Nikkō Seamount () is a

submarine volcano Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ridges ...

in the

Volcano Islands The or are a group of three Japanese-governed islands in Micronesia. They lie south of the Ogasawara Islands and belong to the municipality of Ogasawara, Tokyo, Tokyo Metropolis, Japan. The islands are all active volcanoes lying ato ...

region of Japan. It is the southernmost volcano of Japan.

Geography

The Nikkō caldera is a volcanic complex consisting of a caldera and 2 other

cones In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the ''apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines, ...

that are the active parts of the volcano which last had an activity in 1979. It is south-southeast of

Iwo Jima is one of the Japanese Volcano Islands, which lie south of the Bonin Islands and together with them make up the Ogasawara Subprefecture, Ogasawara Archipelago. Together with the Izu Islands, they make up Japan's Nanpō Islands. Although sout ...

and north-northwest of

Saipan Saipan () is the largest island and capital of the Northern Mariana Islands, an unincorporated Territories of the United States, territory of the United States in the western Pacific Ocean. According to 2020 estimates by the United States Cens ...

Marine life

Nikkō is home to many underwater species, specifically 14 species which come from 12

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

including the ''

Symphurus thermophilus ''Symphurus thermophilus'' is a species of tonguefish notable for being the only flatfish known to be an obligate inhabitant of hydrothermal vents. It is known to inhabit several widely dispersed locations in the western Pacific Ocean and occurs ...

'', which are species that live in

hydrothermal vent Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hot ...

environments, which Nikkō has hydrothermal vents considering it is an active volcano. The seamount does also have endemic

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

, including the '' Paragiopagurus ventilatus''.

Activity

The volcano isn't the most active volcano, however the last activity recorded was in 1979. In July 12, 1979, a pale-green and wide patch of discolored water was observed over Nikkō Seamount.

2006 expedition

In 2006, the

NOAA The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with forecasting weather, monitoring oceanic and atmospheric conditions, charting the seas, conducting deep-sea exploratio ...

Ocean Explorer program launched an expedition called 'The Submarine Ring of Fire 2006 Expedition'. This expedition started in April 18, 2006 and ended in May 13, 2006. During the expedition, in 12 May 2006, the

research vessel A research vessel (RV or R/V) is a ship or boat designed, modified, or equipped to carry out research at sea. Research vessels carry out a number of roles. Some of these roles can be combined into a single vessel but others require a dedicated ...

arrived near the Nikkō area. The

remotely operated underwater vehicle A remotely operated underwater vehicle (ROUV) or remotely operated vehicle (ROV) is a free-swimming submersible craft used to perform underwater observation, inspection and physical tasks such as valve operations, hydraulic functions and other g ...

''Jason II'' was deployed. With the vehicle, the caldera floor of Nikkō was observed. Large

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

deposits were found and hydrothermal vents were seen.

References

{{reflist Volcanoes of Japan Seamounts of the Pacific Ocean Submarine volcanoes

Geography

Marine life

Activity

2006 expedition

See also

References