[S-GD02] 地殻変動

[SGD02-08] Interseismic slip rate and fault geometry along the northwest Himalaya

*Yogendra Sharma¹、Kuo-En Ching¹、Sumanta Pasari² (1.National Cheng Kung University, Taiwan、2.Birla Institute of TEchnology and Science Pilani)

キーワード：Interseismic crustal deformation, Slip rate and fault geometry, Locking-to-creeping transition zone, Northwest Himalaya

Geodetic networks enable us to investigate interseismic crustal deformation along the northwest Himalaya. Using 94 GNSS surface velocities in a Bayesian inversion model, we estimate the slip rate and fault geometry of the Main Himalayan Thrust (MHT) along six arc-normal transects in the northwest Himalaya. The MHT is found to be completely locked from the surface down to a depth of 6 km to 9 km. The locking-to-creeping transition zone along the decollement extends from the edge of the fully locked area to a deeper depth (13 km) to the tip of the creeping zone of the MHT (19 km) with a slip rate of 1.6 mm/yr to 2.7 mm/yr. The deeper part of the MHT is inferred to be creeping with an average slip rate of ~19.1 mm/yr along the northwest Himalaya. Modeling results, such as locking depth and locking-to-creeping transition zone show a good agreement with observed seismicity in the study region. We compare single-fault modeling results with a splay-fault model that enables a distributed slip rate of the decollement at the locking-to-creeping transition zone. The updated fault kinematics inevitably contribute to the improvement of seismic hazard evaluation along the northwest Himalaya.