Dependence of Post Seismicity on Prior StressEnvironment, and It's Correlation with Earth Processes

Abstract:

The prediction of forthcoming earthquakes is crucial for
mitigation of seismic hazards, which remains unsuccessful
despite rigorous efforts. The correlation of post
seismicity with temporal variation of lithospheric stress
by precedent large earthquakes is examined. The Coulomb
stress changes of earthquakes with magnitudes greater
than 7.0 during 1976-2013 is calculated over the globe.
The seismicity in the following year is compared with the
induced Coulomb stress changes by earthquakes with
magnitudes of 7.0 or greater during 1976 to the previous
year. The seismicity of events with magnitude of 4 to 5
in the following year is found to be negatively
correlated with the cumulative Coulomb stress changes up
to previous year. In other words, high seismicity is
observed in regions of large negative cumulative Coulomb
stress changes. Such negative correlations are observed
feature is also observed in regions of positive Coulomb
stress changes. The observation suggests that regions
with weakly-discharged stress produce more seismicity to
compensate the cumulated energy in the media. The
correlation of Coulomb stress changes with physical
properties including plate velocities, plate ages, slab
dipping angles and heat flows is investigated. It is
observed that the largest stress drop occurs in plate
boundaries with high convergent speeds. Examples include
the 2010 M8.8 Maule earthquake, the 2004 M9.1
Sumatra-Andaman earthquake, and the 2011 M9.0 Tohoku-Oki
earthquake. It is observed that The cumulative Coulomb
stress changes have strong correlations with the plate
velocities and strain rates, while weak correlations with
the plate ages, slab dipping angles and heat flows. The
observation suggests that large stress accumulation may
occur at regions of high plate speeds where high
lithostatic strain rates are expected.