Highlights Our slip model with Bayesian inversion reveals the 2020 Nima event ruptured a blind normal slip with high dip angle. Slip rate and local stress analysis on YCRC fault indicate its high potential earthquake risk. Frequent extensional earthquake activities in central Tibet support the upwelling of soft material.

    Abstract Normal faults and conjugate strike-slip faults have been considered to play an important role in response to the extension deformation of central Tibet. On 22 July 2020, a Mw 6.3 earthquake struck the Nima county, central Tibet, in China, which provides a rare opportunity to get insights into how the normal faults in central Tibet accommodates the east-west extension caused by the Indian-Eurasian convergence. In this study, the Sentinel-1 images are collected to measure the coseismic deformation associated with this 2020 event and image its slip distribution. To mitigate the atmospheric phase effects, the generic atmospheric correction online service (GACOS) model is used to correct the coseismic inteferograms. The final coseismic deformation results show mainly negative displacement with a maximum value of ∼ 30 cm in the line of sight (LOS) direction. After that, a Bayesian inversion method is used to invert the fault model. Our results reveal the optimal seismogenic fault of this event with a strike angle of 31.3°, a dip angle of 51.6°, and show that its slip distribution is dominated by normal slip with a maximum value of 2.55 m at a depth of 4.79–9.53 km, which suggest it’s a blind normal rupture with high east-trending dip angle. The total released geodetic moment is, equivalent to Mw 6.3. In addition, we analyze the Coulomb stress change due to the 2008 Gaize and this 2020 Nima events, suggesting the 2020 event should not be triggered by the 2008 event. Finally, we estimate an interseismic slip rate of 4.7 ± 1.2 mm/yr on the Yibug Caka-RigainPun Co (YCRC) fault with published global navigation satellite system (GNSS) measurements. Given that these high frequent normal slip events but a low crustal extension rate of 4.7 ± 1.2 mm/yr in this region, we speculate that the asthenosphere material upwelling should be also a possible reason for E-W extensional activities in central Tibet.


    Zugriff

    Zugriff prüfen

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Source mechanism of the 2020 Mw 6.3 Nima earthquake derived from Bayesian inversions with InSAR observations: Insight into E-W extensional activity in the central Tibet


    Beteiligte:
    Hu, Xiaoping (Autor:in) / He, Ping (Autor:in) / Zhang, Jue (Autor:in)

    Erschienen in:

    Advances in Space Research ; 70 , 7 ; 1721-1736


    Erscheinungsdatum :

    2022-06-26


    Format / Umfang :

    16 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch