BMKG: South Garut Fault Activity Is The Trigger For The Earthquake In West Java A Few Days Ago

Illustration. (Photo: Unsplash)

JAKARTA - Head of the Earthquake Center of the Meteorology, Climatology and Geophysics Agency (BMKG) Daryono stated that the announcement of the South Garut Fault (Garsela) activity as a trigger for the destructive earthquake in West Java a few days ago was based on the results of data analysis.

"The earthquake in Bandung Regency and Garut 5.0 magnitudes is undisputedly triggered by the activities of the Garsela Fault," he said in a short message in Jakarta, quoted from Antara, Saturday, September 21.

He explained that it was convincing that after his party re-analyzed it using more aftershock data, hypocenter relocation was carried out and analysis of the source mechanism.

The Garsela fault is a deformation zone consisting of many faults, so the distribution of earthquake epicenters in this zone is very wide, as has been exposed to previous BMKG seismic maps.

"The mechanism for this earthquake source has a fault orientation that is northeast-southwest, in accordance with the Garsela Fault route," he said.

The BMKG classified an earthquake with a magnitude of 5.0 which resulted in hundreds of houses being damaged and dozens injured, on Wednesday (18/9) it was recorded as the largest earthquake currently triggered by the activities of the Garsela Fault.

Based on the distribution of aftershocks, this earthquake was categorized as a shallow crustal earthquake with a source mechanism for the shear fault to irrigate (sinistral strike-slip).

The previous Garsela fault also triggered an earthquake with a magnitude of 4.2 on November 6, 2016, and an earthquake with a magnitude of 3.9 on July 18, 2017. Both earthquakes caused damage to a number of buildings in Pangalengan and Kamojang.

Or on the other hand, Daryono said, because currently the new mapped Segment of Rakutai and Segmen Kencana, it could be that the 5.0 magnitude earthquake can also be recognized as a new segment in the Garsela Sesar zone, so some experts assess that further examination is needed to obtain the latest information in order to strengthen the impact mitigation efforts caused by the earthquake in the future.