[1] The September 25, 1999 Chi-Chi Taiwan aftershock (Mw=6.4) occurred on a down dip extension of the fault ruptured in the mainshock. Strong motion data were used to invert for the finite-source process and test for the causative fault plane. We performed a grid-search over a range of focal mechanisms and found a preferred model (strike=5 , dip=30 , slip=100 ) different from teleseismic studie...

The three principal New Madrid mainshocks of 1811–1812 were followed by extensive aftershock sequences that included numerous felt events. Although no instrumental data are available for either the mainshocks or the aftershocks, available historical accounts do provide information that can be used to estimate magnitudes and locations for the large events. In this article we investigate two of t...

Fault slip during plate boundary earthquakes releases a portion of the shear stress accumulated due to frictional resistance to relative plate motions. Investigation of 101 large [moment magnitude (Mw) ≥ 7] subduction zone plate boundary mainshocks with consistently determined coseismic slip distributions establishes that 15 to 55% of all master event-relocated aftershocks with Mw ≥ 5.2 are loc...

The rate- and state-dependent constitutive formulation for fault slip characterizes an exceptional variety of materials over a wide range of sliding conditions. This formulation provides a unified representation of diverse sliding phenomena including slip weakening over a characteristic sliding distance Dc, apparent fracture energy at a rupture front, time-dependent healing after rapid slip, an...

We analyze the spatial relationship of relocated aftershocks to the principal rupture planes of the Mw 7.3 1992 Landers mainshock from a structural point of view. We find that the aftershocks constitute primarily a several-kilometer-wide damage zone centered on the mainshock rupture planes. The intensity of damage decreases away from the principal faults. Less than half of the aftershocks occur...

[1] The 2011, Mw9.0 Tohoku earthquake was followed by an abundant amount of seismicity providing a unique opportunity to analyze the triggering mechanism of great earthquakes. Although the Tohoku earthquake occurred close to a dense seismic network, many aftershocks that occurred in the first few hours after the mainshock are not recorded in the earthquake catalogs. Here we use a template wavef...

Using the epidemic-type aftershock sequence (ETAS) branching model of triggered seismicity, we apply the formalism of generating probability functions to calculate exactly the average difference between the magnitude of a mainshock and the magnitude of its largest aftershock over all generations. This average magnitude difference is found empirically to be independent of the mainshock magnitude...

The empirical Bath’s law states that the average magnitude difference 〈∆m〉 between a mainshock and its largest aftershock is 1.2, regardless of the mainshock magnitude. We first point out that the standard interpretation of Bath’s law in terms of the two largest events of a self-similar set of independent events is incorrect, because it neglects the selection procedure entering the definition o...

We demonstrate that the statistics of earthquake data in the global Centroid Moment Tensor (CMT) and National Earthquake Information Center (NEIC) catalogs and local California Council of the National Seismic System (CNSS) catalog are consistent with the idea that a single physical triggering mechanism is responsible for the occurrence of aftershocks, foreshocks, and multiplets. Specifically, w...

Significant power-law long-range correlated structures have been identified in the Italian seismicity from 1983 to 2003. We performed the Allan Factor Analysis and the Detrended Fluctuation Analysis on both the full and the aftershock-depleted seismic data, extracted by the INGV (National Institute of Geophysics and Volcanology) instrumental catalog. Our findings suggest that (i) the time-scali...