Aftershock study of the 2019 Ambon earthquake using moment tensor inversion: identification of fault reactivation in northern Banda, Indonesia
Abstract On September 26, 2019, an Mw 6.5 earthquake occurred 23 km northeast of Ambon City, Indonesia, followed by numerous aftershock series related to a complex fault network reactivation in the Ambon and Seram region. Using moment tensor inversion, we identify the kinematics of fault reactivatio...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2023-08-01
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| Series: | Earth, Planets and Space |
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| Online Access: | https://doi.org/10.1186/s40623-023-01860-1 |
| _version_ | 1797453630201135104 |
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| author | Aria W. Baskara David P. Sahara Andri D. Nugraha Andi Azhar Rusdin Z. Zulfakriza Sri Widiyantoro Wahyu Triyoso Awali Priyono Nanang T. Puspito Hasbi Ash Shiddiqi Dian Kusumawati Alfend Rudyawan Erfin Elly |
| author_facet | Aria W. Baskara David P. Sahara Andri D. Nugraha Andi Azhar Rusdin Z. Zulfakriza Sri Widiyantoro Wahyu Triyoso Awali Priyono Nanang T. Puspito Hasbi Ash Shiddiqi Dian Kusumawati Alfend Rudyawan Erfin Elly |
| author_sort | Aria W. Baskara |
| collection | DOAJ |
| description | Abstract On September 26, 2019, an Mw 6.5 earthquake occurred 23 km northeast of Ambon City, Indonesia, followed by numerous aftershock series related to a complex fault network reactivation in the Ambon and Seram region. Using moment tensor inversion, we identify the kinematics of fault reactivation based on the focal mechanism solution of 20 aftershocks with Mw > 3.2 and analyze the earthquake sequence from both focal mechanism solutions and spatiotemporal seismicity. The MTs solution of aftershocks revealed three different characteristics of fault reactivation: (i) a 35 km long N-S oriented main fault characterized by dextral strike-slip (ii) a NE-SW reverse fault segment with a ~ 55° northeastward dip located in southwest Seram, and (iii) two strike-slip segments (NNW-SSE and NNE-SSW trends) and an E-W normal fault in Ambon Island. Analysis of spatiotemporal seismicity with the MTs solution suggests that the Mw 6.5 Ambon aftershock sequences can be described as follows: (i) an Mw 6.5 mainshock rupture that was primarily made up of a major strike-slip component and an insignificant minor normal fault; (ii) first aftershock cluster propagate along the main N-S ruptures, followed by the strike-slip and normal cluster in Ambon Island (iii) The reverse fault events cluster appeared next in Southwest Seram. The presence of complex strike-slip segments in Ambon agrees with the regional structure trends in Halmahera, located in the north of the study area, while the E-W oriented normal fault might be related to the eastward velocity increase in Banda Arc, which causes extensional deformation. Given that the fault reactivation identified in Ambon and Seram is located close to the densely populated urban regions of Ambon City and Kairatu, the analysis of future seismic hazards related to this fault reactivation should consider the risks in a region with complex fault settings. Graphical Abstract |
| first_indexed | 2024-03-09T15:25:36Z |
| format | Article |
| id | doaj.art-b8cd04d96ad2443faf61f3979b1419b5 |
| institution | Directory Open Access Journal |
| issn | 1880-5981 |
| language | English |
| last_indexed | 2024-03-09T15:25:36Z |
| publishDate | 2023-08-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Earth, Planets and Space |
| spelling | doaj.art-b8cd04d96ad2443faf61f3979b1419b52023-11-26T12:35:02ZengSpringerOpenEarth, Planets and Space1880-59812023-08-0175112310.1186/s40623-023-01860-1Aftershock study of the 2019 Ambon earthquake using moment tensor inversion: identification of fault reactivation in northern Banda, IndonesiaAria W. Baskara0David P. Sahara1Andri D. Nugraha2Andi Azhar Rusdin3Z. Zulfakriza4Sri Widiyantoro5Wahyu Triyoso6Awali Priyono7Nanang T. Puspito8Hasbi Ash Shiddiqi9Dian Kusumawati10Alfend Rudyawan11Erfin Elly12Geophysical Engineering Study Program, Institut Teknologi BandungGlobal Geophysics Research Group, Institut Teknologi BandungGlobal Geophysics Research Group, Institut Teknologi BandungAgency of Meteorology, Climatology, and Geophysics of IndonesiaGlobal Geophysics Research Group, Institut Teknologi BandungGlobal Geophysics Research Group, Institut Teknologi BandungGlobal Geophysics Research Group, Institut Teknologi BandungGlobal Geophysics Research Group, Institut Teknologi BandungGlobal Geophysics Research Group, Institut Teknologi BandungDepartment of Earth Science, University of BergenGeophysical Engineering Study Program, Institut Teknologi BandungGeological Engineering Study Program, Institut Teknologi BandungGeological Engineering Study Program, Pattimura UniversityAbstract On September 26, 2019, an Mw 6.5 earthquake occurred 23 km northeast of Ambon City, Indonesia, followed by numerous aftershock series related to a complex fault network reactivation in the Ambon and Seram region. Using moment tensor inversion, we identify the kinematics of fault reactivation based on the focal mechanism solution of 20 aftershocks with Mw > 3.2 and analyze the earthquake sequence from both focal mechanism solutions and spatiotemporal seismicity. The MTs solution of aftershocks revealed three different characteristics of fault reactivation: (i) a 35 km long N-S oriented main fault characterized by dextral strike-slip (ii) a NE-SW reverse fault segment with a ~ 55° northeastward dip located in southwest Seram, and (iii) two strike-slip segments (NNW-SSE and NNE-SSW trends) and an E-W normal fault in Ambon Island. Analysis of spatiotemporal seismicity with the MTs solution suggests that the Mw 6.5 Ambon aftershock sequences can be described as follows: (i) an Mw 6.5 mainshock rupture that was primarily made up of a major strike-slip component and an insignificant minor normal fault; (ii) first aftershock cluster propagate along the main N-S ruptures, followed by the strike-slip and normal cluster in Ambon Island (iii) The reverse fault events cluster appeared next in Southwest Seram. The presence of complex strike-slip segments in Ambon agrees with the regional structure trends in Halmahera, located in the north of the study area, while the E-W oriented normal fault might be related to the eastward velocity increase in Banda Arc, which causes extensional deformation. Given that the fault reactivation identified in Ambon and Seram is located close to the densely populated urban regions of Ambon City and Kairatu, the analysis of future seismic hazards related to this fault reactivation should consider the risks in a region with complex fault settings. Graphical Abstracthttps://doi.org/10.1186/s40623-023-01860-12019 Ambon earthquakeAftershock sequencesSource mechanismMoment tensor inversionFault reactivation |
| spellingShingle | Aria W. Baskara David P. Sahara Andri D. Nugraha Andi Azhar Rusdin Z. Zulfakriza Sri Widiyantoro Wahyu Triyoso Awali Priyono Nanang T. Puspito Hasbi Ash Shiddiqi Dian Kusumawati Alfend Rudyawan Erfin Elly Aftershock study of the 2019 Ambon earthquake using moment tensor inversion: identification of fault reactivation in northern Banda, Indonesia Earth, Planets and Space 2019 Ambon earthquake Aftershock sequences Source mechanism Moment tensor inversion Fault reactivation |
| title | Aftershock study of the 2019 Ambon earthquake using moment tensor inversion: identification of fault reactivation in northern Banda, Indonesia |
| title_full | Aftershock study of the 2019 Ambon earthquake using moment tensor inversion: identification of fault reactivation in northern Banda, Indonesia |
| title_fullStr | Aftershock study of the 2019 Ambon earthquake using moment tensor inversion: identification of fault reactivation in northern Banda, Indonesia |
| title_full_unstemmed | Aftershock study of the 2019 Ambon earthquake using moment tensor inversion: identification of fault reactivation in northern Banda, Indonesia |
| title_short | Aftershock study of the 2019 Ambon earthquake using moment tensor inversion: identification of fault reactivation in northern Banda, Indonesia |
| title_sort | aftershock study of the 2019 ambon earthquake using moment tensor inversion identification of fault reactivation in northern banda indonesia |
| topic | 2019 Ambon earthquake Aftershock sequences Source mechanism Moment tensor inversion Fault reactivation |
| url | https://doi.org/10.1186/s40623-023-01860-1 |
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