Two damaging earthquakes occurred offshore of the Province of Surigao del Sur: the magnitude (MW) 7.4 event on 02 December 2023, 10:37 PM (PST) with maximum Intensity VII, and the MW 6.8 event on 04 December 2023, 03:49 AM (PST) with maximum Intensity VI, based on the Philippine Earthquake Intensity Scale (PEIS).

DOST-PHIVOLCS deployed a Quick Response Team (QRT) from 04 to 09 December 2023 to conduct field surveys and evaluate the earthquakes’ geologic and structural impacts. The team proactively provided information and recommendations to stakeholders, including the national and local governments, media, educational institutions, and individuals. Moreover, the QRT gathered significant information and accounts of tsunami impacts to enhance the early warning system for tsunami monitoring.

Field investigations revealed that in areas that felt PEIS VI - VII, both earthquakes produced substantial ground shaking that damaged 212 structures in Surigao del Sur and Agusan del Sur. About 21 sites in Surigao del Sur had tension cracks, slumping and landslides along the mountainous areas; 23 sites had documented liquefaction manifested by lateral spreading, subsidence and titling of structures in the swampy and coastal barangays; and 23 sites had reported tsunami occurrence. On the coast of Hinatuan, Surigao del Sur, the maximum recorded tsunami height was 2 meters, while the maximum inundation distance was 61 meters.

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