The 2018 MS 5.9 Mojiang Earthquake: Source model and intensity based on near-field seismic recordings
On September 8, 2018, an MS 5.9 earthquake struck Mojiang, a county in Yunnan Province, China. We collect near-field seismic recordings (epicentral distances less than 200 km) to relocate the mainshock and the aftershocks within the first 60 hours to determine the focal mechanism solutions of the ma...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Science Press
2019-05-01
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| Series: | Earth and Planetary Physics |
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| Online Access: | http://www.eppcgs.org/article/doi/10.26464/epp2019028?pageType=en |
| _version_ | 1811218665238953984 |
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| author | Xu Zhang Zhen Fu LiSheng Xu ChunLai Li Hong Fu |
| author_facet | Xu Zhang Zhen Fu LiSheng Xu ChunLai Li Hong Fu |
| author_sort | Xu Zhang |
| collection | DOAJ |
| description | On September 8, 2018, an MS 5.9 earthquake struck Mojiang, a county in Yunnan Province, China. We collect near-field seismic recordings (epicentral distances less than 200 km) to relocate the mainshock and the aftershocks within the first 60 hours to determine the focal mechanism solutions of the mainshock and some of the aftershocks and to invert for the finite-fault model of the mainshock. The focal mechanism solution of the mainshock and the relocation results of the aftershocks constrain the mainshock on a nearly vertical fault plane striking northeast and dipping to the southeast. The inversion of the finite-fault model reveals only a single slip asperity on the fault plane. The major slip is distributed above the initiation point, ~14 km wide along the down-dip direction and ~14 km long along the strike direction, with a maximal slip of ~22 cm at a depth of ~6 km. The focal mechanism solutions of the aftershocks show that most of the aftershocks are of the strike-slip type, a number of them are of the normal-slip type, and only a few of them are of the thrust-slip type. On average, strike-slip is dominant on the fault plane of the mainshock, as the focal mechanism solution of the mainshock suggests, but when examined in detail, slight thrust-slip appears on the southwest of the fault plane while an obvious part of normal-slip appears on the northeast, which is consistent with what the focal mechanism solutions of the aftershocks display. The multiple types of aftershock focal mechanism solutions and the slip details of the mainshock both suggest a complex tectonic setting, stress setting, or both. The intensity contours predicted exhibit a longer axis trending from northeast to southwest and a maximal intensity of Ⅷ around the epicenter and in the northwest. |
| first_indexed | 2024-04-12T07:13:13Z |
| format | Article |
| id | doaj.art-dbd19872c32349efa6bf30e392fdd28b |
| institution | Directory Open Access Journal |
| issn | 2096-3955 |
| language | English |
| last_indexed | 2024-04-12T07:13:13Z |
| publishDate | 2019-05-01 |
| publisher | Science Press |
| record_format | Article |
| series | Earth and Planetary Physics |
| spelling | doaj.art-dbd19872c32349efa6bf30e392fdd28b2022-12-22T03:42:35ZengScience PressEarth and Planetary Physics2096-39552019-05-013326828110.26464/epp2019028xulisheng1The 2018 MS 5.9 Mojiang Earthquake: Source model and intensity based on near-field seismic recordingsXu Zhang0Zhen Fu1LiSheng Xu2ChunLai Li3Hong Fu4Institute of Geophysics, China Earthquake Administration, Beijing 100081, ChinaInstitute of Geophysics, China Earthquake Administration, Beijing 100081, ChinaInstitute of Geophysics, China Earthquake Administration, Beijing 100081, ChinaInstitute of Geophysics, China Earthquake Administration, Beijing 100081, ChinaEarthquake Administration of Yunnan Province, Kunming 650224, ChinaOn September 8, 2018, an MS 5.9 earthquake struck Mojiang, a county in Yunnan Province, China. We collect near-field seismic recordings (epicentral distances less than 200 km) to relocate the mainshock and the aftershocks within the first 60 hours to determine the focal mechanism solutions of the mainshock and some of the aftershocks and to invert for the finite-fault model of the mainshock. The focal mechanism solution of the mainshock and the relocation results of the aftershocks constrain the mainshock on a nearly vertical fault plane striking northeast and dipping to the southeast. The inversion of the finite-fault model reveals only a single slip asperity on the fault plane. The major slip is distributed above the initiation point, ~14 km wide along the down-dip direction and ~14 km long along the strike direction, with a maximal slip of ~22 cm at a depth of ~6 km. The focal mechanism solutions of the aftershocks show that most of the aftershocks are of the strike-slip type, a number of them are of the normal-slip type, and only a few of them are of the thrust-slip type. On average, strike-slip is dominant on the fault plane of the mainshock, as the focal mechanism solution of the mainshock suggests, but when examined in detail, slight thrust-slip appears on the southwest of the fault plane while an obvious part of normal-slip appears on the northeast, which is consistent with what the focal mechanism solutions of the aftershocks display. The multiple types of aftershock focal mechanism solutions and the slip details of the mainshock both suggest a complex tectonic setting, stress setting, or both. The intensity contours predicted exhibit a longer axis trending from northeast to southwest and a maximal intensity of Ⅷ around the epicenter and in the northwest.http://www.eppcgs.org/article/doi/10.26464/epp2019028?pageType=en2018 ms 5.9 mojiang earthquakenear-field seismic recordingfinite-fault modelintensity predictionfocal mechanism solution |
| spellingShingle | Xu Zhang Zhen Fu LiSheng Xu ChunLai Li Hong Fu The 2018 MS 5.9 Mojiang Earthquake: Source model and intensity based on near-field seismic recordings Earth and Planetary Physics 2018 ms 5.9 mojiang earthquake near-field seismic recording finite-fault model intensity prediction focal mechanism solution |
| title | The 2018 MS 5.9 Mojiang Earthquake: Source model and intensity based on near-field seismic recordings |
| title_full | The 2018 MS 5.9 Mojiang Earthquake: Source model and intensity based on near-field seismic recordings |
| title_fullStr | The 2018 MS 5.9 Mojiang Earthquake: Source model and intensity based on near-field seismic recordings |
| title_full_unstemmed | The 2018 MS 5.9 Mojiang Earthquake: Source model and intensity based on near-field seismic recordings |
| title_short | The 2018 MS 5.9 Mojiang Earthquake: Source model and intensity based on near-field seismic recordings |
| title_sort | 2018 ms 5 9 mojiang earthquake source model and intensity based on near field seismic recordings |
| topic | 2018 ms 5.9 mojiang earthquake near-field seismic recording finite-fault model intensity prediction focal mechanism solution |
| url | http://www.eppcgs.org/article/doi/10.26464/epp2019028?pageType=en |
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