How did the Myanmar earthquake occur? Pg 8

Key Highlights

About the Earthquake

• On March 28, a powerful earthquake of magnitude 7.0 hit central Myanmar, ~20 km from Mandalay (second-largest city).

• Followed by aftershocks, including one of 6.4 magnitude, a few minutes later.

• Part of Saging Fault, one of the most active strike-slip faults in Southeast Asia.

Impact

• Devastating effects: Thousands feared dead/injured, major infrastructure damage in Myanmar.

• Thailand and Bangkok (1000 km away) experienced tremors, likely amplified by local geology and water-saturated sediments.

• Historical monuments in Bagan city (UNESCO site) also damaged similar to 2016.

Geological Explanation

Southeast Asia Active Tectonic Region

• Lies at the junction of the Burma Plate and Sunda Plate, with multiple strike-slip and convergent boundaries.

• Sagging Fault:

  • A continental transform fault, ~1,400 km long.

  • Moves ~21 mm/year.

  • Similar to San Andreas Fault (USA).

  • One side slides past the other horizontally.

• Southeast Asia is seismically active due to plate interactions involving:

  • Indian Plate

  • Sunda Plate

  • Eurasian Plate

  • Burma Plate

Accumulated Stress & Quake Triggering

• Quakes occur when accumulated stress at the plate boundaries overcomes friction.

• Saging Fault has caused multiple major quakes over the past century.

Why Bangkok Felt It, India Didnt?

• Bangkok lies on soft, sediment-filled basin amplifies ground shaking.

• Eastern India (e.g., Manipur, Nagaland) lies farther from epicenter and less aligned with seismic wave path.

Mandalay Region's History of Quakes

• Mandalay has seen:

  • Major earthquake in 1839.

  • Smaller quakes periodically since then.

• History indicates long recurrence interval and high potential for future destructive earthquakes.

Mains Mock Question:

"Explain the geological features of the Saging Fault and discuss why Southeast Asia is considered one of the most seismically active zones in the world. Also highlight the risk implications for India."