Estimation of Earthquake Early Warning Parameters for Eastern Gulf of Corinth and Western Attica Region (Greece). First Results.

Filippos Vallianatos,Nikolaos Sakelariou,Andreas Karakonstantis

doi:10.3390/s21155084

Abstract

The main goal of an Earthquake Early Warning System (EEWS) is to alert before the arrival of damaging waves using the first seismic arrival as a proxy, thus becoming an important operational tool for real-time seismic risk management on a short timescale. EEWSs are based on the use of scaling relations between parameters measured on the initial portion of the seismic signal after the arrival of the first wave. To explore the plausibility of EEWSs around the Eastern Gulf of Corinth and Western Attica, amplitude and frequency-based parameters, such as peak displacement (Pd), the integral of squared velocity ( and the characteristic period (τc), were analyzed. All parameters were estimated directly from the initial 3 s, 4 s, and 5 s signal windows (tw) after the P arrival. While further study is required on the behavior of the proxy quantities, we propose that the parameter and the peak amplitudes of the first seconds of the P waves present significant stability and introduce the possibility of a future on-site EEWS for areas affected by earthquakes located in the Eastern Gulf of Corinth and Western Attica. Parameters related to regional-based EEWS need to be further evaluated.

Highlights

The increasing urbanization worldwide has led to the establishment of large metropolitan areas near major active faults, which pose a serious threat to the human population and infrastructures
Attention has shifted to Earthquake Early Warning Systems (EEWS) for reducing earthquake risk [1,2,3,4,5,6], offering, in real-time, information for the incoming destructive seismic waves
We focused on the correlation of (a) peak displacement (Pd) with the magnitude Mw and the hypocentral distance H, (b) the characteristic period τc with magnitude, averaged over the area, (c) the integral of squared velocity (IV2 ) with peak ground acceleration (PGA) on-site and inter-site

Summary

Introduction

The increasing urbanization worldwide has led to the establishment of large metropolitan areas near major active faults (whether on land or offshore), which pose a serious threat to the human population and infrastructures. To estimate the scaling parameters for an EEWS in the area, we retrieved an event catalog for the Eastern Gulf of Corinth and Western Attica from the International Seismological Center (ISC), consisting of 278 earthquakes between January 2008 and February 2021, with a minimum magnitude of 3.0 and a maximum depth of 30.0 km. We set the S-P time exceedance criterion to a priori avoid cases of overlapping windows for pass filter with a corner frequency of 0.075 Hz [51], we determined the peak valu each motion type (hereafter noted as Pd,u,a for displacement, velocity, and accelera respectively) in the three tw, as well as the peak ground acceleration of the shear-w (hereafter, called PGA) in a window ending 20 s after the theoretically esti5mofa21ted S arr if the signal window tw exceeded the estimated S-P time, the measurement rejected.

The Characteristic Period τc

Conclusions