May 28, 1937 Earthquake: Keravia, Rabaul, Kokopo, Papua New Guinea

Reference #414:

1937, May 28/29. There was an eruption of the Raluan and

Tawurwur Volcanoes in Blanche Bay. The eruption was accompanied at different stages by oscillations of the water level in the bay.

The first strong earthquake struck on May 28 at about 13:20. It lasted half a minute and reached a force of 7 degrees (VIII Rossi-Forel).

Slumps occurred in the region of the road to Kokopo. The surface of the ground cracked on the southwest of Raluan Island and a cliff disappeared on the west bank of the lagoon on this island. Buildings suffered at Keravia, but the damage was slight at Rabaul. The intensity of the earthquake rapidly decreased with distance from Blanche Bay. It was weak at Kokopo, Malabunga and Keravat and was not felt at all near the Warangoi River (region from Lamingi to Toma. Tremors were felt almost continuously until the morning of the following day at Rapindik, Keravia and Taliligap, but it was quiet at Rabaul.

At about 14:00, the water in Rabaul Harbor quietly retreated 90 m from shore and then returned to its usual boundary.

On May 29, at about 5:30, a new shock was felt at Rabaul. It was strong enough to awaken sleepers and to knock down bottles, pictures, etc, It was followed by a continuous series of shocks of different intensity which lasted right up until the eruption of the volcano. During the calm between strong shocks, regular rocking of the ground occurred. Especially strong shocks were observed about 10:00. During the entire morning, it was impossible to write. As a result of the shocks, further avalanches occurred in the region of the road to Kokopo, cement floors cracked at Rapindik, reservoirs sprang leaks, and yawning crevices opened up in the ground on Matupi Island.

Between 8:00 and 9:00, an elevation of Kaluan Is was observed. It was especially strong in the passage between the island and the westward lying coast, where several small islands appeared from under the water...

The eruption of the volcano began at 16:15. The island and the adjacent sections of bottom began to rise quickly; the little islands in the passage began to grow and merge, and soon a broad isthmus formed between the island and the mainland. Then the volcano exploded, and a black pillar of ash and steam 9 m wide and 12 m high rose into the air. The column grew with each subsequent explosion, and reached a height of 3 km.

The eruption of the Tawurwur Volcano began on May 30, after 13:00. The eruption lasted until the morning of the following day; about 2,300,000 cubic m of material was ejected.

During the first explosions of the Raluan Volcano, the underground shocks for the most part stopped. The water near Raluan Is was markedly agitated. At Rabaul, the water retreated 45 m several times, returned to the high high tide mark, and retreated again. Then the eruption was almost continuous for 3 hrs, but there were no noticeable oscillations in level.

Beginning at 19:00, the eruption began to pulsate, and periods of explosions began to alternate with periods of relative calm. During the eruption, more than 500 people perished, including those who drowned.