Milna

Geography & Climate

Milna is located in Russia, within the Kuril Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 46.81° N, 151.79° E in the Northern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 1,504 meters above sea level, Milna 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

Milna 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 Russia near Milna, 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

Milna has 6 recorded eruptions in the geological database, spanning from 1842 CE to 1944 CE. The most powerful recorded event was a severe eruption capable of regional ash fall and pyroclastic flows in 1842 CE, reaching VEI 3 on the Volcanic Explosivity Index. This eruption frequency indicates a moderately active volcanic system with periodic reawakenings. The most recent eruption in 1944 CE places this volcano within the modern era of volcanological observation.

Significance

With a maximum recorded VEI of 3, Milna 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. With 6 recorded eruptions on file, Milna has enough documented activity to help scientists identify patterns in its eruptive behavior.

GVP Reference Summary

Milna (or Mil'na) is the southernmost volcano on Simushir Island in the central Kuriles, and includes the Goriaschaia Sopka lava dome on the NW flank. The outer flanks of the steep-sided 1500-m-high volcano are dissected by deep gullies. A 3-km-wide caldera breached widely to the SE was formed during the Pleistocene and became a center of glaciation. A small central cone capped by an andesitic lava dome was constructed within the caldera during postglacial time and forms the highest point on Simushir Island. Lava flows from the cone descend 4-5 km to the sea. Goriaschaia Sopka, previously identified as a distinct volcano, is a historically active andesitic lava dome that grew just beyond what appears to be a NE-SW erosional scarp along the NW flank. Numerous fresh lava flows with prominent marginal levees extend from the dome, with some reaching the sea. It may have formed as recently as the late-19th century; dominantly mild-to-moderate explosive eruptions have occurred since 1842.

— Smithsonian Institution, Global Volcanism Program