A dynamic model of the frequency-dependent rupture process of the 2011 Tohoku-Oki earthquake
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.
© 2013 The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB. Received December 27, 2011; Revised May 7, 2012; Accepted May 17, 2012; Online published January 28, 2013. This work was supported by NSF grants EAR-0944288 and EAR-1015704, the Gordon and Betty Moore Foundation and SCEC (funded by NSF EAR-0106924 and USGS 02HQAG0008 cooperative agreements). We thank Wenbo Wu for generating the Green's functions for our synthetic tests, and Surendra Somala for generating the meshes for our dynamic rupture simulations.