Etorofu-Yakeyama [Grozny Group]

Geography & Climate

Etorofu-Yakeyama [Grozny Group] is located in Japan - administered by Russia, within the Kuril Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 45.01° N, 147.87° E in the Northern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 1,158 meters above sea level, Etorofu-Yakeyama [Grozny Group] 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

Etorofu-Yakeyama [Grozny Group] 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 - administered by Russia near Etorofu-Yakeyama [Grozny Group], 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

Etorofu-Yakeyama [Grozny Group] has 7 recorded eruptions in the geological database, spanning from 1968 CE to 2013 CE. The most powerful recorded event was an explosive event producing ash plumes up to several kilometers in 2013 CE, reaching VEI 2 on the Volcanic Explosivity Index. This eruption frequency indicates a moderately active volcanic system with periodic reawakenings. With eruptive activity as recently as 2013 CE, Etorofu-Yakeyama [Grozny Group] remains an actively monitored volcano.

Significance

With 7 recorded eruptions on file, Etorofu-Yakeyama [Grozny Group] has enough documented activity to help scientists identify patterns in its eruptive behavior. Given its recent activity, Etorofu-Yakeyama [Grozny Group] is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

The Etorofu-Yakeyama (Ivan Grozny) complex is located in the center of Iturup Island. It has a 3-3.5 km diameter caldera open to the south, where a large extrusive andesitic dome was emplaced. Several other lava domes of Holocene age were constructed to the NE; extrusion of these domes has constricted a former lake in the northern side of the caldera to an extremely sinuous shoreline. Recorded eruptions, the first of which took place in 1968, have been from the central Yakeyama (Grozny) dome.

— Smithsonian Institution, Global Volcanism Program