‘Earthquake swarm’ in Gujarat's Amreli, 400 tremors in 2 years: ISR

AHMEDABAD: Amreli district has been the epicentre of an ‘earthquake swarm’ as it has recorded nearly 400 mild tremors in the last two years, according to officials.
A swarm is a sequence of mostly small earthquakes which are usually short-lived but can continue for days, weeks, or sometimes even months and often recur at the same location.
Residents of Amreli’s Mitiyala village, where many of these 400 tremors were felt, have started sleeping outside their houses as a precautionary measure so that they are not caught unawares in case of any major seismic activity.
Explaining the reason behind the ‘earthquake swarm’ in Amreli district of Saurashtra region, Gandhinagar-based Institute of Seismological Research's (ISR) officiating Director General Sumer Chopra said that tectonic setup and hydrological loading are the reasons for the seasonal seismic activities.
In the 48 hours from February 23, Amreli’s Savarkundla and Khamba talukas recorded four tremors in the intensity range of 3.1 to 3.4, making residents worried. The seismic activity in Amreli has been witnessed just after the recent devastating earthquake in Turkiye that killed more than 45,000 people.
In January 2001, a massive earthquake in Kutch district killed 13,800 people and another 1.67 lakh were injured. The earthquake had caused severe damage to properties in various towns and villages of the district.
Asked about the recent seismic activity in Amreli, Chopra said this is an “earthquake swarm” event in which small tremors keep on recurring. This is mostly seasonal.
“In the last two years and two months, we recorded 400 mild tremors in Amreli, out of which 86% were below the intensity of 2, while 13% were between the intensity of 2 and 3 and only in five events, it went above 3 magnitude,” he said.
“Most of these mild tremors are not even felt by the people. Just our machine records them,” he said.
With a caveat that “earthquakes cannot be predicted”, Chopra said the possibility of a major earthquake is low when the ‘earthquake swarm’ is taking place. “Most of the Saurashtra region including Amreli district falls in seismic zone three, which is categorised as moderate damage risk zone. The main reason is there are no major fault lines in that area,” he said.
The fault line in Amreli is of 10 kilometres. For major earthquakes, the fault lines should be of more than 60 to 70 km, the official said.PTI