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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Analysis of tectonic features in US southwest from Skylab photographs

The author has identified the following significant results. Skylab photographs were utilized to study faults and tectonic lines in selected areas of the U.S. Southwest. Emphasis was on elements of the Texas Zone in the Mojave Desert and the tectonic intersection in southern Nevada. Transverse faults believed to represent the continuation of the Texas Zone were found to be anomalous in strike. This suggests that the Mojave Desert block was rotated counterclockwise as a unit with the Sierra Nevada. Left-lateral strike-slip faults in Lake Mead area are interpreted as elements of the Wasatch tectonic zone; their anomalous trend indicates that the Lake Mead area has rotated clockwise with the Colorado Plateau. A tectonic model relating major fault zones to fragmentation and rotation of crustal blocks was developed. Detailed correlation of the high resolution S190B metric camera photographs with U-2 photographs and geologic maps demonstrates the feasibility of utilizing S190B photographs for the identification of geomorphic features associated with recent and active faults and for the assessment of seismic hazards.

Abdel-Gawad, M.↗
NASA NTRS1971

Mechanism of underthrusting in southwest Japan: A model of convergent plate interactions

An elastic rebound mechanism consistent with underthrusting at the time of the magnitude 8.2 Nankaido earthquake of 21 December, 1946 accounts for a reversal in sense between seismic and preseismic changes in elevation throughout a large portion of southwest Japan. It is shown that the seismic movements during the earthquake were generated by slip on a complex thrust fault that is inferred to intersect the surface near the base of the continental slope. The preseismic deformation is explained by strain accumulation equivalent to a virtual dislocation with the same orientation as the fault surface but a sense opposite to that of the real dislocation that occurred at the time of the earthquake. Adjustments by slip along the fault surface and extensions of that surface can account for postseismic movements.

Fitch, T. J.↗
NASA NTRS2012

Plate Margin Deformation and Active Tectonics Along the Northern Edge of the Yakutat Terrane in the Saint Elias Orogen, Alaska and Yukon, Canada

The northwest directed motion of the Pacific plate is accompanied by migration and collision of the Yakutat terrane into the cusp of southern Alaska. The nature and magnitude of accretion and translation on upper crustal faults and folds is poorly constrained, however, due to pervasive glaciation. In this study we used high-resolution topography, geodetic imaging, seismic, and geologic data to advance understanding of the transition from strike-slip motion on the Fairweather fault to plate margin deformation on the Bagley fault, which cuts through the upper plate of the collisional suture above the subduction megathrust. The Fairweather fault terminates by oblique-extensional splay faulting within a structural syntaxis, allowing rapid tectonic upwelling of rocks driven by thrust faulting and crustal contraction. Plate motion is partly transferred from the Fairweather to the Bagley fault, which extends 125 km farther west as a dextral shear zone that is partly reactivated by reverse faulting. The Bagley fault dips steeply through the upper plate to intersect the subduction megathrust at depth, forming a narrow fault-bounded crustal sliver in the obliquely convergent plate margin. Since . 20 Ma the Bagley fault has accommodated more than 50 km of dextral shearing and several kilometers of reverse motion along its southern flank during terrane accretion. The fault is considered capable of generating earthquakes because it is linked to faults that generated large historic earthquakes, suitably oriented for reactivation in the contemporary stress field, and locally marked by seismicity. The fault may generate earthquakes of Mw <= 7.5.

Bruhn, Ronald L.↗
NASA NTRS1986

The structure of the Ishtar Terra central and eastern parts and some tectonic problems of Venus

Moving from the Maxwell Montes to the eastern edge of Ishtar Terra there is a gradual shift in submeridional meandering folded ranges in the western section of the area to straight intersecting disjunctive systems of connected faults and sublatitudinal shifts. These disjunctive systems evidently transform older structures; the major axis of the stresses created by them is primarily oriented sublatitudinally. Relative to younger structures, in the western they occupy a higher hypsometric position. The reason for the formation of this entire system may be a large astenospheric flow wihch rise in the region of Lakashmi Planum and Maxwell Montes and which spreads and plunges in an easterly direction, taking with it deformed blocks of the lithosphere.

Bazilevskiy, A. T.↗
NASA NTRS1988

Tectonic history of the Syria Planum province of Mars

Several new, as well as existing, techniques are employed here to unravel the complex structural history of the Syria Planum province of Mars. Individual faults are first recognized as members of local or extensive fault sets related to distinct tectonic episodes. The relative ages of these fault sets are determined using superposition and intersection relations and crater counts. Correlations are also made with local geology and topography. Morphological characteristics of the fault scarps are measured photoclinometrically from Viking orbiter images and the way that variations in fault morphology are related to tectonic style, thickness of the faulted layer, and amount of extension is interpreted. The overall results present a more complete and coherent, as well as a different, tectonic history for this province than previously attained. The results show that geophysical interpretations of the Tharsis tectonic region require reevaluation.

Tanaka, Kenneth L.↗
NASA NTRS1984

The origin and evolution of terrestrial and Martian rock labyrinths

The morphological characteristics and evolutionary development of rock labyrinths on Earth (in sandstone, volcanics, and carbonates) are compared with those on Mars. On Earth rock labyrinths originate as parallel, an echelon, or intersecting narrow grabens, or develop where fault and joint networks are selectively eroded. Labyrinths frequently contain both downfaulted and erosional elements. Closed labyrinths contain depressions; open labyrinths do not, they are simple part of a fluvial network generally of low order. As closed labyrinths made up of intersecting grabens or made up of connected erosional depressions are extremely common on Mars, the research focussed on an understanding of these labyrinth types. Field investigations were carried out in Canyonlands National Park, Utah, and in the Chirachahua Mountains of Arizona. Martian labyrinths were investigated using Viking orbiter images. In addition, research was undertaken on apparent thermokarst features in Lunae Planum and Chryse Planitia where closed depressions are numerous and resemble atlas topography.

Brook, G. A.↗
NASA NTRS1993

A structural origin for the cantaloupe terrain of Triton

Cantaloupe terrain is unique to Triton. It is Triton's oldest terrain and includes about 250,000 km sq. region displaying sparsely cratered, closely spaced, nearly circular dimples about 30-40 km across. This terrain is found on no other planet because, only on Triton the final major global thermal pulse (1) caused completed (or nearly) interior melting resulting in a cooling history where large thermal stresses shattered and contorted a thin, weak lithosphere, and (2) occurred after heavy bombardment so that the surface features were preserved. The cantaloupe terrain is composed of intersecting sets of structures (folds and/or faults) that have developed as a result of global compression generated by volumetric changes associated with cooling of Triton's interior. Further, it is proposed that these structures developed after the period of heavy bombardment, and resulted from the last major global thermal epoch in Triton's unique history (either caused by tidal or radio metric heating). Initially, as the body cooled and the structures formed, their surface topography was most likely modified by thermal relaxation of the warm surface ices. In other bodies like Mercury, thermal stresses generated from global cooling and contraction have resulted in widely spaced thrust faults, whereas on Triton, thermal stresses produced more closely-spaced folds and faults sets. This difference in structural style is probably due to differences in lithospheric properties (thickness, strength, etc.), the magnitude of stress (directly dependent on the thermal history), and when the structures formed, relative to the period of heavy bombardment.

Boyce, Joseph M.↗
DOE OSTI2021

Complex Fault Geometry of the 2020 M ww 6.5 Monte Cristo Range, Nevada, Earthquake Sequence

On 15 May 2020 an M ww 6.5 earthquake occurred beneath the Monte Cristo Range in the Mina Deflection region of western Nevada. Rapid deployment of eight temporary seismic stations enabled detailed analysis of its productive and slowly decaying aftershock sequence (p=0.8), which included ~18,000 autodetected events in 3.5 months. Double-difference, waveform-based relative relocation of 16,714 earthquakes reveals a complex network of faults, many of which cross the inferred 35-km-long east–northeast-striking, left-lateral mainshock rupture. Seismicity aligns with left-lateral, right-lateral, and normal mechanism moment tensors of 128 of the largest earthquakes. The mainshock occurred near the middle of the aftershock zone at the intersection of two distinct zones of seismicity. In the western section, numerous subparallel, shallow, north-northeast-striking faults form a broad flower-structure-like fault mesh that coalesces at depth into a near-vertical, left-lateral fault. We infer the near-vertical fault to be a region of significant slip in the mainshock and an eastward extension of the left-lateral Candelaria fault. Near the mainshock hypocenter, seismicity occurs on a northeast-striking, west-dipping structure that extends north from the eastern Columbus Salt Marsh normal fault. Together, these two intersecting structures bound the Columbus Salt Marsh tectonic basin. East of this intersection and the mainshock hypocenter, seismicity occurs in a narrow, near-vertical, east-northeast-striking fault zone through to its eastern terminus. At the eastern end, the aftershock zone broadens and extends northwest toward the southern extension of the northwest-striking, right-lateral Petrified Springs fault system. The eastern section hosts significantly fewer aftershocks than the western section, but has more moment release. We infer that shallow aftershocks throughout the system highlight fault-fracture meshes that connect mapped fault systems at depth. Here, comparing earthquake data with surface ruptures and a simple geodetic fault model sheds light on the complexity of this recent M 6.5 Walker Lane earthquake.

58 GEOSCIENCES↗
NASA NTRS1975

Identification and interpretation of tectonic features from Skylab imagery

The author has identified the following significant results. The fault pattern in the southern Nevada tectonic intersection and adjacent Mojave block was found to be consistent with a model partly suggested by Hamilton and Myers (1966). The model has the following basic elements: (1) a major Laramide left-lateral shear on the Texas Zone, (2) counterclockwise rotation of the Sierra Nevada-Klamath Mountain block, (3) clockwise rotation of the Colorado Plateau, and (4) crustal extension and intrusion of volcanics in Nevada.

Abdel-Gawad, M.↗
NASA NTRS1985

Geometric and chronologic evolution of the Verde and Payson Basins of Central Arizona and possible relationships to detachment faulting

The Transition Zone of Arizona and the structural basins therein have been poorly understood features from a structural standpoint. This is true both of their overall geometry as well as their formation. Yet these basins have developed within the last 13 million years and thus represent perhaps the most recent phase of development related to the extensional tectonics of the Basin and Range province. Recent work (Smith, 1984; Vance, 1983) as well as some older studies (Anderson and Creasy, 1985; Pedersen and Royce, 1970) provide data on the geometry of the Verde and Payson basins which can be used to constrain some hypotheses related to the development of these basins. The work of Cloos (1868), Anderson et. al. (1983), Wernicke and Burchfiel (1982) and Davis et. al. (l980) suggest a spatial and chronologic relation exists between planar high angle normal faults and low angle detachment faults. Perhaps one of the clearest examples from the Basin and Range area appears to be from seismic reflection profiles of the Sevier Desert Basin area of Utah (Fig. 1). These profiles suggest the existence fault-controlled extension basin development above it. Faults that appear either listric or planar intersect it from above.

Brumbaugh, D. S.↗
NASA NTRS1973

Structural lineaments of Gaspe from ERTS imagery

A test study was conducted to assess the value of ERTS images for mapping geologic features of the Gaspe Peninsula, Quebec. The specific objectives of the study were: 1) to ascertain the best procedure to follow in order to obtain valuable geologic data as a result of interpretation; and 2) to indicate in which way these data could relate to mineral exploration. Of the four spectral bands of the Multispectral scanner, the band from 700 to 800 nanometers, which seems to possess the best informational content for geologic study, was selected for analysis. The original ERTS image at a scale of 1:3,700,000 was enlarged about 15 times and reproduced on film. Geologically meaningful lines, called structural lineaments, were outlined and classified according to five categories: morpho-lithologic boundaries, morpho-lithologic lineaments, fault traces, fracture zones and undefined lineaments. Comparison with the geologic map of Gaspe shows that morpho-lithologic boundaries correspond to contacts between regional stratigraphic units. Morpholithologic lineaments follow bedding trends, whereas fracture traces appear as sets of parallel lineaments, intersecting at high angles the previous category of lineaments. Fault traces mark more precisely the location of faults already mapped and spot the presence of presumable faults, not indicated on the geologic map.

Steffensen, R.↗
NASA NTRS1992

Distributed traffic signal control using fuzzy logic

We present a distributed approach to traffic signal control, where the signal timing parameters at a given intersection are adjusted as functions of the local traffic condition and of the signal timing parameters at adjacent intersections. Thus, the signal timing parameters evolve dynamically using only local information to improve traffic flow. This distributed approach provides for a fault-tolerant, highly responsive traffic management system. The signal timing at an intersection is defined by three parameters: cycle time, phase split, and offset. We use fuzzy decision rules to adjust these three parameters based only on local information. The amount of change in the timing parameters during each cycle is limited to a small fraction of the current parameters to ensure smooth transition. We show the effectiveness of this method through simulation of the traffic flow in a network of controlled intersections.

Chiu, Stephen↗
NASA NTRS1973

Tectonic mapping in Alaska with ERTS-1 imagery

The author has identified the following significant results. A mosaic of ERTS-1 imagery for a portion of interior Alaska covering approximately 57,000 sq km has proved to be a valuable tool in identifying structural elements previously not recognized. Mapped faults are clearly recognizable and are found to be part of a larger system of faults and lineaments identified on the imagery. A previously unrecognized set of conjugate fractures imply regional compression in a NNW-SSE direction in agreement with known fault dislocations. Earthquakes have a marked tendency to occur at intersections of lineaments seen on the imagery.

Gedney, L. D.↗
NASA NTRS1981

Modification of multi-ring basins - The Imbrium model

It is shown that the gross variations in wall height around Imbrium result largely from intersection of the Imbrium basin with pre-existing basins and faulting: angle of impact and slumping played a lesser modifying role. The gross irregularities in plan of the northern part of Imbrium is hypothesized to result from the collapse of large crustal blocks into the Imbrium and Serenitatis cavities. Lithosphere thickness is believed to play an important role in the mechanisms of formation and modification of large craters and basins. The deduction of slow sub-lithospheric flow of material toward the cavity centers does not lend support to the tsunami model, requires a minor modification of the nested-crater model and provides a mechanism for the production of megaterraces. Spatial and temporal lithosphere variations satisfy constraints requiring the overlap of morphology/diameter characteristics, variable onset diameters between planets, variable ring spacings from planet to planet and provide a mechanism for producing local irregularities in ring structures.

Whitford-Stark, J. L.↗
NASA NTRS1972

Evaluation of feasibility of mapping seismically active faults in Alaska

The author has identified the following significant results. A previously unmapped seismically active fault has been identified in south-central Alaska on the basis of ERTS-1 imagery. It can be traced for at least 120 km. An unmapped fault was found on the northwest flank of Mt. Sanford that is apparently a reverse fault. A large scale, seismically active fracture system has been identified in central Alaska on the basis of MSS imagery. The system consists of two sets of fractures which intersect at an angle of about 55 degrees. The dominant feature of the system is the Minook Creek fault, on which an earthquake of magnitude 6.5 occurred on October 29, 1968. A possible related feature is a 60 km long lineament near the Toklat River north of Mt. McKinley. These areas are all moderately seismically active. Focal mechanism studies of the 1968 earthquake revealed that left-lateral displacement had occurred on the Minook Creek fault due to compressive stress. A similarly oriented direction of compressive stress could be responsible for the entire fracture system.

Gedney, L. D.↗
NASA NTRS1973

Evaluation of commercial utility of ERTS-A imagery in structural reconnaissance for minerals and petroleum

The author has identified the following significant results. In areas 2 and 3 (Colorado and New Mexico - Texas) continuing correlations are observed between lineaments selected from the ERTS imagery and known fault and fracture zones. There continues to be a correlation between lineament intersectional areas and known mining areas. Initial contacts with mining and/or petroleum companies regarding the use of ERTS-1 imagery as an interpreted medium for guiding reconnaissance operations seems to indicate that the technology and economics will be commercially acceptable for initial investigatory investments.

Saunders, D. F.↗
NASA NTRS1974

Structural lineaments in the southern Sierra Nevada, California

The author has identified the following significant results. Several lineaments observed in ERTS-1 MSS imagery over the southern Sierra Nevada of California have been studied in the field in an attempt to explain their geologic origins and significance. The lineaments are expressed topographically as alignments of linear valleys, elongate ridges, breaks in slope or combinations of these. Natural outcrop exposures along them are characteristically poor. Two lineaments were found to align with foliated metamorphic roof pendants and screens within granitic country rocks. Along other lineaments, the most consistant correlations were found to be alignments of diabase dikes of Cretaceous age, and younger cataclastic shear zones and minor faults. The location of several Pliocene and Pleistocene volcanic centers at or near lineament intersections suggests that the lineaments may represent zones of crustal weakness which have provided conduits for rising magma.

Liggett, M. A.↗
NASA NTRS1988

Lunar mare ridges - Analysis of ridge-crater intersections and implications for the tectonic origin of mare ridges

Models proposed for the origin of lunar mare ridges belong to one of the three categories: volcanic, tectonic, and a combination of volcanic and tectonic. This paper presents the results of an analysis of ridge-crater intersections in Oceanus Procellarum and Maria Cognitum, Imbrium, and Serenitatis and examines the range of fault attitudes and displacements associated with mare ridge development. The results indicate tectonic, rather than volcanic, involvement. The evidence cited to support a volcanic origin for mare ridges is reassessed. In addition, plausible end-member tectonic models are presented.

Sharpton, Virgil L.↗