EASOt-AP: An open-source MATLAB package to estimate the seismic moment, rupture radius, and stress-drop of earthquakes from time-dependent P-wave displacements

Abstract

We developed a MATLAB package, to rapidly obtain the apparent EArthquake SOurce time function using the Average of near-source P-wave displacement records (EASOt-AP) and to estimate the source parameters of the seismic moment, the rupture radius, and the average static stress drop. The algorithm implemented in this package is based on a rapid and straightforward methodology that is recently developed by Zollo et al. (2021). To this purpose, EASOt-AP models a LPDT curve, which is the average P-wave displacement versus time in the logarithm scale. In this paper, the performance of the EASOt-AP has been shown by evaluating the strong motion data recorded in the near-source range of small magnitude events (2 = Mw ≤ 3) that occurred in the Irpinia region, southern Italy. The source parameters follow a self-similar, constant-stress-drop scaling with a relatively low average stress drop of about 01-0.2 MPa. This Tool is designed for an easy use, and all steps of data processing are performed completely within the numerical environment of MATLAB.