CHIANG RAI – Monday’s large aftershock in Chiang Rai’s Mae Suai district has deepened worries that similarly sized tremors could continue for weeks.
The jolt, measuring 4.8 on the Richter scale, hit at 5.32am with a 3.9-magnitude shaker following 10 minutes later, the seismology office of the Meteorological Department reported on its website.
The aftershocks reportedly were six kilometers underground, with the epicenter near the Chiang Mai provincial border.
Suwith Kosuwan, director of the Active Fault Research Division of the Mineral Resources Department, told the Bangkok Post the two temblors were not newly originated earthquakes. “They were aftershocks from the quake on May 5,” he said.
Aftershocks are normal after a major earthquake and more jolts from the May 5 upheaval will occur at least until the end of September, the official added.
The 6.3-magnitude quake that hit neighboring Mae Lao district of Chiang Rai in May was one of the most-destructive bouts of seismic activity in recent history of Thailand. It extensively damaged buildings, houses and roads in the areas and the jolt could be felt as far as Chiang Rai, Chiang Mai, Lampang and Phayao municipalities. The quake hit the Phayao fault line.
More than 800 aftershocks, most of them small, have been recorded in the area since, the seismology office said.
Aftershocks of at least 3.0 on the Richter scale are seen as significant as they can be felt by people. “There were hundreds of them of a 3.0 scale and more,” Mr Suwith said.
Mai Suai continues to be prone to shaking as aftershocks normally take place south of the location where a quake happens, he added.
”An aftershock of 4.8 on Monday was quite big. I’m certain that more exciting aftershocks will certainly come,” the official added.
Another aftershock of 3.4 on the Richter scale was recorded in Mae Lao Sunday with no reports of damage, the seismology office said.
Sawang Pomdee, chief of the disaster prevention and mitigation office in Chiang Rai, said the aftershocks on Monday caused no damage as they did not hit residential areas, according to FM 100.5 radio programme. Officials are monitoring signs of landslides, he added.
Mr Suwith also warned people living in the area of the aftershocks in Mae Suai and Mae Lao to ”stay extremely alert” on possible flash floods and landslides as a result of the quakes.
The ground shaking has loosen soil in the area in the area and heavy rains would exacerbate the risk of flash flooding, if not landslides, he said. Northern provinces face heavy rainfalls in August and September.