open access

https://hdl.handle.net/2115/66865

Depth variations in seismic velocity in the subducting crust : Evidence for fluid-related embrittlement for intermediate-depth earthquakes

英語

fluid-related embrittelment

2017-01-28

American Geophysical Union

Geophysical research letters

44(2)

810-817

We investigated seismic wave velocity in the subducting crust of the Pacific slab beneath eastern Hokkaido, northern Japan. To detect depth-dependent properties of the seismic velocities in the crust, we analyzed guided waves that propagate in the crust and estimated P wave velocity (V-p) of 6.5-7.5km/s and S wave velocity (V-s) of 3.6-4.2km/s at depths of 50-100km. The results show that the obtained V-p and V-s are 10-15% lower than those expected for the fully hydrated mid-ocean ridge basalt, suggesting the existence of aqueous fluids by similar to 1 vol % in the crust at this depth range. Our observations suggest that overpressurized fluids channeled in the subducting crust plays as a dominant factor for facilitating the genesis of crustal earthquakes at intermediate depths.

学術雑誌論文

Version of Record

An edited version of this paper was published by AGU. Copyright 2017 American Geophysical Union. Shiina, T., J. Nakajima, T. Matsuzawa, G. Toyokuni, and S. Kita (2017), Depth variations in seismic velocity in the subducting crust: Evidence for fluid- related embrittlement for intermediate- depth earthquakes, Geophys. Res. Lett., 44, 810–817, doi:10.1002/ 2016GL071798. To view the published open abstract, go to http://dx.doi.org and enter the DOI.

0094-8276