Slow slip events following the afterslip of the 2002 Mw 7.1 Hualien offshore earthquake, Taiwan
Abstract Geodetic evidence for slow slip recurrence changed by stress perturbations was rare, especially from afterslip following a nearby large earthquake. The first observed slow slip events in the southernmost Ryukyu subduction had occurred in 2005, 2009, and 2015 following the nearby 2002 March...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-04-01
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| Series: | Earth, Planets and Space |
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| Online Access: | https://doi.org/10.1186/s40623-022-01629-y |
| _version_ | 1818263850982572032 |
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| author | Sean Kuanhsiang Chen Yih-Min Wu Yu-Chang Chan |
| author_facet | Sean Kuanhsiang Chen Yih-Min Wu Yu-Chang Chan |
| author_sort | Sean Kuanhsiang Chen |
| collection | DOAJ |
| description | Abstract Geodetic evidence for slow slip recurrence changed by stress perturbations was rare, especially from afterslip following a nearby large earthquake. The first observed slow slip events in the southernmost Ryukyu subduction had occurred in 2005, 2009, and 2015 following the nearby 2002 March 31 Mw 7.1 Hualien offshore earthquake. To investigate whether the Mw 7.1 earthquake had influenced the occurrence times of the slow slip, we calculated the coseismic slip distribution and afterslip distribution using the surface displacements from onshore Global Navigation Satellite System observations. The stress perturbation on the slow-slip regions caused by the coseismic slip was quantified using the Coulomb failure criteria. We also examined the aftershock distribution and the evolution with time to clarify the stress perturbations from the afterslip offshore. Our results show that the primary afterslip distribution may have overlapped the 2009 and 2015 slow-slip patch at the downdip of the earthquake. The coseismic stress perturbation may have influenced the SSEs area directly by a Coulomb stress increase of probably 0.10 MPa. However, the 2005 SSE patch in the updip depths had only a little coseismic slip and afterslip with the Coulomb stress increase of approximately 0.06 MPa. We find that most of the aftershocks had occurred in the 2009 and 2015 slow-slip region that evolved into a typical aftershock sequence at least 2.5 years after the earthquake. The surface geodetic displacements reveal that the afterslip may have lasted longer than 4.5 years after the earthquake. The evidence for the afterslip proves that the 2009 and 2015 slow-slip patch was influenced by the afterslip directly for years. We suggest that the ongoing afterslip may have modulated the coseismic stress perturbation. It may explain the delay of the 2009 slow slip occurrence compared with the recurrence interval between the 2009 and 2015 slow slip events. Graphical Abstract |
| first_indexed | 2024-12-12T19:25:35Z |
| format | Article |
| id | doaj.art-c4b1a6250dc44ea49a9e59c3abc96589 |
| institution | Directory Open Access Journal |
| issn | 1880-5981 |
| language | English |
| last_indexed | 2024-12-12T19:25:35Z |
| publishDate | 2022-04-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Earth, Planets and Space |
| spelling | doaj.art-c4b1a6250dc44ea49a9e59c3abc965892022-12-22T00:14:32ZengSpringerOpenEarth, Planets and Space1880-59812022-04-0174111310.1186/s40623-022-01629-ySlow slip events following the afterslip of the 2002 Mw 7.1 Hualien offshore earthquake, TaiwanSean Kuanhsiang Chen0Yih-Min Wu1Yu-Chang Chan2Department of Geosciences, National Taiwan UniversityDepartment of Geosciences, National Taiwan UniversityInstitute of Earth Sciences, Academia SinicaAbstract Geodetic evidence for slow slip recurrence changed by stress perturbations was rare, especially from afterslip following a nearby large earthquake. The first observed slow slip events in the southernmost Ryukyu subduction had occurred in 2005, 2009, and 2015 following the nearby 2002 March 31 Mw 7.1 Hualien offshore earthquake. To investigate whether the Mw 7.1 earthquake had influenced the occurrence times of the slow slip, we calculated the coseismic slip distribution and afterslip distribution using the surface displacements from onshore Global Navigation Satellite System observations. The stress perturbation on the slow-slip regions caused by the coseismic slip was quantified using the Coulomb failure criteria. We also examined the aftershock distribution and the evolution with time to clarify the stress perturbations from the afterslip offshore. Our results show that the primary afterslip distribution may have overlapped the 2009 and 2015 slow-slip patch at the downdip of the earthquake. The coseismic stress perturbation may have influenced the SSEs area directly by a Coulomb stress increase of probably 0.10 MPa. However, the 2005 SSE patch in the updip depths had only a little coseismic slip and afterslip with the Coulomb stress increase of approximately 0.06 MPa. We find that most of the aftershocks had occurred in the 2009 and 2015 slow-slip region that evolved into a typical aftershock sequence at least 2.5 years after the earthquake. The surface geodetic displacements reveal that the afterslip may have lasted longer than 4.5 years after the earthquake. The evidence for the afterslip proves that the 2009 and 2015 slow-slip patch was influenced by the afterslip directly for years. We suggest that the ongoing afterslip may have modulated the coseismic stress perturbation. It may explain the delay of the 2009 slow slip occurrence compared with the recurrence interval between the 2009 and 2015 slow slip events. Graphical Abstracthttps://doi.org/10.1186/s40623-022-01629-ySlow slip eventsCoseismic slipAfterslipAftershockCoulomb stress change |
| spellingShingle | Sean Kuanhsiang Chen Yih-Min Wu Yu-Chang Chan Slow slip events following the afterslip of the 2002 Mw 7.1 Hualien offshore earthquake, Taiwan Earth, Planets and Space Slow slip events Coseismic slip Afterslip Aftershock Coulomb stress change |
| title | Slow slip events following the afterslip of the 2002 Mw 7.1 Hualien offshore earthquake, Taiwan |
| title_full | Slow slip events following the afterslip of the 2002 Mw 7.1 Hualien offshore earthquake, Taiwan |
| title_fullStr | Slow slip events following the afterslip of the 2002 Mw 7.1 Hualien offshore earthquake, Taiwan |
| title_full_unstemmed | Slow slip events following the afterslip of the 2002 Mw 7.1 Hualien offshore earthquake, Taiwan |
| title_short | Slow slip events following the afterslip of the 2002 Mw 7.1 Hualien offshore earthquake, Taiwan |
| title_sort | slow slip events following the afterslip of the 2002 mw 7 1 hualien offshore earthquake taiwan |
| topic | Slow slip events Coseismic slip Afterslip Aftershock Coulomb stress change |
| url | https://doi.org/10.1186/s40623-022-01629-y |
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