On June 8, the first day of school for 3.2 million Filipino children became a day of disaster. At 7:37 in the morning, a powerful magnitude 7.8 earthquake struck offshore near Sarangani province in southern Mindanao. The epicenter was roughly 20 miles southwest of Maasim, beneath the sea. By the end of the day, at least 32 people had died and over 200 were injured.
General Santos City, a major port city with more than 700,000 people, suffered the worst damage. Several buildings collapsed, including a commercial building with a Jollibee restaurant and a school where students were trapped. DZRH radio station's office building partially collapsed. St. Elizabeth Hospital, which was supposed to help the injured, was so badly damaged that everyone had to leave. At least seven people died in the city alone, and twelve more were missing. Property damage was estimated at around one billion pesos, roughly twenty million U.S. dollars.
In Sarangani province, near the epicenter, a deadly landslide caused many deaths. A tsunami of about one meter reached Philippine coasts, and waves of 4.6 feet hit Kiamba town. The Pacific Tsunami Warning Center warned that waves were possible in Indonesia, Palau, Taiwan and Papua New Guinea. Waves were later detected across the region, even reaching Japan.
President Ferdinand Marcos Jr. ordered classes suspended and directed disaster agencies to respond. About 6,224 public schools had their opening day disrupted. The earthquake caused numerous aftershocks, the strongest measuring magnitude 6.5. General Santos airport closed and about 17 domestic flights were canceled.