Asosan

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 32.884°N
  • 131.104°E

  • 1592 m
    5222 ft

  • 282110
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

19 February-25 February 2014

JMA reported that a very small explosion from Asosan's Nakadake Crater occurred on 19 February. An off-white plume rose 200 m above the crater rim and drifted SW. During fieldwork on 21 February volcanologists noted that sulfur dioxide emissions remained high. The Alert Level remained at 2 (on a scale of 1-5).

Source: Japan Meteorological Agency (JMA)



 Available Weekly Reports


2014: January | February
2011: May | June
2005: April
2004: January
2003: July
2002: August


19 February-25 February 2014

JMA reported that a very small explosion from Asosan's Nakadake Crater occurred on 19 February. An off-white plume rose 200 m above the crater rim and drifted SW. During fieldwork on 21 February volcanologists noted that sulfur dioxide emissions remained high. The Alert Level remained at 2 (on a scale of 1-5).

Source: Japan Meteorological Agency (JMA)


12 February-18 February 2014

JMA reported that a very small explosion from Asosan's Nakadake Crater occurred on 16 February. An off-white plume rose 300 m above the crater rim and drifted S. The Alert Level remained at 2 (on a scale of 1-5).

Source: Japan Meteorological Agency (JMA)


5 February-11 February 2014

According to a JMA report, volcanologists conducting a field survey of Asosan's Nakadake Crater on 5 February detected decreased sulfur dioxide emissions and fewer volcanic earthquakes. The Alert Level remained at 2 (on a scale of 1-5).

Source: Japan Meteorological Agency (JMA)


29 January-4 February 2014

Based on pilot observations, the Tokyo VAAC reported that on 29 January an ash plume from Asosan rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted NW. Later that day a plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted N. JMA reported that a very small explosion from Naka-daka Crater occurred on 31 January. An off-white plume rose 100 m above the crater rim and drifted S. The Alert Level remained at 2 (on a scale of 1-5).

Sources: Japan Meteorological Agency (JMA), Tokyo Volcanic Ash Advisory Center (VAAC)


22 January-28 January 2014

JMA reported that seismicity at Asosan increased from 21 to 23 January, and then decreased on 24 January. On 23 January a volcanologist observed ash plumes rising from the central vent on the crater floor. The Alert Level remained at 2 (on a scale of 1-5).

Source: Japan Meteorological Agency (JMA)


8 January-14 January 2014

On 27 December 2013 JMA raised the Alert Level for Aso to 2 (on a scale of 1-5) because volcanic tremor amplitude had been increasing since 20 December. However, on 2 January 2014 the amplitude rapidly decreased. Sulfur dioxide emissions were 1,200 tons per day during 2-9 January and 1,500 tons on 10 January. Volcanic tremor amplitude increased between 0800 and 1900 on 12 January. At 1215 on 13 January a very small eruption from Naka-dake Crater generated a grayish white plume that rose 600 m and drifted S, producing ashfall downwind.

Source: Japan Meteorological Agency (JMA)


8 June-14 June 2011

Based on notices from JMA, the Tokyo VAAC reported that during 7-9 June plumes from Aso rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted NW, N, NE, and E.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)


1 June-7 June 2011

Based on notices from JMA, the Tokyo VAAC reported that during 1-7 June plumes from Aso rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifted NW, N, NE, E, and S.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)


25 May-31 May 2011

Based on notices from JMA, the Tokyo VAAC reported that during 25, 27-28, and 31 May ash plumes from Aso rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted NW, N, E, and S.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)


18 May-24 May 2011

Based on notices from JMA, the Tokyo VAAC reported that during 18-22 May ash plumes from Aso rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifted N, NE, and SE. A pilot noted on 18 May that an ash plume rose to an altitude of 3 km (10,000 ft) a.s.l.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)


11 May-17 May 2011

Based on pilot observations, the Tokyo VAAC reported that on 15 May an ash plume from Aso rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted NE. JMA reported that the next day plumes rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. A pilot noted that an ash plume rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted N that same day. During 17-18 May the JMA reported that ash plumes rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted E and SE.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)


13 April-19 April 2005

According to a news article, a small explosion at Aso on 14 April emitted a plume of "white smoke" to ~200 m above the crater (~5,900 ft a.s.l.) and deposited ash around the crater. The explosion occurred after hundreds of small earthquakes were recorded by JMA during the previous 2 weeks.

Source: Associated Press


14 January-20 January 2004

According to the Japanese Meteorological Agency, a "mud eruption" occurred at Aso's Crater 1 on 14 January at 1541. The eruption was accompanied by volcanic tremor and ash emissions that rose to low levels above the crater. Small amounts of very fine ash fell in Takamori Town about 10 km ESE of the crater. The level of thermal activity at Aso had risen during the previous year, with the last "mud eruption" occurring in July 2003. The Alert Level at Aso was raised from 2 to 3, and no tourists were permitted entrance within 1 km of the crater.

Sources: Volcano Research Center-Earthquake Research Institute (University of Tokyo), Reuters


23 July-29 July 2003

During 12-14 July, JMA recorded seismic signals at Aso that were associated with five small phreatic eruptions. Around 1400 on 27 July continuous volcanic tremor started. Such activity had not been recorded at Aso since November 1995. As of 28 July ~10 earthquakes occurred per day, and around 100 isolated tremor events had occurred since 23 July. On the 28th the crater lake in Crater 1 was gray, 76 °C, and bubbling in the center.

Source: Japan Meteorological Agency (JMA)


9 July-15 July 2003

A tremor event with a moderate amplitude was recorded at Aso on 10 July at 1718. Aso weather station personnel inspected the area around Nakadake crater and found a small amount of tephra newly deposited at Hakoishi-Toge about 6 km ENE of the crater. Dr. Yasuaki Sudo of Aso Volcanological Laboratory, Kyoto University, inspected the crater area and determined that a phreatic eruption had occurred. Mud emitted during the eruption reached as far as 10 km from the crater. The color of the crater lake surface changed to dark gray from green, its color on 8 July.

Source: Japan Meteorological Agency (JMA)


21 August-27 August 2002

By 21 August isolated tremor events that began at Aso's Crater 1 on 5 August decreased in number after peaking on 15 August. On the 21st the temperature of the crater's southern inner rim was still high (314 ºC), as it had been the previous week.

Source: Japan Meteorological Agency (JMA) via the Volcano Research Center


14 August-20 August 2002

During 5 August to at least 15 August, isolated volcanic-tremor events occurred at Naka-dake, Aso's historically-active intra-caldera cone. The maximum number of events (335) was recorded on 12 August. Scientists found that the temperature of the southern crater wall remained high (307 ºC on 14 August) as it has since April 2002. There were no changes in water-pool temperature in the crater, nor had changes occurred in water level, sediment content, or fumarolic activity in the crater. The last time over 300 isolated volcanic-tremor events per day had been recorded at Aso was during 19 June-2 July 1992.

Source: Japan Meteorological Agency (JMA) via the Volcano Research Center


Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2011 May 15 2011 Jun 9 Confirmed 1 Historical Observations Naka-dake
2008 Feb 17 2008 Feb 17 Confirmed 1 Historical Observations Naka-dake
2005 Apr 14 2005 Aug Confirmed 1 Historical Observations Naka-dake
2004 Jan 14 2004 Jan 14 Confirmed 1 Historical Observations Naka-dake
2003 Jul 10 2003 Jul 14 Confirmed 1 Historical Observations Naka-dake
1994 May 2 1995 Nov Confirmed 2 Historical Observations Naka-dake
1992 Apr 23 1993 Jun 10 (?) Confirmed 2 Historical Observations Naka-dake
1989 Apr 5 1991 Feb 9 Confirmed 2 Historical Observations Naka-dake
1988 May 26 ± 5 days 1989 Jan Confirmed 1 Historical Observations Naka-dake
1984 Apr 13 ± 3 days 1985 Jun 24 Confirmed 1 Historical Observations Naka-dake
1983 Jul 1983 Oct Confirmed 1 Historical Observations Naka-dake
1981 Jun 15 1981 Jun 15 Confirmed 1 Historical Observations Naka-dake
1980 Sep 24 1980 Sep 24 Confirmed 1 Historical Observations Naka-dake
1979 Jun 5 ± 4 days 1980 Mar 8 Confirmed 2 Historical Observations Naka-dake
1977 Apr 11 1978 Aug Confirmed 2 Historical Observations Naka-dake
1975 Oct 1976 Jan 13 Confirmed 1 Historical Observations Naka-dake
1973 Jan 1975 Jun Confirmed 2 Historical Observations Naka-dake
1970 Apr 21 1972 Sep Confirmed 2 Historical Observations Naka-dake
1967 May 1969 Dec Confirmed 1 Historical Observations Naka-dake
1964 Oct 1966 Dec Confirmed 2 Historical Observations Naka-dake
1964 May 14 1964 May 14 Confirmed 1 Historical Observations Naka-dake
1963 Nov 10 1964 Jan Confirmed 2 Historical Observations Naka-dake
1963 Apr 21 1963 Jul Confirmed 1 Historical Observations Naka-dake
1960 Sep 1962 Nov Confirmed 1 Historical Observations Naka-dake
1960 Jan 1960 Apr 9 Confirmed 2 Historical Observations Naka-dake
1959 Jul 1959 Oct 2 Confirmed 1 Historical Observations Naka-dake
1957 Oct 1958 Dec Confirmed 2 Historical Observations Naka-dake
1957 Apr 12 1957 Apr 12 Confirmed 1 Historical Observations Naka-dake
1956 Dec 21 1956 Dec 21 Confirmed 1 Historical Observations Naka-dake
1956 Aug Unknown Confirmed 2 Historical Observations Naka-dake
1956 Jan 3 (?) 1956 Jan 13 Confirmed 2 Historical Observations Naka-dake
1955 Jul 25 1955 Jul 28 Confirmed 1 Historical Observations Naka-dake
1954 May 26 1954 May 26 Confirmed 1 Historical Observations Naka-dake
1953 Dec 1953 Dec Confirmed 1 Historical Observations Naka-dake
1953 Apr 27 1953 Jul 30 Confirmed 2 Historical Observations Naka-dake
[ 1952 ] [ Unknown ] Uncertain     Naka-dake
1951 May 4 1951 Aug Confirmed 2 Historical Observations Naka-dake
1950 Nov 1951 Jan Confirmed 2 Historical Observations Naka-dake
1949 Dec 26 1950 Apr 15 Confirmed 2 Historical Observations Naka-dake
1948 Apr 9 1948 Dec Confirmed 1 Historical Observations Naka-dake
1947 May 26 1947 Sep Confirmed 2 Historical Observations Naka-dake
1946 Dec 30 1946 Dec 30 Confirmed 2 Historical Observations Naka-dake
1946 Apr 29 1946 Jun 24 Confirmed 2 Historical Observations Naka-dake
1945 Sep 16 1945 Sep 19 Confirmed 2 Historical Observations Naka-dake
1943 Dec 9 1944 Feb Confirmed 2 Historical Observations Naka-dake
1943 Jun 21 1943 Jun 24 Confirmed 2 Historical Observations Naka-dake
[ 1942 Jun 8 ] [ 1942 Jun 22 ] Uncertain 1   Naka-dake
1940 Apr 20 1941 Aug 8 Confirmed 2 Historical Observations Naka-dake
1938 1939 Aug 11 Confirmed 2 Historical Observations Naka-dake
1937 May 7 1937 May 13 Confirmed 2 Historical Observations Naka-dake
1937 Jan 13 1937 Jan 13 Confirmed 2 Historical Observations Naka-dake
1936 Aug 8 1936 Aug 14 Confirmed 2 Historical Observations Naka-dake
1936 Feb 5 1936 Feb 5 Confirmed 2 Historical Observations Naka-dake
1935 Jan 7 1935 Oct 8 Confirmed 2 Historical Observations Naka-dake
1934 Jul 16 Unknown Confirmed 2 Historical Observations Naka-dake
1932 Jun 1933 Sep 28 Confirmed 2 Historical Observations Naka-dake
[ 1931 Oct 18 ] [ Unknown ] Uncertain 1   Naka-dake
1930 Sep 3 1930 Sep 6 Confirmed 2 Historical Observations Naka-dake
1928 Sep 6 1929 Oct 23 Confirmed 2 Historical Observations Naka-dake
1926 Sep 21 1928 Jan 13 Confirmed 2 Historical Observations Naka-dake
1925 Jan 6 Unknown Confirmed 2 Historical Observations Naka-dake
1923 Jan 1923 Sep 17 Confirmed 2 Historical Observations Naka-dake
1920 Unknown Confirmed 2 Historical Observations Naka-dake
1919 Apr 1919 May Confirmed 2 Historical Observations Naka-dake
1918 Jan 16 Unknown Confirmed 2 Historical Observations Naka-dake
1916 Apr 19 Unknown Confirmed 2 Historical Observations Naka-dake
1914 Jan 13 Unknown Confirmed 2 Historical Observations Naka-dake
1911 1912 Confirmed 2 Historical Observations Naka-dake
1910 Apr 3 Unknown Confirmed 2 Historical Observations Naka-dake
1909 Apr Unknown Confirmed 2 Historical Observations Naka-dake
1908 Jan 17 1908 Jan 29 (?) Confirmed 2 Historical Observations Naka-dake
1907 Dec 12 Unknown Confirmed 2 Historical Observations Naka-dake
1906 Jun 7 Unknown Confirmed 3 Historical Observations Naka-dake
1898 Aug (?) 1899 Apr (in or after) Confirmed 2 Historical Observations Naka-dake
1897 Feb 24 ± 4 days Unknown Confirmed 2 Historical Observations Naka-dake
1894 Mar 6 1894 Aug 30 Confirmed 2 Historical Observations Naka-dake
1884 Mar 21 1884 Jun Confirmed 2 Historical Observations Naka-dake
1874 Feb 7 Unknown Confirmed 2 Historical Observations Naka-dake
1872 Dec 1 1873 Jun 8 Confirmed 3 Historical Observations Naka-dake
1856 Mar 18 1856 Jun 13 Confirmed 2 Historical Observations Naka-dake
1854 Feb 26 Unknown Confirmed 2 Historical Observations Naka-dake
1838 Mar 4 Unknown Confirmed 2 Historical Observations Naka-dake
1837 Oct 8 Unknown Confirmed 2 Historical Observations Naka-dake
1835 May 1 Unknown Confirmed 2 Historical Observations Naka-dake
1830 Aug 11 1832 Aug Confirmed 2 Historical Observations Naka-dake
1830 Feb 16 1830 Mar Confirmed 2 Historical Observations Naka-dake
1829 Jun Unknown Confirmed 2 Historical Observations Naka-dake
1828 Jun Unknown Confirmed 2 Historical Observations Naka-dake
1827 Nov 12 1828 Jan Confirmed 2 Historical Observations Naka-dake
1827 May Unknown Confirmed 2 Historical Observations Naka-dake
1826 Oct 3 1826 Nov 22 Confirmed 2 Historical Observations Naka-dake
1816 Jun 9 1816 Jul 6 Confirmed 2 Historical Observations Naka-dake and west flank (Yunotani)
1815 Feb 10 1815 Oct Confirmed 2 Historical Observations Naka-dake
1814 Unknown Confirmed 2 Historical Observations Naka-dake
1806 Jun (?) 1806 Oct (?) Confirmed 2 Historical Observations Naka-dake
1804 Sep 5 Unknown Confirmed 2 Historical Observations Naka-dake
1781 1788 Confirmed 1 Historical Observations Naka-dake
1772 1780 Confirmed 2 Historical Observations Naka-dake
1765 Jan (?) 1765 Oct (?) Confirmed 3 Historical Observations Naka-dake
[ 1753 ] [ 1754 ] Uncertain 2   Naka-dake
1709 Feb 13 Unknown Confirmed 2 Historical Observations Naka-dake
[ 1708 Sep 17 ] [ Unknown ] Uncertain 2   Naka-dake
1691 Apr 1691 Aug Confirmed 2 Historical Observations Naka-dake
1683 Jun Unknown Confirmed 2 Historical Observations Naka-dake
1675 Feb 16 Unknown Confirmed 2 Historical Observations Naka-dake
[ 1671 ] [ Unknown ] Uncertain 2   Naka-dake
1668 Aug 1669 Confirmed 2 Historical Observations Naka-dake
1668 Feb Unknown Confirmed 2 Historical Observations Naka-dake
1649 Jul 1649 Aug Confirmed 2 Historical Observations Naka-dake
1637 Sep 29 1637 Oct 5 Confirmed 2 Historical Observations Naka-dake
1631 Dec Unknown Confirmed 2 Historical Observations Naka-dake
1620 Jun 3 Unknown Confirmed 2 Historical Observations Naka-dake
1613 Aug 8 Unknown Confirmed 2 Historical Observations Naka-dake
1612 Aug 12 Unknown Confirmed 2 Historical Observations Naka-dake
1611 Unknown Confirmed 2 Historical Observations Naka-dake
1598 Dec 1599 Confirmed 2 Historical Observations Naka-dake
1592 Unknown Confirmed 2 Historical Observations Naka-dake
1587 Unknown Confirmed 2 Historical Observations Naka-dake
1584 Aug Unknown Confirmed 2 Historical Observations Naka-dake
1583 Dec 14 Unknown Confirmed 2 Historical Observations Naka-dake
1582 Feb 17 Unknown Confirmed 2 Historical Observations Naka-dake
1576 Nov 15 Unknown Confirmed 2 Historical Observations Naka-dake
1574 Unknown Confirmed 2 Historical Observations Naka-dake
1573 Unknown Confirmed 2 Historical Observations Naka-dake
1564 Dec Unknown Confirmed 2 Historical Observations Naka-dake
[ 1563 May 3 ] [ Unknown ] Uncertain 2   Naka-dake
1562 Mar Unknown Confirmed 2 Historical Observations Naka-dake
1558 1559 Confirmed 2 Historical Observations Naka-dake
1542 Apr 29 Unknown Confirmed 2 Historical Observations Naka-dake
1533 Jul 17 Unknown Confirmed 2 Historical Observations Naka-dake
1522 Feb 15 Unknown Confirmed 2 Historical Observations Naka-dake
1506 Apr 6 Unknown Confirmed 2 Historical Observations Naka-dake
1505 Feb Unknown Confirmed 2 Historical Observations Naka-dake
1485 Jan 5 Unknown Confirmed 2 Historical Observations Naka-dake
1473 May 16 1474 Apr 15 ± 45 days Confirmed 2 Historical Observations Naka-dake
1438 Jan 9 1438 Feb 18 Confirmed 2 Historical Observations Naka-dake
1434 May 10 1434 May 18 Confirmed 2 Historical Observations Naka-dake
[ 1390 ] [ Unknown ] Uncertain 2   Naka-dake
[ 1388 Oct 16 ] [ Unknown ] Uncertain 2   Naka-dake
1387 Jun 19 Unknown Confirmed 2 Historical Observations Naka-dake
1377 May 6 Unknown Confirmed 2 Historical Observations Naka-dake
1376 Jun 20 Unknown Confirmed 2 Historical Observations Naka-dake
1375 Dec 20 1376 Jan 31 Confirmed 2 Historical Observations Naka-dake
[ 1369 ] [ Unknown ] Uncertain 2   Naka-dake
[ 1346 ] [ Unknown ] Uncertain 2   Naka-dake
1343 Unknown Confirmed 2 Historical Observations Naka-dake
1340 Feb 3 1340 Feb 25 Confirmed 2 Historical Observations Naka-dake
1335 Feb 7 1335 Mar 26 Confirmed 2 Historical Observations Naka-dake
1331 Dec 1333 Jun Confirmed 2 Historical Observations Naka-dake
1331 Apr 1331 Apr Confirmed 2 Historical Observations Naka-dake
1324 Sep 7 Unknown Confirmed 2 Historical Observations Naka-dake
1305 May 2 Unknown Confirmed 2 Historical Observations Naka-dake
1286 Aug 30 Unknown Confirmed 2 Historical Observations Naka-dake
1281 Jul 1281 Aug Confirmed 2 Historical Observations Naka-dake
1274 Unknown Confirmed 2 Historical Observations Naka-dake
1273 Aug Unknown Confirmed 2 Historical Observations Naka-dake
1272 Nov 29 Unknown Confirmed 2 Historical Observations Naka-dake
1272 Apr 16 Unknown Confirmed 2 Historical Observations Naka-dake
1271 Jan 5 Unknown Confirmed 2 Historical Observations Naka-dake
1269 Aug Unknown Confirmed 2 Historical Observations Naka-dake
1265 Dec 1 (?) Unknown Confirmed 2 Historical Observations Naka-dake
1240 Unknown Confirmed 2 Historical Observations Naka-dake
1239 Feb 8 Unknown Confirmed 2 Historical Observations Naka-dake
[ 1229 Dec 31 ± 365 days ] [ Unknown ] Uncertain 2   Naka-dake
[ 0986 Sep 2 ] [ Unknown ] Uncertain 2   Naka-dake
0867 Jun 20 (?) Unknown Confirmed 2 Historical Observations Naka-dake
0864 Nov 9 Unknown Confirmed 3 Historical Observations Naka-dake
[ 0796 Aug ] [ Unknown ] Uncertain 0   Naka-dake
[ 0553 ] [ Unknown ] Uncertain 3   Naka-dake
0440 ± 75 years Unknown Confirmed 3 Radiocarbon (corrected) Naka-dake, N2S tephra
0630 BCE ± 50 years Unknown Confirmed   Radiocarbon (uncorrected)
1270 BCE ± 75 years Unknown Confirmed   Radiocarbon (uncorrected)
1350 BCE (?) Unknown Confirmed 3 Radiocarbon (corrected) Komezuka
1650 BCE (?) Unknown Confirmed 3 Radiocarbon (corrected) Ojo-dake, OjS tephra
1830 BCE ± 75 years Unknown Confirmed   Radiocarbon (uncorrected)
2050 BCE (?) Unknown Confirmed 3 Radiocarbon (corrected) Kishima-dake, KsS tephra
2150 BCE (?) Unknown Confirmed   Radiocarbon (corrected) ACP-1 tephra
2350 BCE ± 75 years Unknown Confirmed   Radiocarbon (uncorrected)
2550 BCE (?) Unknown Confirmed 1 Tephrochronology Jigoku explosion crater, Ikph1 tephra
2850 BCE (?) Unknown Confirmed 0 Tephrochronology Naka-dake
3610 BCE ± 50 years Unknown Confirmed   Radiocarbon (uncorrected)
8050 BCE ± 1000 years Unknown Confirmed 1 Tephrochronology Jigoku explosion crater, Ikph2 tephra

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Aoki K, 2008. Revised age and distribution of ca. 87 ka Aso-4 tephra based on new evidence from the northwest Pacific Ocean. Quat Internatl, 178: 100-118.

Fujii J, Nakajima T, Kamata H, 2001. Paleomagnetic directions of the Aso pyroclastic-flow and the Aso-4 co-ignimbrite ash-fall deposits in Japan. Earth, Planets, Space, 53: 1137-1150.

Green J, Short N M, 1971. Volcanic Landforms and Surface Features: a Photographic Atlas and Glossary. New York: Springer-Verlag, 519 p.

Ikebe S, Fujioka M, 2001. "Yunotani Catastrophe" of 1816, in Aso volcano, southwest Japan--historical records of steam explosion. Bull Volc Soc Japan (Kazan), 46: 147-163 (in Japanese with English abs).

Ikebe S, Watanabe K, Miyabuchi Y, 2008. The sequence and style of the 1988-1995 eruptions of Nakadake Aso volcano, Kyushu, Japan. Bull Volc Soc Japan (Kazan), 53: 15-33 (in Japanese with English abs).

Iki T, 1926. Geological notes on the Aso volcano. Pan-Pacific Sci Cong Guidebook Excur, E-4: 1-14.

Japan Meteorological Agency, 1996. National Catalogue of the Active Volcanoes in Japan (second edition). Tokyo: Japan Meteorological Agency, 502 p (in Japanese).

Japan Meteorological Agency, 2013. National Catalogue of the Active Volcanoes in Japan (fourth edition, English version). Japan Meteorological Agency.

Kaneko K, Kamata H, Koyaguchi T, Yoshikawa M, Furukawa K, 2007. Repeated large-scale eruptions from a single compositionally stratified magma chamber: an example from Aso volcano, Southwest Japan. J Volc Geotherm Res, 167: 160-180.

Kawakatsu H, Kaneshima S, Matsubayashi H, Ohminato T, Sudo Y, Tsutsui T, Uhira K, Yamasato H, Ito H, Legrand D, 2000. Aso94: Aso seismic observation with broadband instruments. J Volc Geotherm Res, 101: 129-154.

Kuno H, 1962. Japan, Taiwan and Marianas. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 11: 1-332.

Masuda N, Watanabe K, Miyabuchi Y, 2004. Rhyolite to dacite lava flows newly-discovered on the western slope of Aso Central Cones, southwestern Japan. Bull Volc Soc Japan (Kazan), 49: 119-128 (in Japanese with English abs).

Miyabuchi Y, 2010. Eruption age of Komezuka at Aso volcano, Japan. Bull Volc Soc Japan (Kazan), 55: 219-225 (in Japanese with English abs).

Miyabuchi Y, 2009. A 90,000-year tephrostratigraphic framework of Aso volcano, Japan. Sed Geol, 220: 169-189.

Miyabuchi Y, Hoshizumi H, Takada H, Watanabe K, Xu S, 2003. Pumice-fall deposits from Aso volcano during the past 90,000 years, southwestern Japan. Bull Volc Soc Japan (Kazan), 48: 195-214 (in Japanese with English abs).

Miyabuchi Y, Hoshizumi H, Watanabe K, 2004. Late-Pleistocene tephrostratigraphy of Aso volcano, southwestrn Japan, after deposition of AT Ash. Bull Volc Soc Japan (Kazan), 49: 51-64 (in Japanese with English abs).

Miyabuchi Y, Ikebe S, 2008. The February 2008 ash deposit from the Nakadake crater, Aso volcano, Japan. Bull Volc Soc Japan (Kazan), 53: 201-206 (in Japanese with English abs).

Miyabuchi Y, Ikebe S, Watanabe K, 2008. Geological constraints on the 2003-2005 ash emissions from the Nakadake crater lake, Aso volcano, Japan. J Volc Geotherm Res, 178: 169-183.

Miyabuchi Y, Masuda N, Watanabe K, 2004. Geologic history of the western part of post-caldera central cones of Aso volcano, southwestern Japan, based on stratigraphic relationships between lava flows and airfall tephra layers. Bull Volc Soc Japan (Kazan), 49: 267-282 (in Japanese with English abs).

Miyabuchi Y, Watanabe K, 1997. Eruption ages of Holocene tephras from Aso volcano, southwestern Japan, inferred from 14C ages of buried andisols. Bull Volc Soc Japan (Kazan), 42: 403-408 (in Japanese with English abs).

Miyabuchi Y, Watanabe K, 2000. Phreatic explosions and ejecta around Jigoku Spa, southwestern part of the central cones of Aso volcano, Japan. Bull Volc Soc Japan (Kazan), 45: 25-32 (in Japanese with English abs).

Miyabuchi Y, Watanabe K, Egawa Y, 2006. A pyroclastic flow deposit occurring at the northeastern foot of Nakadake, Aso volcano (Japan) and its stratigraphic significance. Bull Volc Soc Japan (Kazan), 51: 231-243 (in Japanese with English abs).

Nakano S, Yamamoto T, Iwaya T, Itoh J, Takada A, 2001-. Quaternary Volcanoes of Japan. Geol Surv Japan, AIST, http://www.aist.go.jp/RIODB/strata/VOL_JP/.

Ono K, Kubotera A, Ota K, 1981. Aso volcano. In: Kubotera A (ed) {Symp Arc Volc Field Excur Guide to Sakurajima, Kirishima and Aso Volcanoes, Part 3}, Tokyo: Volc Soc Japan, p 33-52.

Ono K, Watanabe K, 1985. Geologic map of Aso volcano. Geol Surv Japan, 1:50,000 geol map and text (in Japanese with English summary).

Ono K, Watanabe K, Hoshizumi H, Ikebe S, 1995. Ash eruption of the Naka-dake crater, Aso volcano, southwestern Japan. J Volc Geotherm Res, 66: 137-148.

Tanaka Y, 1993. Eruption mechanism as inferred from geomagnetic changes with special attention to the 1989-1990 activity of Aso volcano. J Volc Geotherm Res, 56: 319-338.

Yamasaki T, Hayashi M, 1976. Geologic background of Otake and other geothermal areas in north-central Kyushu, southwestern Japan. In: {Proc 2nd United Nations Symp Devel Use Geotherm Resour, San Francisco}, Washington D C: U S Government Printing Office, 1: 673-684.

The 24-km-wide Asosan caldera was formed during four major explosive eruptions from 300,000 to 90,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. The last of these, the Aso-4 eruption, produced more than 600 cu km of airfall tephra and pyroclastic-flow deposits. A group of 17 central cones was constructed in the middle of the caldera, one of which, Nakadake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 AD. The Nakadake complex has remained active throughout the Holocene. Several other cones have been active during the Holocene, including the Kometsuka scoria cone as recently as about 210 CE. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic strombolian and phreatomagmatic activity. The summit crater of Nakadake is accessible by toll road and cable car, and is one of Kyushu's most popular tourist destinations.