March 17, 1973 Earthquake: Calaug,lopez,guiayangan, Quezon City, Philippines

Maximum intensity VII (Rossi-Fore;) at Hondagua, Lopez, Calauag and Guinayangan, Quezon Province. 15 killed, 64 injured, approximately $450,000 in damage. (Philippine fault ruptured across Tayabas Isthmus with left-lateral displacement of 1.85 m on the north side 4 km east of Calauag and 3.2 m on the south side where it crossed the shoreline south of Guinayangan. (reference #1053)

The town worst hit by the earthquake is Calauag, Quezon where 98 houses were totally destroyed and 270 others were partially destroyed. In Barrio Sumulong of the same town, 70% of the school building was damaged. The town of Lopez ranks next to Calauag with respect to the extent of the destruction. The place is relatively farther from the causative fault and the epicenter of the main shock, but soft underlying sediments present in Calauag are similarly found in Lopez. The sea at the western end of the sea-wall in Calaug was observed to go beyond the shore by 20 meters. This was due to a rise in sea level of 1.3 meters. Rise in sea level was similarly noticed in the town of Quezon City at the southern tip of Alabat Island. (reference #1187)

This earthquake, which occurred at 4:30 PM and whose epicenter was at Ragay Gulf, generated a 30-km long ground rupture and intense shaking which caused heavy damages to the Quezon towns of Calauag, Hondagua and Lopez. It was felt as far as Dagupan City to the NW and the town of Virac in the province of Catanduanes to the east. In the village of Sumulong in Calauag, 98 houses collapsed and 270 others were partially destroyed. The Sumulong Bridge was split into two. In the town of Lopez, walls of various structures fell. In Hondagua, a restaurant-turned-theatre collapsed while the old Spanish church partially collapsed, too. (reference #10958)