SL more vulnerable to earthquakes

Ishara Mudugamuwa

Sri Lanka can no longer be considered isolated from the effects of seismic activities, said chairman of the Sub Committee on Developing Building Guidelines for Earthquake Resistant Designs, of the Disaster Management Centre (DMC) K.L.S.Sahabandu.

Addressing the Terms of Reference of Knowledge and Experience Seminar on Disaster Management at the Disaster Management Ministry yesterday, the chairman said recent geological studies have identified that the Indo - Australian Plate is splitting at a distance of 500- 700 km away from the southwest coast of Sri Lanka, creating a new plate margin. This may lead Sri Lanka to be more vulnerable to earthquakes in the future that what are experience today.

“The first documented earthquake in Sri Lanka occurred in 1615 AD which killed thousands of people. In the recent past we have experienced many earth tremors, but, no major damage to structures were reported.

"But any future earthquake close to a city centre such as, Colombo will have disastrous consequences due to its present development and population. Therefore we have understood the necessity to study the seismic effects on Sri Lanka and take appropriate action to mitigate the same,” said the Chairman.

He also said it is not possible to prevent the occurrence of an earthquake since it is a natural phenomenon. But damage can be minimized through preparedness. During the last decade both government and non-government have been engaged in this direction. Presently the DMC take the lead role in this en devour.

“There is a strong need to establish national building design guidelines for both engineered and non-engineered buildings to resist seismic loads. To meet this objective, the DMC formed a subcommittee to develop building guidelines for earthquake resistance designs,” he said.

Chairman Sahabandu further said the subcommittee investigate seismic activities around the country and determine characteristics of earthquakes which may occur in future. The subcommittee also review the current design practice which does not generally cater for seismic resistance and develop effective design process to mitigate the effects of earthquake hazard in future. National policy on earthquake resistance designs shall be prepared based on scientific evidence.

The Subcommittee to Develop Building Guidelines for Earthquake Resistance Designs has also made proposals to conduct studies on reviewing the seismic monitoring systems and propose improvement to the system, developing seismic hazard map including earthquake intensities, acceleration coefficients, response spectrum, return periods, etc., development of a 3D sub-surface model that improves the susceptibility of consequences against the possible earthquake in Sri Lanka, development of national guidelines for seismic analysis and design of engineered and non-engineered buildings in Sri Lanka, improvement of the available detailing manual “Reinforcement Detailing for Mitigation of Seismic Effects” published by Sri Lanka and preparation of guidelines for retrofitting works. Disaster Management Deputy Minister Dulip Wijesekara, Ministry Secretary S.M.Mohomad, Embassy of Japan Head of the Economic Cooperation Suguru Minoya, JICA Sri Lanka Office Chief Representative Harumi Ao, Japanese Disaster Management Experts Prof. Fumuhiko Imamura, Dr.Satoru Nishikawa, JICA Senior Adviser Tatsuo Narafu, Meteorology Department Director General S.H.Kariyawasam, National Building Research Organization Director General Asiri Karunawardane and many other heads of the institutions and officials participated to the occasion.