A Reliable Way to Track Rupture Process of Earthquakes

Abstract:

Compressive sensing (CS) is an algorithm which could find the solution to a sparse linear problem, which is physically consist with inversion problem of rupture process. Because relative to the whole fault plane, the seismic power radiation area is sparse in a specific moment during a great earthquake. CS method is used to invert the rupture process from teleseismic P wave data recorded by multiple seismic arrays with different azimuths and epicentral distances. Synthetic tests illustrate that, our method can suppress the artifacts caused by interference phases ( eg. PcP ) thus we can obtain a more reliable result than using the data from a single array. Moreover, the “swimming effect” in traditional back-projection method can be reduced due to the better azimuth coverage. Then the rupture process of the Mw7.9 earthquake in the Aleutian Islands, occurred at June 23, 2014 20:53 UTC is inverted. The results show that the rupture is along the subduction zone, which can be used to locate the primary fault plane combined with central moment tensor. In addition, where the released power concentrates in the earthquake is also given, which could help us determine which area is effected by the earthquake most heavily, thus the rescue operation can be effective. In conclusion, different from traditional beamforming method, CS can offer a high-resolution solution.