August 15, 1918 Earthquake: Cotabato, Mindanao, Philippines

Reference #414:

1918, August 15, 20:18 [local time, 12:18.2 UTC]. There were strong tremors of very great duration all over Mindanao Island. They were accompanied by an enormous number of aftershocks. The station at Butan, 450 km to the north-northeast of the epicenter, equipped with a Weichert seismograph, registered 600 shocks before the end of August; 250 of these registered on the 15th and 16th.

The earthquake did great damage on the coast of the Celebes Sea between Cotabato and Davao Bay and was accompanied by colossal sea waves, which washed away everything on the coast between Lebac and Glan Ports. Details about these events were received only from the above-mentioned points.

At Glan, the earthquake lasted more than 3 minutes and destroyed all the homes on the coast of Sarangani Bay. Forty-six people died. A landslide occurred on the slopes of one of the large mountains adjoining the bay.

The tsunami reached a height of 7 m (24 feet) at some places, and it reached a height of 5 1/2 m (18 feet) at the police station at Glan. It destroyed all that remained of the buildings after the earthquake, swamped people, cattle, horses and other domestic animals, washed away stocks of food, and ruined the harvest in low-lying places. All boats were smashed or washed out to sea. Large rivers disappeared completely and reappeared.

On the north of Sulawesi and Halmahera Islands, at Bocat, Paleleh, Gorontalo, Manado and Tobelo, the earthquake took the form of rather strong regular oscillations lasting 1-5 minutes. There was slight damage to a stone bridge at Paleleh. Doors and various hanging objects swayed at Manado.

Gutenberg, Richter (1954) : 15.VIII; 12h18.2m; 5.5 N., 123 E.; M=8.25.

Reference #88:

1918, August 15, 12:18:12 UTC, 5.5 N, 123 E, shallow depth, magnitude 8.3 MS.

Reference #1187:

1918, August 15. All houses were either destroyed or badly shaken, cracks were produced in the ground and landslides on the mountains causing the death of about 50 persons in the civil settlements in the Sarangani Bay area. The origin of this great earthquake was in the sea, probably between the meridians 124 and 125 E and parallels 5 and 6 N. Shortly after the earthquake, a tsunami, estimated at some places at 24 ft high, invaded the coast in an extension of about 150 kms from near Port Lebak to Glan, drowning and carrying away many persons and animals...

Reference #79:

1918, August 15, 5.5N, 123 E, 8.25 Gutenberg-Richter magnitude.

Reference #1058:

1918, August 15. Intensity X. Cotabato. Very destructive, tidal wave: 50 victims.

Reference #13456, #13546:

1918, August 15, 12:18:24 UTC, 5.538 N, 123.994 E, 20 km depth, magnitude 8.3 Mw.