The 2016 Kaikōura earthquake : simultaneous rupture of the subduction interface and overlying faults
The distribution of slip during an earthquake and how it propagates among faults in the subduction system play a major role in seismic and tsunami hazards, yet they are poorly understood because offshore observations are often lacking. Here we derive the slip distribution and rupture evolution durin...
| Main Authors: | , , , , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
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2019
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| Online Access: | https://hdl.handle.net/10356/106351 http://hdl.handle.net/10220/49585 |
| _version_ | 1826117468665413632 |
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| author | Wang, Teng Wei, Shengji Shi, Xuhua Qiu, Qiang Li, Linlin Peng, Dongju Weldon, Ray J. Barbot, Sylvain |
| author2 | Asian School of the Environment |
| author_facet | Asian School of the Environment Wang, Teng Wei, Shengji Shi, Xuhua Qiu, Qiang Li, Linlin Peng, Dongju Weldon, Ray J. Barbot, Sylvain |
| author_sort | Wang, Teng |
| collection | NTU |
| description | The distribution of slip during an earthquake and how it propagates among faults in the subduction system play a major role in seismic and tsunami hazards, yet they are poorly understood because offshore observations are often lacking. Here we derive the slip distribution and rupture evolution during the 2016 Mw 7.9 Kaikōura (New Zealand) earthquake that reconcile the surface rupture, space geodetic measurements, seismological and tsunami waveform records. We use twelve fault segments, with eleven in the crust and one on the megathrust interface, to model the geodetic data and match the major features of the complex surface ruptures. Our modeling result indicates that a large portion of the moment is distributed on the subduction interface, making a significant contribution to the far field surface deformation and teleseismic body waves. The inclusion of local strong motion and teleseismic waveform data in the joint inversion reveals a unilateral rupture towards northeast with a relatively low averaged rupture speed of ∼1.5 km/s. The first 30 s of the rupture took place on the crustal faults with oblique slip motion and jumped between fault segments that have large differences in strike and dip. The peak moment release occurred at ∼65 s, corresponding to simultaneous rupture of both plate interface and the overlying splay faults with rake angle changes progressively from thrust to strike-slip. The slip on the Papatea fault produced more than 2 m of offshore uplift, making a major contribution to the tsunami at the Kaikōura station, while the northeastern end of the rupture can explain the main features at the Wellington station. Our inversions and simulations illuminate complex up-dip rupture behavior that should be taken into consideration in both seismic and tsunami hazard assessment. The extreme complex rupture behavior also brings new challenges to the earthquake dynamic simulations and understanding the physics of earthquakes. |
| first_indexed | 2024-10-01T04:28:05Z |
| format | Journal Article |
| id | ntu-10356/106351 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:28:05Z |
| publishDate | 2019 |
| record_format | dspace |
| spelling | ntu-10356/1063512020-09-26T21:28:52Z The 2016 Kaikōura earthquake : simultaneous rupture of the subduction interface and overlying faults Wang, Teng Wei, Shengji Shi, Xuhua Qiu, Qiang Li, Linlin Peng, Dongju Weldon, Ray J. Barbot, Sylvain Asian School of the Environment Earth Observatory of Singapore Finite Rupture Model Strong Motion Social sciences::Geography The distribution of slip during an earthquake and how it propagates among faults in the subduction system play a major role in seismic and tsunami hazards, yet they are poorly understood because offshore observations are often lacking. Here we derive the slip distribution and rupture evolution during the 2016 Mw 7.9 Kaikōura (New Zealand) earthquake that reconcile the surface rupture, space geodetic measurements, seismological and tsunami waveform records. We use twelve fault segments, with eleven in the crust and one on the megathrust interface, to model the geodetic data and match the major features of the complex surface ruptures. Our modeling result indicates that a large portion of the moment is distributed on the subduction interface, making a significant contribution to the far field surface deformation and teleseismic body waves. The inclusion of local strong motion and teleseismic waveform data in the joint inversion reveals a unilateral rupture towards northeast with a relatively low averaged rupture speed of ∼1.5 km/s. The first 30 s of the rupture took place on the crustal faults with oblique slip motion and jumped between fault segments that have large differences in strike and dip. The peak moment release occurred at ∼65 s, corresponding to simultaneous rupture of both plate interface and the overlying splay faults with rake angle changes progressively from thrust to strike-slip. The slip on the Papatea fault produced more than 2 m of offshore uplift, making a major contribution to the tsunami at the Kaikōura station, while the northeastern end of the rupture can explain the main features at the Wellington station. Our inversions and simulations illuminate complex up-dip rupture behavior that should be taken into consideration in both seismic and tsunami hazard assessment. The extreme complex rupture behavior also brings new challenges to the earthquake dynamic simulations and understanding the physics of earthquakes. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Published version 2019-08-07T08:45:12Z 2019-12-06T22:09:39Z 2019-08-07T08:45:12Z 2019-12-06T22:09:39Z 2017 Journal Article Wang, T., Wei, S., Shi, X., Qiu, Q., Li, L., Peng, D., . . . Barbot, S. (2018). The 2016 Kaikōura earthquake : simultaneous rupture of the subduction interface and overlying faults. Earth and Planetary Science Letters, 482, 44-51. doi:10.1016/j.epsl.2017.10.056 0012-821X https://hdl.handle.net/10356/106351 http://hdl.handle.net/10220/49585 10.1016/j.epsl.2017.10.056 en Earth and Planetary Science Letters © 2017 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 8 p. application/pdf |
| spellingShingle | Finite Rupture Model Strong Motion Social sciences::Geography Wang, Teng Wei, Shengji Shi, Xuhua Qiu, Qiang Li, Linlin Peng, Dongju Weldon, Ray J. Barbot, Sylvain The 2016 Kaikōura earthquake : simultaneous rupture of the subduction interface and overlying faults |
| title | The 2016 Kaikōura earthquake : simultaneous rupture of the subduction interface and overlying faults |
| title_full | The 2016 Kaikōura earthquake : simultaneous rupture of the subduction interface and overlying faults |
| title_fullStr | The 2016 Kaikōura earthquake : simultaneous rupture of the subduction interface and overlying faults |
| title_full_unstemmed | The 2016 Kaikōura earthquake : simultaneous rupture of the subduction interface and overlying faults |
| title_short | The 2016 Kaikōura earthquake : simultaneous rupture of the subduction interface and overlying faults |
| title_sort | 2016 kaikoura earthquake simultaneous rupture of the subduction interface and overlying faults |
| topic | Finite Rupture Model Strong Motion Social sciences::Geography |
| url | https://hdl.handle.net/10356/106351 http://hdl.handle.net/10220/49585 |
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