Gyalshing Earthquake Highlights Tista Fault Seismicity
In News
What Happened
Why It Matters
Background
History & Context
What Changed
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BEFORE: India's seismic zonation map featured four operational zones (Zones II to V), with Sikkim and the sub-Himalayan region classified as High Damage Risk Zone IV. NOW: The BIS has introduced a new highest-risk category, Zone VI, which now fully encompasses Sikkim and the broader Himalayan arc.
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BEFORE: Regional seismic hazard mitigation primarily focused on major longitudinal boundary thrusts like the Main Central Thrust (MCT). NOW: Seismologists heavily factor in transverse structures like the Tista Lineament, which actively generate strike-slip earthquakes and complex aftershock swarms.
Prelims Angle
NCERT Connection
Practice Questions
Q1
Correct Statement(s)Which of the following statements regarding the seismotectonics of Sikkim is/are correct? 1. The Tista Lineament is a major transverse fault in the eastern Himalayas known to generate strike-slip earthquakes. 2. Under the latest updated Bureau of Indian Standards (BIS) seismic zonation map, Sikkim is classified under Seismic Zone V.