FAULT TECTONICS OF THE SHILLONG PLATEAU AND ADJOINING REGIONS, NORTHEAST INDIA USING REMOTE-SENSING DATA

The Shillong plateau in north-east India shows innumerable fracture li neaments on satellite images. In fact the whole plateau is criss-cross ed by fractures. The plateau has been subjected to extensive compressi onal forces mainly in N-S and E-W directions resulting from the collis ion of the Indian plate with the Tibetan and Burmese plates, respectiv ely. This type of plate tectonism has been responsible for the formati on of many significant faults, folds and other tectonic features in th e Shillong plateau and adjoining regions. The well known E-W trending Dauki fault, N-S trending faults, NE-SW trending shear zone and other prominent lineaments and their associated structural features could be studied on the basis of remote sensing techniques. Folding in soft se diments along the Dauki fault reveals the compression direction. Direc tional compressional tectonism has been expressed through lateral move ments along the NE-SW trending shear zone and N-S trending faults and folds in the area just south of the Haflong thrust. It has been observ ed from the studies that the Dauki fault zone and the areas in Banglad esh show various tectonic features, which are mostly controlled by ver tical movements. Seismicity of the Shillong plateau is quite scattered all over the area. The occurrence of several deep earthquakes (> 100 km) indicate deep tectonic activities in the upper mantle. Earthquakes have been found to occur near some faults and this is probably an ind ication of recent activities along these faults.