25 This is a second paper in a study of statistical identification and classification of 26 earthquake clusters using a relocated catalog of 1981-2011 seismicity in southern 27 California and synthetic catalogs produced by the ETAS model. Here we focus on 28 classification of event families – statistically significant clusters comprised of foreshocks, 29 mainshocks and aftershocks – that are de...

[1] A fundamental question in earthquake physics is whether aftershocks are predominantly triggered by static stress changes (permanent stress changes associated with fault displacement) or dynamic stresses (temporary stress changes associated with earthquake shaking). Both classes of models provide plausible explanations for earthquake triggering of aftershocks, but only the static stress mode...

We estimate the rate of aftershocks triggered by a heterogeneous stress change, using the rate-and-state model of Dieterich [1994]. We show than an exponential stress distribution P (τ) ∼ exp(−τ/τ0) gives an Omori law decay of aftershocks with time ∼ 1/t, with an exponent p = 1−Aσn/τ0, where A is a parameter of the rate-and-state friction law, and σn the normal stress. Omori exponent p thus dec...

Major earthquakes were followed by a large number of aftershocks and significant outbreaks of dizziness occurred over a large area. However it is unclear why major earthquake causes dizziness. We conducted an intergroup trial on equilibrium dysfunction and psychological states associated with equilibrium dysfunction in individuals exposed to repetitive aftershocks versus those who were rarely e...

Initiation, Response, and Feedback(IRF) sequences are the most frequent interaction network in any classroom contexts. IRF sequences have been examined profusely in previous studies and were reported to be negatively correlated with participation opportunities (Kasper, 2006; Cazden, 2001; Ellis, 1994).In all these studies, all contingent factors of any classroom context which might influence in...

[1] This is a second paper in a study of statistical identification and classification of earthquake clusters using a relocated catalog of 1981–2011 seismicity in southern California and synthetic catalogs produced by the Epidemic Type Aftershock Sequence model. Here we focus on classification of event families—statistically significant clusters composed of foreshocks, mainshocks, and aftershoc...

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...

The (Mw6.1, 7.3, 6.2) 1992 Landers earthquakes began on April 23 with the Mw6.1 1992 Joshua Tree preshock and form the most substantial earthquake sequence to occur in California in the last 40 years. This sequence ruptured almost 100 km of both surficial and concealed faults and caused aftershocks over an area 100 km wide by 180 km long. The faulting was predominantly strike slip and three mai...