Yufu-Tsurumi

Geography & Climate

Yufu-Tsurumi is located in Japan, within the Nankai Volcanic Arc of the broader Western Pacific Volcanic Regions. Situated at 33.28° N, 131.39° E in the Northern Hemisphere, the volcano lies within a subtropical climate zone. With a summit elevation of 1,584 meters above sea level, Yufu-Tsurumi 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

Yufu-Tsurumi 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 near Yufu-Tsurumi, 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

Yufu-Tsurumi has 3 recorded eruptions in the geological database, spanning from 200 BCE to 867 CE. The most powerful recorded event was a cataclysmic eruption with ash columns reaching the stratosphere in 200 BCE, reaching VEI 4 on the Volcanic Explosivity Index. Notable eruptions include 867 CE (VEI 3), 200 BCE (VEI 4). These eruptions span roughly 1,067 years of volcanic history.

Significance

With a maximum recorded VEI of 4, Yufu-Tsurumi 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.

GVP Reference Summary

A group of lava domes rises above the hot spring resort city of Beppu on Japan's Inland Sea, possibly within an ancient breached caldera. Two large lava domes, Tsurumidake and Yufudake (the highest at 1,584 m), are located at the east and west sides of the complex, respectively. Three smaller lava domes are on the N flank of Tsurumidake, including Garandake. The latest activity at both the andesitic-to-dacitic Tsurumi and Yufu groups postdates the 6,300-year-old Akahoya ash from Kikai volcano. Pyroclastic flows dominated during older eruptions, whereas lava domes and lava flows are most common in more recent eruptions. An eruption about 2,200 years ago from Yufudake began with collapse of the N flank that produced a debris avalanche and was followed by lava dome growth and associated pyroclastic flows. The most recent known eruption was from Tsurumi in 867 CE, when there was explosive activity from the summit area. The colorful hot spring pools and mudpots of Beppu along the coast are a noted thermal area.

— Smithsonian Institution, Global Volcanism Program