At noon, on March 28, Mandalay in Myanmar, a city with a 1.5 million population, suffered catastrophic damage. India’s NCS instantly reported that a powerful M7.5 earthquake struck central Myanmar, with an M7.0 aftershock within 15 minutes, and nearly 25 lower magnitude quakes followed. The epicentre was located just 16 kilometres from the city of Sagaing, and approximately 250 kilometres from the capital, Naypyidaw.
Till now, over 1,000 people have been confirmed dead, with 2,500 injured and several reported missing. Neighbouring Thailand also reported deaths and numerous injuries, including collapse of an under-construction building in Bangkok.
Destructive shallow earthquake
Earthquakes occur at various depths, from shallow crust to the base of the mantle transition zone. However, destructive earthquakes are usually shallow, concentrated in the upper crust of continents. Shallow earthquakes are typically more destructive as seismic waves travel a shorter distance to the surface, retaining much of their energy.
With a focal depth of 10 kilometres, the earthquake caused intense shaking, severely damaging buildings and infrastructure. Poorly constructed structures, especially older brick or stone buildings, were most vulnerable. Moreover, shallow-focus earthquakes provide minimal time for early warnings, leaving residents with little opportunity to seek safety. The amplified ground shaking also increases the risk of liquefaction in susceptible areas, further damaging roads, bridges, and buildings.
Following the earthquake, USGS had issued a red alert, predicting extensive fatalities and economic losses. Ground shaking intensities ranging from VIII to X on the Modified Mercalli Intensity (MMI) scale were reported in cities such as Mandalay, Sagaing, and Meiktila.
Damage to Infrastructure
Critical infrastructure, including roads, hospitals, and schools, was severely damaged. Initial assessments indicated that at least 2,900 buildings, 30 roads, and seven bridges were affected in Myanmar. Due to significant destruction, Naypyidaw and Mandalay international airports were temporarily closed but have since restored operations. The collapse of the Ava Bridge, a historic 16-span bridge connecting the Ava and Sagaing regions across the Irrawaddy River, has significantly impacted transportation and hindered relief efforts.
Secondary hazards such as fire also emerged form this massive earthquake as well. A massive fire tore through Mandalay University, exacerbating the damage. Reports suggest the city’s historic monasteries, vital to Myanmar’s cultural and religious heritage, have also sustained damage, further underlining the quake’s devastating impact. Several schools and hospitals sustained damage, which is particularly concerning as these facilities are crucial for providing emergency shelter and medical care following a disaster. Fortunately, in Myanmar, schools were closed for the summer vacation, preventing potential casualties among children.
Fault Lines in Myanmar
Earthquakes in Myanmar have mostly originated along an active subduction zone (Andaman Megathrust Zone) in the west and along a large transform fault zone (Sagaing Fault Zone) in the middle part of the country. This series of earthquakes originated from the Sagaing Fault, which runs approximately 1,200 kilometres north to south of Myanmar and has a history of significant seismic activity. Several significant quakes of M7.0 or higher have struck near the Sagaing Fault, including an M6.8 in the ancient capital Bagan in 2016, which resulted in several casualties and damage to valuable heritage sites.
Shallow earthquakes within the Indo-Burmese Arc, predominantly occur on a combination of strike-slip and reverse faults, including the Sagaing, Kabaw and Dauki faults. The recent earthquake originated from strike-slip faulting, where one side of the fault moves horizontally past the other, as opposed to subduction of a fault, which slides under another.
According to the USGS, this is a finite fault solution, which indicates a north striking right-lateral fault. This solution is consistent with the earthquake potentially occurring on the right-lateral Sagaing Fault that defines the plate boundary between Indian and Sunda plates.
Historically, it has been observed that earthquakes of this size are more appropriately described as slip over a larger fault area. The finite fault solution indicates the size of the March 28, 2025 event is about 200 km by 20 km (length x width).
Impact on South and South East Asia
The earthquake’s tremors were felt across Southeast Asia, with reports of shaking in Thailand, India, Bangladesh, and Vietnam. In Bangkok, nearly 1000 km from the epicenter, metro and rail services in Bangkok were temporarily suspended, and a large under-construction building in the Chatuchak Park area came crashed in a matter of seconds in Bangkok.
The dramatic collapse of the tall building under construction in Bangkok warrants particular attention, especially considering its location nearly 1,000 kilometers from Mandalay. While seismic waves traveling such a distance generally lose significant energy, the underlying geological features in Bangkok may have amplified ground motion. Factors such as construction on deep, soft soils and the ‘basin effect’ are known to intensify ground shaking. Additionally, the possibility of a ‘soft-storey’ collapse, where the lower floors of a structure fail due to insufficient strength or stiffness relative to upper floors, could have further contributed to the building’s failure. This incident underscores the need for a thorough structural assessment of other tall buildings in Bangkok, particularly those constructed on similar soil conditions, to ensure their resilience against seismic events.
Lessons for India
The tragic events in Myanmar underscore the importance of proactive measures for earthquake risk mitigation particularly in Zones IV and V. There is need to conduct seismic micro-zonation of all urban agglomerations, expand India’s network of seismic monitoring stations, and establish early warning systems, which offer a few seconds of warning to far reaches after detecting the first of two waves that make an earthquake. These systems can automatically shut down critical infrastructure like trains, airports and gas pipelines, preventing secondary disasters such as fires and derailments.
Strict compliance with the building codes bye-laws is a non-negotiable policy imperative, while retrofitting of critical infrastructure like hospitals, schools and fire stations is must. Most fatalities during earthquakes result from the collapse of buildings, especially older or non-engineered structures. Past earthquakes, such as the Bhuj earthquake, have demonstrated how damage to critical facilities can severely hamper relief efforts. Regular earthquake preparedness drills, widespread community awareness campaigns and well-equipped collapsed structure search and rescue teams, is vital.
Ranu Chauhan is a senior consultant at NDMA.
