TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 64 (No. 12), pp. 1061-1066, 2012

A dynamic model of the frequency-dependent rupture process of the 2011 Tohoku-Oki earthquake

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)

Abstract: 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.

Corresponding author E-mail: yihe@gps.caltech.edu

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