Cause of the Earthquake
- The earthquake originated in central Myanmar, about 20 km from Mandalay, a seismically active region.
- It had a magnitude of 7.7 and struck at 12:50 pm local time, followed by strong aftershocks, including one of 6.4 magnitude just 11 minutes later.
- The event was triggered by movement along the Sagaing fault, a major strike-slip fault in Myanmar.
- The earthquake’s shallow depth (10 km) contributed to its devastating impact.
Relevance :GS 1(Geography )
Impact of the Earthquake
- Widespread destruction: Thousands of people died, and infrastructure, including homes, bridges, mosques, and pagodas, suffered severe damage.
- Mandalay, a city with 1.5 million people, was among the worst-hit areas.
- The southern Sagaing fault saw the most destruction due to thicker alluvial deposits, which amplified seismic energy.
- The total death toll is estimated to exceed 10,000, according to USGS models.
Effects in Bangkok
- Despite being 1,000 km away, Bangkok experienced minor structural impacts:
- A 33-storey high-rise collapsed during construction.
- A swimming pool on a high-rise building overflowed due to seismic seiches (water oscillations triggered by seismic waves).
- The long-period seismic waves caused tall buildings to sway, amplifying the effects.
Why Eastern India Avoided Damage
- The energy released by the earthquake was directed in a north-south direction, following the trend of the Sagaing fault.
- China’s Yunnan province (north of the fault) also escaped damage due to different geological conditions.
History of Earthquakes Along the Sagaing Fault
- The Sagaing fault runs 1,400 km, from the Andaman Sea to the Eastern Himalayan bend.
- It has experienced several earthquakes over the last century:
- 1930–1956: Six earthquakes of magnitude 7+.
- 1839: Ava earthquake (magnitude 7.8), killing 500+ people.
- 1927: Strong quake felt north of Yangon.
- 1946: Another magnitude 7.7 event near Mandalay.
- 2016: A destructive earthquake hit Bagan, an ancient city known for its Buddhist monuments.
Why Southeast Asia is a Seismically Active Region
- The plate boundary in Southeast Asia is among the most tectonically active in the world.
- It results from the collision of the Indian and Eurasian Plates about 40 million years ago.
- Notable seismic events include:
- 2004 Indian Ocean Earthquake (M 9.2) – triggered a transcontinental tsunami.
- 1792 Megathrust Earthquake (M 8.5) – generated a tsunami in Bay of Bengal and caused soil liquefaction in Chittagong, Bangladesh.
- The Indo-Burmese subduction zone and the Chittagong-Tripura fold belt experience frequent seismic activity.
Geodynamics of the Sagaing Fault
- The Sagaing fault forms the boundary between:
- Central Myanmar Lowlands and Indo-Burman Range.
- The Burma plate (Burma sliver) exists between the Indian Plate and the Sagaing Fault, due to strain partitioning at the subduction front.
- The fault is a strike-slip fault, accommodating 15-25 mm/year of lateral movement, with an accumulated slippage of 100-700 km.
- It absorbs 50-55% of overall plate motion in the region.
- Similar to the San Andreas Fault (California, USA), it produces shallow earthquakes (10-15 km depth).
Lessons from the 2025 Myanmar Earthquake
- Myanmar is struggling with the aftermath, worsened by civil unrest.
- The Sagaing fault is highly active, meaning future earthquakes are likely.
- India, being one of the most earthquake-prone countries in South Asia, should:
- Implement scientific safety measures.
- Strengthen seismic-resistant infrastructure.
- Improve early warning systems and disaster response mechanisms.
