Morphotectonic and sedimentological aspects in describing the relationship with ancient failure surfaces in southern part of Aizawl anticline, Mizoram, India


Population growth in Aizawl city has caused urban areas to expand into landslide-prone areas. These areas comprised of Bhuban Formation rocks of Surma Group and have geological features that frequently generate ground instabilities. The present study integrated with morphotectonic analysis, geotectonic characterization, role of litho-units including their sedimentological aspects and analyses of precipitation time series reveals that the southern part of Aizawl city is tectonically active and lithologically vulnerable towards landslide disaster. Greater surface slope and similar bed attitude enhance the risk of failure. The massive sandstone overlies upon weak clay surfaces that are regularly lubricated by high down pour. Even moderate rainfall can trigger the landslides. The clay layers can mobilize the geological litho-sequences as a combined result of the tropical humid climate and observed weak slope stability conditions. A catastrophic landslide had killed more than 80 people and many other sliding events have been recorded in adjacent areas. Therefore, this study presents tectonic and geologic conditions which can help to predict future slides.

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