Additional file 1 of Geodetic plate coupling and seismic potential on the main Himalayan thrust in Nepal
Creators: name: Tabei, Takao
name: Ohzono, Mako
name: Silwal, Bishow R.
name: Bhandari, Rajendra P.
name: Adhikari, Lok B.
name: Chand, Janak B.
name: Kandel, Thakur P.
Publisher: name: figshare
Year: 2024
Subjects: subject: Geology
subject: FOS: Earth and related environmental sciences
subject: Geophysics

description: Additional file 1: Table S1. Secular velocities in ITRF2014 and 1-σ uncertainties at the continuousGNSS stations in and around Nepal. Fig S1. Coordinate time series based on ITRF2014 and locations of selected GNSSstations: (a) East, (b) north, and (c) up components and (d) site map. Time series are sorted into four categories: (1) no significant trend change is recognized after the 25 April 2015 Gorkha earthquake (Mw 7.8) and full data are used for velocity estimation (JMSM and NPGJ), (2) significant trend change and/or postseismic transient are identified after the earthquake but data obtained before the earthquake are available (CHLM and SYBC), (3) data are available only after the earthquake but station is located outside of the postseismic deformation area (SHYN and CDUT), and (4) data are available only after the earthquake and station is located inside the postseismic deformation area (JIR2 and DNC4, velocity not used in this study). Yellow star in (d) indicates the epicenter of the 2015 Gorkha earthquake. Also ellipses in (d) indicate approximate extent of the postseismic deformation area during the period of 2015.31–2017.31 (red dashed line) and 2017.31–2019.31 (blue one) inferred from Tian et al(2020). Fig S2. Map view of the Main Himalayan Thrust in Nepal. (a) 2-km-interval isobath from a regional structural model by Hubbard et al. (2016) (the MHT model). (b) Isobath from a global subduction zone geometry model by Hayes (2018) (the Slab-2 model). Surface trace in (b) (red broken line) is copied from the MHT model because it is not included in the original data file. Fig S3. Spatial resolution test of the inversion. (a) Pre-defined binary slip (unit slip of 1 or 0) distribution every 2 x 2 nodes on the MHT model fault. (b) Recovered slip distribution after the inversion of simulated site velocities with 5% errors. Orange dots show locations of the simulated sites. Fig S4. Rigid and elastic velocities for the MHT model. Black and yellow arrows show velocities due to the rigid rotation of the overriding block and those produced by plate coupling, respectively. Plate coupling distribution on the plate boundary is the same as in Figure 4. Fig S5. Pre-defined angular velocity increment for rigid block rotation and post-fit velocity residuals. The inversions for slip deficit rate distribution on the MHT model are repeated by fixing the rigid rotation of the overriding block. The pole position of rigid rotation is always fixed to the location that is determined by the original inversion while angular velocity is incremented by ±5%, ±10%, ±15%, ±20%, and ±30% from the original estimate. Calculated velocities are produced by the slip deficit rates on the plateboundary, whereas the upper limit of the slip deficit rate is constrained by the block velocity of the rigid rotation. Fig S6. Horizontal strain rate field predicted from the inversion result. (a) Areal dilatation, (b) maximum shear, and (c) principal strain. Predicted velocities from the MHT model (yellow arrows in Figure 4 in the main text) are differentiated by spatial interpolation and filtering with a distance-decaying constant of 50 km (Shen et al.1996). Fig S7. Interseismic plate coupling in Nepal for the revised MHT model. The lower margin of the MHT model fault is extended to the depth of 35 km. (a) Distribution of plate coupling ratio along with the observed (black arrows) and model-predicted (yellow arrows) site velocities relative to the Indian plate. (b) Distribution of the slip deficit rate vector on the plate interface.