Several studies have considered Achankovil shear zone as NW–SE trending Precambrian crustal scale structure. Two major faults, namely Thenmala and Thenmala south faults, are identified associated with this shear zone. The present study identified NW–SE trending segmented lineaments in these zones. Major drainages and rock units surrounding these faults show NW–SE trend. The present study applied both conventional and recent geomorphic parameters to identify anomalies related to these structures. Morphometric results suggest that the area between Thenmala fault and Thenmala south fault, especially the central part, exhibits anomalies supporting active tectonism. Field investigation carried out in this zone identified continuities of NW–SE trending faults as brittle deformation in the southeastern part of the study area. Faults observed in the well sections along these lineaments show multiple slip planes and gouge formations. Morphometric results and field evidences suggest reactivation of these NW–SE structures associated with the present stress regime of peninsular India. Moreover, several instances of historic and recent earthquakes reported from this area. Considering the general trend of the seismic source zone reported in the peninsular India the NW–SE trending faults can generate a magnitude > 5.0. In view of this peak ground acceleration is calculated for a magnitude of 5.5 as the maximum credible earthquake that can be generated by these two faults. Frequent earthquakes within short duration around these faults indicate that the above-mentioned structures may be tectonically active and may generate a ground acceleration between 2.6 and 2.8 in the nearby cities.