Earth Planets Space, Vol. 64 (No. 12), pp. 1061-1066, 2012
Yihe Huang, Lingsen Meng, and Jean-Paul Ampuero
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, U.S.A.
(Received December 27, 2011; Revised May 7, 2012; Accepted May 17, 2012; Online published January 28, 2013)
We present a 2D dynamic rupture model that provides a
physical interpretation of the key features of the 2011 Tohoku-Oki
earthquake rupture. This minimalistic model assumes linear
slip-weakening friction, the presence of deep asperities and
depth-dependent initial stresses. It reproduces the first-order
observations of the along-dip rupture process during its initial
100 s, such as large static slip and low-frequency radiation up-dip
from the hypocenter, and slow rupture punctuated by high-frequency
radiation in deeper regions. We also derive quantitative
constraints on the ratio of shallow versus deep radiation from
teleseismic back-projection source imaging. This ratio is explained
in our model by the rupture of deep asperities surrounded by low
stress drop regions, and by the decrease of initial stresses
towards the trench.
Key words: Dynamic rupture model, Tohoku earthquake, back projection, high-frequency radiation, deep asperities.