BRIN Geologist Warns of Potential for Megathrust Earthquake in Mentawai-Siberut Segment

TEMPO.CO, Bandung - A geology and disaster researcher at the National Research and Innovation Agency (BRIN), Danny Hilman Natawidjaja, has highlighted the significant potential for a megathrust earthquake in the Mentawai-Siberut segment and the Sunda Strait. While the exact timing of such an event remains unpredictable, the risk necessitates increased public awareness and preparedness.

“Because minimizing casualties must be intensified,” emphasized Danny on Wednesday, August 21, 2024. These efforts should include training residents in evacuation procedures, reviewing and upgrading infrastructure, and enhancing emergency response capabilities.

Danny expressed concern that public preparedness might wane over time, leading people to forget about the potential for a megathrust earthquake disaster in their region. The Mentawai-Siberut segment, in particular, has a confirmed history of significant seismic activity. 

"The likelihood of a megathrust event is indeed quite high," he stated.

Danny highlighted that an earthquake of magnitude 8.5 occurred in the Mentawai-Siberut segment in 1797, and its estimated recurrence period has likely elapsed without the release of equivalent energy. The earthquakes that struck in 2007 and 2010, he explained, occurred at the segment's edges, leaving a substantial amount of unreleased energy.

According to Danny, inter-earthquake events can occur rapidly, as exemplified by the 2005 Nias Earthquake, which followed the 2004 Aceh Earthquake and Tsunami. However, they can also take place over extended periods, as seen in the region around Mentawai.

“The 1797 earthquake in Mentawai-Siberut was followed by the 1830 earthquake to the south,” he said. Both events occurred within the same megathrust area but in different segments.

Despite the potential for a large earthquake, scientists and earthquake researchers cannot accurately predict when it will happen. “The seismic pattern is difficult to use as a basis for making predictions,” Danny added.

Comparing Indonesia to Japan

Danny drew a comparison between Indonesia and Japan, noting that Japan has issued early warnings about potential megathrust earthquakes, such as the one following the 7.1 magnitude earthquake on August 8. He acknowledged that the conditions in Japan and Indonesia differ, with Japan having conducted extensive research on megathrust events, allowing for predictions based on statistics and scientific data.

Additionally, he considered the Japanese population to be more prepared, having a long history of disaster mitigation and taking preparedness measures more seriously. “The early earthquake warning in Japan led to a positive response from the public,” he said.

Returning to Indonesia, he emphasized that the potential for a large earthquake is also high in the Maluku and Nusa Tenggara regions, although earthquake data in these areas is limited. The Sunda Strait also poses a significant risk, with no major earthquakes recorded in centuries, indicating a seismic gap.

ANWAR SISWADI (CONTRIBUTOR)

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