The Bhuj earthquake (Mw=7.9) occurred in the western part of India on 26th January 2001 and resulted in the loss of 20,000 lives and caused extensive damage to property. Soil liquefaction related ground failures such as lateral spreading caused significant damage to bridges, dams and other civil engineering structures in entire Kachchh peninsula. The Bhuj area is a part of large sedimentary basin filled with Jurassic, Tertiary and Quaternary deposits. This work pertains to mapping the areas that showed sudden increase in soil moisture after the seismic event, using remote sensing technique. Multi-spectral, spatial and temporal data sets from Indian Remote Sensing Satellite are used to derive the Liquefaction Sensitivity Index (LSeI). The basic concept behind LSeI is that the near infrared and shortwave infrared regions of electromagnetic spectrum are highly absorbed by soil moisture. Thus, the LSeI is herein used to identify the areas with increase in soil moisture after the seismic event. The LSeI map of Bhuj is then correlated with field-based observation on Cyclic Stress Ratio (CSR) and Cyclic Resistance Ratio (CRR), depth to water table, soil density and Liquefaction Severity Index (LSI). The derived LSeI values are in agreement with liquefaction susceptible criteria and observed LSI (R 2 =0.97). The results of the study indicate that the LSeI after calibration with LSI can be used as a quick tool to map the liquefied areas. On the basis of LSeI, LSI, CRR, CSR and saturation, the unconsolidated sediments of the Bhuj area are classified into three susceptibility classes.

In this paper, methods for the generation of residual and prospecting geoids and free-air gravity anomaly using satellite altimeter data are developed. Maps of residual geoid, gravity anomaly, and their spectral components generated over Indian o shore using ERS-1 altimeter data are presented and interpreted. A number of known megastructures over the study area, for example, Bombay High, Saurastra platform, 90ß east ridge, etc., are interpreted successfully from these maps. Some of the anomalous zones (the basins near Mangalore and o Bombay High in the western o shore and Palar basin o Madras coast in the eastern o shore) have been identi® ed as potential sites for occurrences of hydrocarbon-bearing structures, for which detailed ship-borne geophysical surveys have been commissioned by the Oil

The wavelet transform allows multi-resolution decomposition, analysis and reconstruction of remotely sensed images. This study attempts to demonstrate its ability for local or scale-dependent image enhancement using an ERS-1 SAR image. The performance of the proposed wavelet transform enhancement has been assessed with reference to the Fourier domain enhancement.

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