The earthquake prone Andaman and Nicobar islands of India were hit by a series of nine medium intensity earthquakes within a span of two hours early this morning (Monday, April 1).
The earthquakes were in the range of 4.7 to 5.2 on the Richter scale, according to the National Centre for Seismology. The first jolt with a magnitude of 4.9 occurred at 5.14 AM, followed by another jolt with a magnitude of 5 a couple of minutes later, reported PTI. The last jolt was recorded at 6.54 AM with a magnitude of 5.2, it said.
The Andaman and the Nicobar archipelago is prone to earthquakes and it is not unusual for the islands to witness more than two-three quakes a day.
The Andaman & Nicobar Islands lie in Zone V of seismicity. The Bureau of Indian Standards has grouped the country into four seismic zones, viz. Zone II, III, IV and V. Of these, Zone V is seismically the most active region, while Zone II is the least.
According to Pune-based Amateur Seismic Centre (ASC) that keeps track of regional seismicity, the Andaman and Nicobar Islands are located near the boundary of the Indian plate and the Burmese Microplate. The Andaman Trench marks this boundary and lies in the Bay of Bengal to the west of the archipelago. Another prominent feature is the north-south West Andaman fault which is strike-slip in nature and lies in the Andaman Sea, to the east of this island chain.
The Andaman Sea, just like the Atlantic Ocean, is presently being widened by a tectonic process called “Sea Floor spreading”. This is taking place along undersea ridges on the seafloor. The Indian plate is diving beneath the Burmese subplate along the Andaman Trench in a process known as “Subduction”.
Shallow and occasional intermediate-depth earthquakes delineate the subducted slab under the Andaman-Nicobar islands joining the seismicity trend of the Indo-Burman ranges. However, ASC says, it must be stated that proximity to faults does not necessarily translate into a higher hazard as compared to areas located further away, as damage from earthquakes depends on numerous factors such as subsurface geology as well as adherence to the building codes.