Accelerating seismicity and stress accumulation before large earthquakes

Abstract

The stress field that existed before a large earthquake can be calculated based on the known source parameters of the event. This stress field can be used to define a region that shows greater seismic moment rate changes prior to the event than arbitrarily shaped regions, allowing us to link two previously unrelated subjects: Coulomb stress interactions and accelerating seismicity before large earthquakes. As an example, we have examined all M•_6.5 earthquakes in California since 1950. While we illustrate the model using seismicity in California, the technique is general and can be applied to any tectonically active region. We show that where sufficient knowledge of the regional tectonics exists, this method can be used to augment current techniques for seismic hazard estimation.

An 8 month slow slip event triggers progressive nucleation of the 2014 Chile megathrust

“…Two concurrent models have been proposed to explain the initiation of seismic rupture [Dodge et al, 1996]. A first model assumes that the accelerated moment release observed before large earthquakes [Bowman and King, 2001] is triggered by a slow slip event on the fault interface [Bouchon et al, 2013;Ruiz et al, 2014;Dodge et al, 1996]. Alternatively a slow cascade of failures eventually may trigger the main shock [Dodge et al, 1996].…”

Occurrence of Finite-Time Singularities in Epidemic Models of Rupture, Earthquakes, and Starquakes

“…Theoretical support has also come from simple computer models of critical rupture [9] and experiments of material rupture [10], cellular automata, with [11] and without [12] long-range interaction, and from granular simulators [13]. Models of regional seismicity with more faithful fault geometry have been developed that also show accelerating seismicity before large model events [14,15,16].There are at least five different mechanisms that are known to lead to critical accelerated seismicity of the formending at the critical time t c , where N (t) is the seismicity rate (or acoustic emission rate for material rupture). Such finite-time-singularities are quite common and have been found in many well-established models of natural systems, either at special points in space such as in the Euler equations of inviscid fluids, in vortex collapse of systems of point vortices, in the equations of General Relativity coupled to a mass field leading to the formation of black holes, in models of micro-organisms aggregating to form fruiting bodies, or in the more prosaic rotating coin (Euler's disk).…”

“…Theoretical support has also come from simple computer models of critical rupture [9] and experiments of material rupture [10], cellular automata, with [11] and without [12] long-range interaction, and from granular simulators [13]. Models of regional seismicity with more faithful fault geometry have been developed that also show accelerating seismicity before large model events [14,15,16].…”

“…Such finite-time-singularities are quite common and have been found in many well-established models of natural systems, either at special points in space such as in the Euler equations of inviscid fluids, in vortex collapse of systems of point vortices, in the equations of General Relativity coupled to a mass field leading to the formation of black holes, in models of micro-organisms aggregating to form fruiting bodies, or in the more prosaic rotating coin (Euler's disk). They all involve some kind of positive feedback, which in the rupture context can be the following (see [17] for a review): sub-critical crack growth [18], geometrical feedback in creep rupture [19], feedback of damage on the elastic coefficients with strain dependent damage rate [16], feedback in a percolation model of regional seismicity [17], feedback in a stress-shadow model for regional seismicity [15,17].While these mechanisms are plausible, their relevance to the earth crust remains unproven. Here, we present a novel mechanism leading to a new kind of critical stochastic finite-time-singularity in the seismicity rate, using the well-established epidemic-type aftershock sequence (ETAS) model for aftershocks, introduced by [20,21], based solely on the most solidly documented stylized facts of seismicity mentioned above.…”

A statistical feature of anomalous seismic activity prior to large shallow earthquakes in Japan revealed by the pattern informatics method

“…Therefore, investigation of temporal changes in seismic activity is essential to understand temporal variations in such stress and may, in turn, provide information regarding the possibility of occurrence of future large earthquakes. Temporal changes in seismic activity before large earthquakes have been reported for various regions including Alaska (Bufe et al, 1994;Kisslinger and Kindel, 1994), California (Bowman et al, 1998;Bowman and King, 2001;Bufe and Varnes, 1993;Jaume and Sykes, 1999;Papazachos et al, 2005;Resenberg and Matthews, 1988;Sobolev, 2003;Stuart, 1991;Sykes and Jaume, 1990), central Asia (particularly the IndiaEurasia collision zone; Zheng et al, 1995), China (Wei et al, 1978;Yu et al, 2011), Greece (Karakaisis et al, 2002;(Huang et al, 2001;Mogi, 1969;Nagao et al, 2011;Ogata, 2004Ogata, , 2005Resenberg and Matthews, 1988;Papazachos et al, 2010;Katsumata, 2011aKatsumata, , 2011b, Russia (Borovik et al, 1971), Taiwan (Chen, 2003;Chen et al, 2005Chen et al, , 2006Chen and Wu, 2006;Wu and Chiao, 2006;Wu and Chen, 2007;Wu et al, 2008aWu et al, , 2008bWu et al, , 2011, and Turkey (Öztürk and Bayrak, 2012).…”