Myanmar quake: Soil liquefaction caused severe damage, says Indian agency NCS

New Delhi: India's earthquake monitoring agency NCS said the temblor that struck Myanmar and Thailand Friday afternoon caused severe damage because its shaking frequency matched the natural vibration of buildings.

Soil liquefaction -- when soil loses its characteristics and behaves like thick liquid -- was also one of the reasons for damage, O P Mishra, the head of the National Centre for Seismology (NCS), said.

Thailand's capital, Bangkok, which is over a thousand kilometres from the epicentre in Mandalay, Myanmar, suffered significant damage as the rupture's direction was toward it, he said.

The NCS said that seven aftershocks, ranging in magnitude from 3.5 to 7, followed the main earthquake of magnitude 7.5, which struck Mandalay around 11:50 am (IST).

Northeast India also felt the main earthquake and its aftershocks.

The agency said the earthquake was caused by the Sagaing Fault, a major fault line located 1,200 km east of the Indo-Burma subduction zone. The energy from the earthquake spread toward Bangkok, Thailand.

Another major reason for the damage was that the earthquake's shaking frequency matched the natural vibration of buildings, making them more vulnerable, the NCS said.

"The rupture direction is towards Bangkok, Thailand, causing severe damage to structures in the region due to liquefactions and matching of earthquake shaking frequency with the spectral frequency of the structures," it said.

A strong aftershock of magnitude 7 occurred just 12 minutes later, about 90 km southwest of the first earthquake, the NCS said.

It said the region has experienced major earthquakes in the past, including a magnitude 7.5 earthquake in 1912 and a magnitude 7.2 earthquake in 1956.

Media reports said the earthquake killed at least three people in Bangkok and buried dozens when a high-rise building under construction collapsed.

Myanmar's military-run government declared a state of emergency in six regions and states, including the capital Nay Pyi Taw and Mandalay, the reports said.