Stress field

About: Stress field is a research topic. Over the lifetime, 11926 publications have been published within this topic receiving 226417 citations.

Evolution of the stress field in southern California and triggering of moderate-size earthquakes: A 200-year perspective

Abstract: Changes in stress in southern California are modeled from 1812 to 2025 using as input (1) stress drops associated with six large (7.0 7.5) earthquakes through 1995 and (2) stress buildup associated with major faults with slip rates > 3 mm/yr as constrained by geodetic, paleoseismic, and seismic measurements. Evolution of stress and the triggering of moderate to large earthquakes are treated in a tensoffal rather than a scalar manner. We present snapshots of the cumulative Coulomb failure function (ACFF) as a function of time for faults of various strike, dip, and rake throughout southern California. We take ACFF to be zero everywhere just prior to the great shock of 1812. We find that about 95% of those well-located M > 6 earthquakes whose mechanisms involve either strike-slip or reverse faulting are consistent with the Coulomb stress evolutionary model; that is, they occurred in areas of positive ACFF. The interaction between slow-moving faults and stresses generated by faster-moving faults significantly advanced the occurrence of the 1933 Long Beach and 1992 Landers events in their earthquake cycles. Coulomb stresses near major thrust faults of the western and central Transverse Ranges have been accumulating for a long time. Future great earthquakes along the San Andreas fault, especially if the San Bernardino and Coachella Valley segments rupture together, can trigger moderate to large earthquakes in the Transverse Ranges, as appears to have happened in the Santa Barbara earthquake that occurred 13 days after the great San Andreas shock of 1812. Maps of current ACFF provide additional guides to long-term earthquake prediction.

The application of failure mode diagrams for exploring the roles of fluid pressure and stress states in controlling styles of fracture‐controlled permeability enhancement in faults and shear zones

Abstract: Geofluids (2010) 10, 217–233 Abstract Permeability enhancement associated with deformation processes in faults and shear zones plays a key role in facilitating fluid redistribution between fluid reservoirs in the crust. Especially in high fluid flux hydrothermal systems, fracture-controlled permeability can be relatively short-lived, unless it is repeatedly regenerated by ongoing deformation. Failure mode diagrams in pore fluid factor and differential stress space, here termed λ–σ failure mode diagrams, provide a powerful tool for analysing how fluid pressure and stress states drive failure, associated permeability enhancement and vein styles during deformation in faults and shear zones. During fault-valve behaviour in the seismogenic regime, relative rates of recovery of pore fluid factor, differential stress and fault cohesive strength between rupture events impact on styles of veining and associated, fracture-controlled permeability enhancement in faults and shear zones. Examples of vein-rich fault zones are used to illustrate how constraints can be placed, not just on fluid pressure and stress states at failure, but also on the fluid pressurization and loading paths associated with failure and transitory permeability enhancement in faults and shear zones. This provides insights about when, during the fault-valve cycle, various types of veins can form. The use of failure mode diagrams also provides insights about the relative roles of optimally oriented faults and misoriented faults as hydraulically conductive structures. The analysis highlights the dynamics of competition between fluid pressures and loading rates in driving failure and repeated permeability regeneration in fracture-controlled, hydrothermal systems.

Tectonic analysis of the Dead Sea Rift Region since the Late-Cretaceous based on mesostructures

Abstract: We have measured the orientations of small faults, slickensides, tectonic stylolites, vein with secondary mineralization, small folds and dikes in Israel and Sinai. These structures are indicators of paleo-stress or strain and provide the pattern of tectonic deformation. Data were collected at 130 stations, most with tens of separate measurements; most stations showed consistent deformation. Stations were located on exposures ranging from Precambrian crystalline rocks to Pleistocene sediments. We have defined two tectonic stress fields, each relatively uniform in both time and space. One stress field, with dominating maximum horizontal compression trending W to WNW, in the Late Cretaceous to Eocene rocks in the folds and plateaus west of the Dead Sea rift. The second field, with dominating horizontal extension trending E to ENE, in all rocks inside the rift and proximal thereto. The first stress field is called the Syrian Arc stress, and the second is called the Dead Sea stress. A change in style of tectonic deformation, which corresponds to the two stress fields, is manifested also in the major structures in Israel. The Late Cretaceous to Neogene deformation is characterized by long wavelength folds and monoclines, whereas the Neogene to Recent deformation is characterized by normal and strike slip faults and volcanic activity.