MECHANISM OF THE GRABENS THAT FORMED IN THE ASO CALDERA DURING THE 2016 KUMAMOTO EARTHQUAKE

2021 ◽  
Vol 21 (6) ◽  
pp. 6_31-6_56
Author(s):  
Susumu YASUDA ◽  
Naoto OHBO ◽  
Masanobu SHIMADA ◽  
Tatsuro CHIBA ◽  
Hideo NAGASE ◽  
...  
Keyword(s):  
2016 Kumamoto Earthquake ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Aso Caldera

EARTHFLOW DEPOSITS TRIGGERED BY THE 2016 KUMAMOTO EARTHQUAKE IN ASO CALDERA, SW JAPAN

2016 ◽  
Author(s):  
Mitsuru Okuno ◽  
◽  
Masayuki Torii ◽  
Ken-ichi Nishiyama ◽  
Toshimichi Nakanishi ◽  
...  
Keyword(s):  
2016 Kumamoto Earthquake ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Aso Caldera ◽  
Sw Japan

scholarly journals Postseismic Deformation Following the 2016 Kumamoto Earthquake Detected by ALOS-2/PALSAR-2

2020 ◽  
Author(s):  
Manabu Hashimoto
Keyword(s):  
Surface Deformation ◽  
Postseismic Deformation ◽  
Mountainous Area ◽  
2016 Kumamoto Earthquake ◽  
Ionospheric Correction ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Aso Caldera ◽  
Surface Ruptures ◽  
High Coherence

Abstract We have been conducting study of postseismic deformation following the 2016 Kumamoto earthquake using ALOS-2/PALSAR-2 acquired till 2018. We apply ionospheric correction to interferograms of ALOS-2/PALSAR-2. L-band SAR gives us high coherence enough to reveal surface deformation even in vegetated or mountainous area for pairs of images acquired more than 2 years. Ionospheric disturbances are seen both in the ascending and descending images, but spatial characteristics may be different each other. Postseismic deoformation following the Kumamoto earthquake is much larger than those observed after recent inland earthquakes in Japan with GPS, which exceeds 10 cm during two years at some spots in and around Kumamoto city and Aso caldera. There are sharp changes across several coseismic surface ruptures such as Futagawa, Hinagu and Idenokuchi faults. Time constant of postseismic decay ranges from 1 month to 600 days at selected points, but that LOS changes during the first epochs or two are dominant. This result suggests multiple source of postseismic deformation. LOS changes around the Hinagu and Suinzenji faults that appeared during the mainshock in Kumamoto City may be explained with right lateral afterslip on these faults. LOS changes around the Hinagu and Idenokuchi faults cannot be explained with right-lateral afterslip, which requires another unknown source. Deformation in northern part of Aso caldera may be the result of right lateral afterslip on unknown fault.

Mechanism of the Grabens that formed in the Aso Caldera during the 2016 Kumamoto Earthquake

2021 ◽  
Vol 21 (1) ◽  
pp. 1_135-1_158
Author(s):  
Susumu YASUDA ◽  
Naoto OHBO ◽  
Masanobu SHIMADA ◽  
Tatsuro CHIBA ◽  
Hideo NAGASE ◽  
...  
Keyword(s):  
2016 Kumamoto Earthquake ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Aso Caldera

scholarly journals Postseismic Deformation Following the 2016 Kumamoto Earthquake Detected by ALOS-2/PALSAR-2

2020 ◽  
Author(s):  
Manabu Hashimoto
Keyword(s):  
Surface Deformation ◽  
Postseismic Deformation ◽  
Mountainous Area ◽  
2016 Kumamoto Earthquake ◽  
Ionospheric Correction ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Aso Caldera ◽  
Surface Ruptures ◽  
Buried Fault

Abstract I have been conducting a study of postseismic deformation following the 2016 Kumamoto earthquake using ALOS-2/PALSAR-2 acquired till 2018. I apply ionospheric correction to interferograms of ALOS-2/PALSAR-2. L-band SAR gives us high coherence enough to reveal surface deformation even in vegetated or mountainous area for pairs of images acquired more than 2 years. Postseismic deformation following the Kumamoto earthquake exceeds 10 cm during two years at some spots in and around Kumamoto city and Aso caldera. Westward motion of ~6 cm/yr was dominant on the southeast side of the Hinagu fault, while westward shift was detected on both side of the Futagawa fault. The area of latter deformation seems to have correlation with distribution of pyroclastic flow deposits. Significant uplift was found around the eastern Futagawa fault and on the southwestern frank of Aso caldera, whose rate reaches 4 cm/yr. There are sharp changes across several coseismic surface ruptures such as Futagawa, Hinagu, and Idenokuchi faults. Rapid subsidence between Futagawa and Idenokuchi faults also found. It is confirmed that local subsidence continued along the Suizenji fault, which newly appeared during the mainshock in Kumamoto City. Subsidence with westward shift of up to 4 cm/yr was also found in Aso caldera.Time constant of postseismic decay ranges from 1 month to 600 days at selected points, but that postseismic deformation during the first epochs or two are dominant at point in the Kumamoto Plain. This result suggests multiple source of deformation. Westward motion around the Hinagu fault may be explained with right lateral afterslip on the shallow part of this fault. Subsidence along the Suizenji fault can be attributed to normal faulting on dipping westward. Deformation around the Hinagu and Idenokuchi faults cannot be explained with right-lateral afterslip of Futagawa fault, which requires other sources. Deformation in northern part of Aso caldera might be the result of right lateral afterslip on a possible buried fault.

scholarly journals Postseismic Deformation Following the 2016 Kumamoto Earthquake Detected by ALOS-2/PALSAR-2

2020 ◽  
Author(s):  
Manabu Hashimoto
Keyword(s):  
Surface Deformation ◽  
Postseismic Deformation ◽  
Mountainous Area ◽  
2016 Kumamoto Earthquake ◽  
Ionospheric Correction ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Aso Caldera ◽  
Surface Ruptures ◽  
Buried Fault

Abstract I have been conducting a study of postseismic deformation following the 2016 Kumamoto earthquake using ALOS-2/PALSAR-2 acquired till 2018. I apply ionospheric correction to interferograms of ALOS-2/PALSAR-2. L-band SAR gives us high coherence enough to reveal surface deformation even in vegetated or mountainous area for pairs of images acquired more than 2 years. Postseismic deformation following the Kumamoto earthquake exceeds 10 cm during two years at some spots in and around Kumamoto city and Aso caldera. Westward motion of ~6 cm/yr was dominant on the southeast side of the Hinagu fault, while westward shift was detected on both side of the Futagawa fault. The area of latter deformation seems to have correlation with distribution of pyroclastic flow deposits. Significant uplift was found around the eastern Futagawa fault and on the southwestern frank of Aso caldera, whose rate reaches 4 cm/yr. There are sharp changes across several coseismic surface ruptures such as Futagawa, Hinagu, and Idenokuchi faults. Rapid subsidence between Futagawa and Idenokuchi faults also found. It is confirmed that local subsidence continued along the Suizenji fault, which newly appeared during the mainshock in Kumamoto City. Subsidence with westward shift of up to 4 cm/yr was also found in Aso caldera. Time constant of postseismic decay ranges from 1 month to 600 days at selected points, but that postseismic deformation during the first epochs or two are dominant at point in the Kumamoto Plain. This result suggests multiple source of deformation. Westward motion around the Hinagu fault may be explained with right lateral afterslip on the shallow part of this fault. Subsidence along the Suizenji fault can be attributed to normal faulting on dipping westward. Deformation around the Hinagu and Idenokuchi faults cannot be explained with right-lateral afterslip of Futagawa fault, which requires other sources. Deformation in northern part of Aso caldera might be the result of right lateral afterslip on a possible buried fault.

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

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Manabu Hashimoto
Keyword(s):  
Surface Deformation ◽  
Postseismic Deformation ◽  
Mountainous Area ◽  
2016 Kumamoto Earthquake ◽  
Ionospheric Correction ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Aso Caldera ◽  
Surface Ruptures ◽  
Buried Fault

Abstract I have been conducting a study of postseismic deformation following the 2016 Kumamoto earthquake using ALOS-2/PALSAR-2 acquired till 2018. I apply ionospheric correction to interferograms of ALOS-2/PALSAR-2. L-band SAR gives us high coherence enough to reveal surface deformation even in vegetated or mountainous area for pairs of images acquired more than 2 years. Postseismic deformation following the Kumamoto earthquake exceeds 10 cm during 2 years at some spots in and around Kumamoto city and Aso caldera. Westward motion of ~ 6 cm/year was dominant on the southeast side of the Hinagu fault, while westward shift was detected on both sides of the Futagawa fault. The area of latter deformation seems to have correlation with distribution of pyroclastic flow deposits. Significant uplift was found around the eastern Futagawa fault and on the southwestern frank of Aso caldera, whose rate reaches 4 cm/year. There are sharp changes across several coseismic surface ruptures such as Futagawa, Hinagu, and Idenokuchi faults. Rapid subsidence between Futagawa and Idenokuchi faults also found. It is confirmed that local subsidence continued along the Suizenji fault, which newly appeared during the mainshock in Kumamoto City. Subsidence with westward shift of up to 4 cm/year was also found in Aso caldera. Time constant of postseismic decay ranges from 1 month to 600 days at selected points, but that postseismic deformation during the first epochs or two is dominant at point in the Kumamoto Plain. This result suggests multiple source of deformation. Westward motion around the Hinagu fault may be explained with right lateral afterslip on the shallow part of this fault. Subsidence along the Suizenji fault can be attributed to normal faulting on dipping westward. Deformation around the Hinagu and Idenokuchi faults cannot be explained with right lateral afterslip of Futagawa fault, which requires other sources. Deformation in northern part of Aso caldera might be the result of right lateral afterslip on a possible buried fault.

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