A low-intensity earthquake on Sunday morning measuring 2.2 on the Richter Scale spread panic among residents of Shivamogga’s Thirthahalli taluk. Tremors were felt in parts of Thirthahalli, Agumbe, Hosanagara, Yedur and also in Siddapura in Udupi district. No loss of life or property damage was reported in the areas, but several alarmed residents rushed out of their homes when the tremors occurred.
Reports of a second earthquake began to do the rounds on Monday, after panic-stricken residents of Yadur village claimed that they heard a loud sound and felt fresh tremors at 12:20 pm. Following this, Shivamogga Deputy Commissioner KA Dayananda reached out to the state disaster body asking for a clarification. Then Karnataka State Natural Disaster Monitoring Centre (KSNDMC) stated that there was no fresh earthquake recorded in Thirthahalli on Monday afternoon.
“There was a low-intensity earthquake on Sunday. However, no activity was registered from the area on Monday,” said Ramesh L Dikpal, a scientist working in the earthquake division of KSNDMC.
He also said that quarrying activity would not lead to an earthquake of the magnitude recorded in Shivamogga. “The earthquake has occurred on the lineament or a discontinuity in the strata. These are natural fault zones or weaker zones that are prone to earthquakes. Due to stress and strains occurring in and around the lineament reaching the maximum limit, earthquakes recur in these areas, usually once in 100 years," said Ramesh. A lineament or a fault is a thin zone of crushed rock which separates blocks of the earth's crust.
KA Dayananda also dismissed doubts that quarrying could have caused the earthquake. “The only stone quarrying unit in the area was closed down a year ago, and there was no quarrying activity in the area where the earthquake has occurred,” he said.
Similar earthquakes were registered in the area in 1843 and 1975, and the one on Sunday occurred 43 years after the last recorded earthquake. The epicentre of the earthquake was located in Vittalnagar, on the outskirts of Thirthahalli, where a small stone mining quarry is located. The epicentre is also close to Mani Dam, part of the Varahi Hydroelectric Power Plant.
However, scientists warn that quarrying activity can cause earthquakes to recur in shorter periods of time. “Quarrying often involves high-intensity explosions and can indirectly lead to earthquakes. It can bring down the time period between recurrences of earthquakes," Ramesh, the KSNDMC scientist, added.