Seismic microzonation of Srinagar city, Jammu and Kashmir

Abstract

The seismic vulnerability of Kashmir basin is evident from the historical and instrumental earthquake records in general and the capital city of Srinagar in particular. An attempt is made here to deliver the seismic microzonation map of this scenic city. To do so, probabilistic and geotechnical hazard representing the primary seismic hazard, secondary seismic hazard and site conditions are used as input themes. The themes considered for the holistic integrated hazard quantification are the peak ground acceleration at engineering bedrock, shear wave velocity distribution representing site conditions, liquefaction potential index, site amplification ratio and predominant frequency distribution. All these themes have been assigned appropriate weights and their features. The highest weight was given to peak ground acceleration, followed by shear wave velocity distribution, liquefaction potential index, site amplification ratio and predominant frequency themes. These weighted themes are then integrated in the GIS environment to generate seismic microzonation map of the Srinagar city. This map is expressed in terms of the Seismic Hazard Index (SHI) and is accordingly grouped into two classes: very high and severe. The results demonstrate that Srinagar city is susceptible to very high seismic hazard, especially when predicted peak ground acceleration is of the order of 0.605–0.63 g at the bedrock.