A Review on the Seismic Vulnerability of Oil and Gas Pipelines in Guwahati City

Abstract

Crude oil in the north-eastern state of Assam was discovered in the late nineteenth century in the eastern reaches of the state. With passage of time the oil, natural gas and petroleum products were transported from Assam to various parts of the country via pipelines. The pipelines traversing through the length of the state pass over are located close to several tectonically active faults. Some of the noteworthy faults are Oldham fault, Kopili fault and Dhubri fault. These faults have been the sources of several past damaging earthquakes (EQs) such as the 1897 Assam EQ (MW = 8.1), 1869 Cachar EQ (MW = 7.5), 1943 Assam EQ (Ms = 7.2) and 1930 Dhubri EQ (Ms = 7.1), respectively. The 1157 km long automated trunk pipeline used to carry products from Oil India Limited (OIL) and Oil and Natural Gas Corporation (ONGC) pass directly over the Kopili fault. The upcoming Barauni-Guwahati gas pipeline by GAIL will cross the Dhubri fault and will also be located very close to the Oldham fault. Thus, the pipelines are at risk of being subjected to high intensity of shaking from future earthquakes. Further, since the time of laying of the pipelines, no major or great earthquakes have occurred in Assam. Hence, the seismic vulnerability of the pipelines remains unknown. This review study is an attempt to understand the seismic vulnerability of the pipelines located in the vicinity of the Guwahati city and in case of failure its impact on the inhabitants of the city.