The relation with seismic coupling and outer-rise event
Speaker: Hsin-Hua Lee
Date:2012/11/29Abstract
Seismic coupling means that the lock in the interface of the plate, so if the plate locked tightly to each plates be called strong coupling, it will invoke great earthquakes. The reason is that the strength of coupling between upper and down going plates may be determined as the area of contact and stress on the contact zone. Since large thrust earthquakes along subduction zones represent a stress release on these contact zones, the seismic moment magnitude (Mw) can be related to the strength of coupling.
Seismic coupling is the major factor controlling the size of the largest event. Coupling in the subduction will affect the regional intraplate stress. By the researcher of Hank 1971 and so on, their model show that large regional stress match with the outer-rise profile. Then, give you an idea about the how outer-rise events affect in the different coupling zone.
We introduce the definition be called outer-rise events. It occurs in the oceanic plates and there stress axes most horizontal or perpendicular to the trench. There are two kinds of the outer-rise events. One is the extensional outer-rise events imply the normal earthquake; other is the compressional outer-rise evens indicate the thrust earthquake.
In uncoupled region, we could find out the normal earthquake all along the trench. In the coupled region, two kinds of events will discover. Find out that the thrust events before the great earthquake; otherwise the normal events after the great earthquakes.
To sum up the ideals, we could assume that seismic coupling correlated with the outer-rise events.
References
Ruff, L. and Kanamori, H., Seismicity and the subduction process, Physics of the Earth and Planetary Interiors, 23 (1980) 240-252.
Christensen, D. H. and Ruff, L. , Seismic coupling and outer rise earthquakes, Journal of Geophysical research, 1988, vol. 93, NO. B11, 13421-13444.<full text>