Aira Caldera

Aira Caldera (姶良カルデラ, Aira-Karudera) is a gigantic volcanic caldera in the south of the island of Kyūshū. It contains the post-caldera Sakurajima, which is considered one of the most active volcanoes in Japan.[1]

Sakura-jima from space.jpg
Space radar image of Aira Caldera, with Sakurajima in the bay formed by the caldera.
Highest point
Coordinates31°40′01″N 130°40′01″E / 31.667°N 130.667°E / 31.667; 130.667Coordinates: 31°40′01″N 130°40′01″E / 31.667°N 130.667°E / 31.667; 130.667
Mountain typeCaldera
Somma volcano
Last eruptionc. 22,000 years ago


The caldera was originally thought to have been created by a massive eruption, approximately 22,000 years ago[2]. This eruption, whose widespread deposits are generically known as the Aira-Tanzawa tephra, is now thought to be rather older. The tephra eruption is estimated to have occurred 29,000 years ago.[3] The latest/best age estimates derive from cores from Lakes Biwa and Suigetsu indicate an age of 29,430-30,150 years ago. Eruption of voluminous Ito pyroclastic flows accompanied the formation of the 17 × 23 km-wide Aira caldera.[1] Together with a large pumice fall, these amounted to approximately 400 km3 of tephra (VEI 7).

The major city of Kagoshima and the 16,000-year-old Sakurajima volcano lie within the caldera. Sakura-jima, one of Japan's most active volcanoes, is a post-caldera cone of the Aira caldera at the northern half of Kagoshima Bay.

Relief Map


  • Smith, V.C. (2013). "Identification and correlation of visible tephras in the Lake Suigetsu SG06 sedimentary archive, Japan". Quaternary Science Reviews. 67: 121–137.

External linksEdit

  • Aira - Smithsonian Institution: Global Volcanism Program
  • Aira Caldera - Geological Survey of Japan


  1. ^ a b "Global Volcanism Program | Report on Aira (Japan) — 11 September-17 September 2019". Retrieved 2020-03-31.
  2. ^ Dinwiddie, Robert; Lamb, Simon; Ross, Reynolds (2011). Violent Earth: Volcanoes, Earthquakes, Hurricanes, Mudslides, Tsunamis. New York: DK Publishing. p. 129. ISBN 978-0-7566-8685-7.
  3. ^ Kawanabe, Hiroya; Nishino, Machiko; Maehata, Masayoshi (2012). Lake Biwa: Interactions between Nature and People. Dordrecht: Springer Science & Business Media. p. 7. ISBN 978-94-007-1783-1.