Tsunami detection by GPS-derived ionospheric total electron content

Mahesh N Shrivastava,Rafael Aranguiz,Poikayil S Sunil,Ajeet K Maurya,Juan Gonzalez,Gabriel Gonzalez,Pablo Salazar

doi:10.1038/s41598-021-92479-3

Abstract

To unravel the relationship between earthquake and tsunami using ionospheric total electron content (TEC) changes, we analyzed two Chilean tsunamigenic subduction earthquakes: the 2014 Pisagua Mw 8.1 and the 2015 Illapel Mw 8.3. During the Pisagua earthquake, the TEC changes were detected at the GPS sites located to the north and south of the earthquake epicenter, whereas during the Illapel earthquake, we registered the changes only in the northward direction. Tide-gauge sites mimicked the propagation direction of tsunami waves similar to the TEC change pattern during both earthquakes. The TEC changes were represented by three signals. The initial weaker signal correlated well with Acoustic Rayleigh wave (AWRayleigh), while the following stronger perturbation was interpreted to be caused by Acoustic Gravity wave (AGWepi) and Internal Gravity wave (IGWtsuna) induced by earthquakes and subsequent tsunamis respectively. Inevitably, TEC changes can be utilized to evaluate earthquake occurrence and tsunami propagation within a framework of multi-parameter early warning systems.

Highlights

To unravel the relationship between earthquake and tsunami using ionospheric total electron content (TEC) changes, we analyzed two Chilean tsunamigenic subduction earthquakes: the 2014 Pisagua Mw 8.1 and the 2015 Illapel Mw 8.3
It has been demonstrated that surface deformation related to earthquake and tsunami propagation produce ionospheric changes in the total electron content (TEC)[2,3,4,5,6,7,8]
As per the current knowledge of the seismic-ionospheric phenomena studied by many earlier r esearchers[8,9,10,11,12,13,14] suggest observations of three waves, namely acoustic gravity waves at epicenter (AGWepi), internal gravity waves induced by Tsunami ( IGWtsuna), and acoustic wave due to seismic Rayleigh wave ( AWRayleigh), following the nomenclature introduced by Occhipinti et al.[11]

Summary

Introduction

To unravel the relationship between earthquake and tsunami using ionospheric total electron content (TEC) changes, we analyzed two Chilean tsunamigenic subduction earthquakes: the 2014 Pisagua Mw 8.1 and the 2015 Illapel Mw 8.3. A WRayleigh is close to the acoustic wave speed, the corresponding time to reach the ionospheric layers is in the order of 10–15 min These waves are essentially observed by GNSS-TEC and have been reported in several investigations in the past during the tsunami e vents[10,11,21,22]. These changes can be detected by GPS instrumentation[2,6,7,9,10,13,14,23] The identification of these coupled seismo-ionospheric induced signals are essential from a scientific point of view and have been used to improve the tsunami early warning systems (TEWS)[24]. Both earthquakes (the 2014 Pisagua earthquake M w 8.1 (Fig. 1B) and the 2015 Illapel earthquake M w 8.3 (Fig. 1C))

Methods

Results

Discussion

Conclusion