Postseismic deformation associated with the 2015 Mw 7.8 Gorkha earthquake, Nepal: Investigating ongoing afterslip and constraining crustal rheology

Jiang, Zhongshan; Yuan, Linguo; Huang, Dingfa; Yang, Zhongrong; Hassan, Abubakr

doi:10.1016/j.jseaes.2017.12.039

Cited by 21 publications

(42 citation statements)

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“…The affected GNSS stations surround the coseismic rupture with stations to the north showing the greatest deformation (e.g., CHLM). These observations are in agreement with previously published work (Gualandi et al, 2016;Jiang et al, 2018;Mencin et al, 2016;Zhao et al, 2017).…”

Section: Observations Summarysupporting

confidence: 94%

“…Our assessment of the postseismic deformation following the Gorkha event largely agrees with previous work (Gualandi et al, 2016;Jiang et al, 2018;Mencin et al, 2016;Sreejith et al, 2016;Wang & Fialko, 2018;Zhao et al, 2017). GNSS and InSAR measurements show that postseismic deformation is relatively localized and predominantly north (downdip) of the coseismic deformation.…”

Section: Postseismic Deformationsupporting

confidence: 90%

“…The spatial location and extent of postseismic surface deformation for the Gorkha earthquake suggests that slip downdip of the coseismic rupture is a likely cause of the observations, as inferred by previous authors (Gualandi et al, 2016;Jiang et al, 2018;Mencin et al, 2016;Sreejith et al, 2016;Wang & Fialko, 2018;Zhao et al, 2017). We used VISCO-1D (Pollitz, 1997) to perform simple viscoelastic relaxation calculations.…”

Section: Deformation Mechanismmentioning

confidence: 89%

“…Coseismic and interseismic deformation data are readily available for Nepal, having been acquired prior to and during the 2015 M w 7.8 Gorkha earthquake (e.g., Ader et al, 2012;Elliott et al, 2016;Galetzka et al, 2015;Jackson & Bilham, 1994;Lindsey et al, 2015). There have been a handful of postseismic deformation studies carried out for this event (Gualandi et al, 2016;Jiang et al, 2018;Mencin et al, 2016;Sreejith et al, 2016;Zhao et al, 2017). These postseismic studies find a relatively small deformation signal, which is more dependent on the data processing methods applied.…”

Section: 1029/2019jb019201mentioning

confidence: 99%

“…This means that inferred postseismic deformation models are largely unconstrained north of the Himalayan range. Zhao et al (2017) and Jiang et al (2018) supplemented GNSS stations south of the Himalayan range with a small number of stations operating in southern Tibet. These far-field stations record small postseismic displacements toward the rupture zone, while the stations south of the range show similar displacements to other studies.…”

Section: Previous Studiesmentioning

confidence: 99%

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Constraints on the Geometry and Frictional Properties of the Main Himalayan Thrust Using Coseismic, Postseismic, and Interseismic Deformation in Nepal

et al. 2020

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The geometry and frictional properties of a fault system are key parameters required to understand its seismic behavior. The Main Himalayan Thrust in Nepal is the type example of a continental megathrust and forms part of a fault system which accommodates a significant fraction of India‐Eurasia convergence. Despite extensive study of this zone of shortening, the geometry of the fault system remains controversial. Here, we use interseismic, coseismic, and postseismic geodetic data in Nepal to investigate the proposed downdip geometries. We use interseismic and coseismic data from previous studies, acquired before and during the 2015 Mw 7.8 Gorkha earthquake. We then supplement these by processing our own postseismic deformation data, acquired following the Gorkha earthquake. We find that kinematic modeling of geodetic data alone cannot easily distinguish between the previously proposed geometries. We therefore develop a mechanical joint coseismic‐postseismic slip inversion which simultaneously solves for the distribution of coseismic slip and rate‐strengthening friction parameters. We run this inversion using the proposed geometries and find that they are all capable of explaining the majority of geodetic data. We find values for the rate parameter, a, from the rate‐and‐state friction law that are between 0.8 and 1.6×10−3, depending on the geometry used. These values are in agreement with results from laboratory studies and those inferred from other earthquakes. We suggest that the limitations of earthquake cycle geodesy partly explain the continued controversy over the geometry and role of various faults in the Nepal Himalaya.

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Section: Observations Summarysupporting

confidence: 94%