Experts at the Centre for Earth Observing and Space Research in George Mason University in Virginia on Saturday said last week's killer quake off Sumatra were moving northwards along 90-degree Ridge.

"If the sequence of these aftershocks moves further north, then it may trigger a very big earthquake in Assam region," Ramesh P Singh, a member of the team and Vice Chairman of the International Union of Geodesy and Geophysics (IUGG) Risk Commission, was quoted as saying.

The seven northeastern states, Assam, Meghalaya, Mizoram, Tripura, Nagaland, Arunachal Pradesh and Manipur, considered by seismologists as the sixth major earthquake prone belt in the world, experienced India's worst jolts measuring 8.7 on the Richter scale in 1897, killing 1,600 people.

Assam experienced a massive tremor measuring 8.5 on the Richter scale on August 15, 1950 that claimed some 1,500 lives.