Alney-Chashakondzha

Geography & Climate

Alney-Chashakondzha is located in Russia, within the Central Kamchatka Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 56.66° N, 159.65° E in the Northern Hemisphere, the volcano lies within a subarctic climate zone. At 2,570 meters above sea level, Alney-Chashakondzha rises above the surrounding terrain into montane or subalpine conditions. The elevation creates distinct ecological zones along its flanks, from forested lower slopes to exposed rocky terrain near the summit. 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

Alney-Chashakondzha 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 Alney-Chashakondzha, 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 basalt / picro-basalt, 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

Alney-Chashakondzha has 3 recorded eruptions in the geological database, spanning from 660 BCE to 1600 CE. The most powerful recorded event was a severe eruption capable of regional ash fall and pyroclastic flows in 650 BCE, reaching VEI 3 on the Volcanic Explosivity Index. Notable eruptions include 650 BCE (VEI 3), 660 BCE (VEI 3). These eruptions span roughly 2,260 years of volcanic history.

Significance

With a maximum recorded VEI of 3, Alney-Chashakondzha 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.

GVP Reference Summary

The glacier-capped Alney-Chashakondzha complex, one of the largest volcanoes of the Sredinny Range, consists of two large mostly Pleistocene andesitic stratovolcanoes constructed on a large Pliocene shield volcano. Both Alney on the north and Chashakondzha on the south are capped with andesitic lava domes. Three rhyodacitic-to-rhyolitic lava domes and associated lava flows were emplaced along ring faults enclosing a 15 x 20 km area. Two cinder cones on the east flanks of Alney and Chashakondzha erupted about 2600 years ago and produced lava flows, one of which traveled as far as 9 km. Alney is one of the few large stratovolcanoes in the Sredinny Range known to have been active throughout the Holocene, with more than 30 documented pyroclastic deposits. The last intense eruption took place about 350 years ago.

— Smithsonian Institution, Global Volcanism Program