The westward expansion of the city went as far as Lucao , which was also swampland . Local historian Restituto Basa surmised that the name '' Lucao '' may have been derived from the shellfish called '' lukan '' that used to abound in the swampy area . In June 1962 , Dagupan was shaken by a series of strong earthquakes which occurred at irregular intervals for about three weeks . The quakes toppled the belfry of the Roman Catholic Church . Many people from Calmay , Carael and island barrios evacuated to other towns . In 1968 , the national government agencies opened offices in Dagupan and other key cities across the country . The daytime population increased substantially , causing congestion in the city that began to see the appearance of public utility tricycles . On July 16 , 1990 , a magnitude 7.7 earthquake struck northern Luzon , causing liquefaction , which made buildings tilt and sink due to their heavy weight and the looseness of the ground , which turned into sediment-rich mud . The Magsaysay Bridge , one of the two bridges especially spanning the Pantal River , collapsed , delaying people from crossing to the other banks and vice versa . Major damage caused businesses to be permanently transferred to the neighbouring towns of Mangaldan and Calasiao , but somehow , Dagupan and its inhabitants managed to recover from the earthquake
magnitude 7.7 earthquake struck northern Luzon
1990 Luzon earthquake
Dagupan