Chachadake [Tiatia]

Geography & Climate

Chachadake [Tiatia] is located in Japan - administered by Russia, within the Kuril Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 44.35° N, 146.25° E in the Northern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 1,822 meters above sea level, Chachadake [Tiatia] 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

Chachadake [Tiatia] 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 Chachadake [Tiatia], 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

Chachadake [Tiatia] has 5 recorded eruptions in the geological database, spanning from 1812 CE to 1982 CE. The most powerful recorded event was a cataclysmic eruption with ash columns reaching the stratosphere in 1973 CE, reaching VEI 4 on the Volcanic Explosivity Index. This eruption frequency indicates a moderately active volcanic system with periodic reawakenings. The most recent eruption in 1982 CE places this volcano within the modern era of volcanological observation.

Significance

With a maximum recorded VEI of 4, Chachadake [Tiatia] 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, Chachadake [Tiatia] has enough documented activity to help scientists identify patterns in its eruptive behavior. Given its recent activity, Chachadake [Tiatia] is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

The symmetrical Chachadake, also known as Tiatia, is on the SE side of northern Kunashir Island in the southern Kuriles. The active cone rises above the rim of a filled 2.1 x 2.4 km summit caldera with erosionally furrowed flanks. The central cone, mostly formed by basaltic to basaltic andesite Strombolian eruptions, rises 400 m above the floor of the caldera and contains a 400 x 250 m wide crater with two explosion vents separated by a linear septum. Fresh lava flows cover much of the SW caldera floor and have overflowed the rim, extending to the foot of the older edifice, which formed during the late Pleistocene or early Holocene. A 500-m-wide crater about 2 km down the SE flank from the caldera rim is surrounded by an unvegetated area of volcanic deposits. The first recorded eruption was in 1812, and a major explosive eruption with lava flows in 1973 originated from vents on the central cone.

— Smithsonian Institution, Global Volcanism Program