Bangkok at Risk from "Sleeping Giant" Fault Lines, Experts Warn

Bangkok faces a significant risk from three major "sleeping giant" fault lines, which could trigger devastating earthquakes, experts have warned. 

The recent seismic activity in Mandalay, Myanmar, has highlighted the vulnerability of the Thai capital to tremors originating from distant fault lines.

Prof Dr Penneung Wanichchai, director of the National Earthquake Research Center, revealed that Bangkok's soft soil basin amplifies seismic waves by three to four times, particularly affecting high-rise buildings. 

Penneung Wanichchai

This phenomenon, known as resonance, occurs when the frequency of the earthquake's waves matches the natural oscillation of tall structures.

"The impact on high-rise buildings is disproportionately severe," Dr Penneung explained. "Low-rise buildings are far less affected."
 

He outlined three critical earthquake scenarios that pose a threat to Bangkok:

Kanchanaburi Fault: A dormant fault line in Kanchanaburi Province, just 200 kilometres from Bangkok, could produce earthquakes of magnitude 7-7.5.

Sagaing Fault: This fault line, extending through Myanmar, including Mandalay and Naypyidaw, and into the Andaman Sea, could generate magnitude 8 earthquakes, impacting Bangkok.

Andaman Subduction Zone: Located along the Arakan subduction zone, this area has the potential for magnitude 8.5-9 earthquakes. Although further away than the Sagaing Fault, its potential impact on Bangkok is equally significant.
 

Historical studies indicate that the Andaman region has experienced earthquakes of magnitude 8.5 or higher, with the last major event occurring approximately 260 years ago. 

"This region has a seismic cycle of 400-500 years," Dr Penneung noted, adding that the timing of the next major earthquake is unpredictable.

Penneung Wanichchai

"We cannot precisely predict when these 'sleeping giants' will awaken," he cautioned. "But we must prepare for the worst-case scenarios."

The experts stressed the importance of constructing buildings in Bangkok to withstand these potential seismic events. The three scenarios outlined serve as the basis for designing structures capable of withstanding the most extreme possible tremors.