[Back]

P. Gerstoft, H. Yao, P. M. Shearer, C. Mecklenbräuker:
"Compressive sensing of the Tohoku-Oki Mw9.0 Earthquake: Frequency-dependent Rupture Modes";
Talk: American Geophysical Union Fall Meeting 2011, San Francisco (CA), USA; 12-05-2011 - 12-09-2011.

For this complex earthquake rupture, we seek a sparse set of spatio-temporal source locations consistent with the measurements. Compressive sensing (CS) is a technique for finding sparse signal representations to underdetermined linear measurement equations. We use CS to locate seismic sources during the rupture of the 2011 Tohoku-Oki Mw9.0 earthquake in Japan from teleseismic P waves recorded by an array of stations in the US. The seismic sources are located by minimizing the L2-norm of the difference between the observed and modeled waveforms penalized by the L1-norm of the seismic source vector. The resulting minimization problem is convex and can be solved efficiently. Our results show clear frequency-dependent rupture modes with high-frequency energy radiation dominant in the down-dip region and low-frequency radiation in the up-dip region, which may be caused by differences in rupture behavior (more intermittently or continuously) at the slab interface due to heterogeneous frictional properties.