Mandalay Earthquake 2025: Sagaing Fault and Seismic Lessons
Why in the news
A very strong earthquake hit central Myanmar on 28 March 2025, causing deaths and damage in Myanmar and tremors felt as far as Thailand.
Key facts
- Epicentre: 20 km from Mandalay, Myanmar’s second-largest city (1.5 million people).
- Magnitude 7.7; the strongest aftershock was 6.4, 11 minutes later.
- Cause: slip along the Sagaing fault.
- The USGS estimated over 10,000 fatalities.
- Mandalay’s pagodas, mosques and bridges suffered; Irrawaddy alluvium amplified shaking along the southern fault.
| Place | What happened |
|---|---|
| Bangkok (about 1,000 km away) | 33-storey tower under construction fell; rooftop pools overflowed due to seismic seiches |
| Yunnan, China | Escaped major harm because energy spread north-south |
| Eastern India | Little impact as energy dissipated along the fault |
About the Sagaing fault
- Length 1,400 km; a strike-slip fault producing horizontal motion, unlike subduction zones.
- Takes up 50-55% of plate motion; slip rate 15-25 mm a year; accumulated displacement 100-700 km.
- Shallow quakes at 10-15 km depth cause intense surface shaking.
- The India-Eurasia plate collision is oblique, so strain splits into strike-slip and thrust faulting; compared with the San Andreas fault in the USA.
Earlier quakes listed
- 2004 Sumatra (M 9.2) with a devastating tsunami; 1792 Arakan Coast (M 8.5) with tsunami and liquefaction in Bangladesh.
- 1839 Ava (M 7.8); 1927 and 1946 Sagaing events (M 7.7); 2016 Bagan quake.
Significance
- Roughly half of the Sagaing fault has ruptured in recent decades, so activity continues.
- South Asia sits near the Himalayas, Shillong Plateau, Indo-Burman Range and Andaman-Nicobar subduction zone.
- Weak enforcement of quake-resistant building raises risk; better monitoring and preparedness are needed in India, Bangladesh and Myanmar.
Exam angle
- Fault type: Sagaing is strike-slip; magnitude 7.7; city nearest the epicentre: Mandalay.
- Related terms: seismic seiche, alluvium, oblique convergence, subduction zone.