Seismicity around Sri Lanka from Historical Records and its Engineering Implications

This paper describes a study carried out to analyse the historical records of earthquakes in the vicinity of Sri Lanka. The records indicate that the 1615 earthquake was the most significant earthquake that affected Sri Lanka. By analysing over 300 records of earthquakes around Sri Lanka, it was found that Mannar rift zone and Comorin ridge is the critical zone of influence which is capable of generating a seismic event of magnitude 6.9 at a 475 year return period at a depth of 10 – 15 km below the sea level. The study demonstrates that seismicity around Sri Lanka cannot be no longer ignored and engineering design should include seismic hazards.