Monitoring of tectonic deformation in the seismic gap of the Mentawai Islands using ALOS-1 and ALOS-2

TL;DR

This study uses ALOS-1 and ALOS-2 satellite data to monitor tectonic deformation in the Mentawai Islands' seismic gap, providing insights into ongoing crustal movements relevant for earthquake risk assessment.

Contribution

It introduces a novel application of SAR and GPS data to analyze tectonic activity in the Mentawai seismic gap, highlighting deformation patterns for earthquake preparedness.

Findings

Pagai Islands show consistent tectonic deformation.

Significant subsidence in North Pagai and North South Pagai.

Significant uplift in southwest North Pagai and southern South Pagai.

Abstract

Ever since the last occurrence of a significant earthquake in the Mentawai megathrust zone in 2000, no significant earthquake events have been recorded, which, according to the earthquake repetition cycle, suggests that the zone is a potential epicenter of future earthquakes. The southern and northern parts of the zone have been struck by a significant earthquake with magnitude M > 8.0; however, in the potential location of the Mentawai Islands, earthquake energy has not been released. This research shows the tectonic activity, velocity, and shift that occurred owing to the thrust of the plate. The information is a vital reference for estimating the epicenter of the earthquake whose energy has not yet been released. We analyzed the tectonic characteristics according to the synthetic aperture radar data and geodetic global positioning system observations. The results show that the Pagai Islands are experiencing consistent tectonic deformations. The northern region of North Pagai and the Northern region of South Pagai are experiencing significant subsidence, while the southwest (SW) region of North Pagai and the south segment of South Pagai are experiencing significant uplift. The government and local authorities can use this information as a guide for developing strategies for disaster preparation.