Estimated Magnitude of Megathrust Earthquakes in Indonesia: Largest in Aceh

Based on the *2017 Indonesian Earthquake Source and Hazard Map*, a large part of Indonesia lies within megathrust zones.

Megathrust is a zone of collision between tectonic plates that can trigger major earthquakes.

Indonesia's megathrust zone stretches from the northern part of Sumatra Island, extending southwards to Java, Bali, Nusa Tenggara, and the Banda Sea. Similar zones also exist in northern Sulawesi and Maluku.

This vast zone is divided into 16 segments. The strongest potential earthquake is located in the Aceh-Andaman megathrust segment, with an estimated maximum magnitude of 9.2.

This potential disaster was realized in 2004, when Aceh was struck by an earthquake of approximately 9.1 magnitude.

Quoting a report from the Tsunami and Disaster Mitigation Research Center (TDMRC) of Syiah Kuala University, this earthquake triggered a massive tsunami that impacted numerous countries, including Thailand, Malaysia, Myanmar, Bangladesh, India, and Sri Lanka, resulting in a total death toll of around 226,000.

Similar earthquake potential exists in other segments outside Aceh, as detailed in the graph.

However, according to the Meteorology, Climatology, and Geophysics Agency (BMKG) website, the timing of disasters in all these segments cannot be predicted.

"Although experts can calculate the estimated maximum magnitude of earthquakes in the megathrust zone, current technology cannot accurately predict, let alone determine, when such megathrust earthquakes will occur," they stated.

"In this uncertainty, what needs to be done is appropriate mitigation, preparing concrete steps that need to be taken immediately to minimize the risk of socio-economic losses and casualties should an earthquake actually occur, particularly by preparing the community and its infrastructure," they continued.