Early Assessment of Damage Factors and Surface Faulting in the Yatsushiro Area, Distant from the Epicenter of the 2026 Kumamoto Earthquake : Detailed Surveys Using Aircraft and UAVs

Abstract

The 2026 Kumamoto Earthquake (M 7.1) caused severe damage around Yatsushiro, 15 km southwest of the epicenter. Terra Labo conducted rapid aircraft and UAV surveys to identify and document heavily damaged areas. A reconnaissance flight on 30 July covered 330 km² at 22 cm GSD, identifying surface faulting in Yatsushiro. Combined with ALOS-2/ALOS-4 interferometry, the results guided a detailed 7 cm GSD survey of 41.63 km² on 31 July. UAV surveys documented fault-related damage around Yatsushiro Junction. Survey results were rapidly shared with response agencies and integrated into a web-GIS Common Operational Picture released publicly on 4 August.