Seismic regime relaxation properties from in situ and laboratory dataстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
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Дата последнего поиска статьи во внешних источниках: 2 сентября 2014 г.
Аннотация:Aftershock sequences of earthquakes possess characteristic statistical properties. The intensity
decay in the aftershock flow with time obeys the Omori power law: with attenuation of the aftershock activity,
the recurrence plot slope
b
increases and the fractal dimension of the set of hypocenters
d
decreases. The origin
of aftershock sequences is traditionally related to the relaxation of the seismic regime initiated by the main
shock. Analysis of laboratory results obtained from relaxation simulation during fracture of rocks showed that
statistical relaxation properties are the same as those observed in perturbation modes of the fracture regime,
when a main shock source is absent. With steplike loading of a sample (when its deformation abruptly increases
and held afterward constant), each loading step gives rise to a sequence of acoustic events similar to aftershock
sequences. The properties of sequences of acoustic events examined by determining experimentally their times
and sources were found to be the same as in aftershock sequences of earthquakes: activity decay by the Omori
law, an increase in
b
, and a decrease in
d
. The inferred results indicate that the presence of a main shock is not
a necessary condition for the formation of relaxation processes similar to aftershock sequences. Such processes
are likely initiated by an abrupt change in a certain region of the stress field whose relaxation is characterized
by the aforementioned features of the transient seismicity regime. Main shocks typical of seismicity are only
one of the possible sources of local perturbations in the stress field.