Stress triggering in thrust and subduction earthquakes and stress interaction between the southern San Andreas and nearby thrust and strike‐slip faults

Abstract

[1] We argue that key features of thrust earthquake triggering, inhibition, and clustering can be explained by Coulomb stress changes, which we illustrate by a suite of representative models and by detailed examples. Whereas slip on surface-cutting thrust faults drops the stress in most of the adjacent crust, slip on blind thrust faults increases the stress on some nearby zones, particularly above the source fault. Blind thrusts can thus trigger slip on secondary faults at shallow depth and typically produce broadly distributed aftershocks. Short thrust ruptures are particularly efficient at triggering earthquakes of similar size on adjacent thrust faults. We calculate that during a progressive thrust sequence in central California the 1983 M w = 6.7 Coalinga earthquake brought the subsequent 1983 M w = 6.0 Nuñez and 1985 M w = 6.0 Kettleman Hills ruptures 10 bars and 1 bar closer to Coulomb failure. The idealized stress change calculations also reconcile the distribution of seismicity accompanying large subduction events, in agreement with findings of prior investigations. Subduction zone ruptures are calculated to promote normal faulting events in the outer rise and to promote thrust-faulting events on the periphery of the seismic rupture and its downdip extension. These features are evident in aftershocks of the 1957 M w = 9.1 Aleutian and other large subduction earthquakes. We further examine stress changes on the rupture surface imparted by the 1960 M w = 9.5 and 1995 M w = 8.1 Chile earthquakes, for which detailed slip models are available. Calculated Coulomb stress increases of 2-20 bars correspond closely to sites of aftershocks and postseismic slip, whereas aftershocks are absent where the stress drops by more than 10 bars. We also argue that slip on major strike-slip systems modulates the stress acting on nearby thrust and strike-slip faults. We calculate that the 1857 M w = 7.9 Fort Tejon earthquake on the San Andreas fault and subsequent interseismic slip brought the Coalinga fault $1 bar closer to failure but inhibited failure elsewhere on the Coast Ranges thrust faults. The 1857 earthquake also promoted failure on the White Wolf reverse fault by 8 bars, which ruptured in the 1952 M w = 7.3 Kern County shock but inhibited slip on the left-lateral Garlock fault, which has not ruptured since 1857. We thus contend that stress transfer exerts a control on the seismicity of thrust faults across a broad spectrum of spatial and temporal scales.INDEX TERMS: 7209 Seismology: Earthquake dynamics and mechanics; 7230 Seismology: Seismicity and seismotectonics; 7223 Seismology: Seismic hazard assessment and prediction; 8164 Tectonophysics: Stresses-crust and lithosphere; 8123 Tectonophysics: Dynamics, seismotectonics; KEYWORDS: earthquake triggering, thrust and subduction earthquakes, stress transfer, fault interaction, blind thrust, San Andreas Fault Citation: Lin, J., and R. S. Stein (2004), Stress triggering in thrust and subduction earthquakes and stress interaction between the southern San Andreas and nearb...

The 2011 Mw 7.1 Van (Eastern Turkey) earthquake

“…Given that the surface trace of the fault is clearly visible in the geomorphology of the mountain range to the north of Van (Figure 3) and that fault gouge was found in Quaternary sediments at the surface (Figure 4), it is very likely that the upper portion of the crust is seismogenic. The change in Coulomb stress [Lin and Stein, 2004] is predicted to have brought this upper section of the fault closer to failure (Figure 16) across the remaining unruptured fault width of 10 km, with a similar average slip of 3 m, would yield a scalar moment of 3 10 19 Nm, equivalent to a M w 6.9 earthquake. The shallower nature of such a rupture could potentially have a greater impact on Van.…”

Patterns and mechanisms of coseismic and postseismic slips of the 2011 M W 7.1 Van (Turkey) earthquake revealed by multi-platform synthetic aperture radar interferometry

“…Particularly, slip on blind thrust faults can significantly increase stress above the source fault and in other nearby zones (Lin and Stein, 2004). Driven by the coseismic stress, a fault may creep aseismically (Barbot et al, 2009).…”

Shallow inland earthquakes in NE Japan possibly triggered by the 2011 off the Pacific coast of Tohoku Earthquake

“…We also assume the rake from each focal mechanism. We adopted the Coulomb 3.2 (Lin and Stein, 2004;Toda et al, 2005), assuming a frictional coefficient of 0.65. We calculate the static stress on each fault in a uniform and isotropic elastic half-space following Okada (1992).…”

“…In this study, we have investigated, in detail, hypocenter distributions of several events that occurred after the M w 9.0 earthquake in order to discriminate the fault plane from the auxiliary plane of the focal mechanism. We then calculated the Coulomb stress change (Lin and Stein, 2004;Toda et al, 2005) on each fault attributable to the 2011 M w 9.0 Tohoku Earthquake to explore whether or not they were likely triggered by the M w 9.0 event.…”