Kurikomayama

Geography & Climate

Kurikomayama is located in Japan, within the Northeast Japan Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 38.96° N, 140.79° E in the Northern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 1,627 meters above sea level, Kurikomayama 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

Kurikomayama 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 Kurikomayama, 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

Kurikomayama has 8 recorded eruptions in the geological database, spanning from 3540 BCE to 1950 CE. The most powerful recorded event was an explosive event producing ash plumes up to several kilometers in 1950 CE, reaching VEI 2 on the Volcanic Explosivity Index. This eruption frequency indicates a moderately active volcanic system with periodic reawakenings. The most recent eruption in 1950 CE places this volcano within the modern era of volcanological observation.

Significance

With 8 recorded eruptions on file, Kurikomayama has enough documented activity to help scientists identify patterns in its eruptive behavior. Given its recent activity, Kurikomayama is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

The summit of Kurikomayama volcano is cut by a 4-km-wide caldera breached to the north that is partially filled by the Tsurugi-dake central cone, once mined for sulfur. The complex andesitic-to-dacitic stratovolcano was constructed over a relatively high basement of welded and unwelded Tertiary dacitic tuffs and sedimentary rocks and thus has a smaller volume than its height suggests. Early stage eruptions beginning about 500,000 years ago produced lava flows to the north and south, followed by growth of the Higashi-Kurikoma (East Kurikoma) stratovolcano. Magusadake volcano on the western side of the complex was active until about 100,000 years ago. Construction of the main cone concluded with lava flows to the E, SE, and W. Daichigamori lava dome and Aguroshi-yama pyroclastic cone are located on the southern flank. Minor phreatic eruptions have occurred in historical time from the central cone.

— Smithsonian Institution, Global Volcanism Program