🌑Knowledge Drop – 44: India’s Updated Seismic Zonation Map (2025) | For Prelims: InDepth MCQs| For Mains, All G.S Papers: High Quality Essays
🌍 Knowledge Drop – 44
India’s Updated Seismic Zonation Map (2025)
📅 29 November 2025
📚 Syllabus: GS3 (Disaster Management)
In News
🇮🇳📍
India has released an updated Seismic Zonation Map (2025) under the new Earthquake Design Code (IS 1893:2025), replacing the earlier 2016 map. The revision aligns India’s seismic safety framework with modern scientific understanding and global best practices.
Why Was an Update Necessary? ⚠️
1️⃣ Underestimation of Himalayan Seismic Risk
🏔️
Earlier maps classified the Himalayas largely under Zones IV and V, despite the region lying along one of the most active tectonic collision zones globally. This underestimated the true seismic potential of the Himalayan arc.
2️⃣ Outdated Methodology
📉
Previous zonation relied heavily on:
- Historical earthquake epicentres
- Past damage records
- Broad geology and soil types
Such approaches failed to capture future probabilistic risks.
3️⃣ Ignoring Rupture Propagation
🔄
Earlier models did not adequately consider southward rupture propagation along the Himalayan Frontal Thrust (HFT).
As a result, densely populated foothill regions like Dehradun (Mohand region) faced underestimated seismic risk.
4️⃣ Rising Exposure
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Nearly three-fourths of India’s population now resides in seismically active zones, amplifying potential disaster impact.
5️⃣ Gap with Global Standards
🌐
India needed to shift toward Probabilistic Seismic Hazard Assessment (PSHA), which is internationally accepted.
What Is a Seismic Zonation Map? 🗺️
A seismic zonation map:
- Divides regions based on expected earthquake intensity and frequency
- Is published by the Bureau of Indian Standards (BIS)
- Forms the foundation of the Earthquake Design Code
- Guides urban planning, infrastructure design, and disaster preparedness
Key Features of the New Seismic Zonation Map (2025) 🔍
1️⃣ Introduction of Zone VI
🚨
- A new highest-risk zone has been created
- The entire Himalayan arc, from Jammu & Kashmir–Ladakh to Arunachal Pradesh, is now classified under Zone VI
- Acknowledges sustained extreme tectonic stress at the Indian–Eurasian plate boundary
2️⃣ Adoption of PSHA Methodology
📊
The new map is based on Probabilistic Seismic Hazard Assessment, which considers:
- Ground shaking attenuation with distance
- Tectonic regime and fault behaviour
- Underlying lithology
This enables future-oriented risk estimation, not just past-event analysis.
3️⃣ Expanded Hazard Coverage
📈
- 61% of India’s landmass now falls under moderate to high hazard zones (up from 59%)
- Southern peninsula shows minor refinements, reflecting relatively stable tectonics
4️⃣ Boundary Rule Enhancement
⚖️
- Towns located along boundaries of two seismic zones will now be automatically placed in the higher-risk zone
- Eliminates ambiguity and under-design risks
5️⃣ Focus on Non-Structural Safety
🏗️
For the first time, explicit attention is given to non-structural components, including:
- Parapets and façade panels
- Ceilings and suspended fixtures
- Overhead tanks and electrical lines
- Lifts and utility systems
These elements are often responsible for maximum casualties during earthquakes.
6️⃣ Near-Fault Provisions
📐
Buildings near active faults must now consider:
- Pulse-like ground motions
- Updated limits on displacement and ductility
- Enhanced energy dissipation requirements
7️⃣ Site-Specific Design Requirements
🧪
- Provisions for liquefaction risk, soil flexibility, and local site response spectra
- Emphasises geotechnical investigations prior to construction
8️⃣ Critical Infrastructure Resilience
🏥🏫
Hospitals, schools, bridges, pipelines, and major public buildings must be designed to:
- Remain functional after major earthquakes
- Support emergency response and recovery
Implementation Challenges 🚧
- Retrofitting legacy infrastructure is costly and technically complex
- Higher construction costs due to stricter standards
- Specialised expertise & equipment needed for site-specific assessments
- Coordination challenges across States and urban bodies
Why This Matters for India 🧭
🌏
The 2025 seismic zonation map marks a decisive shift from reactive disaster response to anticipatory risk governance. By aligning science, safety, and planning, India strengthens its capacity to protect lives, infrastructure, and economic stability in a seismically dynamic landscape.
Target IAS-26: Daily MCQs :
📌 Prelims Practice MCQs
Topic: SET-1
MCQ 1 TYPE 1 — How Many Statements Are Correct?
Consider the following statements regarding India’s Seismic Zonation Map (2025):
1)The updated seismic zonation map is incorporated into the Earthquake Design Code IS 1893.
2)The map is published by the National Disaster Management Authority.
3)The revision replaces historical epicentre-based seismic assessment models.
4)The updated map aligns India’s standards with Probabilistic Seismic Hazard Assessment methods.
How many of the above statements are correct?
A) Only one
B) Only two
C) Only three
D) All four
🌀 Didn’t get it? Click here (▸) for the Correct Answer & Explanation.
🟩 Correct Answer: C) Only three
🧠 Explanation:
1)✅ True – Integrated into IS 1893 (Earthquake Design Code).
2)❌ False – Published by the Bureau of Indian Standards (BIS).
3)✅ True – Moves away from purely historical epicentre models.
4)✅ True – Uses PSHA methodology.
MCQ 2 TYPE 2 — Two-Statement Type
Consider the following statements:
1)Probabilistic Seismic Hazard Assessment considers future earthquake probability rather than only past events.
2)PSHA ignores ground-shaking attenuation with distance.
Which of the above statements is/are correct?
A) Only 1
B) Only 2
C) Both 1 and 2
D) Neither 1 nor 2
🌀 Didn’t get it? Click here (▸) for the Correct Answer & Explanation.
🟩 Correct Answer: A) Only 1
Explanation:
1)✅ True – PSHA is forward-looking and probability-based.
2)❌ False – Attenuation with distance is a core PSHA parameter.
MCQ 3 TYPE 3 — Code-Based Statement Selection
With reference to the updated Seismic Zonation Map (2025), consider the following statements:
1)A new highest-risk seismic Zone VI has been introduced.
2)The entire Himalayan arc has been classified under Zone VI.
3)The southern peninsular region shows major upward revision in seismic risk.
Which of the above statements are correct?
A) 1 and 2 only
B) 2 and 3 only
C) 1 and 3 only
D) 1, 2 and 3
🌀 Didn’t get it? Click here (▸) for the Correct Answer & Explanation.
Correct Answer: A) 1 and 2 only
🧠 Explanation:
1)✅ True – Zone VI is newly created.
2)✅ True – Entire Himalayan arc placed under highest risk.
3)❌ False – Southern peninsula remains largely stable with minor refinements.
MCQ 4 TYPE 4 — Direct Factual Question
Which of the following regions has seen a significant reassessment of seismic risk due to southward rupture propagation of Himalayan thrusts?
A) Indo-Gangetic Plains
B) Deccan Plateau
C) Himalayan foothill regions such as Dehradun
D) Western Coastal Plains
🌀 Didn’t get it? Click here (▸) for the Correct Answer & Explanation.
🟩 Correct Answer: C)
🧠 Explanation:
Foothill regions near Himalayan Frontal Thrusts were earlier underestimated.
MCQ 5 TYPE 5 — UPSC 2025 Linkage Reasoning Format (I, II, III)
Consider the following statements:
Statement I:
The updated seismic zonation map emphasises safety of non-structural components.
Statement II:
Non-structural elements are often responsible for maximum casualties during earthquakes.
Which one of the following is correct?
A) Both Statement I and Statement II are correct and Statement II explains Statement I
B) Both Statement I and Statement II are correct but Statement II does not explain Statement I
C) Statement I is correct but Statement II is incorrect
D) Statement I is incorrect but Statement II is correct
🌀 Didn’t get it? Click here (▸) for the Correct Answer & Explanation.
🟩 Correct Answer: A) 🧠 Explanation:
✅ Non-structural failures cause injuries and fatalities.
✅ Hence, the new code explicitly addresses them.
