Effects of the 2016 Kumamoto earthquakes on the Aso volcanic edifice

Abstract

Large earthquakes occurred in the central part of Kumamoto Prefecture on April 14-16, 2016, causing severe damage to the northern segment of the Hinagu faults and the eastern segment of the Futagawa faults. Earthquake surface ruptures appeared along these faults and on the Aso volcanic edifice, which in turn generated landslides. We conducted landform change analysis of the central cones of Aso volcano by using satellite and aerial photographs. First, we categorized the topographical changes as surface scarps, arc-shaped cracks, and linear cracks. Field survey indicated that landslides caused the scarps and arc-shaped cracks, whereas faulting caused the linear cracks. We discovered a surface rupture concentration zone (RCZ) formed three ruptures bands with many surface ruptures and landslides extending from the west foot to the center of the Aso volcanic edifice. The magmatic volcanic vents that formed during the past 10,000 years are located along the north margin of the RCZ. Moreover, the distribution and dip of the core of rupture concentration zone correspond with the Nakadake craters. We conclude that a strong relationship exists between the volcanic vents and fault structures in the central cones of Aso volcano.

Resolving the Kinematics and Moment Release of Early Afterslip Within the First Hours Following the 2016 Mw 7.1 Kumamoto Earthquake: Implications for the Shallow Slip Deficit and Frictional Behavior of Aseismic Creep

“…The mainshock slip model is able to fit the geodetic data well, with POVR values of 91% for the GPS, 97% for the ALOS-2 radar fault offsets, 89% for the Sentinel-1A azimuthal offsets, 93% for the Sentinel-1 range offsets, 63% for the descending InSAR, and 86% for the ascending InSAR (see Figure S3 for fits and residuals). The relatively poor model fit to the descending InSAR data is likely the result of the inability of the elastic model to reproduce the complex nontectonic deformation within the Aso caldera that resulted from lateral spreads and shaking-induced slumping, where we find the largest misfits ( Figure S3) (Tajima et al, 2017;Tsuji et al, 2017).…”

Repeated triggered ruptures on a distributed secondary fault system: an example from the 2016 Kumamoto earthquake, southwest Japan

“…Many secondary surface ruptures appeared on the mapped and unmapped active fault traces (Fujiwara et al 2016). Mass movement on the slopes and lateral movements also occurred in the caldera (Tsuji et al 2016;Fujiwara et al 2017;Tajima et al 2017;Saito et al 2018).…”

Detection of Earthquake-Induced Landslides during the 2018 Kumamoto Earthquake Using Multitemporal Airborne Lidar Data

“…Doi et al [35] used geological and geophysical methods to understand the generation mechanism of the landslides that occurred in Minami-Aso village. Tajima et al [36] conducted landform change analysis of the central cones of the Aso volcano using satellite and aerial images. Tamkuan and Nagi [37] combined Landsat-8 and interferometric ALOS-2 coherence data to classify building damage, liquefaction and landslides.…”