Banua Wuhu Volcano — Indonesia

The submarine Banua Wuhu volcanic cone lies ~600 m off the western coast of Mahengatang Island, the emergent summit of a large submarine edifice, in the Sangihe Islands. Several ephemeral islands were constructed during the 19th and 20th centuries. An island 90 m high was formed in 1835, but had eroded to only a few rocks by 1848. Another island formed in 1889 was 50 m high in 1894. Five craters were reported during an eruption that built an island in 1904. An island that formed in 1919 had disappeared by 1935. Bathymetry shows shallow water over an area larger than Mahengatang Island towards the W (Haryanto, 2020). Satellite imagery frequently shows two sources of discolored water in the area, and it is a popular location for divers, who report sulfur odors and bubbling.