Golovnin volcano (Tomari-yama in Japanese) is the southernmost volcano in the Kurile Islands and forms the southern end of Kunashir Island, located only 33 km across the Nemuro Strait from Hokkaido Island in Japan. It has a 4x5 km wide caldera with an 1x2.5 km wide lake, active solfataric areas at the northern lake shore and several explosion craters, one of which contains a hot crater lake with reported temperatures ranging between 36-100 degrees C. The lake drains through a narrow gap in the western caldera wall. It is part of a protected reserve and swimming in the lake is prohibited. The only known historical eruption of Golovnin volcano consisted in a minor explosion in 1848.

The andesitic-dacitic Golovnin volcano has mainly had explosive eruptions and there are no exposed lava flows.

The volcano has gentle slopes and contains a 4-5 km wide caldera that formed during a series of eruptions beginning about 43,000 years ago. Several lava domes grew later on the caldera floor.

Condensates from volcanic vapours at Golovnin volcano have been measured to contain a higher quantity of cations as compared to anions. The main cations included calcium, magnesium, silicon, alkaline metals. The condensates were opaque, opalescent and consisted probably of colloid solutions.

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Sources:

- GVP Golovnin volcano information

- S. I. Naboko (1959) "Volcanic exhalations and products of their reactions as exemplified by Kamchatka-Kuriles volcanoes", Bull. Volc., v 20 (1), pp. 121-136