Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E–W Thinning in Northern Tibet
Extensional earthquakes in the Tibetan Plateau play an important role in the plateau’s orogenic evolution and cause heavy seismic hazard, yet their mechanisms remain poorly known, in particular in harsh northern Tibet. On 25 June 2020, a Mw 6.2 earthquake struck Yutian, Xinjiang, offering us a rare...
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MDPI AG
2020-09-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/12/18/3012 |
| _version_ | 1827706153218342912 |
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| author | Ping He Yangmao Wen Kaihua Ding Caijun Xu |
| author_facet | Ping He Yangmao Wen Kaihua Ding Caijun Xu |
| author_sort | Ping He |
| collection | DOAJ |
| description | Extensional earthquakes in the Tibetan Plateau play an important role in the plateau’s orogenic evolution and cause heavy seismic hazard, yet their mechanisms remain poorly known, in particular in harsh northern Tibet. On 25 June 2020, a Mw 6.2 earthquake struck Yutian, Xinjiang, offering us a rare chance to gain insights into its mechanism and implications in the Tibetan extension. We used both descending and ascending Sentinel-1 images to generate coseismic deformation associated with this event, which indicates a typical extensional mechanism with a maximum subsidence displacement of 25 cm and minor uplift. The causative fault constrained with interferometric synthetic aperture radar (InSAR) data based on a finite fault model suggests that the fault plane has a strike of 186.4° and westward dip of 64.8°, and the main rupture is concentrated at a depth of 3.6–10.8 km with a peak slip of 0.85 m. Our source model indicates that the 2020 Yutian event ruptured an unknown high-angle blind normal fault with N–S striking. The total released geodetic moment yields 2.69 × 10<sup>18</sup> N·m, equivalent to Mw 6.23. We used dense interseismic global positioning system (GPS) measurements to reveal an approximate 7 mm/yr extensional motion in the Yutian region, but it still does not seem large enough to support high local seismicity for normal events within 12 years, i.e., Mw 7.1 in 2008, Mw 6.2 in 2012, and this event in 2020. Combined with Coulomb stress change modeling, we speculate that the seismicity in Yutian is related to the lower lithospheric dynamics. |
| first_indexed | 2024-03-10T16:17:36Z |
| format | Article |
| id | doaj.art-6dfd11ac6f80404cb1d55ddc153e8f3a |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T16:17:36Z |
| publishDate | 2020-09-01 |
| publisher | MDPI AG |
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| series | Remote Sensing |
| spelling | doaj.art-6dfd11ac6f80404cb1d55ddc153e8f3a2023-11-20T13:54:45ZengMDPI AGRemote Sensing2072-42922020-09-011218301210.3390/rs12183012Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E–W Thinning in Northern TibetPing He0Yangmao Wen1Kaihua Ding2Caijun Xu3Hubei Subsurface Multi-Scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, ChinaSchool of Geodesy and Geomatics, Wuhan University, Wuhan 430079, ChinaFaculty of Information Engineering, China University of Geosciences, Wuhan 430074, ChinaSchool of Geodesy and Geomatics, Wuhan University, Wuhan 430079, ChinaExtensional earthquakes in the Tibetan Plateau play an important role in the plateau’s orogenic evolution and cause heavy seismic hazard, yet their mechanisms remain poorly known, in particular in harsh northern Tibet. On 25 June 2020, a Mw 6.2 earthquake struck Yutian, Xinjiang, offering us a rare chance to gain insights into its mechanism and implications in the Tibetan extension. We used both descending and ascending Sentinel-1 images to generate coseismic deformation associated with this event, which indicates a typical extensional mechanism with a maximum subsidence displacement of 25 cm and minor uplift. The causative fault constrained with interferometric synthetic aperture radar (InSAR) data based on a finite fault model suggests that the fault plane has a strike of 186.4° and westward dip of 64.8°, and the main rupture is concentrated at a depth of 3.6–10.8 km with a peak slip of 0.85 m. Our source model indicates that the 2020 Yutian event ruptured an unknown high-angle blind normal fault with N–S striking. The total released geodetic moment yields 2.69 × 10<sup>18</sup> N·m, equivalent to Mw 6.23. We used dense interseismic global positioning system (GPS) measurements to reveal an approximate 7 mm/yr extensional motion in the Yutian region, but it still does not seem large enough to support high local seismicity for normal events within 12 years, i.e., Mw 7.1 in 2008, Mw 6.2 in 2012, and this event in 2020. Combined with Coulomb stress change modeling, we speculate that the seismicity in Yutian is related to the lower lithospheric dynamics.https://www.mdpi.com/2072-4292/12/18/30122020 Yutian earthquakeInSAR coseismic displacementinterseismic GPSnorthern Tibet extension |
| spellingShingle | Ping He Yangmao Wen Kaihua Ding Caijun Xu Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E–W Thinning in Northern Tibet Remote Sensing 2020 Yutian earthquake InSAR coseismic displacement interseismic GPS northern Tibet extension |
| title | Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E–W Thinning in Northern Tibet |
| title_full | Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E–W Thinning in Northern Tibet |
| title_fullStr | Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E–W Thinning in Northern Tibet |
| title_full_unstemmed | Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E–W Thinning in Northern Tibet |
| title_short | Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E–W Thinning in Northern Tibet |
| title_sort | normal faulting in the 2020 mw 6 2 yutian event implications for ongoing e w thinning in northern tibet |
| topic | 2020 Yutian earthquake InSAR coseismic displacement interseismic GPS northern Tibet extension |
| url | https://www.mdpi.com/2072-4292/12/18/3012 |
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