# Identifying the occurrence time of an impending mainshock: A very recent case

## TL;DR

This paper reviews a natural time analysis method to identify the imminent mainshock timing using seismicity and electric signals, demonstrated on a 2014 Greece earthquake and discussed with recent SES data.

## Contribution

It applies and validates a natural time analysis procedure for predicting mainshock occurrence based on seismic electric signals and seismicity data.

## Key findings

- The 2014 Greece mainshock was predicted to occur early on 15 November 2014.
- The method successfully identified the critical point approaching the mainshock.
- Recent SES activities are also analyzed in the context of earthquake prediction.

## Abstract

The procedure by means of which the occurrence time of an impending mainshock can be identified by analyzing in natural time the seismicity in the candidate area subsequent to the recording of a precursory Seismic Electric Signals (SES) activity is reviewed. Here, we report the application of this procedure to an Mw5.4 mainshock that occurred in Greece on 17 November 2014 and was strongly felt in Athens. This mainshock (which is pretty rare since it is the strongest in that area for more than half a century) was preceded by an SES activity recorded on 27 July 2014 and the results of the natural time analysis reveal that the system approached the critical point (mainshock occurrence) early in the morning on 15 November 2014. SES activities that have been recently recorded are also presented. Furthermore, in a Note we discuss the case of the Mw5.3 earthquake that was also strongly felt in Athens on 19 July 2019 (Parnitha fault).