Publication Date:
2016-09-09
Description:
Large coseismic slip was thought to be unlikely to occur on the shallow portions of plate-boundary
thrusts, but the 11 March 2011 Tohoku-Oki earthquake [moment magnitude (Mw) = 9.0] produced
huge displacements of ~50 meters near the Japan Trench with a resultant devastating tsunami.
To investigate the mechanisms of the very large fault movements, we conducted high-velocity
(1.3 meters per second) friction experiments on samples retrieved from the plate-boundary
thrust associated with the earthquake. The results show a small stress drop with very low peak
and steady-state shear stress. The very low shear stress can be attributed to the abundance
of weak clay (smectite) and thermal pressurization effects, which can facilitate fault slip.
This behavior provides an explanation for the huge shallow slip that occurred during the
earthquake.
Type:
Article
,
PeerReviewed
Format:
text
Format:
text