Comparative response of Kashmir Basin and its surroundings to the earthquake shaking based on various site effects

Abstract

The Kashmir Basin is located in seismic zone V, seismogenic faults and damaging earthquakes of 1555, 1885 and 2005 support this classification. Tectonic features are preserved in older hard rocks, and soft-sediment deformation structures (seismites) in the Karewa deposits. Older basement rocks are overlain unconformably by ~1300 m Karewa deposits followed by unconsolidated fluvial sediments that greatly influence earthquake amplitude and duration of shaking. Seismic waves show a drastic change in peak ground velocity and acceleration when travelling through Karewa deposits. The surrounding epicentre zones are dominated by large earthquakes with shallow depth (4–24 km). Ruggedness, steep-slopes and basin curvature can cause PGA amplification during an unpredicted earthquake. The ill consideration of infrastructure on the water saturated rugged terrain causes ground collapse, and consequently threat to life during seismic shaking. The proximity and linear trend of tectonic structures, epicentre distribution, shallow depth seismicity, thickness and material properties of near surface sediments are unfavourable for safety of the infrastructure and the population.