1967 Koynanagar Earthquake occurred in and around Koynanagar town in Maharashtra, India. On 11 December the 6.5 magnitude earthquake hit near the site of Koyna dam. The earthquake claimed at least 180 human lives and injured over 1500 people. The earthquake also damaged more than 80% of the houses in Koyana Nagar Township. However it didn't cause any major damage to the dam except some cracks which were repaired afterwards. There have been several earthquakes of smaller magnitude there since 1967. The deadly earthquake had caused a 10-15 cm fissure in the ground which spread over a length of 25 km.
Some geologists believe that the earthquake was due to reservoir-triggered seismic activity. But senior project officials have repeatedly denied this conclusion.