The event, ascribed to Malaysia Airlines missing plane, occurred at about 2:55 am local time on Saturday, about one and a half hours after the plane's last definitive sighting on civilian radar, state-run Xinhua news agency reported, suggesting a tremor of a kind on the floor bed of the sea.
The area, 116 km northeast from where the last contact with the Boeing plane was recorded, used to be a non-seismic region, according to a research group on seismology and physics of the earth's interior under the University of Science and Technology of China.
The seafloor event could have been caused by the Malaysia Airlines plane possibly plunging into the sea, the research group said.
The plane carrying 239 passengers and crew went missing on last Friday. There was no clue so far about its whereabouts despite intense search involving planes and ships from several countries.
On Thursday US official caused a flutter after he said that the missing Malaysia Airlines plane pinged a satellite for four hours after it went missing, indicating that it may have stayed in the air long after its last contact with the ground causing Malaysian authorities to widen their search westward, toward India, as a result.
India has deployed a number of ships and helicopters to locate the plane, but found nothing yet.