scholarly journals Comprehensive Investigation of Capabilities of the Left-Looking InSAR Observations in Coseismic Surface Deformation Mapping and Faulting Model Estimation Using Multi-Pass Measurements: An Example of the 2016 Kumamoto, Japan Earthquake

2021 ◽  
Vol 13 (11) ◽  
pp. 2034
Author(s):  
Ying-Hui Yang ◽  
Qiang Chen ◽  
Qian Xu ◽  
Jing-Jing Zhao ◽  
Jyr-Ching Hu ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Normal Fault ◽  
Alos Palsar ◽  
Model Inversion ◽  
Kumamoto Earthquake ◽  
Rupture Length ◽  
The 2016 Kumamoto Earthquake ◽  
Aso Caldera ◽  
The Right ◽  
Offset Tracking

We here present an example of the 2016 Kumamoto earthquake with its coseismic surface deformation mapped by the ALOS-2 satellite both in the right- and left-looking observation modes. It provides the opportunity to reveal the coseismic surface deformation and to explore the performance of the unusual left-looking data in faulting model inversion. Firstly, three tracks (ascending and descending right-looking and descending left-looking) of ALOS PALSAR-2 images are used to extract the surface deformation fields. It suggests that the displacements measured by the descending left-looking InSAR coincide well with the ascending right-looking track observations. Then, the location and strike angle of the fault are determined from the SAR pixel offset-tracking technique. A complicated four-segment fault geometry is inferred for explaining the coseismic faulting of the Kumamoto earthquake due to the interpretation of derived deformation fields. Quantitative comparisons between models constrained by the right-looking only data and by joint right- and left-looking data suggest that left-looking InSAR could provide comparable constraints for geodetic modelling to right-looking InSAR. Furthermore, the slip model suggests that the series of events are dominated by the dextral strike-slip with some normal fault motions. The fault rupture initiates on the Hinagu fault segment and propagates from southwest to northeast along the Hinagu fault, then transforms to Futagawa fault with a slip maximum of 4.96 m, and finally ends up at ~7 km NW of the Aso caldera, with a rupture length of ~55 km. The talent of left-looking InSAR in surface deformation detection and coseismic faulting inversion indicates that left-looking InSAR can be effectively utilized in the investigation of the geologic hazards in the future, same as right-looking InSAR.

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.

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.

scholarly journals Characteristics of Secondary-Ruptured Faults in The Aso Caldera Triggered by The 2016 Mw 7.0 Kumamoto Earthquake

2020 ◽  
Author(s):  
Yo Fukushima ◽  
Daisuke Ishimura
Keyword(s):  
Scaling Law ◽  
Fault Slip ◽  
Sediment Layer ◽  
Seismogenic Fault ◽  
Kumamoto Earthquake ◽  
Synthetic Aperture Radar Interferometry ◽  
Vertical Fault ◽  
Aso Caldera ◽  
The Difference ◽  
The Right

Abstract The 16 April 2016 Mw 7.0 Kumamoto earthquake caused prominent fault displacements and crustal deformation, not only around the main rupture faults but also around numerous secondary-ruptured faults. The physics and characteristics of such secondary faulting have not yet been studied in detail. We investigated a set of two secondary faults that appeared at the timing of the Mw 7.0 quake in the Aso Caldera by mainly using synthetic aperture radar interferometry and fault slip modeling. The two faults were found to be associated with surface slip of several centimeters or more, in the oblique sense of right-lateral and vertical. Fault slip inversions found that the slip was dominantly in normal sense with smaller contribution from the right-lateral component. The deeper limit of the slips was estimated to be around 1.3¥,km, which may coincide with the boundary between the superficial sediment layer and the basement rock. The shallowness of the slip and the difference in the dip angles of the main secondary fault and the Mw 7.0 seismogenic fault suggest separation of the two fault systems, although the fault strike and sense of motions were similar. The amount of slip on the two secondary faults was larger than that expected from the scaling law derived from seismogenic faults, which may indicate the difference in the physics of seismogenic and secondary faultings.

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

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

scholarly journals Characteristics of secondary-ruptured faults in the Aso Caldera triggered by the 2016 Mw 7.0 Kumamoto earthquake

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Yo Fukushima ◽  
Daisuke Ishimura
Keyword(s):  
Scaling Law ◽  
Surface Displacement ◽  
Vertical Motion ◽  
Fault Slip ◽  
Sediment Layer ◽  
Seismogenic Fault ◽  
Kumamoto Earthquake ◽  
Aso Caldera ◽  
The Difference ◽  
The Right

AbstractThe 16 April 2016 Mw 7.0 Kumamoto earthquake caused prominent fault displacements and crustal deformation, not only around the main rupture faults but also around numerous secondary-ruptured faults. The physics and characteristics of such secondary faulting have not yet been studied in detail. We investigated a set of two secondary faults that appeared at the timing of the Mw 7.0 quake in the Aso Caldera by mainly using synthetic aperture radar interferometry and fault slip modeling. The two faults were found to be associated with surface displacement offsets of several centimeters or more, in the oblique sense of right-lateral and vertical motion. Fault slip inversions found that the slip was dominantly in normal sense with smaller contribution from the right-lateral component. The deeper limit of the slips was estimated to be around 1.3 km, which may coincide with the boundary between the superficial sediment layer and the basement rock. The shallowness of the slip and the difference in the dip angles of the main secondary fault and the Mw 7.0 seismogenic fault suggest separation of the two fault systems, although the fault strike and sense of motions were similar. The amount of slip on the two secondary faults was larger than that expected from the scaling law derived from seismogenic faults, which may indicate the difference in the physics of seismogenic and secondary faultings.

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 Characteristics of secondary-ruptured faults in the Aso Caldera triggered by the 2016 Mw 7.0 Kumamoto earthquake

2020 ◽  
Author(s):  
Yo Fukushima ◽  
Daisuke Ishimura
Keyword(s):  
Scaling Law ◽  
Surface Displacement ◽  
Vertical Motion ◽  
Fault Slip ◽  
Sediment Layer ◽  
Seismogenic Fault ◽  
Kumamoto Earthquake ◽  
Aso Caldera ◽  
The Difference ◽  
The Right

Abstract The 16 April 2016 Mw 7.0 Kumamoto earthquake caused prominent fault displacements and crustal deformation, not only around the main rupture faults but also around numerous secondary-ruptured faults. The physics and characteristics of such secondary faulting have not yet been studied in detail. We investigated a set of two secondary faults that appeared at the timing of the Mw 7.0 quake in the Aso Caldera by mainly using synthetic aperture radar interferometry and fault slip modeling. The two faults were found to be associated with surface displacement offsets of several centimeters or more, in the oblique sense of right-lateral and vertical motion. Fault slip inversions found that the slip was dominantly in normal sense with smaller contribution from the right-lateral component. The deeper limit of the slips was estimated to be around 1.3 km, which may coincide with the boundary between the superficial sediment layer and the basement rock. The shallowness of the slip and the difference in the dip angles of the main secondary fault and the Mw 7.0 seismogenic fault suggest separation of the two fault systems, although the fault strike and sense of motions were similar. The amount of slip on the two secondary faults was larger than that expected from the scaling law derived from seismogenic faults, which may indicate the difference in the physics of seismogenic and secondary faultings.

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