Myanmar Earthquake: Scientists Explain Why It Was So Deadly

A powerful earthquake struck Myanmar on Friday, with experts suggesting it may be the strongest to hit the country in decades. Disaster modeling indicates that the death toll could reach into the thousands.

7.7-Magnitude Earthquake

According to automatic assessments from the United States Geological Survey (USGS), the 7.7-magnitude earthquake, which occurred northwest of the central city of Sagaing, triggered a red alert for fatalities and economic losses.

“High casualties and extensive damage are probable, and the disaster is likely widespread,” the USGS reported, pinpointing the epicenter near Mandalay, a city home to over a million people.

The ruling junta confirmed on Saturday morning that the death toll had surpassed 1,000, with more than 2,000 people injured. However, USGS estimates suggest a 35 percent chance that fatalities could range between 10,000 and 100,000.

Financial damage is also expected to be severe. The USGS warned that economic losses could reach tens of billions of dollars, potentially surpassing Myanmar’s gross domestic product.

The Dangerous Sagaing Fault: A Major Geological Threat

Experts believe the earthquake was likely caused by the movement of the Sagaing Fault, one of the most active and dangerous fault lines in Southeast Asia. Bill McGuire, emeritus professor of geophysical and climate hazards at University College London (UCL), described it to AFP as “probably the biggest earthquake on the Myanmar mainland in three-quarters of a century.”

A powerful 6.7-magnitude aftershock followed minutes later, with McGuire warning that “more can be expected.”

Rebecca Bell, a tectonics expert at Imperial College London (ICL), explained to AFP that the earthquake resulted from a “strike-slip” motion, where the Indian tectonic plate meets the Sunda plate.

“The Sagaing fault is very long, about 1,200 kilometers (745 miles), and very straight,” Bell said. “This means earthquakes can rupture over large areas, and the larger the fault slip, the larger the earthquake.”

Since the quake occurred at a shallow depth, its seismic energy had little time to dissipate before reaching the surface, leading to intense ground shaking.

A History of Earthquakes in Myanmar

Myanmar has experienced several powerful earthquakes in the past. Over the last century, there have been more than 14 earthquakes of magnitude 6 or greater. A 6.8-magnitude quake struck near Mandalay in 1956, according to Brian Baptie, a seismologist with the British Geological Survey.

However, Ian Watkinson, an expert in earth sciences at Royal Holloway University of London, noted a critical difference in the recent disaster.

“During previous magnitude 7 or larger earthquakes along the Sagaing Fault, Myanmar was relatively undeveloped, with mostly low-rise timber-framed buildings and brick-built religious monuments,” Watkinson said.

In contrast, rapid urbanization has led to a boom in high-rise buildings made from reinforced concrete. Many of these structures lack proper regulatory oversight due to the country’s political instability.

Poorly Constructed Buildings Increased Casualties

The severity of the destruction was amplified by weak infrastructure. Baptie estimated that at least 2.8 million people were in high-impact zones, with many residing in timber and unreinforced brick masonry buildings that are particularly vulnerable to earthquakes.

“The usual mantra is that ‘earthquakes don’t kill people; collapsing infrastructure does,'” said Ilan Kelman, a disaster reduction expert at UCL.

“Governments are responsible for planning regulations and building codes. This disaster exposes what Myanmar’s authorities failed to do long before the earthquake, which would have saved lives during the shaking.”

Impact Reaches Thailand: Skyscraper Collapses in Bangkok

The earthquake’s tremors extended to neighboring Thailand, where a 30-story skyscraper under construction in Bangkok collapsed, trapping workers under the debris.

Christian Malaga-Chuquitaype, from ICL’s civil and environmental engineering department, explained that Bangkok’s soft soil amplified the shaking, despite the city being approximately 1,000 kilometers (620 miles) from the epicenter.

“Even though Bangkok is far from active faults, its soft soil amplifies the shaking,” he noted. “This particularly affects tall buildings during distant earthquakes.”

Malaga-Chuquitaype also pointed to problematic construction techniques in Bangkok, specifically the use of “flat slabs,” where floors are supported only by columns without reinforcing beams.

“This design performs poorly during earthquakes, often failing in a brittle and sudden manner,” he said. Video analysis of the collapsed skyscraper suggests this design may have contributed to its failure.

Roberto Gentile, a catastrophe risk modeling expert from UCL, warned that the “dramatic collapse” of the Bangkok tower indicated the need for “a thorough assessment of other tall buildings in the city.”

Bangkok authorities have responded by deploying over 100 engineers to inspect buildings, following more than 2,000 reports of damage across the city.

Also Read: What Caused The Myanmar-Thailand Earthquake? The Science Behind The Destruction And The Role Of The Sagaing Fault