A minor tremor measuring 3.1 on the Richter scale occurred in Manuguru in Bhadradri Kothagudem district in the Godavari basin, at 4.43 am on Friday.
Dr. Purnachandra Rao, chief scientist, and head, of environmental seismology of the National Geophysical Research Institute (NGRI), said, "It is a very weak tremor and not capable of any damage. The area in the Godavari River is a zone filled with cracks inside the earth, which are billions of years old. These faults are capable of causing earthquakes whenever there is some disturbance."
He explained that the Indian sub-continent was stressed against the Himalayan mountains and was moving north at the rate of 5 cm per year.
"In the process, the stress
is propagated southwards as well, which causes earthquakes in the fault lines which slide due to the stress. The Godavari River is a rift valley, a valley of faults that were active in the past. They get reactivated sometimes, causing tremors. The Godavari valley is known to have earthquakes when compared with the rest of the Deccan plateau."
The largest earthquake in the Telugu states, Dr Rao said, was in 1967 in Bhadrachalam of a magnitude of 5.7, and no major earthquakes were recorded after that.
It is to be noted that the last tremor of magnitude 3.0 was recorded in February along the borders of Andhra Pradesh and Telangana near Pulichintala and Chintalapalem.