Absence of aftershocks rattles geologists

A SENIOR geologist in Thailand has warned that the 6.8-magnitude earthquake that shook central Myanmar last week could be followed by an even stronger seismic event, given the absence of aftershocks so far.

Suwit Khosuwan, the active fault director of Thailand’s Department of Mineral Resources, was quoted in the Bangkok Post as saying that officials in his department were closely monitoring the Rakhine Fault – which caused the August 24 quake – for an aftershock, and that without one there could be another strong quake of at least 7.0 magnitude.

There had been three foreshocks preceding the earthquake centred 25 kilometres (16 miles) west of Chauk in Magwe Region, Mr Suwit said, adding that it was “strange” that there had not been any aftershocks.

U Myo Thant, secretary of the Myanmar Earthquake Committee, said aftershocks could occur up to two months after the main earthquake, with magnitudes of around 5.0 to 6.0.

“The August 24 earthquake was caused by the subduction of the India tectonic plate under the Burma plate,” he said.

He added that the 6.9-magnitude quake that struck on April 13 at a depth of 122 kilometres (76 miles) was also caused by the movement of the India and Burma plates.

“If these 6.8 and 6.9 earthquakes were foreshocks rather than main shocks, could an even more powerful quake be lurking in the future? This is just one possibility that we are considering,” U Myo Thant said.

“I don’t want to speculate on the probability, but it’s better to stay alert. It’s too early to guess why there have not been any aftershocks [since the August 24 tremor].”