scholarly journals Retraction:PRELIMINARY ANALYSIS OF NEAR-SOURCE STRONG MOTION RECORDS DURING THE MAIN SHOCK OF THE 2016 KUMAMOTO EARTHQUAKE —CAUSE OF DAMAGING GROUND MOTIONS IN MASHIKI—

2017 ◽  
Vol 73 (4) ◽  
pp. I_959-I_969
Author(s):  
Atsushi NOZU ◽  
Yosuke NAGASAKA
Keyword(s):  
Main Shock ◽  
Ground Motions ◽  
Strong Motion ◽  
2016 Kumamoto Earthquake ◽  
Strong Motion Records ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake

scholarly journals Surface displacements of Aso volcano after the 2016 Kumamoto earthquake based on SAR interferometry: implications for dynamic triggering of earthquake–volcano interactions

2019 ◽  
Vol 218 (2) ◽  
pp. 755-761
Author(s):  
Wataru Yamada ◽  
Kazuya Ishitsuka ◽  
Toru Mogi ◽  
Mitsuru Utsugi
Keyword(s):  
Synthetic Aperture Radar ◽  
Main Shock ◽  
Synthetic Aperture ◽  
Source Depth ◽  
2016 Kumamoto Earthquake ◽  
Aso Volcano ◽  
Kumamoto Earthquake ◽  
Surface Displacements ◽  
The 2016 Kumamoto Earthquake ◽  
Aperture Radar

SUMMARY The 2016 Kumamoto earthquake involved a series of events culminating in an Mw 7.0 main shock on 2016 April 16; the main-shock fault terminated in the caldera of Aso volcano. In this study, we estimated surface displacements after the 2016 Kumamoto earthquake using synthetic aperture radar interferometry analysis of 16 Phased Array Type L-band Synthetic Aperture Radar-2 images acquired from 2016 April 18 to 2017 June 12 and compared them with four images acquired before the earthquake. Ground subsidence of about 8 cm was observed within about a 3 km radius in the northwestern part of Aso caldera. Because this displacement was not seen in data acquired before the 2016 Kumamoto earthquake, we attribute this displacement to the 2016 Kumamoto earthquake. Furthermore, to estimate the source depth of the surface displacement, we applied the Markov chain Monte Carlo method to a spherical source model and obtained a source depth of about 4.8 km. This depth and position are nearly in agreement with the top of a low-resistivity area previously inferred from magnetotelluric data; this area is thought to represent a deep hydrothermal reservoir. We concluded that this displacement is due to the migration of magma or aqueous fluids.

Investigation of Damages in Immediate Vicinity of Co-Seismic Faults During the 2016 Kumamoto Earthquake

2017 ◽  
Vol 12 (5) ◽  
pp. 899-915 ◽  
Author(s):  
Shohei Naito ◽  
Ken Xiansheng Hao ◽  
Shigeki Senna ◽  
Takuma Saeki ◽  
Hiromitsu Nakamura ◽  
...  
Keyword(s):  
Fault Zone ◽  
Active Fault ◽  
Strong Motion ◽  
Site Amplification ◽  
Building Damage ◽  
2016 Kumamoto Earthquake ◽  
Severe Damage ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
The Relationship

In the 2016 Kumamoto earthquake, the Futagawa fault zone and the Hinagu fault zone were active in some sections, causing severe damage in neighboring areas along the faults. We conducted a detailed investigation of the surface earthquake fault, building damage, and site amplification of shallow ground within about 1 km of the neighboring areas of the fault. The focus was mainly on Kawayou district, Minamiaso village and Miyazono district, Mashiki town, and locations that suffered particularly severe building damage. We explored the relationship between local strong motion and building damage caused in areas that were in the immediate vicinity of the active fault.

scholarly journals Simulation of building damage distribution in downtown Mashiki, Kumamoto, Japan caused by the 2016 Kumamoto earthquake based on site-specific ground motions and nonlinear structural analyses

2021 ◽  
Author(s):  
Jikai Sun ◽  
Fumiaki Nagashima ◽  
Hiroshi Kawase ◽  
Shinichi Matsushima ◽  
Baoyintu
Keyword(s):  
Ground Motions ◽  
Target Area ◽  
2016 Kumamoto Earthquake ◽  
Ground Acceleration ◽  
Site Specific ◽  
Construction Period ◽  
Kumamoto Earthquake ◽  
Velocity Models ◽  
The 2016 Kumamoto Earthquake ◽  
Wooden Structures

AbstractMost of the buildings damaged by the mainshock of the 2016 Kumamoto earthquake were concentrated in downtown Mashiki in Kumamoto Prefecture, Japan. We obtained 1D subsurface velocity structures at 535 grid points covering this area based on 57 identified velocity models, used the linear and equivalent linear analyses to obtain site-specific ground motions, and generated detailed distribution maps of the peak ground acceleration and velocity in Mashiki. We determined the construction period of every individual building in the target area corresponding to updates to the Japanese building codes. Finally, we estimated the damage probability by the nonlinear response model of wooden structures with different ages. The distribution map of the estimated damage probabilities was similar to the map of the damage ratios from a field survey, and moderate damage was estimated in the northwest where no damage survey was conducted. We found that both the detailed site amplification and the construction period of wooden houses are important factors for evaluating the seismic risk of wooden structures.

scholarly journals Hydrological changes after the 2016 Kumamoto earthquake, Japan

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Naoji Koizumi ◽  
Shinsuke Minote ◽  
Tatsuya Tanaka ◽  
Azumi Mori ◽  
Takumi Ajiki ◽  
...  
Keyword(s):  
Main Shock ◽  
2016 Kumamoto Earthquake ◽  
Kumamoto Earthquake ◽  
Daily Streamflow ◽  
Hydrological Changes ◽  
The 2016 Kumamoto Earthquake ◽  
Streamflow Data ◽  
Spring Flow ◽  
Water Springs ◽  
Water Holding

AbstractThe 2016 Kumamoto earthquake, whose main shock was an M7.3 event on April 16, 2016, 28 h after a foreshock of M6.5, caused severe damage in and around Kumamoto Prefecture, Japan. It also caused postseismic hydrological changes in Kumamoto Prefecture. In this study, we analyzed daily streamflow data collected by eight observation stations from 2001 to 2017 in regions that experienced strong ground motion during the 2016 Kumamoto earthquake. We also surveyed 11 water springs in the region several times after the main shock. Streamflow had no or slight change immediately after the earthquake; however, large increases were recorded at some of the eight stations following a heavy rainfall that occurred 2 months after the earthquake. A decrease in the water-holding capacity of the catchment caused by earthquake-induced landslides can explain this delayed streamflow increase. Conversely, earthquake-related changes to the spring flow rate were not so clear. Water temperature and chemical composition of spring waters were also hardly changed. Only the concentration of NO3−, which is usually considered to be supplied from the surface, changed slightly just after the earthquake. These results show that the postseismic hydrological changes were caused mainly by earthquake-induced surface phenomena and that there was little contribution from hydrothermal fluid.

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