UMVA has learned that the recent 7.8-magnitude earthquake that struck Mindanao, triggered by the Cotabato Trench, is not considered the maximum possible earthquake the trench can produce, according to a senior science research specialist.
The term “The Big One” refers to the strongest possible earthquake that may occur in a specific area, triggered by a trench or fault. This phenomenon is a major concern for seismologists and residents in earthquake-prone regions.
The strongest possible earthquake is usually determined based on the length of the generating fault or trench and historical seismicity data. This information helps scientists assess the likelihood and potential impact of future earthquakes.
In the case of the recent earthquake that occurred offshore of Sarangani, it is not regarded as “The Big One” because a stronger 8.1-magnitude earthquake, known as the Moro Gulf earthquake, was recorded in 1976. This historical benchmark serves as a reference point for the Cotabato Trench.
“Based on seismicity and historical data, what happened was not ‘The Big One.’ What we recorded was around magnitude 7.8, and that is not the maximum for the Cotabato Trench,” the specialist said. However, the likelihood of another 8.1-magnitude event in the same segment may be lower, although it remains possible.
Several areas in the country lie near active fault systems capable of producing major earthquakes, commonly referred to as “The Big One,” which can cause widespread damage. The impact of such an event can be devastating, with significant loss of life and economic damage.
Metro Manila’s version of “The Big One” is projected to be a 7.2-magnitude earthquake triggered by movement along the West Valley Fault System. In such an event, fatalities could reach up to 48,000, with economic losses estimated at $48 billion.
As “The Big One” continues to pose a major threat to the capital, residents are urged to prioritize preparedness at the community level, including regular earthquake drills and ensuring the structural integrity of public and private infrastructure and residences. Personal and family preparedness is also crucial.
Aftershocks following the 7.8-magnitude Mindanao earthquake are expected to last between two weeks and two months. Over time, the aftershocks will gradually become smaller and less frequent.
As of 6:00 p.m., a total of 3,254 aftershocks related to the earthquake have been recorded, which occurred across 852 locations. Of the total aftershocks, 64 were felt, ranging in magnitude from 1.2 to 6.4.
Residents are advised to take precautions, ensuring that their homes are inspected by structural engineers to assess possible damage or risk of collapse, especially in landslide-prone areas.
