Megathrust, an actual threat to Indonesia, has several zones in the country such as in the Sunda Strait, the south coast of Java, and the Mentawai-Siberut region. Research conducted by the Geological Disaster Research Center of the National Research and Innovation Agency (BRIN) revealed that megathrust earthquakes in southern Java have a recurrence interval of about 400-600 years, with the last event estimated to have occurred in 1699, indicating that the accumulated energy has reached a critical point. This information highlights the importance of disaster preparedness and mitigation in saving lives, as learned from the Aceh tsunami. The potential disasters posed by megathrust earthquakes in the southern Java region, including the Sunda Strait, can trigger tsunamis similar to the one in Aceh, requiring serious attention from stakeholders and the community to effectively mitigate the risks and impacts. Research findings suggest that the megathrust segment in southern Java, including the Sunda Strait, holds significant tectonic energy that could unleash earthquakes ranging from magnitude 8.7 to 9.1, potentially leading to widespread impacts, including in Jakarta, with a tsunami arrival time of about 2.5 hours. Simulations indicate that if a tsunami were to occur, wave heights could reach 20 meters on the south coast of Java, 3-15 meters in the Sunda Strait, and around 1.8 meters on the north coast of Jakarta. To address this, BRIN emphasizes the importance of mitigation through both structural and non-structural approaches. Structural measures include the construction of tsunami barriers, wave breakers, and coastal spatial planning, ensuring a safe distance of 250 meters from the coastline. Additionally, coastal reforestation with natural vegetation like pandanus and mangroves can help absorb tsunami wave energy. Non-structural approaches involve community preparedness through disaster mitigation education, evacuation training, and providing adequate evacuation routes and sites. Urban areas such as Jakarta, with high population density and vulnerable soil sediments, also require seismic mitigation efforts like retrofitting buildings for increased structural strength. It is crucial to consider seismic hazards in industrial areas like Cilegon, where earthquakes could potentially trigger fires due to fuel or chemical leaks in large factories, necessitating strict safety standards to manage such secondary hazards effectively.
“Pembahasan Megathrust Indonesia: Temuan BRIN yang Menjelaskan”
