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| Titel |
Coseismic and postseismic stress in the northern "Eastern California Shear Zone" over the past 150 years. |
| VerfasserIn |
Alessandro Verdecchia, Sara Carena |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250075388
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| Zusammenfassung |
| Diffuse plate boundary regions are characterized by a high rate of deformation, but
distributed over a wider zone when compared to plate boundary faults like the San Andreas
and the North Anatolian faults. In diffuse plate boundaries the space–time relationship
between activity on specific faults and the location of previous and subsequent events in the
region are not clear. The Eastern California Shear Zone (ECSZ) is part of such a diffuse
boundary. The purpose of our work is to determine how faults in the northern ECSZ
interact in terms of static stress transfer at different spatial and temporal scales.
Here we calculate the evolution of Coulomb stress in the northern ECSZ due to
coseismic and postseismic redistribution of static stress induced by moderate and large
(Mw -¥ 6) earthquakes, beginning with the 1872 Mw 7.8 Owens Valley event. Our
preliminary results show that the 1872 Owens Valley earthquake, the largest event to
have occurred in the region over the past 150 years, has a significant influence in
terms of coseismic and postseismic stress changes. This event produced significant
stress increase in northern Owens Valley, where seven Mw -¥ 6 earthquakes struck
between 1980 and 1986. Stress changes were significantly amplified by postseismic
relaxation. The total stress increase may have influenced the renewed activity of
the Long Valley Caldera resurgent dome. In turn, magmatic activity in the caldera
increased stress in the region of the 1980-1986 earthquake sequences. Several of the
1980-1986 events also appear to be connected to one another in terms of Coulomb stress
loading. Finally, we find that significant stress, in the order of 3-4 bars, has by now
accumulated on the White Mountains fault and the northern Death Valley fault, where no
historical events have been recorded. Both these faults are capable of producing
Mw -¥ 7 earthquakes. We are now working on improving our model in terms of fault
geometry and kinematics, and on extending it to the western Basin and Range. |
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