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NASA NTRS1975

Airborne remote sensors applied to engineering geology and civil works design investigations

The usefulness of various airborne remote sensing systems in the detection and identification of regional and specific geologic structural features that may affect the design and location of engineering structures on major civil works projects is evaluated. The Butler Valley Dam and Blue Lake Project in northern California was selected as a demonstration site. Findings derived from the interpretation of various kinds of imagery used are given.

Gelnett, R. H.↗

NASA NTRS1977

Significant achievements in the planetary geology program, 1975 - 1976

Developments in planetology research as reported at the 1976 NASA Planetology Program Principal Investigators' meeting are summarized. Topics range from solar system evolution, comparative planetology, and geologic processes to techniques and instrument development for future exploration.

Head, J. W.↗

NASA NTRS1977

Reports of planetary geology program, 1976 - 1977

One hundred seventeen investigations undertaken in the NASA Planetary Geology Program in 1976-1977 are reported in abstract form. Topics discussed include solar system formation; planetary interiors; planetary evolution; asteroids, comets and moons; cratering; volcanic, eolian, fluvial and mass wasting processes; volatiles and the Martian regolith; mapping; and instrument development and techniques. An author index is provided.

Arvidson, R.↗

NASA NTRS1977

LANDSAT (ERTS) used as a basis for geological volcanological mapping in the central Andes

LANDSAT images of the central Andes (N-Chile, W-Bolivia) were effectively used for volcanological mapping of an area about 160,000 km. The map shown exhibits more and better details than the older small scale geological maps of that area. Even on a scale of 1:1,000,000 details greater than 200 m in size are recognizable. The interpretation of LANDSAT images makes it possible to establish relative age sequences of strato-volcanoes. Finally, the images will also be helpful in prospecting for mineral deposits and geothermal sources.

Kussmaul, S.↗

NASA NTRS1977

Geology orbiter comparison study

Instrument requirements of planetary geology orbiters were examined with the objective of determining the feasibility of applying standard instrument designs to a host of terrestrial targets. Within the basic discipline area of geochemistry, gamma-ray, X-ray fluorescence, and atomic spectroscopy remote sensing techniques were considered. Within the discipline area of geophysics, the complementary techniques of gravimetry and radar were studied. Experiments using these techniques were analyzed for comparison at the Moon, Mercury, Mars and the Galilean satellites. On the basis of these comparative assessments, the adaptability of each sensing technique was judged as a basic technique for many targets, as a single instrument applied to many targets, as a single instrument used in different mission modes, and as an instrument capability for nongeoscience objectives.

Cutts, J. A. J.↗

NASA NTRS1977

A simple thermal model of the earth's surface for geologic mapping by remote sensing

Thermal inertia of the earth's surface can be used in geologic mapping as a complement to surface reflectance data as provided by Landsat. Thermal inertia cannot be determined directly but must be inferred from radiation temperature measurements (by thermal IR sensors) made at various times in the diurnal cycle, combined with a model of the surface heating processes. A model is developed which differs from those created previously for this purpose, because it includes sensible and latent heating. Tests of this model using field data indicate that it accurately determines the surface heating. When the model is used with field measurements of meteorological variables and is combined with remotely sensed temperature data, a thermal inertia image can be produced.

Kahle, A. B.↗

NASA NTRS1979

Mounting procedure for geological samples

Mounting procedure originally developed for lunar samples preserves geological specimens. Sequence of potting and grinding operations produces thin sections through grains that are easy to handle and are well protected for storage. Method results in more representative sections of mixture of grains of different sizes and more effective distribution of grains uniformly over slide.

Jezek, D. I.↗

NASA NTRS1977

Some geologic observations concerning lunar geophysical models

The distribution of lunar geologic units in space and time and their mode of origin were considered since they provided significant data which bear on a number of current problems in lunar geophysics. Observations and problems were discussed which deal with the characterization of the upper 25 km of the lunar crust, the tectonic style of the crust, the formation of mascons within major basins, analysis of lunar magnetic anomalies, and the history of the lunar crust.

Head, J. W.↗

NASA NTRS1977

Image analysis techniques with special reference to analysis and interpretation of geological features from LANDSAT imagery

The principal component analysis enhances the contrast existing between the different cover types present in an imagery. A procedure is presented with regards to the determination of the principal components. The method is tested for a portion of the LANDSAT imagery pertaining to Anantapur region. Another technique, using the concept of non-linear contrast stretching is defined and developed and carried out on the same imagery. The results are presented as photographs. An interpretation of the geology of the region is derived from these photographs.

Kamat, D. S.↗

NASA NTRS1977

Evaluation of algorithms for geological thermal-inertia mapping

The errors incurred in producing a thermal inertia map are of three general types: measurement, analysis, and model simplification. To emphasize the geophysical relevance of these errors, they were expressed in terms of uncertainty in thermal inertia and compared with the thermal inertia values of geologic materials. Thus the applications and practical limitations of the technique were illustrated. All errors were calculated using the parameter values appropriate to a site at the Raft River, Id. Although these error values serve to illustrate the magnitudes that can be expected from the three general types of errors, extrapolation to other sites should be done using parameter values particular to the area. Three surface temperature algorithms were evaluated: linear Fourier series, finite difference, and Laplace transform. In terms of resulting errors in thermal inertia, the Laplace transform method is the most accurate (260 TIU), the forward finite difference method is intermediate (300 TIU), and the linear Fourier series method the least accurate (460 TIU).

Miller, S. H.↗

NASA NTRS1978

Activities of the US Geological Survey in Applications of Remote Sensing in the Chesapeake Bay Region

The application of remote sensing in the Chesapeake Bay region has been a central concern of three project activities of the U.S. Geological Survey: two are developmental, and one is operational. The two developmental activities were experiments in land-use and land-cover inventory and change detection using remotely sensed data from aircraft and from the LANDSAT and Skylab satellites. One of these is CARETS (Central Atlantic Regional Ecological Test Site). The other developmental task is the Census Cities Experiment in Urban Change Detection. The present major concern is an operational land-use and land-cover data-analysis program, including a supporting geographical information system.

Wray, J. R.↗

NASA NTRS1976

Geologic interpretation of LANDSAT satellite images for the Qattara Depression area, Egypt

The author has identified the following significant results. For the first time the regional geological units are given. Faults, fractures, and folds are included, as well as drainage lines which help to visualize the environmental impact of the Qattara project for electric power generation and to assess the regional questions involved in its implementation.

Elshazly, E. M.↗

NASA NTRS1978

Application of multispectral radar and LANDSAT imagery to geologic mapping in death valley

Side-Looking Airborne Radar (SLAR) images, acquired by JPL and Strategic Air Command Systems, and visible and near-infrared LANDSAT imagery were applied to studies of the Quaternary alluvial and evaporite deposits in Death Valley, California. Unprocessed radar imagery revealed considerable variation in microwave backscatter, generally correlated with surface roughness. For Death Valley, LANDSAT imagery is of limited value in discriminating the Quaternary units except for alluvial units distinguishable by presence or absence of desert varnish or evaporite units whose extremely rough surfaces are strongly shadowed. In contrast, radar returns are most strongly dependent on surface roughness, a property more strongly correlated with surficial geology than is surface chemistry.

Daily, M.↗

NASA NTRS1977

Preliminary geologic evaluation of L-band radar imagery: Arkansas test site

The relatively small angles of incidence (steep depression angles) of the L-band system provide minimal shadowing on terrain back-slopes and considerable foreshortening on terrain fore-slopes which sacrifice much of the topographic enhancement afforded by a more oblique angle of illumination. In addition, the dynamic range of the return from vegetated surfaces is substantially less for the L-band system, and many surface features defined primarily by subtle changes in vegetation are lost. In areas having terrain conditions similar to those of northern Arkansas, and where LANDSAT and shorter wavelength aircraft radar data are available, the value of the JPL L-band imagery as either a complimentary or supplementary geologic data source is not obvious.

Macdonald, H.↗

NASA NTRS1977

Geology of Chryse Planitia

Chryse Planitia, the site of the first successful landing on Mars by Viking 1, is an asymmetrical basin, centered at 45 deg W and 24 deg N, about 2000 km northeast of Valles Marineris. High-resolution Viking orbiter images show Chryse Planitia to be much more complex than had been suspected from Mariner 9 images. On the basis of a study of the Viking pictures it is concluded that the geological history of Chryse Planitia involves a complex sequence of impact cratering, mantling by extensive deposits of unknown origin, redistribution of mantling and crater materials by erosion and deposition with concurrent eruptions of flood-type basalts, and aeolian activity.

Greeley, R.↗

NASA NTRS1977

Geological Observations in the Cydonia Region of Mars from Viking

During the Viking mission, three broad areas of the northern plains were investigated as possible landing sites for Viking lander 2. We present a geological map of the area designated the B1 landing site in Cydonia centered on 45 deg N latitude, 4 deg W longitude. Viking imagery of this area has given detailed coverage, allowing the northern plains to be examined in more detail over wider areas than was possible from Mariner 9. Some plains areas with polygonal fracture patterns are considered to be pediments in ancient southern hemisphere rocks. The fracture patterns predate at least some of the younger northern plains material. Several northern plains units are distinguished as well as surface textures of unknown origin. Viking pictures provide good data for future studies of stratigraphy and surface process in this region and others like it in northern latitudes.

Guest, J. E.↗

NASA NTRS1977

The geology of the Viking Lander 2 site

Models are discussed of several competitive geologic histories that can be hypothesized for the Viking Lander 2 site, none of which is uniquely persuasive. The craft landed on a flat plain of fine-grained sediment overlain by dispersed evenly distributed boulders. The fine-grain material appears to be part of a high-latitude mantle comprising material swept south of the pole regions. The boulders, which are covered by distinctive deep pits, or vesicles, may be the residue of an ejecta deposit from the crater Mie. Alternatively, they may be the remnants of lava flows which formerly covered the region. Polygonal sediment-filled cracks may have been formed by ice wedging, similar to the process that occurs in terrestrial permafrost regions. The possibility that they are desiccation polygons may not be excluded.

Mutch, T. A.↗

NASA NTRS1977

Geologic interpretation of new observations of the surface of Venus

New radar observations of the surface of Venus provide further evidence of a diverse and complex geologic evolution. The radar bright feature 'Beta' (24 deg N, 85 deg W) is seen to be a 700 km diameter region elevated a maximum of approximately 10 km relative to its surroundings with a 60 x 90 km wide depression at its summit. 'Beta' is interpreted to be a large volcanic construct, analogous to terrestrial and Martian shield volcanoes. Two large, quasi-circular areas of low reflectivity, examples of a class of features interpreted to be impact basins by previous investigators who were without the benefit of actual topographic information, are shown in altimetry maps to be depressions. Thus the term 'basin' can be applied, although we urge a non-genetic usage until more complete understanding of their origin is achieved through analysis of future observations.

Saunders, R. S.↗