Natural disasters in Sri Lanka, recognised as an earthquake-free country, mainly consist of floods and landslides. However, the mild tremors occurred in Gurudeniya, Haragama, Anuragama, Mailapitiya, Ambakote, Digana and Aluthwatta in Kandy on August 29 and September 2, caught the attention of many people.
According to Geological Survey and Mines Bureau (GSMB) Chairman Anura Walpola, the tremors, recorded in the seismic centre at Pallekele, cannot be considered as earthquakes.
“If the magnitude of the tremor is greater than 2.0 on the Richter scale, we consider it as an earthquake. If an earthquake occurred, it has to be recorded in all five seismic centres of the country. But these tremors have been recorded only in the Pallekele seismic centre,” the Bureau chief told the media.
The Bureau has five seismic centres, Mihintale, Pallekele, Hakmana, Puttalam and Colombo.
The GSMB has deployed two teams of six Geophysicists and Seismologists to investigate the incidents. Geophysicist Nilmini Thaldena, a member of an investigation team, told the media that the tremors ‘could be’ a consequence of reservoirs in nearby areas.
“But that is just one cause and it is too early to predict,” she told the media.
Last year, tremors occurred in several areas, including Badulla, Passara, Haliela and Nuwara-Eliya. The tremor occurred in Badulla on March 16, 2019, registered 3.5 on the Richter scale. In 2018, another tremor of similar magnitude was reported in Kinniya, Trincomalee. GSMB Senior Director, Geologist Udaya De Silva told the Sunday Observer yesterday that the investigation report on the tremors would be released to the public tomorrow.
Emeritus Professor of Geology in the University of Peradeniya C.B. Dissanayake in an article titled ‘A new plate boundary near Sri Lanka: Implications for future geohazards’ published in 2005 ‒soon after the tsunami occurred in the Indian Ocean where over 35,000 Sri Lankans lost their lives stated, “The break zone (Indo-Australian split) of the Indo-Australian plate, where the new plate boundary is forming, is centred on a point roughly 600 miles south of the tip of the India.”
It revealed important findings, including the probabilities of earthquakes, minor tremors and most importantly Tsunamis near Sri Lankan coastline in the future as a result of the new plate boundary being created south to Sri Lanka.