Patients are evacuated from a hospital after an earthquake hit the western coast of Sumatra, in Banda Aceh in Aceh province
Patients are evacuated from a hospital after an earthquake hit the western coast of Sumatra, in Banda Aceh in Aceh province April 11, 2012. T

Seismologists have warned that the powerful earthquake that shook western Indonesia recently could have increased the possibility of a tsunami in the region and advanced the likelihood of a cataclysmic "seismic event".

Indonesia is located in the Pacific "Ring of Fire", an arc of volcanos and faultlines encircling the Pacific Basin where 90 per cent of the world's earthquakes occur, according to the US Geological Survey.

The country is vulnerable to earthquakes and tsunamis, and the western coast of Sumatra has suffered serious damages.

In 2004, a 9.1 magnitude earthquake off the coast of Aceh, the most northerly province, triggered a devastating tsunami that took the lives of more than 230,000 people.

Now, seismologists fear that last week's earthquake, which also targeted Indonesia's western coast could increase risks of another tsunami hitting the region.

"The spring was pushed a little bit tighter," Kerry Sieh, director of the Earth Observatory of Singapore told AP news agency.

The natural disaster "could have been advanced by a few years," he said.

The response to the recent 8.6 magnitude also showed that the Aceh province remains unprepared to tackle such disasters. While the earthquake caused little damage, rescue and evacuation efforts were chaotic.

In the past, the country has been struck by some of the most devastating seismic events. Scientists admitted they were not adequately prepared for the 2004 Boxing Day earthquake that triggered a 100ft-high tsunami because its fault, located west of Sumatra Island, had long been quiet.

Scientifics have since stepped up research and analysed past tsunami and earthquake patterns in a bid to improve their understanding of when such events could occur, though predicting them with certainty remains impossible.

Sieh said the early April earthquake squeezed the overlapping tectonic plates that form the fault, AP reported.

"The next megathrust rupture could be in 50 years or in five," he said. "It's impossible to know."

Sieh added that a separate section from the fault could snap within the next 30 years, unleashing a tsunami that would strike the Sumatran city of Padang, where up to one million people live.

Danny Hilman Natawidjaja, a geologist with Indonesia's Institute of Science, said both Aceh and Padang needed to be prepared.

"Authorities need to take a good look at what didn't work well and find a way to fix it," he said.