Myanmar (Burma) Earthquake Explained | Plate Tectonics, Faults & Scales | UPSC Geography

41

The Myanmar (Burma) earthquake stands out as one of the most devastating seismic events in South Asia in recent times. While official figures reported around 2,000–3,000 deaths, the actual impact is likely much higher due to weak governance, poor infrastructure, and limited transparency.

For UPSC aspirants, this earthquake is important not just as a current affair but as a concept-heavy geography case study linking plate tectonics, fault types, earthquake depth, and disaster vulnerability.

Tectonic Setting of the Myanmar Earthquake

At a basic level, earthquakes in this region are often explained as a result of the Indian Plate colliding with the Eurasian Plate. However, this is an oversimplification.

Microplates Involved

• The region actually involves microplates and minor plates
• The key interaction here is between:
  • Burma Microplate
  • Sunda Microplate

The Andaman & Nicobar Islands themselves are part of the Burma Microplate, making this tectonic zone directly relevant for India.

---

Andaman Trench and Regional Geology

• The Andaman Trench exists in this region but is not very active today
• It is largely covered by turbidity sediments
• Unlike the Pacific Ring of Fire trenches, this trench shows lower present-day seismic activity

The real seismic danger here comes from fault movement rather than classic subduction earthquakes.

---

Sagaing Fault: The Core Reason Behind the Earthquake

The Myanmar earthquake occurred along the Sagaing Fault, a major north–south trending fault running through central Myanmar.

Key Characteristics

• Type: Strike-slip fault
• Nature: Right-lateral (dextral) fault
• Comparable to the San Andreas Fault in California

Here, the Burma Microplate moves northward, rubbing against the relatively stable Sunda Plate.

---

Understanding Strike-Slip and Dextral Faults

In a strike-slip fault, plates move horizontally past each other.

• If the opposite block appears to move right, it is a right-slip (dextral) fault
• If it appears to move left, it is a left-slip (sinistral) fault

The Sagaing Fault is a right-slip (dextral) fault, which tends to produce powerful and widespread earthquakes.

---

Why Was the Myanmar Earthquake So Devastating?

There are three major reasons:

1. Shallow Focus Earthquake

• Depth: around 10–15 km
• Shallow earthquakes release energy close to the surface
• Less energy dissipation = greater surface damage

---

2. Linear Rupture Along Strike-Slip Fault

• Energy is released along a long linear fault
• Damage spreads over a wide region (Yangon, Mandalay, central Myanmar)

Analogy:

• Pin prick → localised damage
• Knife cut → extended damage

Strike-slip earthquakes behave like the second case.

---

3. Socio-Economic Vulnerability

• Poor construction standards
• Weak governance and disaster response
• Lack of earthquake-resistant infrastructure

This is why earthquakes in Myanmar, Nepal, Afghanistan, and Pakistan often cause disproportionate damage compared to similar-magnitude events elsewhere.

---

Earthquake Magnitude vs Intensity: Clearing the Confusion

Many aspirants still confuse earthquake scales.

Richter Scale

• Measures energy release
• Becomes unreliable for large earthquakes
• Older scale, denoted as ML

---

Mercalli Scale

• Measures intensity and damage
• Based on observed destruction
• 12-point descriptive scale

---

Moment Magnitude Scale (Mw / MMS)

• Used for modern large earthquakes
• Measures:
  • Energy released
  • Amount of fault displacement
• More accurate for powerful earthquakes

👉 The Myanmar earthquake magnitude (e.g., 7.7) was measured on the Moment Magnitude Scale, not the Richter Scale.

---

Earthquake Zonation in India

India does not use Richter or MMS for zoning.

• India uses the Modified Mercalli Scale (MSK Scale)
• Focuses on expected damage and intensity
• Used to divide India into Seismic Zones II, III, IV, and V

---

Why This Topic Is Important for UPSC

What this really means is:

• Myanmar earthquake links static geography + current affairs
• Tests understanding of:
  • Microplates
  • Fault mechanics
  • Earthquake scales
  • Disaster vulnerability
• Useful for:
  • Prelims MCQs
  • GS-1 (Physical Geography)
  • GS-3 (Disaster Management)

UPSC often asks why an earthquake was destructive, not just where it happened.

Check out our GS Geography Course – Click Here

FAQs

1. #MyanmarEarthquakeUPSC: What tectonic factors caused the Myanmar (Burma) earthquake?
2. #SagaingFaultUPSC: Why is the Sagaing Fault considered highly dangerous?
3. #StrikeSlipFaultUPSC: How do strike-slip (dextral) faults differ from other plate boundaries?
4. #MomentMagnitudeScaleUPSC: Why is the Moment Magnitude Scale preferred over the Richter Scale for large earthquakes?