Delhi needs better seismic monitoring
doi:10.1038/nindia.2007.37 Published online 26 December 2007
Based on the study of 19 earthquake events between 2001 and 2004, the India Meteorological Department (IMD) has urged for an improvised system of seismic monitoring in the tectonically active Delhi region1.
Analysis of seismic events in and around Delhi during the period has revealed a pattern conforming to the structural attributes of the Delhi Fold Belt in which the National Capital Territory is located.
The subsurface strike-slip of the Mahendragarh–Dehradun Subsurface Fault (MDSSF) was also found to act as a major discontinuity zone for seismicity. The Delhi–Sargodha Ridge (DSR), which passes through Delhi and is flanked by the Sahaspur and Bikaner basins, revealed the presence of a belt parallel to the Himalayan fold system. This belt is of significance with regards to seismic hazard as it traverses across the national capital region.
An important find from the pattern analysis was that MDSSF, which was earlier referred to zone of minima 'tectonic flux', is the area of the most significant zone. This was found to account for clustering of 50% of the events with a narrow aperture zone (20 km) along the fault.
- Shukla, A. K. et al. Seismotectonic implications of Delhi region through fault plane solutions of some recent earthquakes. Curr. Sci. 93, 1848-1853 (2007).