2024-03-28T08:37:49Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/2141702020-06-13T01:22:12Zcom_10261_48com_10261_5col_10261_301
2020-06-12T07:52:33Z
urn:hdl:10261/214170
‘Two go together’: Near-simultaneous moment release of two asperities during the 2016 Mw 6.6 Muji, China earthquake
Bie, Lidong
Hicks, Stephen
Garth, Thomas
González, Pablo J.
Rietbrock, Andreas
Natural Environment Research Council (UK)
Near simultaneous failure
Muji earthquake
InSAR
Multiple moment tensor
Inversion
Seismic gap
On 25 November 2016, a Mw 6.6 earthquake ruptured the Muji fault in western Xinjiang, China. We investigate the earthquake rupture independently using geodetic observations from Interferometric Synthetic Aperture Radar (InSAR) and regional seismic recordings. To constrain the fault geometry and slip distribution, we test different combinations of fault dip and slip direction to reproduce InSAR observations. Both InSAR observations and optimal distributed slip model suggest buried rupture of two asperities separated by a gap of greater than 5 km. Additional seismic gaps exist at the end of both asperities that failed in the 2016 earthquake. To reveal the dynamic history of asperity failure, we inverted regional seismic waveforms for multiple centroid moment tensors and construct a moment rate function. The results show a small centroid time gap of 2.6 s between the two sub-events. Considering the >5 km gap between the two asperities and short time interval, we propose that the two asperities failed near-simultaneously, rather than in a cascading rupture propagation style. The second sub-event locates ∼39 km to the east of the epicenter and the centroid time is at 10.7 s. It leads to an estimate of average velocity of 3.7 km/s as an upper bound, consistent with upper crust shear wave velocity in this region. We interpret that the rupture front is propagating at sub-shear wave velocities, but that the second sub-event has a reduced or asymmetric rupture time, leading to the apparent near-simultaneous moment release of the two asperities.
2020-06-12T07:52:33Z
2020-06-12T07:52:33Z
2018-06-01
artículo
Earth and Planetary Science Letters 491: 34-42 (2018)
0012-821X
http://hdl.handle.net/10261/214170
10.1016/j.epsl.2018.03.033
http://dx.doi.org/10.13039/501100000270
eng
Postprint
https://doi.org/10.1016/j.epsl.2018.03.033
No
https://creativecommons.org/licenses/by/4.0/
closedAccess
Elsevier