May 5, 1925 Earthquake: W. Luzon Island, Philippines

Reference #414:

1925, May 5, at 18:07 [local time], 9.3 N, 122.7 E. There was a strong earthquake on the Dumaguete Peninsula (southeast of Negros Island). The settlements of Tolong, Siaton, Tanhay, Bais and others, situated on filled-in ground or on the swampy Quaternary and Tertiary terraces, fringing the steep slopes of the ancient Tigas volcano which makes up the peninsula, suffered most of all. It was mainly poorly built structures and those which had long needed repairs which were damaged: the sugar factories at Bais and Isabela, the school, the church, the monastery and the town hall at Siaton, the monastery and town hall at Tanhay. Some of these were pile structures with weak supports (of rotted beams) and heavy roofs. Brick chimneys of old sugar mills collapsed and the weak parts of the old churches and monasteries fell everywhere at a distance of up to 125 km from the source of Negros Island.

On the neighboring islands, Cebu, Siquijor, and Mindanao, at the same distance from the epicenter, the earthquake was less strong. Many collapses, landslides and mudslides occurred along the valleys of the channels on the steep slopes of the Dumaguete Peninsula; 17 people died as a result. Recurrent shocks were registered almost constantly in the epicentral zone during the first few days and sporadically for several months.

The south coast of Negros Island (and only this coast) was inundated by waves caused by the earthquake.

Gutenberg, Richter (1954): 5.V; 10h06m06s; 9.5 N, 123

E; M=6.75.

Reference #1187:

1925, May 5, 5:07 p.m. Visayas and N Mindanao: Southern

Negros - earthquake of Intensity VIII-IX. The area of destruction was very irregular and conforming to the

nature of the ground. It comprised the half of the southern part of the island formed by the peninsula - like protuberance of Dumaguete extending to the SE, and the real

southern end of the island inclined to the SW. Only the south coast was invaded by the waves caused by the

earthquake... 18 people killed from landslides on the Dumaguete Peninsula.

Reference #1058:

1925, may 5, 10:06:06 UTC, 9.5 N, 123 E, magnitude 6.75.