for detail. The stratigraphic nomenclature used detailed analysis and is shown in Figure 1. A on the map and in this report is that of preliminary report on imagery from the Car- Dibblee (1962). Its use herein does not consti- rizo Plain was made by Wallace and Moxham tute adoption of the names by the U.S. (1966). A published geologic map by Vedder Geological Survey. and Repenning (1965) was extensively used In the image area the Caliente and Temblor Ranges are underlain by steeply dipping * Publication authorized by the Director, U.S. clastic rocks of late Tertiary age. In addi- Geological Survey. tion, three basalt flows occur within the Caliente Range sequence. The Caliente and Figure 5, an aerial photograph of the north- Temblor Ranges in the image area are largely eastern part of the imaged strip, was taken mantled by debris derived from the under- from about 35,000 feet on a midsummer day. lying strata, and extensive outcrops of bare In order to facilitate comparison and dis- bedrock are rare. Generally references to cussion, observation points are numbered on geologic units such as Morales Formation or the pre-dawn and post-sunrise images (Fig- Bitterwater Creek Shale apply to the debris ures 3 and 4) and on the aerial photograph that represents the units at the ground sur- (Figure 5). The annotations tabulated below face. are numbered to correspond to the numbers on Figures 3, 4, and 5. Unless specifically noted ACKNOWLEDGMENTS otherwise, the annotations refer to the pre- Extensive discussion with Malcolm M. dawn image (Figure 3). Clark and critical reviews by R. J. P. Lyon, 1. Subparallel white lines coincide at least in F. F. Sabins, J. G. Vedder, and R. E. Wal- part with local strike ridges on which bare sand-

ABSTRACT:Thermal infrared (8 to 13 micrometers) imagery was obtained in the Caliente and Temblor Ranges and Carrizo Plain, southern Calijornia, in the predawn and post-sunrise hours of June 18, 1965. Field observations, measurements of moisture and specific gravity of the regolith, and rad:ation temperatures, and comparison with geologic maps and aerial photographs lead to the following conclusions: (1) The specific gravities of sztrficial materials (usually not bedrock) influence tonal densities in the pre-dawn imagery. Hence areas underlain by sandy alluvium, sandstone, or conglomerate (highspecific gravity) tend to be brighter in pre-dawn imagery than areas underlain by shale, mudstone, or diatomite (low specific gravity). (2) Geologic interpretation of tonal density patterns is complicated by topographic, atmospheric, and vegetative effects on pre-dawn radiation. (3) Geologic features such as outcrop patterns and some faults are recognizable in the infrared imagery as well as in aerial photographs. -(4) post-sunrise imagery is dominated by the preferential warming of slopes exposed to the early morning sun and resembles low-sun-angle photographs.

lace led to significant improvements in the stone beds and basalt flows are exposed. Pebbly texture is chapparal. manuscript. Illustrations were drafted by 2. White line coincides with sharp break in Mrs. Gertrude Edmondston. slope at the outer edge of a terrace mantled by old alluvium. 3. Flat to slightly concave remnants of an old alluviated surface appear dark, as do portions of The infrared images (Figures 3 and 4) are nearby stream canyons. line-scan displays of the areal distribution of 4. White line coincides with strike ridge on radiation intensities in the 8- to 13-microm- which the uppermost of three basalt flows forms eter wavelength band. Areas of intense a bold outcrop of bare rock. 5. Same strike ridge as 4, but here, where the radiation are relatively light in tone; those of white line is indistinct, the basalt is mantled by relatively weak radiation are dark in tone in soil and rubble. the images. Radiation intensity ,varies di- 6. White line corresponds to bare outcrop of rectly with emissivity and with the fourth hard. light-colored mudstone to sandy mudstone. Adjacent bedrock mantled by soil. power of absolute surface temperature. Cur- 7. Dark band corresponds to the outcrop of vature near the image margins is a distortion the Quatal Formation, a mudstone consisting inherent in the scanning technique. largely of expanding clay in contact with sand- Figure 3 is an image made shortly before stones of the Caliente and Morales Formations. 8. Small dark patches oorrespond to outcrops dawn (0506-0510 PDT), and the effects of of reddish-brown expanding clay in the Morales differential solar heating related to slope Formation. The bordering materials giving orientation are therefore minimized. Figure 4 brighter tones are sandy soils developed on the is an image made shortly after sunrise Morales Formation and deposits of sandy and gravelly alluvium that veneer all but the small (0635-0638). In this image, surfaces warmed areas represented by the dark spots. by the sun appear relatively bright, much as 9. Low hill underlain by claystone, sandstone, they would in early morning photographs. and conglomerate of the Morales Formation; THERMAL IR FOR GEOLOGY 45

EXPLANATION

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o I 2 4 a MIL~S -1 FIG.2. Generalized geologic map of study area. See Figure 1 for location. bounded by broad alluviated areas. In the post- water Creek Shale project through the alluvial sunrise imagery the hill is more distinctly out- apron that underlies the Elkhorn Plain at the lined because of preferential heating of slopes foot of the Temblor Range. Bitterwater Creek exposed to the sun. Shale dark in both pre-dawn and post-sunrise 10. Small hill, a few feet high, relatively imagery but bright in aerial photograph. bright, lies within a dark region that corre- 15. Bitterwater Creek Shale in contact to sponds approximately with the ibwest part of the northeast with very coarse conglomerate of the Carrizo Plain in the image area. Iinages show Santa Margarita Formation. Conglomerate and agricultural field patterns and fan patterns where alluvial apron that bounds it on the southwest intermittent streams debouch onto the broad are bright and contrast sharply with darkly alluviated Carrizo Plain. Because the Carrizo imaged Bitterwater Creek Shale. Note that in Plain is nearly flat, almost no preferential solar the aerial photograph the contact between Santa heating occurs, and the post-sunrise image Margarita conglomerate and alluvium is readily closely resembles the pre-dawn image. apparent because the two units differ in topo- 11. Dark spots represent accumulations of tumbleweed against a fence at the northeast graphic expression. edge of the Carrizo Plain. 15. Outcrops of downfolded Bitterwater Creek 12. Northwest-trending trench along recently Shale dark; bright in aerial photograph. Geo- active trace of San Andreas fault. Well-drained logic map (Figure 2) portrays distribution of gully bottoms, including the trench along the sandstone and shale mapped together as Bitter- fault and the fine gullies forming a filigree pat- water Creek Shale. Imagery and aerial photo- tern on low ridge southwest of the fault, appear graph, on the other hand, display shale facies in bright. sharp contrast to surrounding rocks whether 13. Two elongate hills underlain by Bitter- they be Santa Margarita Formation, a sand- 46 PHOTOGRAMMETRIC ENGINEERING, 197 1

FIG. 3a. Pre-dawn infrared image-Caliente FIG. 4a. Post-sunrise infrared image-Caliente Range and Carrizo Plain. See Figure 1 for location. Range and Carrizo Plain. See Figure 1 for location. For key to numbers, see text. For key to numbers, see text. with rare granitic or metamorphic boulders. stone facies of the Bitterwater Creek, or the Conglomerate facies darker in aerial photograph alluvium of the Elkhorn Plain. than sandstone facies. 16. Sharp radiation contact coincides with a 20. Sharp radiation boundary coincides with fault separating Monterey Shale to the north- crest of Temblor Range. Immediately northeast east from Santa Margarita conglomerate and a of the range crest, Santa Margarita conglomer- sandstone mapped with the Bittenvater Creek ate, Media Shale, and the Temblor or Vaqueros Shale. The conglomerate and the Bitterwater Formations all appear bright. Most of the slope Creek sandstone, inseparable in the imagery as for about a mile and a half northeast of the range well as in the aerial photograph, contrast crest in the image area is underlain by grass- sharply with the Monterey Shale, which is dark covered Monterey Shale colluvium that appears in the pre-dawn image and light in the aerial relatively bright. photograph. 21. Dark band coincides with prominent, 17. Broad dark band occurs in an area under- steep, southwest-facing slope nearly devoid of lain by Monterey Shale, shale and sandstone of vegetation. It is underlain in part by diatomite the Temblor or Vaqueros Formations, and a mapped by Dibblee (1962) as the Reef Ridge sandstone unit at the base of the Santa Mar- Formation (Fig. 2) and in part by Monterey garita Formation. Within the band, shale is the Shale. predominant lithology. 22. Sharp radiation contact between Reef 18. Contact between Monterey Shale (dark Ridge diatomite (dark in image, bright in aerial in image, light in aerial photograph) and over- photograph) and overlying Santa Margarita lying Santa Margarita Formation (light in conglomerate (bright in image, dark in aerial image, dark in aerial photograph). photograph). - 19. Radiation boundary at northwestern limit 23. Small dark spots coincide with windows in of conglomerate facies (light in image) of the gravel colluvium, through which Reef Ridge Santa Margarita Formation within the image diatomite is exuosed in the Fellows oil field. area. Farther northwest within the image area, 24. Dark bind coincides with steep, barren, the Santa Margarita Formation consists pre- southwest-facing slope on which Reef Ridge dominantly of friable sandstone (dark in image) diatomite is exposed. Santa Margarita con- --

THERMAL IR. FOR GEOLOGY 47

FIG. 3b. Pre-dawn infrared image-Carrizo Plain, Elkhorn Plain, and Temblor Range. See Figure 1 for location. For key to numbers and let- FIG. 4b. Post-sunrise infrared image-Carrizo ters, see text. Plain, Elkhorn Plain, and Temblor Range. See Figure 1 for location. For key to numbers and Iet- ters, see text.

glomerate southwest of the diatomite and gravels of the Tulare Formation northeast of the c. Gullied area just southwest of range cre>t, diatomite appear bright. Near the northeast end southeast-facing slopes dark. of the image, the community of Fellows stands d. Three small ridge crests on northeast flank of on undeformed younger alluvial deposits. range; all dark on south side and bright on north side in pre-dawn image. Intensity of pre-dawn infrared radiation in e. Steep northeast-facing canyon walls within the Temblor Range is apparently related in dark band at locality 21 brighter than nearby part to slope orientation. North-facing slopes southwest-facing slopes; all underlain by dia- tomaceous Monterey Shale. tend to be relatively bright; south-facing slopes tend to be dark in the pre-dawn The slope effect is not ubiquitous. It is not imagery (Figure 3). The largest topographic recognizable in the Caliente Range (Figure feature showing this tendency is the crest of 3a) nor at the crest of the Temblor Range in the Temblor Range. Near locality 20 a well- the east (left) half of Figures 3b and 3c, defined radiation boundary separates similar where the bright Santa Margarita conglomer- lithologic types at the range crest. The north- ate outcrop faces southwest. east flank of the range is relatively bright, the southwest flank relatively dark. A few other examples of this tendency, denoted by letters In an attempt to find systematic relation- in Figures 3, 4, and 5, are listed below: ships between ground conditions and tonal a. Steep north-northeast-facing hill in Monterey densities in the pre-dawn infrared image, data Shale bright in pre-dawn imagery (Figure 3) ; on radiation temperature, specific gravity, strikingly warmed by early morning sun in and moisture were collected late in May 1967. post-sunrise imagery (Figure 4). According to Weather Bureau records, no rain b. Hill underlain by basal sandstone of Sarlta Margarita Formation dark on south side, fell in the area in May or June prior to the IR bright on north side (Figure 3). flight on June 18, 1965. Rainfall in April I 48 PHOTOGRAMhlETRIC ENGINEERING, 197 1

FIG. 3c. Pre-dawn infrared image-Temblor FIG. 4c. Post-sunrise infrared image, Tetnblor Range. See Figure 1 for location. For lrey to num- Range. See Figure 1 for location. For key to numbers and letters, see text. bers and letters, see text.

1965 was approximately two inches both east of the area at Maricopa and west of the area T = absolute temperature (OK) at Cuyama. In April 1967, 1.85 inches of rain u = a constant. fell at Maricopa and 2.82 inches fell at Emissivity of an object is the ratio of its Cuyama. During May 1967, 0.02 inches fell emittance (radiant energy emitted per unit at both Cuyama and Maricopa approximately area) to the emittance of a perfect radiator two weeks before the ground data were col- (blackbody) at the same temperature. Black- lected. In spite of the slightly wetter weather bodies exist in theory only; real substances in the spring of 1967, the ground in late May have emissivities smaller than 1. The radi- in the area of Figures 3, 4, and 5 seemed ometer measures emittance, but it reads out thoroughly dry and the grass cover was in a temperature scale based on an emissivity brown. of 1. Because natural materials have emis- Radiation temperatures were measured sivities smaller than 1, radiation temperatures with a hand-held Barnes IT-3 radiometer over are lower than true temperatures. Within a period of two days and three nights, from the temperature range in which this study May 22 to 25, at two different sites near was made, a change of 0.05 in emissivity contacts between the Bitterwater Creek for high emissivities produces a change of Shale and alluvium (locality 13). Infrared about 4OC in apparent temperature. Greater radiation, the quantity measured by the distortion occurs with low emissivities. radiometer, varies as emissivity and as the Laboratory radiometer measurements of fourth power of the absolute temperature: large samples of surficial material collected from the Bitterwater Creek Shale, Santa Margarita conglomerate (cobbles and where boulders excluded), Monterey Shale, Reef W=total radiation per unit area (8-13 Ridge diatomite, Quatal Formation, Morales micrometer radiation in this instance) Formation, and alluvium of the Elkhorn E = emissivity Plain suggest that differences in radiant emit- THERMAL IR FOR GEOLOGY 49

tance are not caused bv emissivitv differences i I I I I I I I I I related to the composition of the surficial debris. Apparent temperatures of the samples, which stood for several weeks in a normally heated room, were other, with a systematic variation that was probably related to position in the room rather than to lithology. The apparent temperatures (near temperature and suggest that all of the samples had high emissivities. Figure 6 displays radiation temperature data collected in the field on typical grass- { ,o covered sandy alluvium and on barren 2 Bitterwater Creek Shale debris. The same relationship, with Bitterwater Creek Shale : appearing colder both day and night, was later repeated as a second site. Radiation i-" from alluvium with relatively sparse grass cover and from Bitterwater Creek Shale with = sparse grass cover was intermediate between the extremes of barren Bitterwater Creek -lo Shale and typically grassy alluvium both day and night. Single boulders in the alluvium were slightly more radiant in the pre-dawn hours than the deposits that included them. -Lll""i"rn The radiometer measurements show that the X-X--X Illtt.?..l.r C..." S".,. ------*-",-.,,---* I I I I I I I I I 1 IIE POT FIG. 6. Radiation temperatures measured by Barnes IT-3 radiometer at locality 13, Temblor Range, May 22-24, 1967. radiation patterns recorded in the imagery are reproducible and suggest that physical properties (such as specific gravity and moisture content) which may have affected radiance when the images were made, were also effective in May 1967 when field observations were made. Densities and moisture contents of repre- sentative surficial materials were determined. Approximately 1,000 cc of soil from the uppermost two inches were carefully collected and immediately weighed. Volume was determined by filling the excavation with a measured quantity of sand, and density was computed. Moisture content was determined by comparing the sample weight after several days of drying at llO°C with its weight at the time of collection. Surficial materials developed on sandy alluvium, sandstone units, and Santa Margarita conglomerate (cobbles and boulders excluded from measurements) FIG. 5. Small-scale aerial photograph of Temblor range in density from about 1.3 to 1.5 and in Range southwest of Fellows. For key to numbers, moisture content from 1.6 to 2.8 percent. see text. Surface materials representing shale units Low pre-dawn radiance High pre-dawn radiance - Low specific gravity (approx. 1.0). High specific gravity (approx. 1.3). Little or no qrass cover. lielatively thick grass cover. Bright in aerial photograph (high reflectivity). Dark in aerial photograph (low reflectivity). Slope Faces south. Slope faces north. Entrapment of cold air -- - - range in density from about 1.0 to 1.1, and ficial material plays an important role in de- their moisture contents range from 5.3 to 8.4 termining its thermal inertia, which is a percent. The specific gravity of diatomite measure of resistance of its surface to temper- surficial debris from the east side of the ature change: - Temblor Range (locality 18) is about 0.9. Thermal inertia = 4KpC X-ray data show that much of the shale and mudstone is montmorillonitic; the high mois- where ture contents probably represent water driven K = thermal conductivity from the clay mineral structure by laboratory p = specific gravity heating rather than high accumulations of C =specific heat. intergranular water. In late May, surficial materials in the area of Figures 3, 4, and 5 Surface materials with high thermal inertia looked and felt thoroughly dry. react slowly to external temperature changes and, other factors being equal, should be warmer in the pre-dawn hours than sur- Comparison of the pre-dawn image, the ficial materials with low thermal inertia. aerial photograph, and the ground data sug- In addition to the relationship previously gest that intensity of pre-dawn radiance may noted between soil of low specific gravity and be related to specific gravity of soil, vegeta- low pre-dawn radiance, the following observa- tive cover, reflectivity, slope orientation, and tions support the correlation between sepecific microclimatic effects as summarized in Ta- gravity and pre-dawn radiance: ble 1. 1. Outcrops of bare bedrock (localities 1,4, 6) Shale, mudstone, and diatomite surficial with specific gravities much higher than those materials have low specific gravities (about of the surrounding soils are displayed in the 1.0) and ordinarily are dark in the pre-dawn imagery as bands of high pre-dawn radiance. It image (Figure 3, localities 7, 8, 13, 14, 15, 16, should be noted that a similar band (lochlity 2) 17, 18, 21, 23, 24). The same materials gener- apparently coincides only with a sharp break in slope. t ally support little or no grass cover and reflect 2. As indicated by radiometer measurhents sunlight relatively intensely, as shown by the in the pre-dawn hours, single boulders were aerial photograph (Figure 5). In contrast, slightly more radiant than the unconsolidated alluvium that surrounded them. surficial materials representing Santa Mar- 3. Tumbleweed piled along a fence at locality garita conglomerate, most sandstone units, 11 forms a surficial material that, because of its and sandy alluvium have higher specific extremely low specific gravity and high porosity, gravities (about 1.3) and tend to be bright has low thermal inertia and appears dark in the pre-dawn image. in the pre-dawn image (Figure 3, localities 8, 4. Wallace and Moxham (1966) showed that 14, 15, 16, 18, 22). They support more in some other Carrizo Plain images unplowed vegetation than the shales and reflect less fields were brighter in the pre-dawn than plowed sunlight, as shown by their darkness in the fields. Plowing, by increasing the porosity and lowering the specific gravity of soil, lowers its aerial photograph. Sabins (1967, p. 748; 1969, thermal inertia. p. 403) found sandstone to be radiometrically warmer than siltstone at night in the Indio Grass cover and reflectizlity. Radiometer Hills and Imperial Valley areas of southern measurements (Figure 6) in late May showed California. In addition, south-facing slopes that typically barren Bitterwater Creek tend to be less radiant in part in the pre- Shale at locality 13 was less radiant than the dawn image than north-facing slopes. Hence, adjacent grassy alluvium both day and night, the intensity of pre-dawn radiance from any an unlikely condition if thermal inertia were surface may be controlled by several factors. the sole controlling influence. Radiant tem- Specific gravity. Specific gravity of sur- peratures on slightly grassy shale and on THERMAL IR FOR GEOLOGY 5 1 alluvium with relatively thin grass cover were slightly warmer and appears brighter in intermediate between the extremes shown in Figure 3. Figure 6, which suggests a direct correlation Measurements made in nearby restricted between increased vegetation and increased depressions in the pre-dawn hours of October infrared emission. Gates (1964, p. 576) states 25, 1967, show upward increases in air that all plant surfaces have emissivities of temperature of as much as 4.S°C within 30 0.95 or greater. Under the existing conditions, inches of the depression floors. Similar up- an increase in emissivitv of 0.05 would Dro- ward increases in near-ground air temper- duce a radiant temperature increase of about ature occur between the depression floors and 4"C, a temperature difference consistent the low bounding hills that stand a few tens with the radiometer results. of feet higher. In addition, the Bitterwater Creek Shale, Gullies at locality 12 appear bright in the as well as other shale units that are brightu in pre-dawn image, and surface temperatures the aerial photograph, may absorb less heat were no doubt warmer than on the adjacent than the surrounding alluvium in the day- interfluves. Although they are local topo- time because of relatively intense reflection graphic lows, the gullies are well drained and of solar radiation: at nightv the shale mav cool presumably do not permit development of the more rapidly because of relatively low ther- stagnation by which a thick cold air layer mal inertia. Probably thermal inertia, vegeta- accumulates. In addition the larger gullies tive cover, and reflectivity interact complexly are floored at least in part by compact alluvial in controlling pre-dawn radiance throughout sand and gravel with greater specific gravity the image area. and presumably greater thermal inertia than Slope orientation. North slopes in the the loose silty soil that forms the gully walls. Temblor Range tend to be more radiant in the pre-dawn image than nearby south slopes underlain by similar lithologies. In some In the Caliente and Temblor Ranges, where places, vegetation is more lush on north geometric geologic features are readily dis- slopes than on south ones, but the relation- cernible, the imagery is largely controlled by ship is not consistent, and the cause of the properties of surficial debris, not bedrock. slope effect is unknown. Surficial materials with relatively high Microclimatic efects. In addition to the specific gravities tend to be bright in the pre- apparent effects of specific gravity, vegeta- dawn image, and those with low specific tive cover, reflectivity, and slope orientation gravities tend to be dark. Consequently areas on image tonal densities, microclimatic underlain by sandy alluvium, sandstone, and effects related to local topographic features conglomerate tend to be bright in the pre- apparently may influence pre-dawn ground dawn imagery, and areas underlain by shale, temperature and cause radiative anomalies. mudstone, or diatomite tend to be dark. How- Low pre-dawn radiance at localities 3 and 10 ever, local atmospheric conditions, topo- mav be due to nocturnal accumulation of cold graphic setting, reflectivity, and vegetation air on poorly drained ground surfaces, a may also produce marked imagery effects. phenomenon extensively documented by Geologic inferences based on qualitative Geiger (1957). The diamond-shaped dark comparisons of radiation from the regolith, area at locality 3 in Figure 3 is a flat surface, with the radiation complexly modified by such or possibly even a shallow closed depression, effects, must be made cautiously. partially enclosed by surrounding hills. The Post-sunrise imagery shows the strong in- surface is underlain by old alluvium, which is fluence of differential solar warming of sur- sandy and closely resembles in both texture faces exposed to the sun. Topography is the and vegetative cover other alluvial deposits dominant control of tonal densities in the that appear bright in Figure 3. The suggested image, which resembles a low-sun-angle interpretation of the diamond-shaped area is photograph. that it represents an area in which cold air REFERENCES accumulates preferentially at night, causing Dibblee, T. W., Jr., 1962, "Displacements on the the surface beneath the colder air to become San Andreas rift zone and related structures in slightly cooler than nearby surfaces. A carriz0 Plain and vicinity (California), in similar interpretation is suggested at locality Guideboolr, Geology of Carrizo Plains and San 10, where the dark region in the image coin- Andreas Fault," San Joaquin Geol. SOL.and Am. ASSOC.Petroleum Geologists-Soc. Econ. Paleon- ,-ides approximately with the lowest part of tologists and Mineralogists, Pacific Sec. weld the valley floor in the image area. A small trip),1962, p. 5-12. hill projecting through the colder air strata is Gates, D. M., 1964, "Characteristics of soil and vegetated surfaces to reflected and emitted radi- Vedder, J. G., and Repenning, C. A,, 1965, "Geo- ation," Symposium Remote Sensing of Environ- logic map of the southeastern Caliente Range, ment, 3d, Michigan Univ., Ann Arbor, Infrared San Luis Obispo County, California," U. S. Physics Lab., Proc., p. 573-600. Geol. Survey Oil and Gas Inv. Map OM-217, scale Geiger, R. E., 1957, The climate near the ground, 1 :24,000. 2d ed., Harvard Univ. Press, Cambridge, Mass., Wallace, R. E., and Moxham, R. M., 1966, "Use 494 pp. Translation by Milroy N. Stewart, and of infrared imagery in study of the San Andreas others from the German. fault system, California," U. S. Geol. Survey Sabins. F. F.. Tr.. 1967. "Infrared imagerv axid Tech. Letter NASA-42; 1967, Use of infrared aspects;" ~hotogrammetric~niindering, imagery in study of the San Andreas Fault sys- v. 33, no. 7,p. 743-750, lulv 1967. tem, California, in Geological Survey Research Sabins, F. F., Tr., 1969, Thermal infrared imagery 1967, U. S. Geol. Survey Prof. Paper 575-D, P. and its application to structural mapping in D147-D156; abs. in Symposium Remote Sens- southern California: Geol. Soc. Amer. Bull.. v. ing of Environment, 4th, Michigan Univ., Ann Arbor, Infrared Physics Lab., Abstracts, p. 24.

1971 CONVENTION WASHINGTON, D.C. M MARCH 7-12

The 37th Annual Meeting of the American Society of Photogrammetry will be held at the Washington Hilton Hotel, Washington, D.C., March 7-12, 1971 as part of the 1971 ASP-ACSM Convention. The ASP Technical Program will feature papers reflecting recent developments in:

Photogrammetric Techniques and Instrumentation Aerial Photography Remote Sensing Photo Interpretation Analytical Photogrammetry Non-Topographic Photogrammetry Photogrammetric Applications

For further information write to American Society of Photogrammetry, 105 N. Vir- ginia Ave., Falls Church, Va. 22046.