Earthquake preparedness is a must for Bangkok as the capital is not far from active fault lines where even a moderate quake could send strong shock waves to the city, seismologists have warned.

City Hall has issued a warning that about 2,700 buildings in the capital could be damaged by an earthquake.

Bangkok is less than 200 kilometres from Kanchanaburi, home to the Chedi Sam Ong fault line, and about 800km from Chiang Mai, where the Mae Ta and Mae Chan fault lines are located.

The Chedi Sam Ong, Mae Ta, and Mae Chan are among 13 active fault lines in Thailand covering 22 provinces.

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Studies showed there is a high possibility that a powerful earthquake of 6-7 magnitude will occur along the fault lines in Kanchanaburi and Chiang Mai provinces, Pennung Warnitchai, a seismologist from the Asian Institute of Technology, said yesterday.

His comment followed the 6.8-magnitude earthquake in northern Burma that killed at least 75 people, including a Thai villager in Chiang Rai, on Thursday.

The quake sent shock waves that could be felt in several parts of Thailand, including Bangkok.

Quakes in Kanchanaburi or Chiang Mai would not only cause severe damage to the two provinces but also to Bangkok, Mr Pennung said.

"We will see severe damage to buildings and other structures in Bangkok," the seismologist said.

He said most people only pay attention to the 13 main fault lines, but studies have confirmed that many sub-fault lines are also active and have the potential to produce mild earthquakes.

The Chedi Sam Ong fault line has eight sub-fault lines, while the Mae Chan fault line in Chiang Mai has up to 18 sub-fault lines, he said.

However, Lertsin Raksaskulwong, director of the Mineral Resources Department's environmental geology and geohazard bureau, disagreed.

He said earthquake damage in Bangkok would not be serious.

"There won't be total building collapse. People will only feel the buildings shaking, like many people in highrises felt on Thursday," he said.

Mr Lertsin also dismissed speculation that Thursday's quake, which had its epicentre at the Nam Ma fault line on the Burma-Laos border, would trigger a quake at the nearby Mae Chan fault line in Chiang Mai and Chiang Rai provinces.

The Nam Ma fault line runs parallel with the Mae Chan fault line, so it would not have any impact on the Thai fault line.

Surachai Ponpattarakul, a senior expert at the Department of Public Works and Town and Country Planning, said the issue of buildings' resistance to earthquakes had become a major concern following frequent natural disasters.

The agency has been drafting a regulation to help owners of buildings constructed before the enforcement of the 2007 Building Control Act improve their buildings' structures to ensure they are earthquake-resistant.

The Building Control Act stipulates that buildings 23 metres or higher and buildings covering more than 10,000 square metres must have structures that can resist an earthquake of at least 5 on the Richter scale.

Under the regulation, tax reductions would be offered to owners wanting to strengthen a building's foundations and structure, Mr Surachai said.

Prime Minister Abhisit Vejjajiva yesterday said that highrise buildings must be designed and built to ensure they can absorb the impact of earthquakes and measures must be put in place to prevent and mitigate disasters related to quakes.

Deputy Bangkok Governor Pornthep Techapaiboon said initial inspections of 12 highrise buildings in Bangkok after Thursday's earthquake found none had been damaged, but a close watch would be kept on the situation.

The buildings, which are located near communities, include Sermmitr Tower, First Tower, MBK Centre, the All Seasons building, Empire Tower, Chai Tower, the Benjinda building, Shinawatra Tower III, the Thai Military Bank building and the Sun Tower building.

Mr Pornthep said a fire that broke out at Platinum Mall at Pratunam had nothing to do with the earthquake.

He said more than 2,700 buildings in Bangkok that stand five metres or higher are still vulnerable to future earthquake tremors.

City Hall has written to ask owners of the buildings to check the strength and security of the structures. Mr Pornthep said 905 of the buildings were built before the Building Control Act came into force.