1888 Ritter Island eruption and tsunami

Ritter Island in the Bismarck Archipelago is an active stratovolcano located off the northeast coast of Papua New Guinea. It is one of the many active volcanoes in Papua New Guinea as a result of subduction of the Solomon Sea plate beneath the Bismarck Plate along the New Britain Trench. Before the eruption of 1888, the island was a steep-sided and almost-circular volcanic cone which was recognisable to sailors passing through the Dampier Strait. It had an estimated height of . In other illustrations, these slopes appeared to be up to 50°, though they were likely exaggerated. Earlier signs of activity in 1699 and 1793 demonstrated Strombolian eruptions. Smoke and steam were observed in 1835 and 1848. The eruptions of 1887 and 1878 remain uncertain, with various sources supporting or denying their existence. An anonymous report stated that ashfall and tremors were recorded at Finschhafen in February 1887 and may have originated from Ritter Island. == Eruption and collapse ==

The collapse of Ritter Island occurred during the early morning of 13 March 1888, though there were no direct observations. After the collapse, only a crescent-shaped island and islet near its southern tip remained of the former volcanic cone. The height of the island was reduced from . A 2019 study published Earth and Planetary Science Letters estimated that of the western edifice collapsed based on seafloor bathymetry analysis. This estimate is slightly smaller than the sector collapse involved in the 1980 eruption of Mount St. Helens (), == Tsunami ==

On Umboi and Sakar, run-ups of were measured while at Hatzfeldhafen and Rabaul, the run-ups were and , respectively. In Arica, Chile, newspapers reported that a series of strong waves smashed and capsized ships. Tide gauges in Sydney, Australia, recorded abnormal readings ruled out as tidal floods and attributed it to a possible tsunami. A search party was sent out to rescue the two Germans missing, but found only five Melanesian workers. They were caught by the wave but survived by clutching onto tree branches before it retreated back to sea. At Hatzfeldhaven, the tsunami arrived at 06:40; the first wave was estimated to be taller than the highest flood mark. The highest wave struck at 09:00, measuring about . == See also ==