​Tragic evening, Pg6

Key Highlights:

• Two powerful earthquakes, measuring magnitudes 7.1 and 7.5, struck Caracas, Venezuela, seconds apart on Wednesday, June 24, 2026.
• The quakes caused widespread destruction, leveling large parts of the capital and the state of La Guaira, resulting in 589 deaths and 2,980 injuries.
• Geologically, these were shallow "doublet" earthquakes, a complex rupture-interaction where the South American and Caribbean plates grind past each other.
• India's Bureau of Indian Standards (BIS) recently withdrew a revised seismic code (IS 1893 (Part 1): 2025) that would have significantly increased design forces and added a Zone VI to the seismic map.
• This withdrawal followed a Cabinet Secretariat order, citing concerns that the stricter standards would "materially affect" ongoing infrastructure projects.

Venezuala Earthquake.png

Detailed Insights:

• The Venezuelan earthquakes' shallow depth, under 30 kilometers, intensified their destructive impact on surface structures.
• The US Geological Survey (USGS) had flagged a plausible death toll exceeding 10,000 for the Venezuela event, indicating the severe potential of such quakes.
• The 2023 Türkiye-Syria earthquakes, which killed over 55,000 people, were also identified as "doublet" events with similar characteristics.
• The withdrawn Indian seismic code, based on a decade of research, aimed to align India's hazard assessment with global standards.
• India's current Zone V designs for 0.36g, significantly lower than the 0.75g in Pakistan and Nepal, or 1g in the US and Japan, for similar seismic regions.
• Approximately 79% of Indians reside in areas prone to moderate to severe seismic threats.
• A staggering 95% of earthquake-related fatalities in India occur in one- to three-storey houses, which often fall outside stringent building code enforcement.
• The shelving of the updated seismic code in India was partly due to concerns over potential cost increases for construction projects, ranging from 10% to 50%.

Key Concepts Involved:

• Doublet earthquake: A sequence of two distinct earthquakes of comparable magnitude occurring close in time and location, where both are considered mainshocks.
• Seismic design forces (g-force): A measure of the maximum ground acceleration, expressed as a fraction of the acceleration due to gravity, used to design earthquake-resistant structures.
• Bureau of Indian Standards (BIS): India's national body responsible for the development and implementation of standards, including those for earthquake-resistant construction.
• Cabinet Secretariat: The principal coordinating agency of the Government of India, responsible for assisting the Cabinet and ensuring inter-ministerial coordination.