May 29, 1937 Tsunami: Rabaul, Papua New Guinea

Reference #414:

1937, May 28/29. Validity likely (3). 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.

At about 14:00, the water in Rabaul Harbor quietly retreated 90 m from shore and then returned to its usual boundary. On Raluan Is, the water also retreated slowly, then flooded the shore to 140 m beyond the high high tideline, after which it returned to its usual mark, leaving many fish on shore. In Keravia Bay, at about 13:30, the water flooded a road, rising 1 1/2-2 m above the usual level.

On May 29, at about 5:30, a new shock was felt at Rabaul.

Between 8:00 and 9:00, an elevation of Kaluan Is was observed.

At 11:00, it was noticed that the reef south of Matupi Is had become exposed. This had never happened before.

At 13:10 the water off the west coast of Raluan Is became turbid and rough. At about the same time, the reef here dried up; the reef was hidden under water at 13:15, but it came to the surface again at 13:20. During the day, many residents collected fish on the reefs, and about 20 of these people died during the eruption.

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. Masses of flames the size of a room or smaller flew up to a height of 1.5 km and then fell to the earth or into the water with A deafening noise. There were no lava flows. 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. It also settled to the northwest of the volcano, that is, in the region of Rabaul, where the layer of ash was several cm thick...

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. It was precisely, during such a period of calm and before 21:00, that is, before the lip of the new crater of the volcano had completely risen above the water, that considerable oscillations in level were observed in the harbor. Four to five minutes passed between the rise and fall of the water. The amplitude of at least three of the waves was 2-2.5 m above and below the mean water level. A schooner was run aground by the wave onto a small pier and then dragged to the depths of the bay together with the pier. Several boats ran aground, and one or two sank. Subsequently, the oscillations apparently diminished, but their range was still 1/2 m early in the morning on the 30th.

During the eruption, more than 500 people perished, including those who drowned.

Reference #1412:

1937, May 29. Official death toll is 507.