Report on Yufu-Tsurumi (Japan) — 27 July-2 August 2022
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
27 July-2 August 2022
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2022. Report on Yufu-Tsurumi (Japan). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 27 July-2 August 2022. Smithsonian Institution and US Geological Survey.
33.282°N, 131.39°E; summit elev. 1584 m
All times are local (unless otherwise noted)
JMA lowered the Alert Level for Yufu-Tsurumi to 1 (on a scale of 1-5) on 27 July, noting that seismicity had decreased after the 8 July earthquake swarm; no volcanic earthquakes were recorded on 9 July and afterwards.
Geological Summary. A group of lava domes rises above the noted 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 6300-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 2200 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. Only a single eruption, from Tsurumi in 867 CE, is known in historical time. The colorful hot spring pools and mudpots of Beppu along the coast form one of Japan's most noted thermal areas.