Coseismic and Postseismic Deformation of the 2016 Central Tottori Earthquake and its Slip Model

Abstract

We analyze Global Navigation Satellite System (GNSS), Interferometric Synthetic Aperture Radar, and accelerometer data within the San‐in Shear Zone in order to clarify the coseismic and postseismic slip distributions associated with the Mw6.2 2016 Central Tottori earthquake. Inversion of the coseismic displacement data to estimate the slip distribution on the rupture fault shows a patch of large slip to the northwest of the hypocenter of the mainshock location. Relocated aftershocks and off‐fault seismicity 1 month after the mainshock are in agreement with stress change patterns caused by the mainshock fault. Inversion of near‐field GNSS displacements in 7 months following the earthquake under the assumption of afterslip does not show a preferred slip patch but rather a smooth distribution of the slip at shallow depths. Restricted slip propagation of afterslip on the 2016 event might suggest that inland faults in the San‐in Shear Zone are immature. Limited resolution of the GNSS data might inhibit us from finding the slip at depth.

Complete Three‐Dimensional Coseismic Deformation Field of the 2016 Central Tottori Earthquake by Integrating Left‐ and Right‐Looking InSAR Observations With the Improved SM‐VCE Method

“…The search parameters of the fault geometry are summarized in Table 2, and the slip distribution from the source model inversion is exhibited in Figure 5. The causative fault has a strike angle of N160°E and a dip angle of 90°, which are consistent with seismological solutions and previous research (Meneses-Gutierrez et al, 2019;USGS, 2016). As shown in Figure 5, the majority of fault slip occurs at shallow depths within a slip asperity with a maximum value of~1.1 m at a depth of 5 km.…”

Going to Any Lengths: Solving for Fault Size and Fractal Slip for the 2016, Mw 6.2 Central Tottori Earthquake, Japan, Using a Transdimensional Inversion Scheme

“…We find the earthquake to have ruptured significantly from depths ∼1.5 km beneath the surface down to 10 km, suggesting that most of the seismogenic zone ruptured in this event. This is a similar result to the recently accepted geodetic study by Meneses‐Gutierrez et al () and is in contrast to the seismological study by Ross et al (), which suggests that significant slip occurred only at depths of ∼10–12 km (supporting information Figure S6). Ross et al () find a concentrated slip patch of ∼5‐m slip with 93% of the seismic moment released below 8 km, which would leave the surface at risk from further faulting and considerable seismic hazard.…”

Postseismic deformation following the 2016 Kumamoto earthquake detected by ALOS-2/PALSAR-2

“…Postseismic deformation usually follows large earthquakes. There are several studies of postseismic deformation following inland earthquakes in Japan mainly using continuous and campaign GNSS data and their origins (e.g., Nakano and Hirahara 1997;Sagiya et al 2005;Hashimoto et al 2008;Ohzono 2011;Ohzono et al 2012;Meneses-Gutierrez et al 2019). These preceding studies speculated afterslip, viscoelastic relaxation and poroelastic rebound for possible mechanism of postseismic deformation, but they did not incorporate complicated geometry of faults or heterogeneous structure of crust due to the limited spatial resolution.…”