Passing On An Active Fault Makes Tarakan The Most Earthquake-prone Area In Kalimantan

Landscape of Tarakan City in North Kalimantan. (doc of the Ministry of Finance)

TARAKAN - The city of Tarakan in North Kalimantan is the most earthquake-prone area in Borneo. The reason is the existence of an active fault line called the Tarakan Fault in the area.

The Coordinator for Earthquake and Tsunami Mitigation of the Meteorology, Climatology and Geophysics Agency (BMKG), Daryono said the Tarakan Fault has a magnitude (M) of up to 7.0.

"The frequent earthquakes in Tarakan cannot be separated from the presence of an active Tarakan fault," said Daryono in Jakarta, Thursday, March 7.

History records that Tarakan was hit by earthquakes several times. Meanwhile, according to the Antara report, including on April 19, 1923 with an estimated magnitude of 7.0, the shock reached an intensity scale of VII-VIII MMI causing damage to many houses and causing soil fractures.

Then the earthquake on February 14, 1925 with a very strong shock reaching the intensity scale VI-VII MMI, causing damage to many houses.

Furthermore, Tarakan was also shaken by an earthquake on February 28, 1936 with a magnitude of 6.5 causing damage to a number of houses. Then on December 21, 2015 there was an earthquake with a magnitude of 6.1 which caused many houses to be built with 16 aftershocks.

Apart from being prone to earthquakes, the Tarakan area is also prone to tsunamis, due to its location opposite the source of the North Sulawesi Megathrust earthquake (North Sulawesi Megathrust).

Earlier on Thursday, April 7, at 15.40.51 WIB, the Tarakan region was also rocked by a tectonic earthquake. The results of the BMKG analysis showed that the earthquake had a magnitude of 3.4.

The epicenter of the earthquake was located at coordinates 3.36 North Latitude and 117.6 East Longitude on land, precisely in the middle of Tarakan Island with a depth of 10 km.

Taking into account the location of the epicenter and the depth of the hypocenter, the earthquake that occurred was a type of shallow crustal earthquake due to active fault activity.

Based on community reports, this earthquake was felt in Tarakan on an MMI (Modified Mercalli Intensity) II-III intensity scale where the shaking felt real as if a truck was passing. Several residents in Tarakan had run out of their homes due to the sudden shock.

So far, there have been no reports of damage caused by the earthquake. As of 16.30 WITA, the results of BMKG monitoring have not shown any aftershock activity.