Automatic Imaging the Rupture Process of the 2014 South Napa Earthquake by Iterative Deconvolution and Stacking the Strong-motion Data

The 2014 South Napa earthquake was well recorded by a densely distributed strong-motion network. By using the automatic iterative deconvolution and stacking (IDS) method, we invert data of strong-motion networks with different apertures and station spacings for rupture processes, in order to examine the influences of networks on the rupture models. By performing a series of inversions, we have found that networks, with apertures more than 60 km and station spacings less than 10 km, are sufficient to imaging the rupture process of the South Napa earthquake. The automatically estimated rupture models of different networks are consistent with each other; all of them suggest that the ruptures mainly propagated to the north and to shallow depths, and formed a unilateral rupture event. The peak slip of this earthquake is about 0.5-0.7 m, located near the ground surface and about 5 km to the north of the epicenter.

This work suggests that, with the IDS method, it is feasible in principle to automatically estimate the earthquake rupture process after the earthquake occurrence. This would be beneficial to the earthquake emergency responses, such as earthquake relief and disaster mitigations.