The Jakarta Post
Authorities and residents of Palu, Central Sulawesi, have been warned by a Meteorology, Climatology and Geophysics Agency (BMKG) geophysics station in Balaroa to be on alert over a possible earthquake caused by the Matano tectonic fault that runs through the province.
The station recorded at least three earthquakes last week that were triggered by the Matano fault. The first one, a 4.9-magnitude quake, occurred on Nov. 23. Its epicenter was located 11 kilometers southwest of Bungku, the capital of Morowali regency, with a depth of 11 km.
The second occurred a day later, with a magnitude of 3.8 and an epicenter that is close to the first one. That quake was followed by a 3.9-magnitude earthquake in Bahodopi district in Morowali with a depth of 11 km.
While the fault has yet to cause very powerful tremors, historical records show that it once triggered a 7-magnitude earthquake in the past.
“The last powerful earthquake caused by the fault occurred in the 1900s. It has been dormant since, but we need to be careful because of its geological cycle,” Henrik told The Jakarta Post on Monday.
Unfortunately, Henrik added, researchers found few accounts of the powerful earthquake as the region was inhabited at that time. The agency only has records of strong earthquakes ranging between 5 and 6 in magnitude between 2011 and March this year.
“Such earthquakes are still considered normal because the Matano fault is an active tectonic fault,” Henrik said.
Areas in Morowali and around Matano Lake in Luwu Timur, South Sulawesi, are densely populated. There is also a mining industry site in the South Sulawesi regency.
“Residents and local administrations should be prepared for a possible earthquake,” he said, adding that strengthening the foundations of buildings would be one way to mitigate a possible disaster.
Another active tectonic fault located in the province, the Palu Koro fault, had caused a 7.4-magnitude earthquake in Central Sulawesi in September last year. Earthquake experts believed the earthquake had triggered an underwater avalanche that later caused a tsunami, which struck the provincial capital of Palu and its surrounding areas.
The disaster killed more than 4,000 people, with hundreds more still missing. It also destroyed more than 110,000 houses across Central Sulawesi. (kuk)