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Fault (geology)

About: Fault (geology) is a research topic. Over the lifetime, 26732 publications have been published within this topic receiving 744535 citations.


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Journal ArticleDOI
TL;DR: In this paper, the effects of shear heating and displacement of cool hanging-wall rocks against hotter footwall rocks are calculated, and the extent to which the features observed are able to explain seismic reflectivity of the lower crust is discussed.

158 citations

Journal ArticleDOI
TL;DR: The Atacama Fault Zone (AFZ) as mentioned in this paper is the dominant feature in the structure of the North Chilean Coastal Cordillera and left lateral displacement took place along its system of longitudinal faults during the Jurassic and early Cretaceous.

158 citations

Journal ArticleDOI
TL;DR: Fault-controlled accumulations in the hydropressured Tertiary section were studied in 10 Louisiana Gulf Coast salt basin fields located on low-relief structures as discussed by the authors.
Abstract: Fault-controlled accumulations in the hydropressured Tertiary section were studied in 10 Louisiana Gulf Coast salt basin fields located on low-relief structures. Investigations were limited to traps associated with faults which restrict vertical migration of hydrocarbons; that is, where an accumulation is in contact with the fault. The fault-lithology-accumulation relations observed are (1) fault sealing, with hydrocarbon-bearing sandstone in lateral juxtaposition with shale; (2) fault nonsealing to lateral migration, with parts of the same sandstone body juxtaposed within the hydrocarbon column; (3) fault nonsealing to lateral migration, with sandstone bodies of different ages juxtaposed within the hydrocarbon column; and (4) fault sealing, with sandstone bodies of diffe ent ages juxtaposed within the hydrocarbon column. In some places, these four relations are present at different levels along the same fault. In the examples studied, only faults nonsealing to lateral migration were observed where parts of the same sandstone body are juxtaposed across a fault. With sandstone bodies of different ages juxtaposed, some faults are sealing and others are nonsealing to lateral migration, but sealing faults are the most common. The fault seal apparently results from the presence of boundary fault-zone material emplaced along the fault by mechanical or chemical processes related directly or indirectly to faulting.

158 citations

Journal ArticleDOI
TL;DR: In this article, the authors provide a detailed analysis of the current stress regime of the actively extending northern Basin and Range province, using deformation data (focal mechanisms and fault slip studies), hydraulic fracturing in situ stress measurements, borehole elongation (breakouts) analyses, and alignment of young volcanic vents.
Abstract: Constraints on the current stress regime of the actively extending northern Basin and Range province are provided by deformation data (focal mechanisms and fault slip studies), hydraulic fracturing in situ stress measurements, borehole elongation (“breakouts”) analyses, and alignment of young volcanic vents. The integrated data indicate significant variations both in principal stress orientations and magnitudes. An approximately E-W least principal stress direction appears to characterize both the eastern and western margins of the Basin and Range province, whereas in the active interior parts of the province extension occurs in response to a least principal stress oriented NW to N60°W. The contrast in stress orientations between the province boundaries and in the interior suggests that along the margins the least principal stress direction may be locally controlled by the generally northerly trending profound lithospheric discontinuities associated with these margins. Active deformation along the southeastern and western province margins is characterized by a combination of strike-slip and normal faulting. Focal mechanisms along northeastern province margin (Wasatch front) and in central Nevada indicate a combination of normal and oblique-normal faulting. Temporal, regional, and depth-dependent variations in the relative magnitudes of the vertical and maximum horizontal stresses can explain much of the observed variations in deformation styles. However, some depth variation in faulting style inferred from focal mechanisms may be apparent and simply a function of the attitude of fault planes being reactivated. Evidence for significant temporal variation (or multiple cycles of variation) in relative stress magnitude comes from the Sierran front-Basin and Range boundary region where recent earthquakes are predominantly strike slip, whereas the profound relative vertical relief across the Sierra frontal fault zone in the last 9–10 m.y. implies a normal faulting stress regime. Using the best data on stress orientation, relative stress magnitudes are constrained from slip vectors of major earthquakes and young fault displacements. Analysis of well-constrained slip vectors in the Owens Valley, California, area indicate that large temporal variations in the magnitude of the approximately N-S oriented maximum horizontal stress are required to explain dominantly dip-slip and strike-slip offsets on subparallel faults. Similar faulting relations are observed throughout much of the boundary zone between the Basin and Range-Sierra Nevada (including the Walker Lane belt). Along the eastern province margin in the Wasatch front area in Utah, available data suggest that the maximum and minimum horizontal stresses may be approximately equal at depths of <4–5 km. Earthquake focal mechanisms in this area suggest more variability in relative magnitude of the two horizontal stresses with depth. Furthermore, superimposed sets of young fault striae along a segment of the Wasatch fault also indicate temporal variations of relative stress magnitudes. Sources of regional and temporal variations in the stress field may be linked to variable shear tractions applied to the base of the brittle crust related to intrusion, thermally induced flow, and the influence of the San Andreas plate boundary. Although difficult to date accurately, the fault slip data suggest that the temporal variations in relative magnitudes stress may occur on the time scale of both a single major earthquake cycle (1000–5000 years) and multiple earthquake cycles (10,000+ years).

158 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used mesoscale structures along a 32 km-long reach of the Yarkand River to document the tectonic evolution of the east flank of the Pamir salient.
Abstract: The Pamir salient defines the western end of the Himalayan-Tibetan orogen and has overthrust the Tarim-Tajik basin to the north by ∼300 km along a late Cenozoic, south-dipping intracontinental subduction zone. Field mapping, structural measurements, and analysis of mesoscale structures along a 32-km-long reach of the Yarkand River document the tectonic evolution of the east flank of this salient, between the North Pamir to the west and the Western Kunlun Shan to the east. The study area is cut by a set of four, north-northwest–striking, steeply dipping brittle faults. Microstructures and asymmetric outcrop- to map-scale folds indicate right slip along these faults. Between these structures, fault-bounded panels of Phanerozoic strata are deformed by en echelon folds with axes that trend more westerly than the adjacent faults, consistent with dextral transpression. The fault system described here extends for ∼350 km along the eastern flank of the Pamir salient. Transpressional right slip along this set of faults, here called the Kashgar-Yecheng transfer system, appears to have accommodated late Cenozoic separation of the North Pamir from the Western Kunlun Shan during south-directed intracontinental subduction beneath the leading edge of the Pamir salient. Correlation of major faults suggests total slip along the Kashgar-Yecheng transfer system is likely on the order of ∼280 km. This offset estimate implies long-term slip rates of 7–15 mm/a along the Kashgar-Yecheng transfer system when combined with previous sedimentologic, stratigraphic, and thermochronologic data that indicate deformation along the east flank of the Pamir started between the late Eocene and early Miocene. These results imply that the first-order structures on the western and eastern flanks of the Pamir are asymmetric: previous work has shown that deformation in the west was accommodated by anticlockwise vertical axis rotation of the Pamir over the eastern margin of the Tajik basin. This rotation is generally interpreted to reflect northwest-directed radial thrusting, in contrast to the transpressional right-slip transfer faulting on the east side reported here.

158 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20242
20234,903
202210,233
20211,417
2020998
2019966