Hydrogeomorphological observations from Thenmala and Thenmala south fault, India

Abstract

Achankovil shear zone is a North West-South East (NW-SE) oriented Precambrian structure of South India. Present work identified evidences of two faults (trending NW-SE) in the southern most end of this shear zone. They are Thenmala fault and Thenmala south Fault. This study is an attempt to understand the structural control of these NW-SE structures over the drainage development of the study area, based on geomorphological evidences and field data. Morphometric analysis of the drainage basins clearly indicate that basins located near NW-SE structures shows more anomalies. This anomalies in the vicinity of lineaments and faults indicate their influence over the drainage development. Observed brittle faults evidences with numerous slip planes from the south eastern end of the study area also support this argument. Morphometric evidences in association with brittle fault observations suggest that Achankovil shear zone may be week and reacting to the current stress regime.