About Hachimantai
Hachimantai is a stratovolcano rising to 1,613 meters (5,292 feet) in Japan's Northwestern Pacific Volcanic Regions. The volcano is currently active, with its most recent eruption in 5350 BCE. The volcano has produced 2 recorded eruptions.
Geography & Climate
Hachimantai is located in Japan, within the Northeast Japan Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 39.96° N, 140.85° E in the Northern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 1,613 meters above sea level, Hachimantai is a moderately sized peak that remains accessible to hikers and researchers for much of the year. The volcanic landform is characterized as a composite, which describes the physical shape and structure of the volcanic edifice as observed from the surface.
Geological Context
Hachimantai sits in a subduction zone, where one tectonic plate dives beneath another, creating intense heat and pressure that generates magma. Subduction zones are responsible for many of the world's most explosive volcanoes and deadliest eruptions. For communities in Japan near Hachimantai, this tectonic setting means the volcano is capable of producing powerful explosive eruptions, pyroclastic flows, and lahars that can threaten populated areas within tens of kilometers of the summit. The dominant rock type is andesite / basaltic andesite, a dark, fine-grained volcanic rock that forms from rapidly cooling, low-viscosity lava. Basaltic eruptions tend to be less explosive and produce fluid lava flows that can travel long distances. While less immediately dangerous than explosive eruptions, basaltic lava flows can destroy structures and infrastructure in their path, and volcanic gases released during these eruptions can affect air quality over a wide area.
Eruption History Summary
Hachimantai has 2 recorded eruptions in the geological database, spanning from 7900 BCE to 5350 BCE. These eruptions span roughly 2,550 years of volcanic history.
GVP Reference Summary
Hachimantai was constructed from widely scattered vents during the Pleistocene and is capped with andesitic lavas from vents in the center of the complex. The summit forms an undulating plateau surrounded by steep slopes. Circular craters are located near Komonomore and Mokkodake in the center of the plateau. The craters are youthful looking, but have not been dated. Hayakawa (1996, pers. comm.) considered Hachimantai to be of possible Holocene age. No historical eruptions have been recorded, but active solfataras are found on the western and southern flanks.
— Smithsonian Institution, Global Volcanism Program
2 Recorded Eruptions
| Year | VEI | Type | Area |
|---|---|---|---|
| 5350 BCE | — | Confirmed Eruption | — |
| 7900 BCE | — | Confirmed Eruption | — |
Real-Time Data
USGS Alert Level
Thermal Anomalies
Frequently Asked Questions About Hachimantai
Is Hachimantai an active volcano?+
Hachimantai is not currently classified as active. Its activity evidence is listed as "Eruption Dated." The last known eruption was in 5350 BCE. However, no volcano is ever considered permanently extinct.
When did Hachimantai last erupt?+
The most recent recorded eruption of Hachimantai occurred in 5350 BCE. The eruption was classified as a "Confirmed Eruption." Hachimantai has 2 recorded eruptions in total.
How high is Hachimantai?+
Hachimantai has a summit elevation of 1,613 meters (5,292 feet) above sea level. At 1,613 meters, it is a moderately sized volcanic peak, roughly comparable to Mount Vesuvius (1,281m).
What type of volcano is Hachimantai?+
Hachimantai is classified as a Stratovolcano. Stratovolcanoes (also called composite volcanoes) are steep, conical volcanoes built up by many layers of hardened lava, tephra, and volcanic ash. They are among the most common and dangerous types, known for explosive eruptions.
Where is Hachimantai located?+
Hachimantai is located in Japan, in the Northwestern Pacific Volcanic Regions. More specifically, it lies within the Northeast Japan Volcanic Arc. Its exact coordinates are 39.958° latitude, 140.854° longitude.
Is it safe to visit Hachimantai?+
Hachimantai can generally be visited, but as with any volcano, visitors should check local conditions and any advisory notices before traveling. Japan may have specific regulations for accessing volcanic areas. Guided tours are often the safest and most informative way to experience a volcano.
