The above tremors are coincident with the cosmetic beautification done by Tamil Nadu authorities to the grandma Mullaperiyar Dam to conceal its chronic ailments from the naked eyes. But the ailments of Mullaperiyar Dam are inherent and deep rooted. This dam was constructed during 1886-1895, when the dam engineering was at infancy. The dam is a composite structure with rubble masonry in lime surkhi mortar as facing on upstream and downstream and a lime surkhi concrete inner core. Later in 1980s, a concrete backing of 10 M width was added to the downstream of the old dam.
22 Major Faults around Mullaperiyar dam considered by IIT, Roorkee
IISc Study of Vulnerability of Central Kerala to Seismicity in 2009
Central Midland region of Kerala appears to have generated larger number of significant earthquakes; the most prominent being the multiple events (doublets) of 1856 and 1953, whose magnitudes are comparable to that of the 2000/2001 (central Kerala) events. Occurrences of these historical events and the recent earthquakes, and the local geology suggest that the NNW-SSE trending faults in central midland Kerala may host discrete potentially active sources that may be capable of generating light to moderate size earthquakes. A simple statistical treatment of the historical information suggests that an earthquake of magnitude ML 4.5 to 5.5 can be expected to recur in the central midland region every 25±22 years. Thus from a hazard point of view, the central midland region must be considered as seismically most potential in Kerala.
The exhaustive study considered the 87 earthquake records recorded at the IMD’s Broadband station at Peechi during December 2000-December 2008. The study also considered all historical earthquakes reported from 18th Century onwards in the region. an important point to be noted is that there was a general increase of seismicity in the southern India after the 2001 (January 26) Bhuj earthquake in particular in the Koyna region, and there was also an M 4.5 earthquake from the Karnataka-Tamil Nadu border on January 29, 2001.
- Normal Operating Condition (Full Reservoir Level without considering earthquake)
- Flood Level Condition (Maximum Water Level without considering earthquake)
- Earthquake Condition (FRL with earthquake and MWL with earthquake)