At 4:19 a.m. on Aug. 2, 1968, a powerful 7.3-magnitude earthquake struck Luzon. The quake killed 268 people.
The Philippine Institute of Volcanology and Seismology (Phivolcs) said Intensity VII was recorded in Manila despite its location being far from the epicenter.
The earthquake's epicenter was the town of Casiguran in Aurora province but it was strong enough to trigger the collapse of the six-story Ruby Tower building in Binondo, Manila.
Several other buildings such as the Aloha Theater, Philippine Bar Association Building, National Library, and Liwayway Hotel in Manila sustained varying levels of structural damages.
The strong tremor created large fissures measuring 10 meters to 20 meters, while in some areas it reached 400 meters to 500 meters.
Likewise, landslides were observed in the mountainous area near the epicenter, and tsunami was recorded based on the tide gauge station in Japan.
Phivolcs considers the 1968 Casiguran earthquake as one of the most destructive earthquakes in the Philippines.