Indonesia's Updated Megathrust Map Now Identifies 14 High-Risk Zones

The risk of a major earthquake in Indonesia has come back into focus following the release of the updated 2024 Indonesian Earthquake Source and Hazard Map, which shows an increase in the number of megathrust zones. The latest map now includes 14 megathrust zones, up from 13 in the 2017 edition. The update indicates an increased level of seismic hazard in several areas. A key highlight is the denser hazard contours on the new map, reflecting a greater potential threat compared to the previous mapping. Iswandi Imran, a member of the Indonesian Academy of Sciences (AIPI) and a professor at the Bandung Institute of Technology (ITB), stated that the changes signal a higher earthquake risk in certain regions. The 2024 map also records the potential for very large earthquakes in several zones. The Java Megathrust, for instance, has a maximum potential magnitude of 9.1, while other zones such as Enggano and Mentawai-Pagai could trigger quakes up to 8.9. The 14 megathrust zones and their maximum potential magnitudes are: Aceh-Andaman (9.2), Nias-Simeulue (8.7), Batu (7.8), Mentawai-Siberut (8.9), Mentawai-Pagai (8.9), Enggano (8.9), Java (9.1), West Java (8.9), East Java (8.9), Sumba (8.9), North Sulawesi (8.5), Cotabato Trench (8.3), South Philippines (8.2), and Central Philippines (8.1). The Meteorology, Climatology and Geophysics Agency (BMKG) previously noted that two megathrust zones are ‘just waiting to release’ their energy: the Sunda Strait Megathrust, which last ruptured in 1757, and the Mentawai-Siberut Megathrust, which last did so in 1797. BMKG explained this condition is known as a seismic gap, where a geologically active area has stored significant energy due to a long absence of major quakes. The agency clarified that the phrase ‘waiting to happen’ is not a prediction but a call for vigilance based on historical and geological data, and it is not meant to cause public panic.