Editing Kikai Caldera

{{short description|Mostly-submerged caldera in the Ōsumi Islands of Kagoshima Prefecture, Japan}}
{{hatnote|Not to be confused with the island [[Kikaijima]] nor the town on it [[Kikai, Kagoshima]]}}
{{Infobox mountain
| name = Kikai Caldera
| native_name ={{native name|ja|鬼界カルデラ}}
| other_name = 
| etymology = 
| photo = Kikai Caldera Relief Map, SRTM, English.jpg
| photo_caption =
| photo_size =
| country = Japan
| subdivision1 = Kagoshima Prefecture
| subdivision2_type = Region
| subdivision2 = Ōsumi Islands
| subdivision3 = [[Kagoshima District, Kagoshima|Kagoshima District]]
| settlement_type = Municipality
| settlement = [[Mishima, Kagoshima|Mishima]]
| coordinates = {{coord|30.79|N|130.31|E|type:mountain_region:IT_scale:100000|format=dms|display=inline,title}}
| coordinates_ref = <ref>{{Cite web|url=http://volcano.oregonstate.edu/kikai|title=Kikai {{!}} Volcano World {{!}} Oregon State University|website=volcano.oregonstate.edu|date=24 April 2011|language=en|access-date=2017-04-11}}</ref>
| subdivision4_type = Subdivisions
| subdivision4 = {{hlist|Mount Yahazu|Mount Iō (Iōjima)|Mount Inamura (Iōjima)|[[Iōjima, Kagoshima|Iōjima]]|Shin Iōjima|[[Takeshima, Kagoshima|Takeshima]]|Mount Nakasone|Mount Asase|Mount Shitakisone|Iō Tai|Takeshima Tai}}
| highest= Mount Iō (Iōjima)
| highest_location = [[Iōjima, Kagoshima|Iōjima]], Ōsumi Islands, Japan
| elevation_m = 704
| length_km = 17
| length_orientation = NS
| width_km = 20 
| width_orientation = EW
| area_km2 = 
| geology = 
| orogeny =
| age = 6,300 to 95,000 years ago
| map =
| map_caption = 
}}
{{nihongo|'''Kikai Caldera'''|鬼界カルデラ|Kikai karudera}} (alternatively '''Kikaiga-shima''', '''Kikai Caldera Complex''') is a massive, mostly submerged [[caldera]] up to {{convert|19|km|mi}} in diameter in the [[Ōsumi Islands]] of [[Kagoshima Prefecture]], Japan.<ref name="gbank">{{Cite web |title=噴火史 - Iwojima |url=https://gbank.gsj.jp/volcano/Act_Vol/satsumaioujima/vr/doc/012.html |access-date=2023-05-25 |website=gbank.gsj.jp}}</ref>

==Geology==
The Kikai Caldera Complex has twin ovoid caldera {{convert|20|km|abbr=on}} by {{convert|17|km|abbr=on}} in diameter.<ref name="gbank"/> Yahazu-dake (north west part of [[Iōjima (Kagoshima)|Satsuma Io-jima]]) and [[Takeshima (Kagoshima)|Takeshima]], located on the caldera rim, are pre-caldera volcanoes.<ref name="gbank"/> The pre-caldera stage of volcanic activity involved [[rhyolite]], [[basalt]], and [[andesite]] phases.<ref name="gbank" /><ref name=":2">{{Cite book |last1=小野 |first1=晃司 |url=https://ci.nii.ac.jp/ncid/BA36838038 |title=薩摩硫黄島地域の地質 |last2=曽屋 |first2=龍典 |last3=細野 |first3=武男 |date=1982 |publisher=地質調査所 |language=ja}}</ref> The earliest definitive caldera formation has been dated back to at least 140,000 years ago, resulting from the eruption of Koabiyama [[pyroclastic flow]]s.<ref name="gbank" /><ref name=":3">Nishino, Y., Takarada, S. and Geshi, N. (2019) [https://www.gsj.jp/researches/openfile/openfile2019/openfile0680.html Volcanic activities and eruption sequence of the large-scale eruption at Aira, Kikai, Ata, Kutcharo, Towada, Mashu and Ikeda Volcanoes.] Open-File Report of the Geological Survey of Japan, AIST, no.680, p. 1-126.</ref><ref name=":2" /> The formation of caldera has been associated with at least three catastrophic [[ignimbrite]] eruptions.<ref name="gbank" /><ref name=":3" /><ref name=":2" /> Additionally, there are two older deposits (Koseda pyroclastic flows and Anbo tephra) of large caldera-forming eruptions in the vicinity, although their attribution to the Kikai caldera remains controversial.<ref>{{Cite journal |last1=Ito |first1=Hisatoshi |last2=Uesawa |first2=Shimpei |last3=Nanayama |first3=Futoshi |last4=Nakagawa |first4=Shojiro |date=2017-05-15 |title=Zircon U–Pb dating using LA-ICP-MS: Quaternary tephras in Yakushima Island, Japan |url=https://linkinghub.elsevier.com/retrieve/pii/S0377027316303079 |journal=Journal of Volcanology and Geothermal Research |language=en |volume=338 |pages=92–100 |doi=10.1016/j.jvolgeores.2017.02.003|bibcode=2017JVGR..338...92I |url-access=subscription }}</ref><ref>{{Cite journal |last1=Moriwaki |first1=Hiroshi |last2=Westgate |first2=John A. |last3=Sandhu |first3=Amanjit S. |last4=Preece |first4=Shari J. |last5=Arai |first5=Fusao |date=2008-02-01 |title=New glass fission-track ages of Middle Pleistocene tephras on Yakushima Island, southern Japan |url=https://www.sciencedirect.com/science/article/pii/S1040618206002874 |journal=Quaternary International |series=Global Tephra Studies: John Westgate and Andrei Sarna-Wojcicki Commemorative Volume |language=en |volume=178 |issue=1 |pages=128–137 |doi=10.1016/j.quaint.2006.11.013 |bibcode=2008QuInt.178..128M |issn=1040-6182|url-access=subscription }}</ref><ref>{{Cite journal |last1=久敏 |first1=伊藤 |last2=真平 |first2=上澤 |date=2017 |title=鬼界カルデラにおける鬼界アカホヤ噴火以前の大噴火について |url=https://www.jstage.jst.go.jp/article/geosocabst/2017/0/2017_023/_article/-char/ja/ |journal=日本地質学会学術大会講演要旨 |volume=2017 |pages=023 |doi=10.14863/geosocabst.2017.0_023}}</ref>

=== Kikai-Koabiyama eruption ===
The Kikai-Koabiyama (K-Kob) pyroclastic flows are rhyolitic and are distributed across most of Takeshima and the plateau-like area on the northwest side of the caldera rim of Satsuma Iwo-Jima. They consist of numerous thin flow units and fill the basins in the basement, exhibiting significant variation in thickness. In Takeshima, the pyroclastic flows are thick, ranging from {{Convert|20-100|m|ft|abbr=on}}, whereas in Iwo Jima, they are relatively thin, measuring a few to {{Convert|30|m|ft|abbr=on}}.<ref name="gbank" /><ref name=":2" />

The eruption of the K-Kob pyroclastic flows has been dated using [[K–Ar dating|K-Ar dating]] to be {{Val|140000|20000|fmt=commas}} years before present.<ref name="gbank" /> While no distal tephra from this eruption has been reported, a tephra layer with potential geochemical and age correlation has been discovered in [[Lake Suigetsu]].<ref>{{Cite journal |last1=Maruyama |first1=Seiji |last2=Takemura |first2=Keiji |last3=Hirata |first3=Takafumi |last4=Yamashita |first4=Tohru |last5=Danhara |first5=Tohru |date=2019-08-11 |title=Major and trace element abundances in volcanic glass shards in visible tephras in SG93 and SG06 drillcore samples from Lake Suigetsu, central Japan, obtained using femtosecond LA–ICP–MS |journal=Journal of Quaternary Science |volume=35 |issue=1–2 |pages=66–80 |doi=10.1002/jqs.3124 |issn=0267-8179|doi-access=free }}</ref>

===Kikai-Tozurahara eruption===
Kikai-Tozurahara (K-Tz) [[tephra]] is a widespread rhyolitic tephra layer of [[Late Pleistocene]] age, attributed to a large [[Volcanic explosivity index|VEI]]-7 eruption from the Kikai caldera.<ref name=":0">{{Cite journal |last1=洋 |first1=町田 |last2=房夫 |first2=新井 |date=1983 |title=101. 鬼界カルデラ起源の新広域テフラと九州における更新世後期大火砕流の噴出年代(日本火山学会 1983 年度春季大会講演要旨) |url=https://www.jstage.jst.go.jp/article/kazanc/28/2/28_KJ00003453684/_article/-char/ja/ |journal=火山.第２集 |volume=28 |issue=2 |pages=206 |doi=10.18940/kazanc.28.2_206_2}}</ref> This layer is confirmed to have a wide distribution, extending from south [[Kyushu]] to eastern [[Honshu]] and reaching the [[Pacific Ocean]],<ref name=":1">{{Cite journal |last=Machida |first=Hiroshi |date=1999 |title=The stratigraphy, chronology and distribution of distal marker-tephras in and around Japan |url=https://linkinghub.elsevier.com/retrieve/pii/S0921818199000089 |journal=Global and Planetary Change |language=en |volume=21 |issue=1–3 |pages=71–94 |doi=10.1016/S0921-8181(99)00008-9|bibcode=1999GPC....21...71M |url-access=subscription }}</ref> and possibly including the [[Shandong Peninsula]].<ref>{{Cite journal |last1=Eden |first1=Dennis N. |last2=Froggatt |first2=Paul C. |last3=Zheng |first3=Honghan |last4=Machida |first4=Hiroshi |date=1996-01-01 |title=Volcanic glass found in Late Quaternary Chinese loess: A pointer for future studies? |url=https://dx.doi.org/10.1016/1040-6182%2895%2900074-7 |journal=Quaternary International |language=en |volume=34-36 |pages=107–111 |doi=10.1016/1040-6182(95)00074-7 |bibcode=1996QuInt..34..107E |issn=1040-6182|url-access=subscription }}</ref> The proximal equivalents of K-Tz are the Nagase [[pyroclastic flow]] and the Nishinoomote [[pyroclastic surge]]s.<ref name=":0" /><ref>{{Cite journal |last=信治 |first=長岡 |date=1988 |title=最終間氷期末に起きた鬼界カルデラの珪長質火砕流噴火と火砕サージの形成 |url=https://www.jstage.jst.go.jp/article/jgeography1889/97/3/97_3_156/_article/-char/ja/ |journal=地學雜誌 |volume=97 |issue=3 |pages=156–169 |doi=10.5026/jgeography.97.3_156|doi-access=free }}</ref> The combined bulk volume of both distal and proximal deposits is estimated to exceed {{Convert|150|km3|mi3|abbr=on}}.<ref name=":1" />

In [[Marine isotope stages|marine isotope stratigraphy]] (MIS), K-Tz is located between MIS 5.2 and 5.3, providing a loosely constrained preliminary eruption age of approximately 95,000 years before present.<ref name=":1" /> More reliable age constraints were imposed by the high-resolution chronology derived from the Lake Suigetsu sediment sequence, which yielded an age of {{Val|94500|4800|fmt=commas}} years before present for this eruption.<ref>{{Cite journal |last1=Albert |first1=Paul G. |last2=Smith |first2=Victoria C. |last3=Suzuki |first3=Takehiko |last4=McLean |first4=Danielle |last5=Tomlinson |first5=Emma L. |last6=Miyabuchi |first6=Yasuo |last7=Kitaba |first7=Ikuko |last8=Mark |first8=Darren F. |last9=Moriwaki |first9=Hiroshi |last10=Nakagawa |first10=Takeshi |date=2019 |title=Geochemical characterisation of the Late Quaternary widespread Japanese tephrostratigraphic markers and correlations to the Lake Suigetsu sedimentary archive (SG06 core) |url=https://linkinghub.elsevier.com/retrieve/pii/S1871101418300967 |journal=Quaternary Geochronology |language=en |volume=52 |pages=103–131 |doi=10.1016/j.quageo.2019.01.005|bibcode=2019QuGeo..52..103A |hdl=2262/93449 |s2cid=134899116 |hdl-access=free }}</ref>

===Kikai-Akahoya eruption===
[[File:Kikai K-Ah tephra 7,3ka.svg|thumb|left|alt=Impact|Kikai-Kikai-Akahoya (K-Ah) [[tephra]] and pyroclastic flow impact from [[Akahoya eruption|Kikai-Akahoya eruption]]]]
{{main|Akahoya eruption}}
The caldera was the source of the [[Akahoya eruption|Kikai-Akahoya eruption]], one of the largest eruptions during the [[Holocene]] (10,000&nbsp;years ago to present) that produced the Kikai-Akahoya (K-Ah) [[tephra]].<ref name="Tsuji2018">{{cite journal|first1=Tomohiro |last1=Tsuji|first2= Michiharu |last2=Ikeda|first3= Akira |last3=Furusawa|first4= Chisato |last4=Nakamura|first5= Kiyoshi |last5=Ichikawa|first6= Makoto |last6=Yanagida|first7= Naoki |last7=Nishizaka|first8= Kozo |last8=Ohnishi|first9= Yuki |last9=Ohno|title=High resolution record of Quaternary explosive volcanism recorded in fluvio-lacustrine sediments of the Uwa basin, southwest Japan |journal=Quaternary International |volume=471 |year=2018 |pages=278–297 |issn=1040-6182 |doi=10.1016/j.quaint.2017.10.016 |doi-access=free |bibcode=2018QuInt.471..278T }}</ref> Between 7,200 and 7,300&nbsp;years ago,<ref name="Tsuji2018"/><ref name="Okuno2019">{{cite journal |last1=Okuno |first1=Mitsuru |date=2019-04-15 |title=Chronological study on widespread tephra and volcanic stratigraphy of the past 100,000 years |url=https://www.jstage.jst.go.jp/article/geosoc/125/1/125_2018.0069/_article/-char/en |journal=The Journal of the Geological Society of Japan |volume=125 |issue=1 |pages=41–53 |doi=10.5575/geosoc.2018.0069 |issn=1349-9963 |s2cid=146526393|doi-access=free }}</ref><ref name="Smith2013">{{cite journal|first1=Victoria C. |last1=Smith|first2= Richard A. |last2=Staff|first3= Simon P.E. |last3=Blockley|first4= Christopher Bronk |last4=Ramsey|first5= Takeshi |last5=Nakagawa|first6= Darren F. |last6=Mark|first7= Keiji |last7=Takemura|first8= Toru |last8=Danhara |title=Identification and correlation of visible tephras in the Lake Suigetsu SG06 sedimentary archive, Japan: chronostratigraphic markers for synchronising of east Asian/west Pacific palaeoclimatic records across the last 150 ka |journal= Quaternary Science Reviews |volume=67|year=2013 | pages=121–137 |issn=0277-3791 |doi=10.1016/j.quascirev.2013.01.026 |bibcode=2013QSRv...67..121S |url=https://www.sciencedirect.com/science/article/pii/S0277379113000413 |url-access=subscription }}</ref> [[pyroclastic flow]]s producing Koya [[ignimbrite]] from that eruption reached the coast of southern [[Kyūshū]] up to {{convert|100|km|mi|abbr=on}} away, and ash fell as far as [[Hokkaido]]. The eruption produced about {{cvt|133|–|183|km3|cumi}}&nbsp;[[Dense rock equivalent|DRE]], most of it tephra.<ref>{{cite journal |doi=10.1016/j.jvolgeores.2024.108017 |author1=Satoshi Shimizu |author2=Reina Nakaoka |author3=Nobukazu Seama |author4=Keiko Suzuki-Kamata |author5=Katsuya Kaneko |author6=Koji Kiyosugi |author7=Hikaru Iwamaru |author8=Mamoru Sano |author9=Tetsuo Matsuno |author10=Hiroko Sugioka |author11=Yoshiyuki Tatsumi |date=2024 |title= Submarine pyroclastic deposits from 7.3 ka caldera-forming Kikai-Akahoya eruption|journal=Journal of Volcanology and Geothermal Research |volume= |issue=108017 |pages=|doi-access=free }}</ref><ref name=GVP>{{cite gvp|vn=282060|title=Kikai: Eruptive History|accessdate=2024-02-26}}</ref> giving it a [[Volcanic Explosivity Index]] of 7,<ref name=GVP /> so making it one of the most explosive in the last 10,000 years, ranking alongside the eruptions of [[Santorini]], [[Paektu Mountain|Paektu]], [[Crater Lake]], [[Kurile Lake]], [[Lake Segara Anak|Samalas]] and [[Mount Tambora|Tambora]].<ref>{{cite web |url=http://www.allcountries.org/ranks/volcano_explocivity_index_ranks.html |title=Large Volcano Explocivity Index |work=Countries of the World |access-date=2014-04-24}}</ref>

The eruption had a major impact on the [[Jōmon culture]] in southern [[Kyūshū]] although the impact was not as great as some commentary had suggested with Nishinozono sub-type pottery tradition, that had started prior to the eruption, maintained in Kyūshū.<ref>{{cite web|url=https://www.sainsbury-institute.org/e-bulletin/april-2021/after-a-super-volcanic-eruption-a-new-project-on-social-ecological-impacts-of-the-kikai-akahoya-disaster-7300-years-ago/ |access-date=2022-09-18 |title=After a Super Volcanic Eruption: a new project on social-ecological impacts of the Kikai-Akahoya disaster, 7,300 years ago| year=2021 |first1=Uchiyama |last1=Junzo}}</ref>

== 2024 studies ==
Japanese scientists conducted an extensive study of the volcanic activity of the Kikai underwater caldera. They had estimated the volumes of ejected volcanic material, which range from 332 to 457 cubic kilometers, and proved that it was the largest eruption in the last 11,700 years that occurred here 7,300 years ago. They were able to recreate the sequence of a large-scale volcanic event and identified three directions of flow of eruption products: in the atmosphere, along the seabed and along the water's edge.

Details of the marine expedition include conducting seismological studies and collecting sediment samples around the Kikai caldera. Scientists have confirmed that volcanic formations on the ocean floor and nearby islands have a common position. Analysis of the distribution of these deposits around the eruption site helps to understand how the pyroclastic flow and water interacted. The eruption occurred with a strong ejection of debris and ash, which corresponds to the usual phase of the Plinian type, during which there was a series of prolonged emissions under high pressure of fragmented lava and pumice in the form of a gas-ash mixture. It was a volumetric pyroclastic flow as a final stage, which partially spread along the seabed and released into the atmosphere in the form of an eruptive column (ash, fragments of pumice, small crystals and tephra). The tephra cloud covered an area of more than 2.8 million km2. The volume of ash material amounted to more than 370 km3 in terms of hard rock. The Plinian phase ended with the destruction of the eruptive column. A huge column of hot tephra fell a few hundred meters from the eruption’s center, causing the formation of a pyroclastic flow.

Since the center of the volcano was under water, the Akahoya eruption had the character of a steam explosion (or a series of explosions) due to the instantaneous release of steam upon contact of hot magma with water. As a result, a double caldera was formed.

Scientists had conducted a detailed study of the spread of volcanic material over an area of about 4,500 square kilometers around the center of the eruption and mapped the thickness of the underwater pyroclastic sediment. In their opinion, 133 to 183 cubic kilometers of pumice and ash settled on the studied area.

After analyzing the textures and nature of the fragments of the underwater volcanic strata, the authors concluded that it was formed from a suspended stream, which can cover long distances even up the slope, as it turned out. Having built a model of the Kikai-Akahoya eruption, researchers have found that in addition to the underwater pyroclastic flow and the powerful release of the tephra cloud into the atmosphere, there was also a third stream of thin volcanic material that spread along the surface of the water to the nearest islands.<ref>{{cite web |title=Кальдера Кикай у берегов Японии — место крупнейшего в голоцене извержения вулкана |url=https://elementy.ru/novosti_nauki/434220/Kaldera_Kikay_u_beregov_Yaponii_mesto_krupneyshego_v_golotsene_izverzheniya_vulkana |accessdate=2024-05-22 |publisher=elementy.ru |language=ru}}</ref>

===Eruptive history since Kikai-Akahoya eruption===
Kikai is still an active volcano. [[Mount Iō (Iōjima)|Io-dake (Mount Iō)]], Inamura-dake (south coast of [[Iōjima (Kagoshima)|Satsuma-Io-jima]]), Tokara-Iwo-Jima (north east coast of Satsuma-Io-jima) and [[Shōwa Iōjima]] (Shin-Io-jima) are post-caldera volcanoes within it.<ref name="gbank"/>  Minor eruptions occur frequently on Mount Iō, one of the post-caldera [[subaerial]] volcanic peaks on Iōjima. Iōjima is one of three volcanic islands, two of which lie on the caldera rim.  On June 4, 2013, weak tremors were recorded. Shortly after, eruptions began and continued off-and-on for several hours.<ref name=GVP /> Io-dake is monitored for earthquake, gas and steam plume activity so that between the 2020 and 2023 eruptions it is known to have had continuous low grade activity.<ref name=GVP />

[[file:2015 Satsuma-Iojima Iodake.jpg|thumb|250px|[[Mount Iō (Iōjima)|Mount Iō]], a [[rhyolite]] [[lava dome]], May, 2015, viewed from the east]]
Eruptions occurred:<ref name="gbank"/><ref name="Maeno2005">{{cite journal|last1=Maeno |first1=Fukashi |last2=Taniguchi |first2= Hiromitsu |date=2005-05-20 |pages= 71–85|title=Eruptive History of Satsuma Iwo-jima Island, Kikai Caldera, after a 6.5 ka Caldera-forming Eruption |doi=10.18940/kazan.50.2_71|journal=火山 (Volcano)|volume=50 |url=https://www.jstage.jst.go.jp/article/kazan/50/2/50_KJ00003562590/_article/-char/ja/}}</ref>
*old Iwo-dake stage (stage OIo-I-II)
**phreatomagmatic eruptions and pumice fallout (stage OIo-I), followed by rhyolitic lava with continuous [[tephra]], resulting in a volcanic edifice (stage OIo-II)
**3250 BCE ± 75 years (uncalibrated) Old Iwo-dake
***OIo1a,b tephras<ref name="GVP"/>
**2450 BCE ± 840 years ([[tephrochronology]]) Old Iwo-dake
***OIo2a,b tephras<ref name="GVP"/>
* Inamura-dake stage (stage In-I-IV)
**basaltic lava flows and scoria-cone building (stage In-I-II), then phreatomagmatic eruptions (stage In-III), and then andesitic lava (stage In-IV)
**1830 BCE ± 75 years (uncalibrated) Inamura-dake<ref name="GVP"/>
***In-I tephra
**1090 BCE ± 100 years (uncalibrated) Inamura-dake<ref name="GVP"/>
*young Iwo-dake stage (stage YIo-I-IV)
**continuing with a different magma source including rhyolitic lava and intermittent pumice
**280 BCE ± 75 years (uncalibrated) Iwo-dake<ref name="GVP"/>
**390 ± 100 years (uncalibrated) Iwo-dake<ref name="GVP"/>
**750 (tephrochronology) Iwo-dake<ref name="GVP"/>
**830 ± 40 years (uncalibrated) Iwo-dake<ref name="GVP"/>
***K-Iw-P1 tephra
**1010 ± 40 years (uncalibrated) Iwo-dake<ref name="GVP"/>
*** K-Sk-u-3 tephra
**1030 ± 40 years (uncalibrated) Iwo-dake<ref name="GVP"/>
***K-Sk-u-4 tephra
**1340 ± 30 years (uncalibrated) Iwo-dake<ref name="GVP"/>
***K-Iw-P2 tephra
**1430 ± 75 years (uncalibrated) Iwo-dake<ref name="GVP"/>
** 13 Feb 1914 Tokara-Iwo-Jima<ref name="GVP"/>
**Sep-Nov 1934
***Submarine eruption with [[pumice]]
**7 Dec 1934 -Mar 1935 2&nbsp;km east of Tokara-Iwo-Jima<ref name="gbank"/>
***New island [[Shōwa Iōjima]] (Shin-Io-jima) with [[lava]] finally stabilised 19 January 1935
**1997-2003 Iwo-dake<ref name="gbank"/>
***Formation and enlargement of new pit crater inside the summit crater
**Apr-Nov 1998 Iwo-dake<ref name="gbank"/>
***Ash
**May-Aug 1999 Iwo-dake<ref name="gbank"/>
***Ash
**Jan, Mar, Oct-Dec 2000 Iwo-dake<ref name="gbank"/>
***Ash 
**Feb, Apr-Dec 2001 Iwo-dake<ref name="gbank"/>
***Ash
**May-Jul 2002 Iwo-dake<ref name="gbank"/>
***Ash
**Feb, Apr-Oct 2003 Iwo-dake<ref name="gbank"/>
***Ash 
**May-Apr, Jun, Aug-Oct 2004 Iwo-dake<ref name="gbank"/>
***Ash
**3-5 May, 3-5 Jun 2013 Iwo-dake<ref name="gbank"/>
***Minor eruptions
**2 Nov 2019 Iwo-dake<ref name="gbank"/>
***Minor eruption
**29 Apr 2020 Iwo-dake<ref name="gbank"/>
***Minor eruption
**6 Oct 2020 Iwo-dake<ref name="gbank"/>
***Minor eruption
* 27 Mar 2023 – 22 Nov 2023
***Minor eruptions<ref name=GVP />

==See also==
*[[List of volcanoes in Japan]]

==Further reading==
*{{cite book |title=Natural Disasters and Cultural Change |chapter=The impact of the Kikai-Akahoya explosive eruptions on human societies |last=Machida |first=Hiroshi |author2=Sugiyama, Shinji  |editor=Grattan, John |editor2=Torrence Robin|year=2002 |publisher=Routledge |location=London |isbn=0-415-21696-6 |pages=313&ndash;346 }} but also for more recent corrections to this {{cite web|url=https://www.sainsbury-institute.org/e-bulletin/april-2021/after-a-super-volcanic-eruption-a-new-project-on-social-ecological-impacts-of-the-kikai-akahoya-disaster-7300-years-ago/ |access-date=2022-09-18 |title=After a Super Volcanic Eruption: a new project on social-ecological impacts of the Kikai-Akahoya disaster, 7,300 years ago| year=2021 |first1=Uchiyama |last1=Junzo}}

==References==
*{{cite gvp | vnum=282060 | title=Kikai}}
*{{cite web|url=http://riodb02.ibase.aist.go.jp/strata/VOL_JP/EN/vol/11.htm|title=KIKAI Caldera|year=2006|work=Quaternary Volcanoes in Japan|publisher=Geological Survey of Japan, AIST|access-date=2009-01-08|url-status=dead|archive-url=https://archive.today/20121219190519/http://riodb02.ibase.aist.go.jp/strata/VOL_JP/EN/vol/11.htm|archive-date=2012-12-19}}
*[http://volcano.oregonstate.edu/vwdocs/volc_images/north_asia/kikai/kikai.html VolcanoWorld – Kikai, Kyūshū, Japan] {{Webarchive|url=https://web.archive.org/web/20171217203355/http://volcano.oregonstate.edu/vwdocs/volc_images/north_asia/kikai/kikai.html |date=2017-12-17 }}
*[https://archive.today/20121219031804/http://riodb02.ibase.aist.go.jp/strata/VOL_JP/vol/11.htm 鬼界カルデラ Kikai Caldera 独立行政法人 産業技術総合研究所 地 質 調 査 総 合 セ ン タ ー ]
*[http://geographic.org/photos/volcanoes/volcano_photos_153.html Kikai Caldera – Volcano Photos]
{{reflist}}

== External links ==
* [https://gbank.gsj.jp/volcano/Act_Vol/satsumaioujima/vr/eindex.html Satsuma-iojima] - Geological Survey of Japan
* [https://gbank.gsj.jp/volcano/Quat_Vol/volcano_data/L01.html Kikai] - Geological Survey of Japan
* [http://www.eri.u-tokyo.ac.jp/people/fmaeno/kikai/kikaicaldera.html Geology and eruptive history of Kikai Caldera] - Earthquake Research Institute,The University of Tokyo
* [https://volcano.si.edu/volcano.cfm?vn=282060　Kikai: Global Volcanism Program]- Smithsonian Institution

[[Category:Ōsumi Islands]]
[[Category:VEI-7 volcanoes]]
[[Category:Calderas of Japan]]
[[Category:Active volcanoes]]
[[Category:Submarine calderas]]
[[Category:Volcanoes of Kagoshima Prefecture]]
[[Category:Holocene calderas]]