Changes in Seismicity Pattern Due to the 2016 Kumamoto Earthquakes Identify a Highly Stressed Area on the Hinagu Fault Zone

Abstract A highly stressed area where eventual ruptures have often been observed to nucleate is characterized by low b values of earthquake frequency‐size distribution. Crustal deformation due to the occurrence of large earthquakes causes stress perturbation in nearby regions, so an investigation in...

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Main Authors: K.Z. Nanjo, J. Izutsu, Y. Orihara, M. Kamogawa, T. Nagao
Format: Article
Language:English
Published: Wiley 2019-08-01
Series:Geophysical Research Letters
Online Access:https://doi.org/10.1029/2019GL083463
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author K.Z. Nanjo
J. Izutsu
Y. Orihara
M. Kamogawa
T. Nagao
author_facet K.Z. Nanjo
J. Izutsu
Y. Orihara
M. Kamogawa
T. Nagao
author_sort K.Z. Nanjo
collection DOAJ
description Abstract A highly stressed area where eventual ruptures have often been observed to nucleate is characterized by low b values of earthquake frequency‐size distribution. Crustal deformation due to the occurrence of large earthquakes causes stress perturbation in nearby regions, so an investigation into spatiotemporal b values can play a crucial role in the distribution of postseismic hazards after the 2016 Kumamoto earthquake sequence along the Futagawa‐Hinagu fault zone, which culminated in the magnitude 7.3 mainshock. Together with an analysis of aftershock decay p value that can be used to infer stressing history, a highly stressed area with a characteristic dimension of 10 km at the southern end of the causative faults was found. Our observation is explained by postseismic deformation due to an afterslip on the causative faults and viscoelastic relaxation model. Similar to the Kumamoto mainshock rupture, which started at a low‐b‐value area, the observed highly stressed area shows a high likelihood of future earthquake ruptures.
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institution OA Journals
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language English
publishDate 2019-08-01
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record_format Article
series Geophysical Research Letters
spelling doaj-art-a608e8f317c7471c8bc7bcd5c9045a312025-08-20T02:24:35ZengWileyGeophysical Research Letters0094-82761944-80072019-08-0146169489949610.1029/2019GL083463Changes in Seismicity Pattern Due to the 2016 Kumamoto Earthquakes Identify a Highly Stressed Area on the Hinagu Fault ZoneK.Z. Nanjo0J. Izutsu1Y. Orihara2M. Kamogawa3T. Nagao4Global Center for Asian and Regional Research University of Shizuoka Shizuoka JapanInternational Digital Earth Applied Science Research Center Chubu University Kasugai JapanInstitute of Ocean Research Development Tokai University Shizuoka JapanGlobal Center for Asian and Regional Research University of Shizuoka Shizuoka JapanInstitute of Ocean Research Development Tokai University Shizuoka JapanAbstract A highly stressed area where eventual ruptures have often been observed to nucleate is characterized by low b values of earthquake frequency‐size distribution. Crustal deformation due to the occurrence of large earthquakes causes stress perturbation in nearby regions, so an investigation into spatiotemporal b values can play a crucial role in the distribution of postseismic hazards after the 2016 Kumamoto earthquake sequence along the Futagawa‐Hinagu fault zone, which culminated in the magnitude 7.3 mainshock. Together with an analysis of aftershock decay p value that can be used to infer stressing history, a highly stressed area with a characteristic dimension of 10 km at the southern end of the causative faults was found. Our observation is explained by postseismic deformation due to an afterslip on the causative faults and viscoelastic relaxation model. Similar to the Kumamoto mainshock rupture, which started at a low‐b‐value area, the observed highly stressed area shows a high likelihood of future earthquake ruptures.https://doi.org/10.1029/2019GL083463
spellingShingle K.Z. Nanjo
J. Izutsu
Y. Orihara
M. Kamogawa
T. Nagao
Changes in Seismicity Pattern Due to the 2016 Kumamoto Earthquakes Identify a Highly Stressed Area on the Hinagu Fault Zone
Geophysical Research Letters
title Changes in Seismicity Pattern Due to the 2016 Kumamoto Earthquakes Identify a Highly Stressed Area on the Hinagu Fault Zone
title_full Changes in Seismicity Pattern Due to the 2016 Kumamoto Earthquakes Identify a Highly Stressed Area on the Hinagu Fault Zone
title_fullStr Changes in Seismicity Pattern Due to the 2016 Kumamoto Earthquakes Identify a Highly Stressed Area on the Hinagu Fault Zone
title_full_unstemmed Changes in Seismicity Pattern Due to the 2016 Kumamoto Earthquakes Identify a Highly Stressed Area on the Hinagu Fault Zone
title_short Changes in Seismicity Pattern Due to the 2016 Kumamoto Earthquakes Identify a Highly Stressed Area on the Hinagu Fault Zone
title_sort changes in seismicity pattern due to the 2016 kumamoto earthquakes identify a highly stressed area on the hinagu fault zone
url https://doi.org/10.1029/2019GL083463
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AT yorihara changesinseismicitypatternduetothe2016kumamotoearthquakesidentifyahighlystressedareaonthehinagufaultzone
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