The Dec 26 earthquake that triggered a devastating tsunami along coastlines in South and Southeast Asia, unleashed energy equivalent to a 100 gigaton bomb and shook the whole planet as much as half an inch, experts have said.

Five months after the disaster, the full measure of the earthquake is now being understood.

According to reports published by an international group of seismologists in the journal Science, the earthquake created the longest fault rupture and the longest duration of faulting ever observed, CNN reported.

"Normally, a small earthquake might last less than a second; a moderate sized earthquake might last a few seconds. This earthquake lasted between 500 and 600 seconds (at least 10 minutes)," Charles Ammon, associate professor of geosciences at Penn State University, was quoted as saying.

The quake, whose strength has been revised from nine on the Richter scale to between 9.1 and 9.3, shook the whole planet as much as half an inch.

It unleashed energy equivalent to a 100 gigaton bomb, according to Roger Bilham, professor of geological sciences at the University of Colorado. That level of energy endured longer than any quake ever recorded.

It also created the longest gash in the earth's seabed ever, stretching nearly 1,280 km. The ground moved up and down along the length of the fault by at least five metres, while some places recorded movements of 20 metres.

Scientists believe more earthquakes of this magnitude are likely to happen.

--Indo-Asian News Service