Giant rhyolite lava dome formation after 7.3 ka supereruption at Kikai caldera, SW Japan

Yoshiyuki Tatsumi; Keiko Suzuki-Kamata; Tetsuo Matsuno; Hiroshi Ichihara; Nobukazu Seama; Koji Kiyosugi; Reina Nakaoka; Kazuo Nakahigashi; Hideaki Takizawa; Kazuki Hayashi; Tatsuro Chiba; Satoshi Shimizu; Mamoru Sano; Hikaru Iwamaru; Haruhisa Morozumi; Hiroko Sugioka; Yojiro Yamamoto

doi:10.1038/s41598-018-21066-w

Giant rhyolite lava dome formation after 7.3 ka supereruption at Kikai caldera, SW Japan

Sci Rep. 2018 Feb 9;8(1):2753. doi: 10.1038/s41598-018-21066-w.

Authors

Yoshiyuki Tatsumi¹, Keiko Suzuki-Kamata², Tetsuo Matsuno², Hiroshi Ichihara^{2

3}, Nobukazu Seama^{2

4}, Koji Kiyosugi^{2

5}, Reina Nakaoka², Kazuo Nakahigashi^{2

6}, Hideaki Takizawa⁷, Kazuki Hayashi⁴, Tatsuro Chiba⁸, Satoshi Shimizu^{2

9}, Mamoru Sano^{2

9}, Hikaru Iwamaru^{2

9}, Haruhisa Morozumi^{2

10}, Hiroko Sugioka^{2

4}, Yojiro Yamamoto¹¹

Affiliations

¹ Kobe Ocean-Bottom Exploration Center, Kobe University, Kobe, Japan. tatsumi@diamond.kobe-u.ac.jp.
² Kobe Ocean-Bottom Exploration Center, Kobe University, Kobe, Japan.
³ Earthquake and Volcano Research Center, Nagoya University, Nagoya, Japan.
⁴ Department of Planetology, Kobe University, Kobe, Japan.
⁵ Organization of Advanced Science and Technology, Kobe University, Kobe, Japan.
⁶ Department of Marine Resources and Energy, Tokyo University of Marine Science and Technology, Tokyo, Japan.
⁷ Johnny & Associates, Tokyo, Japan.
⁸ Asia Air Survey, Tokyo, Japan.
⁹ Nippon Marine Enterprises, Yokosuka, Japan.
¹⁰ Japan Oil, Gas and Metals National Corporation, Tokyo, Japan.
¹¹ Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan.

Abstract

Kikai submarine caldera to the south of the Kyushu Island, SW Japan, collapsed at 7.3 ka during the latest supereruption (>500 km³ of magma) in the Japanese Archipelago. Multi functional research surveys of the T/S Fukae Maru in this caldera, including multi-beam echosounder mapping, remotely operated vehicle observation, multi-channel seismic reflection survey, and rock sampling by dredging and diving, provided lines of evidence for creation of a giant rhyolite lava dome (~32 km³) after the caldera collapse. This dome is still active as water column anomalies accompanied by bubbling from its surface are observed. Chemical characteristics of dome-forming rhyolites akin to those of presently active small volcanic cones are different from those of supereruption. The voluminous post-caldera activity is thus not caused simply by squeezing the remnant of syn-caldera magma but may tap a magma system that has evolved both chemically and physically since the 7.3-ka supereruption.