FLASH UPDATE #2 – M7.4 (Corrected from M6.9) Earthquake in Surigao del Sur
Country under monitoring: Philippines
OVERVIEW: At 2137 HRS UTC+7 of 2 December 2023, a M7.4 (corrected from M6.9) earthquake with epicentre at 8.44N, 126.60E and a depth of 25 km (corrected from 8 km), located 30 km offshore of Surigao del Sur, rocked Mindanao as reported by the Philippine Institute of Volcanology and Seismology (PHIVOLCS).
AFFECTED AREAS:
According to the PHIVOLCS Information No. 3, the following intensities were reported:
Intensity VI – Maco, and Monkayo in Davao de Oro
Intensity V – Nabunturan in Davao de Oro; City of Tagum in Davao del Norte; Davao City
Intensity IV – Digos City and Magsaysay in Davao del Sur
Intensity III – Santa Cruz in Davao del Sur; Don Marcelino and Jose Abad Santos in Davao Occidental
Intensity II – Matanao in Davao del Sur
PRELIMINARY ANALYSIS: According to the PHIVOLCS, the origin of the earthquake was tectonic and generated from the Philippine Trench. PHIVOLCS advised that damage and aftershocks are expected. It is estimated that 5.96 Million people, 1.4M households, and 37.6 billion USD of infrastructure (total replacement value) are concentrated within this radius (ASEAN DMRS).
TSUNAMI: According to PHIVOLCS, sea level monitoring confirmed the occurrence of tsunami with the preliminary wave heights 0.64 meters in Mawes Island, Hinatuan, 0.18 meter in Lawigan, Bislig City, 0.05 meter in Port of Dapa, Surigao del Norte, and 0.08 meter in Mati, Davao Oriental. At 0223 HRS UTC+7, the PHIVOLCS released Tsunami Warning #2 which reported that the last recorded tsunami wave arrived at Hinatuan-Bislig Bay Station on Mawes Island at 0152 HRS UTC+7. With this, the PHIVOLCS lifted the threat of tsunami associated with the M7.4 earthquake.
AFTERSHOCKS: PHIVOLCS, reported as of 3 December 2100 HRS UTC+7, 1,279 aftershocks were recorded ranging from M1.5 to M6.6. Of these, 12 were felt and 270 were plotted.
IMPACTS:
- As of 3 December, at 1500 HRS UTC+7, the NDRRMC reported a total of 529 families (2,647 persons) affected in Davao Oriental; there was 1 death and 2 injured persons in Davao del Norte.
- A total of 6 damaged houses, of which 4 were totally damaged.
- There were 2 bridges affected, of which 1 is still not passable.
- There was 1 related incident of structural fire in Davao Oriental.
- 31 Municipalities/cities had power interruption (100% already restored).
PREPAREDNESS AND RESPONSE:
- PHIVOLCS released TSUNAMI WARNING #1 which strongly advised people in the coastal areas of the provinces of Surigao del Sur and Davao Oriental to immediately evacuate to higher grounds or move farther inland.
- The Office of Civil Defense-National Disaster Risk Reduction and Management Council (OCD-NDRRMC) activated National Response Clusters to monitor and facilitate needed emergency response.
- The Regional Disaster Risk Reduction and Management Councils (RDRRMC) XI and XIII, through the Office of Civil Defense (OCD) XI and XIII have raised the alert status of their Emergency Operations Centers (EOC) to Red Alert.
- Continuous monitoring is being conducted by PHIVOLCS.
The AHA Centre will continue to monitor for further developments and issue necessary updates.
DATA SOURCES:
ASEAN Disaster Monitoring & Response System (DMRS); Pacific Disaster Center (PDC Global);
Philippines: NDRRMC, PHIVOLCS;
Verified news media agencies.
