Imagine sipping your morning coffee in Jakarta, Bandung, or Palu, unaware that beneath your feet lies a restless giant. Indonesia, with its breathtaking landscapes and rich culture, sits atop a complex web of active faults and megathrust zones. These geological features are not just lines on a map—they are dynamic, ever-shifting structures that have the potential to reshape our lives in an instant.
1. The Great Sumatran Fault: A 1.900 km Sleeping Giant
Stretching the entire length of Sumatra, the Great Sumatran Fault (also known as the Semangko Fault) is a massive strike-slip fault accommodating the oblique convergence between the Indo-Australian and Eurasian plates. This fault has been responsible for numerous significant earthquakes, including the devastating 2004 Indian Ocean earthquake near Banda Aceh.
2. Baribis Fault: Jakarta’s Underestimated Threat
Running from Purwakarta to Lebak Regency, the 100 km-long Baribis Fault poses a significant risk to the densely populated Jakarta metropolitan area. Despite its potential, public awareness remains low. The last major earthquake on this fault occurred in 1834, but its proximity to Jakarta's urban sprawl makes it a ticking time bomb.
Read also: 4 Countries at High Risk of Megathrust Earthquakes
3. Lembang Fault: Bandung’s Quiet Menace
Located just 10 km north of Bandung, the 29 km-long Lembang Fault has no recorded historical earthquakes but is capable of generating a magnitude 6.5 to 7.0 earthquake. A study revealed that a significant earthquake here could result in damages exceeding IDR 51 trillion, affecting millions of residents.
4. Palu-Koro Fault: The Force Behind the 2018 Disaster
The Palu-Koro Fault, a major left-lateral strike-slip fault in Sulawesi, was responsible for the catastrophic 2018 earthquake and tsunami. With a slip rate of up to 40 mm per year, this fault exemplifies the destructive potential of Indonesia's active fault systems.
5. Sorong Fault: Eastern Indonesia’s Seismic Frontier
Extending over 800 km from Sulawesi to New Guinea, the Sorong Fault is a broad zone of left-lateral shear at the junction of multiple tectonic plates. It has been implicated in numerous large earthquakes, including the deadly 1998 North Maluku earthquake.
6. Sunda Megathrust: The Subduction Zone of Doom
The Sunda Megathrust, stretching approximately 5.500 km from Myanmar to near Australia, is one of the most seismogenic structures on Earth. It was responsible for the 2004 Indian Ocean earthquake and tsunami that killed over 227.000 people. The megathrust's segmentation means that stress released in one area can increase pressure in adjacent segments, heightening the risk of future earthquakes.
7. Kertasari Fault: The Newly Discovered Hazard
Identified near the Garsela Fault in West Java, the Kertasari Fault is a recent addition to Indonesia's list of active faults. Its discovery highlights the ongoing need for geological research and mapping to understand and mitigate seismic risks in the region.
The Alarming Increase in Seismic Activity
Indonesia experiences over 8.000 earthquakes annually, with approximately 350 felt by residents and around 15 causing serious damage. This surge in activity underscores the urgent need for enhanced disaster preparedness and public awareness.
Expert Insights
In an official statement published by Universitas Gadjah Mada (UGM), Dr. Gayatri Indah Marliyani, a geological expert, emphasizes the challenges in mapping active faults due to Indonesia's high erosion rates. She advocates for continuous research and community preparedness to mitigate earthquake impacts.
Meanwhile, in a report by Tempo, Danny Hilman Natawidjaja, a geologist at the National Research and Innovation Agency (BRIN), warns of the significant potential for a megathrust earthquake in the Mentawai-Siberut segment. He stresses the importance of public awareness and preparedness to minimize casualties.
Indonesia's position atop multiple tectonic plates makes it one of the most earthquake-prone countries globally. While we cannot prevent earthquakes, understanding the risks and preparing accordingly can save lives. It's imperative for individuals, communities, and governments to prioritize seismic education, infrastructure resilience, and emergency preparedness.
Read also: When Will It Happen? A Matter of Time Before the Megathrust Earthquakes strikes Indonesia
Are you prepared for the next big quake? Familiarize yourself with local evacuation routes, secure heavy furniture, and participate in community drills. Remember, awareness and preparation are our best defenses against nature's unpredictability.
