Nasudake

Geography & Climate

Nasudake is located in Japan, within the Northeast Japan Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 37.13° N, 139.96° E in the Northern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 1,915 meters above sea level, Nasudake 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

Nasudake 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 Nasudake, 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

Nasudake has 20 recorded eruptions in the geological database, spanning from 7850 BCE to 1963 CE. The most powerful recorded event was a severe eruption capable of regional ash fall and pyroclastic flows in 1410 CE, reaching VEI 3 on the Volcanic Explosivity Index. Notable eruptions include 1410 CE (VEI 3), 1408 CE (VEI 3), 1404 CE (VEI 3). With an average interval of roughly 491 years between eruptions over a span of 9,813 years, this is one of the more frequently active volcanoes in the database. This persistent activity suggests a robust and well-supplied magma system beneath the volcano. The most recent eruption in 1963 CE places this volcano within the modern era of volcanological observation.

Significance

With a maximum recorded VEI of 3, Nasudake has produced eruptions capable of generating pyroclastic flows and significant ash fall in the surrounding area. While not among the largest eruptions globally, VEI 3 events pose serious hazards to local populations and can disrupt regional air travel. Its 20 recorded eruptions make it one of the most prolific volcanoes in our database, reflecting a persistent and well-documented eruptive history that has provided volcanologists with extensive data for understanding eruption patterns and forecasting future activity. Given its recent activity, Nasudake is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

The Nasudake volcanic group consists of a N-S-trending cluster of stratovolcanoes and lava domes at the north end of the Kanto Plain. Volcanic activity dates back about 500,000 years. Growth of three large basaltic-to-dacitic stratovolcanoes, each lasting about 200,000 years, was followed by construction of three smaller andesitic stratovolcanoes, Asahidake, Futamatayama, and Chausudake. Activity during the last 55,000 years included the collapse of Asahidake volcano about 30-40,000 years ago, producing the massive Ofujisan debris-avalanche deposit, which covers a broad area SE of the volcano. The youngest volcano, Chausudake, began forming about 16,000 years ago. Six magmatic eruptions took place since then, the latest in 1408-1410 CE, when the Chausudake summit lava dome formed. These eruptions produced block-and-ash flows and concluded with the extrusion of lava flows. Smaller phreatic eruptions have occurred every few hundred years during the past 5,000 years.

— Smithsonian Institution, Global Volcanism Program