Jakarta, Indonesia Sentinel — Indonesia faces significant seismic risks, with the country experiencing approximately 8,000 quakes each year, according to the Meteorology, Climatology, and Geophysics Agency (BMKG). This alarming number is due to Indonesia’s location, surrounded by multiple megathrust zones and hundreds of active faults.
BMKG’s Head of Earthquake and Tsunami Center, Daryono, explained that Indonesia’s frequent seismic activity is linked to its geography, which places the archipelago amid 13 megathrust zones and 294 active faults.
“Each year, Indonesia experiences more than 8,000 earthquakes. Around 350 of these are significant enough to be felt, with approximately 15 causing serious damage. Additionally, earthquakes capable of triggering tsunamis occur once every two years,” Daryono stated during a press conference at the Ministry of Communication and Information (Kominfo) in Jakarta on Tuesday, October 1.
Indonesia’s seismic vulnerability is due to a combination of major fault lines and megathrust zones. The 2017 Indonesian Earthquake Source and Hazard Map identifies 13 megathrust zones surrounding the country.
However, some have experienced segmentation, leading to the formation of new fault segments, such as the Mentawai Segment, which is now divided into the Mentawai-Siberut and Mentawai-Pagai segments. Similarly, the Java megathrust is segmented into three parts: the Sunda Strait-Banten Segment, West Java Segment, and the Central-East Java Segment.
Megathrusts, areas where tectonic plates meet in subduction zones, are known for generating large earthquakes and massive tsunamis. These zones are where one tectonic plate is forced beneath another, usually located offshore. The potential for devastating seismic events makes megathrusts a significant concern for Indonesia, especially considering the country’s coastal geography.
Indonesia to Launch Disaster Information System on TV and Smartphones, Provides Real-Time Alerts
In addition to megathrusts, active faults pose a constant earthquake threat. Indonesia’s complex geological setting at the convergence of the Indo-Australian, Eurasian, and Pacific tectonic plates has creates numerous active faults that move continuously, increasing the earthquake risk.
Faults are categorized into two types based on their activity: active and passive faults. Active faults, unlike passive ones, continue to move and shift, causing seismic activity.
Active faults are fractures or zones of weakness in the Earth’s crust where two blocks of rock move relative to each other. This movement is driven by tectonic forces caused by the shifting of the Earth’s plates beneath the surface. When the accumulated pressure along these faults is released suddenly, it triggers an earthquake.
Active faults are often the primary source of earthquakes, releasing stored energy that causes the violent shaking felt on the Earth’s surface or underground. As Indonesia remains vulnerable to both megathrust and fault-related quakes, preparedness and awareness are crucial to mitigating the impacts of these natural disasters.
(Raidi/Agung)
