Agusan Sur Quake: Philippine Fault-Agusan Marsh Segment Identified as Likely Source
BUTUAN CITY – The Philippine Institute of Volcanology and Seismology (Phivolcs) has determined that the magnitude 5.3 earthquake that struck Talacogon, Agusan del Sur on December 26, originated from the Philippine Fault-Agusan Marsh segment. This finding underscores the importance of understanding tectonic movements in the region.
Earthquake Analysis by Phivolcs
Phivolcs published a detailed briefer on Friday, identifying the earthquake’s characteristics. The quake, with a depth of 12 kilometers, exhibited strike-slip faulting, indicating horizontal movement along the fault. This type of faulting is common in regions with significant tectonic activity.
Aftershocks and Regional Impact
The initial tremor generated several aftershocks, including a magnitude 4.6 quake at a depth of 7 kilometers. The broader seismic impact was felt across large parts of Mindanao, affecting multiple cities and municipalities.
In Talacogon, the epicenter, seismic intensity reached Level V. In Bislig City and Hinatuan, Surigao del Sur, intensity was recorded at Level IV. Intensity III was observed in cities such as Gingoog, Jasaan, Magsaysay, and Medina in Misamis Oriental, and in Laak, Mabini, Monkayo, and Nabunturan in Davao de Oro. Further afield, intensity levels II were felt in various locations including Bukidnon, Cotabato, and Surigao del Sur.
Understanding the Philippine Fault-Agusan Marsh Segment
The Philippine Fault-Agusan Marsh segment is part of the larger Philippine Fault system that traverses Agusan del Sur. Movements along this segment can have far-reaching effects, potentially impacting neighboring provinces. This highlights the necessity for ongoing preparedness measures across the region.
Seismic Gaps and Tectonic Stress
Earlier this year, Phivolcs released a study on tectonic stress along the Philippine Fault in Mindanao. This research indicated that stress is building up, possibly influenced by recent earthquakes in the region. Notably, on December 2, 2023, a significant magnitude 7.4 earthquake struck off Hinatuan, followed by a 6.8 magnitude event two days later.
Historical seismic gaps, particularly in sections like Esperanza, Agusan Marsh, and Mati, are areas where earthquakes are overdue. These findings reinforce the importance of continuous monitoring and disaster preparedness.
Regional Segments of the Philippine Fault
In Mindanao, the Philippine Fault is segmented into various sections, including Surigao, Esperanza, Agusan Marsh, West Compostela Valley, Central Compostela Valley, Nabunturan, East Compostela Valley, Caraga River, Mati, and Lianga. Each segment plays a critical role in the region’s seismic activity.
Preparedness and Safety Measures
Phivolcs emphasizes that while predicting earthquakes accurately is challenging, communities should approach these risks with caution and readiness. The agency encourages proactive safety measures to mitigate potential damage and loss of life.
Disaster preparedness is crucial in regions prone to seismic activity. Simple steps such as securing furniture, creating emergency kits, and familiarizing oneself with evacuation routes can make a significant difference during an earthquake.
Conclusion
The December 26 earthquake in Agusan del Sur, attributed to the Philippine Fault-Agusan Marsh segment, underscores the dynamic nature of tectonic movements in the region. As stress continues to build along the Philippines Fault, the importance of disaster preparedness is more critical than ever.
Stay informed and take proactive steps to ensure your safety and well-being during seismic events. Continuous monitoring and preparation can help communities better withstand potential earthquakes in the future.
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(Ivy Marie Mangadlao)