Loss assessment of Sylhet city from an event similar to 1918 Srimangal earthquake

摘要

A comprehensive earthquake loss assessment for the Sylhet city of Bangladesh using Geographic Information Technology was performed considering the 1918 Srimangal Earthquake as a scenario event. Site amplification, liquefaction, and landslide microzonation maps for the city were developed for this purpose. For microzonation purpose 167 boreholes with SPT data were used. For the assessment of potential losses, a building inventory was carried out for the Sylhet city. 3040 buildings (12% of the total) were surveyed within the study area. On the other hand for the Iqss assessment of water and gas pipelines, the water and gas delivery network of the city were digitized and put within a GIS platform. Site amplification, liquefaction and landslide microzonation maps were overlaid and combined with the structural inventory maps, and water and gas supply system maps to produce maps of regional damage distributions. The methods to combine the different hazards are based on weighted average approach. For human casualty estimation a morbidity model was used. Finally economic loss was estimated using the damages expected to be suffered due to the scenario event. The expected damage for buildings is 59%, maximum fatalities 7.0% and maximum injuries 8.3% at night. In case of lifeline, affected length for water pipe line is 118.53 km and total number of damage points is 204 and affected length of gas supply system is 436 km and total number of damage points is 981.