Since Greater Bangkok is susceptible to earthquakes, regulations concerning earthquake-resistant design of structures should be amended to include buildings lower than 15 metres, factories with toxic substances and building fittings, experts say.
After the recent quakes in Chiang Rai, concerns about buildings in Bangkok have grown, said Amorn Pimanmas, deputy general secretary of the Council of Engineers and an associate professor at the Sirindhorn International Institute of Technology.
He said buildings lower than 15 metres are now more susceptible to earthquake damage.
"It is not easy and takes time to amend a big law," the lecturer said yesterday at a seminar on earthquakes. "But it's needed because it's about safety."
In the wake of the 2004 tsunami event, the first seismic design standards took effect in 2007, stipulating that buildings taller than 15 metres in Bangkok be designed to withstand earthquakes.
According to Assoc Prof Amorn, the buildings in Bangkok especially susceptible to damage from earthquakes include those built before 2007, government agency buildings like schools and hospitals, and buildings modified without additional strength.
"The regulations should also cover building fittings, not just structures, as overseas research found that 50% of building deaths in an earthquake were caused by building fittings and 50% by the building structure," he said.
Assoc Prof Pennung Warnitchai of the Asian Institute of Technology lists three sources of faults that could have an impact on Bangkok: Kanchanaburi, Myanmar and the Andaman Sea.
In Kanchanaburi, 200 kilometres from the capital, the most severe earthquake in history measured 7.5 on the Richter scale, but so far the Andaman Sea fault has caused the heaviest shaking of buildings in Bangkok.
"The recent quakes in Chiang Rai tell us that earthquakes are not far from us," said Assoc Prof Pennung, an earthquake expert who has spent a long time warning of Bangkok's seismic vulnerability.
Assoc Prof Amorn said the most severely damaged buildings tend to be those built without construction standards and the supervision of engineers.
To enhance and strengthen buildings, he recommends standardised construction, standardised materials like concrete and steel, supervision by engineers and earthquake-resistant design.