Geology 2024 Paper I 50 marks Discuss

Q2

(a) Discuss the intensity and magnitude scale commonly used to assess seismic damage. Write a note on the global distribution pattern of earthquake. Mark the different seismic zones of India on the given map and discuss about them. (20 marks) (b) Discuss in detail the ideas of geomorphic cycle proposed by Davis and Penck. (15 marks) (c) What do contours represent in a toposheet? How do the contour lines help to identify the different geomorphic features of an area? Explain with neat diagrams. (15 marks)

हिंदी में प्रश्न पढ़ें

(a) भूकंपीय क्षति के आकलन में आमतौर पर प्रयुक्त होने वाली तीव्रता मापनी एवं परिमाण मापनी का वर्णन कीजिए। भूकंप के वैश्विक वितरण विन्यास पर एक टिप्पणी लिखिए। भारत के विभिन्न भूकंपीय मंडलों को दिए हुए मानचित्र पर दर्शाते हुए उन पर चर्चा कीजिए। (20 अंक) (b) डेविस तथा पैंक द्वारा प्रस्तावित भू-आकृतिक चक्र की अवधारणा का विस्तार से वर्णन कीजिए। (15 अंक) (c) टोपोशीट पर समोचरेखा क्या दर्शाती हैं? समोचरेखा कैसे किसी क्षेत्र के विभिन्न भू-आकृतिक लक्षणों की पहचान करने में सहायक होती हैं? स्वच्छ चित्र सहित व्याख्या कीजिए। (15 अंक)

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Directive word: Discuss

This question asks you to discuss. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.

See our UPSC directive words guide for a full breakdown of how to respond to each command word.

How this answer will be evaluated

Approach

The directive 'discuss' demands a comprehensive, analytical treatment with balanced coverage across all three sub-parts. Allocate approximately 40% of time/words to part (a) given its 20 marks, and 30% each to parts (b) and (c). Structure with a brief integrated introduction, then dedicated sections for each sub-part with internal sub-headings, and a concluding synthesis on geomorphology-seismology interconnections. For part (a), include a sketch map of India's seismic zones; for part (c), provide neat labeled contour diagrams.

Key points expected

  • Part (a): Distinguish between intensity (Modified Mercalli, MSK-64) and magnitude (Richter, Moment magnitude Mw) scales with their logarithmic bases and damage assessment applications; global seismic belt distribution (Circum-Pacific, Alpide, Mid-oceanic ridges); India's four seismic zones (II-V) with characteristic examples and map marking
  • Part (a): Specific Indian examples - Zone V (Kashmir, Assam), Zone IV (Himachal, Uttarakhand), Zone III (Punjab, Kerala), Zone II (remaining areas); mention 2001 Bhuj, 2015 Nepal-Gorkha earthquakes
  • Part (b): Davisian cycle (youth-mature-old with graded profile, base level, uplift-erosion interplay) and its criticisms (static uplift assumption, time-dependent rather than process-based)
  • Part (b): Penck's model (waxing-waning development, parallel retreat of slopes, crustal movement-erosion simultaneity) and key differences from Davis (endogenetic-exogenetic interaction, slope forms rather than stage)
  • Part (c): Definition of contours as lines joining equal elevation points; contour interval and horizontal equivalent; identification of landforms - V-shaped contours for valleys, U-shaped for spurs, concentric closed contours for hills/depressions, closely spaced for steep slopes, widely spaced for gentle slopes
  • Part (c): Specific geomorphic identifications - ridge lines, saddles, cliffs (overlapping contours), terraces, alluvial fans, drainage patterns from contour patterns; neat labeled diagrams essential

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Precise distinction between intensity (qualitative, site-specific) and magnitude (quantitative, source-specific) scales; accurate logarithmic relationships (Richter: amplitude, Mw: energy); correct Davis-Penck theoretical contrasts; exact contour definitions and landform identification rules without confusionBasic definitions correct but confused intensity/magnitude distinction or incomplete Davis-Penck comparison; contour definitions acceptable but landform identification rules partially wrongFundamental errors like equating intensity with magnitude, confusing Davis and Penck models, or misidentifying contour patterns (e.g., calling ridges valleys)
Diagram / cross-section20%10Neat, labeled sketch map of India showing Zones II-V with key locations; clear comparative diagrams of Davisian stages and Penckian slope forms; precise contour drawings demonstrating at least 4 distinct landforms with proper symbols (hachures for depressions)Acceptable map with zones but poor location marking; basic Davis cycle diagram but weak Penck representation; contour diagrams present but poorly labeled or technically incorrectMissing map or unrecognizable zone demarcation; absent or meaningless diagrams; no contour illustrations or completely wrong landform representations
Field evidence15%7.5Specific Indian earthquake case studies (Bhuj 2001, Latur 1993, Chamoli 1999, Sikkim 2011) with damage intensity correlating to magnitude; field examples of Davisian/Penckian landforms from Indian terrain (Western Ghats escarpments, Siwalik hogbacks); toposheet references (e.g., Survey of India 1:50,000 series)Generic earthquake mentions without specific dates or damage details; general landform examples without Indian specificity; vague toposheet referencesNo specific earthquakes named; purely theoretical treatment without field correlation; no understanding of actual toposheet application
Quantitative reasoning20%10Logarithmic scale calculations (Richter: 1 unit = 10× amplitude, ~31.6× energy; Mw formulas); energy-magnitude relationships; gradient calculations from contours (G=VI/HI); precise zone statistics for India (% area in each zone); frequency-magnitude relationships (Gutenberg-Richter)Mentions logarithmic nature without numerical illustration; basic gradient concept without calculation; general awareness of zone distribution without percentagesNo quantitative treatment; arithmetic rather than logarithmic understanding of scales; inability to relate contour spacing to gradient
Indian / economic relevance20%10Critical analysis of India's seismic hazard (58% land in zones III-V); specific infrastructure vulnerabilities (dams in Himalayas, nuclear plants, urban seismic codes); economic implications of geomorphic cycle models for resource extraction (erosion rates, soil conservation); contour applications in engineering geology, mining, dam sitingGeneral mention of India's seismic vulnerability; basic awareness of hazard zonation; superficial economic links without sectoral specificityNo Indian context; purely academic treatment ignoring hazard assessment, building codes, or applied geomorphology; missing economic/engineering significance entirely

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