Global Precedent-Based Extrapolation Estimate of the M8+ Earthquake Hazard (According to USGS Data as of 1 June 2021)

Abstract

The paper describes the algorithm and the results of the seismic hazard estimate based on the data of the seismological catalog of the US Geological Survey (USGS). The prediction algorithm is based on the search for clusters of seismic activity in which current activity trends correspond to foreshock sequences recorded before strong earthquakes (precedents) that have already occurred. The time of potential hazard of a similar earthquake is calculated by extrapolating the detected trends to the level of activity that took place at the time of the precedent earthquake. It is shown that the lead time of such a forecast reaches 10–15 years, and its implementation is due to the preservation and stability of the identified trends. The adjustment of the hazard assessment algorithm was carried out in retrospect for seven earthquakes (M8+) that had predictability in foreshock preparation. The evolution of the potential seismic hazard from 1 January 2020 to 1 June 2021 has been traced. It is concluded that precedent-based extrapolation assessments have prospects as a tool designed for the early detection and monitoring of potentially hazardous seismic activity.