Numerical precursory study on strong earthquakes in southern and Baja California

Abstract

We examined the spatio-temporal variation of correlation fractal dimension (DC) for M≥2.5 earthquakes in southern and Baja California to ascertain the incidence of seismic precursors before strong earthquakes. The unforeseen 2019 Ridgecrest events have restructured the crustal stress patterns in the adjacent regions signifying the prerequisite for a caveat. The current research attempts to discern the existence of numerical precursors of strong earthquakes (Mw > 7) based on the correlation integral method. A time window of three decades (1990–2020) was analyzed to study the relative changes in the distribution of earthquake clusters and the subsequent variations reflected in DC values. We have successfully demonstrated the numerical precursors for four stronger main shocks (1992 Landers Mw 7.3, 1999 Hectormine Mw 7.1, 2010 El-Mayor Cucapah Mw 7.2, and 2019 Ridgecrest Mw 7.1) through the relative changes in DC. In addition, our study has confirmed the remarkable correlation between low values of DC and spatio-temporal clustering of earthquakes for the study region. Though the present study confers the application of DC on the recognition of seismicity patterns before major events, the constant monitoring of the same can give insights into earthquake forecasting and seismic risk analysis of unstable tectonic terrains.