A magnitude 6.6 earthquake struck off Catanduanes on April 4 at 8:54 pm, according to the Philippine Institute of Volcanology and Seismology (Phivolcs). The tremor hit the province at a depth of 9 kilometers and was located 120 kilometers southeast of Gigmoto town. Following the earthquake, Phivolcs warned of expected damage and aftershocks, as well as potential sea-level disturbances. The institute advised people to stay away from the beach and not go to the coast of the provinces of Catanduanes, Northern Samar, and Eastern Samar until the tsunami advisory is cancelled. The first tsunami waves were expected to arrive between 9:02 pm and 12:54 am on April 5. Minor sea-level disturbance was also possible in the area near the earthquake epicenter. Intensity II was recorded in Palo, Leyte while Intensity IV was recorded in San Jorge, Samar. Other areas that reported Instrumental Intensities included Legazpi City, Albay; Daet, Camarines Norte; Sipocot, Iriga City and Pili, Camarines Sur; Kananga, Dulag and Abuyog towns in Leyte; San Roque, Northern Samar; Bulusan and Prieto Diaz in Sorsogon; Ragay and Pasacao in Camarines Sur; Quinapondan, Eastern Samar; Palo and Alangalang in Leyte; Monreal and Uson in Masbate; Gumaca, Polillo, Mauban and Guinayangan in Quezon, and Donsol, Sorsogon.
