Overview | Earthquake | Drought | Fire | Flood & Cyclones | Landslide & Soil Erosion | Volcano
Geomatics in Earthquake Mitigation
Ramanuj Banerjee, Devendra Kumar, K. K. Mohanty and Shailesh Nayak
ESHD/MWRG-RESA, Space Applications Centre (ISRO),
Ahmedabad - 380015.
Abstract
The modern space-based remote sensing, spatial science and information technologies have opened up efficient means for tectonic studies and evaluation of earthquake risk and mitigation strategy. The areas affected by earthquake are large and generally confined to plate boundaries. Fault rupture and associated surface deformation, liquefaction, damage due to ground shaking can be observed using remote sensing. The measurement of fault displacements using Global Positioning System (GPS) and radar interferometry is useful to study co-seismic and post-seismic deformations. The monitoring of deformation indicates about strain built up. Liquefaction, which occurred during the Kachchh earthquake, was mapped using IRS data (WiFS, LISS-III and PAN). Seismic hazard zonation is essential for regional and urban planning and the only safeguard for earthquake. Seismic micro-zonation maps are derived from estimation of various effects of seismic waves at the terrain surface: ground shaking, surface faulting, liquefaction. GIS helps in analyzing large volume of data on active faults, geological structure, soil type, depth to groundwater table, topography and infrastructure. This article attempts to review the potential of geomatics as tool in earthquake mitigation.
Introduction
Natural disasters like cyclone, flood, drought, landslide, earthquake etc. have devastating effect on life and property. Earthquakes are short-lived, menacing and the most feared natural hazards because of their sudden impact and devastation in a matter of few seconds inflicting immense losses of life and property. Crustal deformation is in fact a direct manifestation of the process that leads to earthquakes. Though areas prone to seismic hazards are fairly well known, there has been very little advance in our ability to predict when, where, or with what magnitude will the next earthquake strike. Since we are not in a position to predict an earthquake, we must atleast try to find out the scientific causes that can lead to such catastrophic earthquakes. For this, study of neotectonics and geology of a particular region is very important. The major thrust is to arrive at a probabilistic zoning map of the study area based on basis of these scientific findings and incorporate all relevant details related to damage assessment, rescue and relief operations.
Geomatics is a recently emerging technology, which can play a vital role in mitigation of natural disasters. Geomatics is a conglomerate of measuring, mapping, geodesy, satellite positioning (GPS), photogrammetry, computer systems and computer graphics, remote sensing, geographic information systems (GIS) and environmental visualization. The earth observation satellites provide comprehensive, synoptic and multi-temporal coverage of large areas for a wide range of scales, from entire continents to details of a few meters in real time and at frequent intervals and thus have become valuable for continuous monitoring of earth and its atmosphere (Roy et al., 2000). Remote sensing and GIS based change detection technique is used to assess earthquake induced damages to houses and other structures accurately and speedily as this technique is cost effective, unbiased, and free from subjectivity, time saving and provides quantitative damage assessment.