Compressive sensing of the Tohoku‐Oki Mw 9.0 earthquake: Frequency‐dependent rupture modes

[1] 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 United States. The seismic sources are located by minimizing the ‘2‐norm of the difference between the observed and modeled waveforms penalized by the ‘1‐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 updip region, which may be caused by differences in rupture behavior (more intermittent or continuous) at the slab interface due to heterogeneous frictional properties. Citation: Yao, H., P. Gerstoft, P. M. Shearer, and C. Mecklenbräuker (2011), Compressive sensing of the Tohoku‐OkiMw9.0 earthquake: Frequency‐ dependent rupture modes, Geophys. Res. Lett., 38, L20310, doi:10.1029/2011GL049223.