Aizawl/Kohima, June 25 Moderate to mild four separate quakes with magnitude ranging from 2.8 to 4.5 on the Richter scale hit several parts of Mizoram, Nagaland, Tripura, Assam and adjoining areas of northeast region bordering Myanmar on Thursday, officials said.
According to the officials, there was no report of any damage or casualty from any part of the northeastern region.
With Thursday's two separate quakes, mountainous Mizoram was hit by the frequent tremors during the past one week.
An official of the India Meteorological Department (IMD) said, Thursday's two moderate earthquakes occurred within an hour with magnitudes of 4.2 and 4.5 on the Richter scale that jolted eastern Mizoram's Champhai area and other adjoining northeastern states.
The IMD official said that the first tremor occurred at Wednesday-Thursday midnight (12.45 a.m.) and the second one happened at 1.14 a.m. on early Thursday. Champhai district officials said that residents had a sleepless night during the last few days following the tremors with various magnitudes and subsequent aftershocks.
A fact-finding team comprising geologists and seismologists is now visiting Champhai to study the multiple aspects of the tremors.
Among the six earthquakes in a week, a moderate earthquake, measuring 5.5 on the Richter scale and the second in 12 hours, shook the same Champhai areas and other adjoining northeastern states bordering Myanmar on Monday, damaging 31 structures, including roads, buildings and important installations.
Prime Minister Narendra Modi, Union Home Minister Amit Shah and DoNER (Development of North Eastern Region) Minister Jitendra Singh spoke to Mizoram Chief Minister Zoramthanga and offered help.
The IMD officials said that two more separate mild quakes with magnitudes 3.8 and 2.8 on the Richter scale hit several parts of Nagaland, Tripura and adjoining northeastern states on Thursday afternoon also. All tremors, which lasted for few seconds, and were at 58 km to 136 km depth of the earth.
Seismologists consider the mountainous northeast region as the sixth major earthquake-prone belt in the world.
In 1897, a Shillong-epicentre quake measuring 8.2 on the Richter scale had hit the area. In 1950, an earthquake measuring 8.7 on the Richter scale had altered the course of the Brahmaputra river.
( With inputs from IANS )