Sinarka

Geography & Climate

Sinarka is located in Russia, within the Kuril Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 48.87° N, 154.18° E in the Northern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 911 meters above sea level, Sinarka 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

Sinarka 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 Sinarka, 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

Sinarka has 5 recorded eruptions in the geological database, spanning from 1725 CE to 2014 CE. The most powerful recorded event was a cataclysmic eruption with ash columns reaching the stratosphere in 1872 CE, reaching VEI 4 on the Volcanic Explosivity Index. Notable eruptions include 1872 CE (VEI 4), 1846 CE (VEI 3). This eruption frequency indicates a moderately active volcanic system with periodic reawakenings. With eruptive activity as recently as 2014 CE, Sinarka remains an actively monitored volcano.

Significance

With a maximum recorded VEI of 4, Sinarka has demonstrated the capacity for significant explosive eruptions that can impact regional aviation, agriculture, and communities tens of kilometers from the summit. VEI 4 eruptions produce ash columns reaching 15-25 kilometers into the atmosphere. With 5 recorded eruptions on file, Sinarka has enough documented activity to help scientists identify patterns in its eruptive behavior. Given its recent activity, Sinarka is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

Sinarka volcano, occupying the northern end of Shiashkotan Island in the central Kuriles, has a complex structure. A small, 2-km-wide depression open to the NW has been largely filled and overtopped by an andesitic postglacial central cone that itself contains a lava dome that forms the high point of the island. Another lava dome, Zheltokamennaya Mountain, lies 1.5 km to the SW along the buried SW rim of the caldera, and a smaller dome lies along the northern caldera rim. Historical eruptions have occurred during the 17th and 18th centuries. The last and largest of these, during 1872-78, was once thought to originate from Kuntomintar volcano at the southern end of the island, but is now attributed to Sinarka (Gorshkov, 1970).

— Smithsonian Institution, Global Volcanism Program