SCP parameters estimation for catalogs with uncertain seismic magnitude values

Abstract

The paper addresses the issue of estimating the coefficients of the sotolongo-costa and posadas (SCP) model in the presence of uncertain earthquake magnitude data. The SCP model offers a more accurate representation of regional seismicity compared to the traditional Gutenberg–Richter (G-R) law and has been integrated into the probabilistic seismic hazard analysis (PSHA) framework as NEPSHA. The study aims to develop a method to calculate the SCP coefficients in the presence of uncertain magnitude data, implement the process in R programming language, and validate its effectiveness through a case study. The methodology involves developing the mathematical relationship for estimating the SCP parameters using maximum likelihood estimation (MLE) and modifying the MLE approach to account for magnitude uncertainty. The method is tested using simulated earthquake catalogs with varying degrees of magnitude uncertainty. The results demonstrate that the proposed method can alter the estimated values of the SCP parameters, particularly the a value, by approximately 50% when magnitude uncertainty is considered. The q variable is found to be less affected by the estimation method.