Spatio-temporal evolution of low-magnitude seismicity before the May 24, 2013, Sea of Okhotsk earthquake recovered by waveform cross correlation. Is it an earthquake prediction case?

TL;DR

This study used waveform cross correlation to recover and analyze low-magnitude seismicity before the 2013 Sea of Okhotsk earthquake, revealing potential precursory patterns.

Contribution

It demonstrates a method to detect and analyze low-magnitude earthquakes preceding a major event using waveform cross correlation, suggesting possible earthquake precursors.

Findings

Over 200 low-magnitude events detected before the mainshock.

A sudden increase in event occurrence rate was observed on May 19.

Evolution of seismicity features may relate to earthquake initiation.

Abstract

According to the International Data Centre (IDC), the Sea of Okhotsk earthquake occurred at 05:44:49.7 on May 24, 2013, had coordinates 54.89{\deg}N,153.31{\deg}E, mb=6.27, and depth of 604 km. The USGS moment magnitude is 8.3. The previous event detected by the IDC in the surrounding volume 53{\deg}N-57{\deg}N, 151{\deg}E-155{\deg}E, depth from 400 to 700 km occurred on February 6, 2012. Using the same seismic data from the stations of the International Monitoring System together with detection and phase association methods based on waveform cross correlation, a series of low-magnitude earthquakes was recovered immediately before this major earthquake. More than 200 events obeying the Event Definition Criteria adapted by the IDC were found between May 13 and the mainshock, with a sudden increase in their occurrence rate starting on the afternoon May 19. The evolution of the numbers of these low-magnitude earthquakes in various ranges of statistical significance within the source volume demonstrates some features, which can be related to the approaching initiation of the Sea of Okhotsk earthquake.