Nurris Ishak and Evangeline Majawat
New Straits Times

KUALA LUMPUR: Just as three more earthquakes hammered Indonesia yesterday and early today, an Australian seismologist said it was sheer luck that an earlier — and more powerful — quake on Wednesday did not generate a devastating tsunami.
And a Malaysian expert warned that the next big quake would likely happen off Padang in Indonesia.

Geologist Prof Datuk Dr Ibrahim Komoo, however, said neither its timing nor intensity could be predicted.

For the past two years, scientists from the Indonesian Institute of Sciences and Malaysian Academy of Science, including Ibrahim, have been collaborating on studies on earthquakes in the region.

“There are seven to eight segments in the earth plate around the region from the Andaman Islands to Sulawesi, running about 3,500km.
“Five of the segments — Acheh, Nias, Java, Sulawesi and now Bengkulu — have experienced major earthquakes in recent years.”

“Every 50 to 100 years, each segment will rupture, and the Padang segment has yet to rupture.”

They think the next big one could be off Padang.

Australian seismologist Mike Turnbull said Wednesday’s 8.4 magnitude quake off Bengkulu was equivalent in energy to more than 800,000 atomic bombs being exploded.

However, the huge force of water displaced by the ocean earthquake was pushed out to sea, rather than towards land, he was quoted as saying by the Sydney Morning Herald.

The Central Queensland University scientist said: “It was very fortunate in fact that the plate mechanisms that caused the earthquake caused the tsunami to go to the south west, out into the Indian Ocean and then the Southern Ocean. So there was very little effect from it.”

If the water had been forced north, or south, rather than southwest, Turnbull said “it would have been awful”.

Meanwhile, waves of fear spread to countries around the Indian Ocean yesterday as Indonesia was hit by several more earthquakes and suffered more than 30 aftershocks within 24 hours.

Countries such as Australia, India, Sri Lanka, Malaysia and Kenya all went on tsunami alert. However, the alerts were called off hours later. But some of Indonesia’s neighbouring countries felt the tremors.

An earthquake — measuring 6.4 on the Richter scale at a depth of 30km — struck southeast of Sulawesi island about 5.49pm.

It was far away from Wednesday’s 8.4 magnitude earthquake and series of aftershocks that struck south Sumatra hours earlier.

According to the Malaysian Meteorological Department, the magnitude 8.4 earthquake struck 155km southwest of Bengkulu at 7.10pm on Wednesday.

It was followed by a second earthquake measuring 7.8 on the Richter scale some 207km northwest of Bengkulu and 575km southwest of Johor Baru at 7.49am yesterday.

Although the region was rocked by three powerful earthquakes within a period of 24 hours, the department declared that the country was safe from tsunami threats.

The department’s Seismology Division director, Dr Mohd Rosaidi Che Abas, said there was no cause for alarm here.

The department reported moderate tremors measuring between 4.5 and 6.0 on the Richter scale following the earthquake which shook Bengkulu late on Wednesday.

“The epicentre of the early morning quake was about 575km from Johor Baru and the tremor could be felt in most of the southern part of Peninsular Malaysia, from Selangor down to Johor,” he said.

Regarding the earthquake off Pulau Talaud, near Sulawesi, he said: “There is a seismic belt along Sulawesi and the whole area is within the ring of fire which is prone to earthquakes and volcanic activities.”

Rosaidi said the quake could be a foreshock or a main shock. Should it be a foreshock, consequent earthquakes of higher magnitudes could be expected.

Indonesia, located on an arc of volcanoes and geologic fault lines surrounding the Pacific Basin, lies in a zone where four tectonic plates meet.

These plates constantly shift, sometimes causing devastating earthquakes.