Monitoring of Tectonic Deformation in the Seismic Gap of the Mentawai Islands using ALOS-1 and ALOS-2

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.