The 1968 Casiguran earthquake occurred on 04:19:22 local time on August 2 with a moment magnitude of 7.6 and a maximum Mercalli intensity of IX (Violent).

In Manila, many structures that suffered severe damage had been built near the mouth of the Pasig River on huge alluvial deposits.

268 people were reported to have died during the collapse of the six-story Ruby Tower, located at the corner of Doroteo Jose and Teodora Alonzo Streets in the district of Santa Cruz.

[7] In the district of Santa Ana, one person was injured by debris from a damaged apartment building.

[9] The former location of Ruby Tower in Santa Cruz district is now a memorial hall which stands today.