Aoga-shima volcano (青ヶ島, Aogashima) is a stratovolcano forming a beautiful small 2.5 x 3.5 km island with steep cliffs in the Izu island chain, 300 km south of Tokyo.
The dominantly basaltic Aoga-shima volcano contains a complex caldera (Ikenosawa Crater) with a diameter of... [more]
Doyo Seamount is the southernmost of the 7 Shichiyo Seamounts, named for the 7 days of the week. Doyo ("Saturday") is a basaltic-andesite submarine caldera that rises 2340 m from the sea floor to within 860 m of the sea surface.
It has a large horseshoe-shaped 3 x 10 km wi... [more]
Hachijo-jima volcano (八丈島, Hachijōjima) forms an 14 km NW-SE elongated island in the central Izu Islands about 300 km south of Tokyo. It consists of 2 small overlapping, mainly basaltic stratovolcanoes (Higashi-yama and Nishi-yama).
The last eruptions were from the younger ... [more]
Kozu-shima volcano (神津島, Kōzushima) forms a small 6 x 4 km island consisting of 18 lava domes. The last eruption was in the 9th century AD. [more]
Kuruse Hole is a submarine circular caldera located between Mikurajima and Hachijojima in the Izu Islands chain. The caldera is 600-760 deep and 5–7 km wide. A flat-topped rim of a probable somma (pre-caldera cone) rises to within 107 m of the sea surface.
Large amounts of... [more]
Mikura-jima volcano (御蔵島, Mikurajima) forms a small steep-sided island between Miyake-jima and Hachijo-jima volcanoes in the Izu Islands of Japan. The sparsely populated island is surrounded by 500 m high cliffs on the S and E side.
Mikura-jima volcano contains of a strato... [more]
Miyake-jima (三宅島 Miyakejima) is an active stratovolcano in the northern Izu Islands, about 200 km south of Tokyo. It forms a 8 km diameter circular island and is one of the most frequently active volcanoes in the island chain. It typically erupts every 10-30 years. The last serie... [more]
Mokuyo volcano is an active seamount belonging to the 7 Shichiyo Seamounts, named for the 7 days of the week. Mokuyo ("Thursday") contains a basaltic-andesite submarine caldera that rises 1780 m from the sea floor to within 920 m of the sea surface. The summit caldera is 3 x 2.3 ... [more]
Myojin Knoll volcano is a large submarine caldera between Aoga-shima and Bayonnaise Rocks volcanoes in the Izu-Bonin arc. The volcano contains a 6-7 km wide and up to 900 m deep caldera with steep walls.
The highest point on the western caldera rim is a pumice-mantled remna... [more]
Myojinsho is a large submarine caldera volcano in the Izu Islands arc, ca. 400 km south of Tokyo. Its most well-known feature are the Bayonnaise Rocks (ベヨネース列岩 Beyonēsu-retsugan), which represent a small exposed rim of the caldera composed of a few rocks rising just above sea lev... [more]
Steam pours from the blocky summit of a lava dome formed at Myojin-sho during a submarine eruption at the Bayonnaise Rocks volcano in 1952. This September 22 photo was taken 6 days after the dome began to breach the sea surface. Later that day the eruption became highly explosive, and the dome was destroyed. Three cycles of dome growth and destruction occurred until October 1953. Myojin-sho is located on the eastern rim of a 7-9 km wide submarine caldera. (Photo: Helen Foster / USGS)
Nii-jima volcano (新島 Niijima) is a group of 8 rhyolitic lava domes located on the northern and on the southern end of the elongated 11 x 2.5 km island of Niijima. The last eruptions occurred in the 9th century, and there were earthquake swarms beneath the volcano in the 20th cent... [more]
Izu-Oshima volcano, 伊豆大島 Izu-ōshima) is the northernmost of the Izu islands of Japan, and one of the world's most active volcanoes. It is a mostly submerged stratovolcano that forms an 11 x 13 km island.
Oshima erupts very frequently, on average every 1-3 years, but has be... [more]
Sofugan is a steep vertical pinnacle that rises 99 m above the sea surface south of Tori-shima volcano. Its dramatic shape gave it its nickname "Lot's Wife Rocks."
In 1975, discolored sea water was observed about 500 m north of Sofugan, and the volcano was reclassified as a... [more]
Suiyo is an active submarine volcano forming one of the Shichiyo Seamounts, which are named for the 7 days of the week and are located south of Sofugan volcano. Suiyo ("Wednesday") is an basaltic-to-dacitic submarine volcano with a caldera and lava dome that rises about 1400 m fr... [more]
Sumisu-jima volcano (also known as Smith Rocks or Smith Island volcano) is a steep, 136 m high pinnacle rising vertically above the sea surface. It is part of the southern rim of a 9 km wide submarine caldera belonging to a larger seamount.
Numerous submarine eruptions hav... [more]
To-shima volcano (利島, Toshima) in the northern Izu Island chain is a stratovolcano forming a small 2 x 2.4 km island south of Oshima volcano. [more]
Tori-shima (鳥島 Torishima or Izu-no-Torishima) is a stratovolcano forming a small 2.7 km wide circular island in the southern Izu volcanic chain. Historical eruptions have occurred from summit and flank vents near the north coast as well as from submarine vents.
Several othe... [more]