Geological and Surface Geophysical Studies of Lineaments along Coastal Corridor from Kakinada to Balasore, India

The present study focuses on integrated geological and geophysical studies in urbanized locales of Kakinada, Visakhapatnam, Vizianagaram and Srikakulam in Andhra Pradesh, and Khurda Road, Bhubaneswar, Cuttack, Bhadrak and Balasore in Odisha. These flat areas along the coastal rivers generally consist of thick layers of soft clay and sand, wherein their susceptibility to liquefaction has devastating consequences during an earthquake. The inherent property of clay and sand amplify certain frequencies of ground motion, there by attributing to an increase in the damage due to an earthquake. To understand the local ground conditions that substantially affect the characteristics of seismic waves propagating towards the surface during earthquakes, combined study of satellite imagery and surface geological studies were done for identification of critical geological features. This led to delineation of 75 lineaments for geophysical survey, which was done at selected locations along the Kakinada to Balasore coastal corridor. The NW-SE trending lineaments viz. Kanada - Kumili fault, ParvatipuramBobbilli fault, Nagavali fault, Vamsadhara faults, Mahanadi, Rushikulya and Brahmoni are the major lineaments identified along the corridor for the study. The geophysical measurements were carried out using Multichannel Analysis of Surface Wave (MASW) and seismic refraction to understand the near surface characteristics of these lineament zones. Subsequently, average shear wave velocities (Vs30) and stiffness were computed using the Vs and empirical relations. The results of the study (L-27, L-28, L-62 & L-64 are showing low Vs ranging from 180m/s350m/s which indicates presence of soft soils with >20m, moderate Vs zone is 300-500m/s and high Vs zone is >600 m/s having shallow bed rock up to <10m to <5m) have an important role in seismic hazard assessment for east coast corridor and aid finding answers to puzzling questions regarding their significance in the seismic design of the engineering structures along or across the lineaments