Seismic vulnerability assessment of earthquake-prone mega-city Shillong,India using geophysical mapping and remote sensing |
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| Authors: | Saurabh Baruah Goutam Kashyap Boruah Sangeeta Sharma Washim Akram Hoque Timangshu Chetia Chandan Dey |
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| Institution: | 1. Geosciences and Technology Division, CSIR North East Institute of Science and Technology, Jorhat, Indiasaurabhb_23@yahoo.com;3. Geosciences and Technology Division, CSIR North East Institute of Science and Technology, Jorhat, India;4. Department of Physics, Gauhati University, Guwahati, India |
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| Abstract: | ABSTRACTThe concept of seismic vulnerability is a yard-stick of damage estimation from a probable earthquake considering physical cum social dimension and enables a basis for decision-makers to develop preparedness and mitigation strategies. We aim at vulnerability assessment of the typical urban system of capital city Shillong situated on hilly terrain. High-resolution satellite imagery of Shillong facilitates analysis of building footprints, communication network, and open ground. Different building typologies are identified taking into account the building’s structural configuration assessed through a rapid visual survey of more than 15% of total residential households. Slope map demarcates the landslide-prone area through discrete elevation modelling. A methodology incorporating several parameters e.g. building typology, slope angle, shear wave velocity characteristics, geomorphology, and the number of occupants in correlation with a physical measurement of vulnerability is presented and is applied to estimate the dimension of vulnerability. Additionally, MASW survey indicates lithology up to 30?m deep along with the existence of stiff soil and rocks at different depths whereas resonant frequency is identified to be in the range of 6–8?Hz through H/V ratio. Integrating all, it is observed that more than 60% of Shillong city falls under moderate to higher vulnerability and the rest is less vulnerable. |
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| Keywords: | Seismic hazard and risk seismic vulnerability Shillong rapid visual screening |
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