Zaozan

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 38.144°N
  • 140.44°E

  • 1841 m
    6038 ft

  • 283190
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Zaozan.

The Global Volcanism Program has no Weekly Reports available for Zaozan.

Index of Monthly Reports

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

09/1992 (BGVN 17:09) Earthquake and numerous aftershocks, but no surface changes evident


Contents of Monthly Reports

All information contained in these reports is preliminary and subject to change.

All times are local (= UTC + 9 hours)

09/1992 (BGVN 17:09) Earthquake and numerous aftershocks, but no surface changes evident

A seismic shock of M 4.7 occurred at 1758 on 1 September a few kilometers ESE of the summit. The shock was felt at JMA intensity IV near the volcano, and was weakly felt at Sendai (35 km E), Fukushima (45 km S), and Onahama (135 km E). Aftershocks were numerous, but declined toward mid-September. The high seismicity was the first at the volcano since July 1990, when there were many small earthquakes below the summit. Surveys of fumarolic areas on 5 September revealed no changes in temperature from the last survey in 1990.

Information Contact: JMA.

The Zaozan volcano group, the most active of northern Honshu, consists of a complex cluster of stratovolcanoes straddling the Pacific Ocean-Japan Sea divide. The Pleistocene Ryuzan volcano forms the western group (Nishi-Zao), and Byobu and Fubo volcanoes form the southern group (Minami-Zao). The complex was constructed over granitic basement rocks as high as 1500 m and thus has a relatively small volume. The 7 cu km Zaozan volcano proper forms the central group (Chuo-Zao), a volcanic complex topped by several lava domes and the Goshikidake tuff cone, aligned along a NW-SE trend. Several episodes of edifice collapse produced debris avalanches during the Pleistocene. Goshikidake contains the active Okama crater, filled with a colorful, strongly acidic crater lake (pH 1.3). It has been the source of most of the frequent historical eruptions, which date back to the 8th century CE.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1940 May 18 1940 May 18 Confirmed 1 Historical Observations Okama
[ 1939 Jul ] [ Unknown ] Uncertain 1   Okama
[ 1927 ] [ Unknown ] Uncertain 1   Okama
[ 1906 ] [ Unknown ] Discredited    
1905 Unknown Confirmed 1 Historical Observations Okama
[ 1897 Jan 14 ] [ 1897 Jan 14 ] Uncertain 1   Okama
[ 1896 Sep 1 (?) ] [ Unknown ] Uncertain 1   Okama
1896 Mar 8 1896 Mar 8 Confirmed 1 Historical Observations Okama
1895 Aug 22 1895 Sep 28 Confirmed 2 Historical Observations Okama
1895 Feb 15 1895 Mar 22 Confirmed 1 Historical Observations Okama
1894 Jul 3 1894 Jul 3 Confirmed 2 Historical Observations Okama
[ 1890 ] [ Unknown ] Uncertain 1   Okama
1873 Aug 1873 Sep Confirmed 1 Historical Observations Okama
1867 Oct 21 Unknown Confirmed 2 Historical Observations Okama
1833 Unknown Confirmed 2 Historical Observations Okama
1831 Nov 22 Unknown Confirmed 2 Historical Observations Okama
1830 Unknown Confirmed 2 Historical Observations Okama
1822 May 1 Unknown Confirmed   Historical Observations
1821 Jan 27 1821 May 1 Confirmed 2 Historical Observations Okama
1809 Jun 12 1809 Dec 29 Confirmed 2 Historical Observations Okama
1806 Jul 12 Unknown Confirmed 2 Historical Observations Okama
1804 May (?) Unknown Confirmed 2 Historical Observations Okama
1796 Mar 24 Unknown Confirmed 2 Historical Observations Okama
1794 Sep 22 1794 Dec (in or after) Confirmed 2 Historical Observations SE side of Okama
1694 May 29 1694 Aug 30 (?) Confirmed 2 Historical Observations Okama
1670 Apr 26 1670 Sep 26 Confirmed 2 Historical Observations Okama
1669 Unknown Confirmed 3 Historical Observations Okama
1668 Aug Unknown Confirmed 2 Historical Observations Okama
1641 Unknown Confirmed 2 Historical Observations Okama
1630 Unknown Confirmed 2 Historical Observations Okama
1623 May 15 (?) 1624 Nov 15 (?) Confirmed 3 Historical Observations Okama
1622 Unknown Confirmed 2 Historical Observations Okama
1620 Unknown Confirmed 2 Historical Observations Okama
1400 ± 100 years Unknown Confirmed 3 Radiocarbon (corrected) Goshiki-dake area, Z-To11 tephra
[ 1350 (?) ] [ Unknown ] Uncertain 2   Okama
[ 1331 ] [ 1333 ] Uncertain 2   Okama
1230 Nov 29 (?) Unknown Confirmed 2 Historical Observations Okama
1227 Oct (?) Unknown Confirmed 3 Historical Observations Okama
1183 May 28 (?) Unknown Confirmed 2 Historical Observations Okama
0884 (?) Unknown Confirmed 3 Historical Observations Okama, Z-To10 tephra?
[ 0773 Nov (?) ] [ Unknown ] Uncertain     Okama
0300 ± 200 years Unknown Confirmed 4 Radiocarbon (corrected) Goshiki-dake area, Z-To9 tephra
1600 BCE (?) Unknown Confirmed   Radiocarbon (corrected) Goshiki-dake
2000 BCE ± 500 years Unknown Confirmed   Tephrochronology Goshiki-dake
2300 BCE ± 75 years Unknown Confirmed   Radiocarbon (corrected) Goshiki-dake area, Z-To8 tephra
2600 BCE ± 200 years Unknown Confirmed   Radiocarbon (corrected) Goshiki-dake area, Z-To7 tephra
3350 BCE ± 50 years Unknown Confirmed   Radiocarbon (corrected) Goshiki-dake area, Z-To6 tephra
3850 BCE ± 200 years Unknown Confirmed   Radiocarbon (corrected) Goshiki-dake area, Z-To5 tephra
4150 BCE ± 200 years Unknown Confirmed   Radiocarbon (corrected) Goshiki-dake area, Z-To5b tephra
5500 BCE (?) Unknown Confirmed   Radiocarbon (corrected) Goshiki-dake area
5600 BCE (?) Unknown Confirmed   Radiocarbon (corrected) Goshiki-dake, Z-To5a tephra
7600 BCE (?) Unknown Confirmed   Radiocarbon (corrected) Goshiki-dake area

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.



Synonyms
Karita-dake | Kumano-dake | Gosei-dake | Kuraishi-dake | Tabashine-yama | Wasurezuno-yama | Zoo-dake | Taka-yama | Shiraishi-dake | Zao


Cones
Feature Name Feature Type Elevation Latitude Longitude
Byobu-dake Stratovolcano 1817 m
Chuo-Zao Stratovolcano 1841 m
Fubo-san Stratovolcano 1705 m
Gando-san Stratovolcano
Goshiki-dake
    Gosiki-dake
Tuff cone 1674 m
Maeeboshi-dake Stratovolcano 1402 m
Manokami-dake Stratovolcano 1585 m
Minami-Zao Stratovolcano 1817 m
Nakamaru-yama Stratovolcano 1557 m
Nishi-Zao Stratovolcano 1364 m
Nonomori-yama Stratovolcano 733 m
Nyodo-san Stratovolcano 1600 m
Nyudo-san Cone 1640 m
Omori-yama Cone 820 m
Onmae-dake Stratovolcano 1705 m
Ryuzan Stratovolcano 1364 m
Sanpokojin-san Stratovolcano 1683 m
Sarukura-yama Stratovolcano 873 m
Sugigamine Stratovolcano 1745 m
Ushiroeboshi-dake Stratovolcano 1666 m
Yokokura-yama Stratovolcano 1152 m


Craters
Feature Name Feature Type Elevation Latitude Longitude
Okama
    Goshiki-numa
    Zao-numa
Crater 1674 m


Domes
Feature Name Feature Type Elevation Latitude Longitude
Jizo-san Dome 1694 m
Katta-dake Dome 1795 m
Kumano-dake Dome 1841 m 38° 8' 26" N 140° 26' 34" E
Torikabuto-yama Dome 1401 m


Thermal
Feature Name Feature Type Elevation Latitude Longitude
Aone Spa Thermal 520 m
Gaga Spa Thermal 800 m
Kamoshika Thermal 1150 m
Togatta Hot Spring Hot Spring
Zao Spa Thermal 840 m
Okama crater of Goryu-dake, the most well-known feature of the Zao volcanic complex, is seen from the east. The 360-m-wide lake is about 60 m deep. The volcanic lake has been the site of many historical eruptions. White mud deposited on the lake floor is periodically disturbed by gas emission, changing the color of the lake water. The Zao volcano group, the most active of northern Honshu, consists of a complex cluster of stratovolcanoes straddling the Pacific Ocean-Japan Sea divide.

Copyrighted photo by Yoshihisa Kawanabe (Japanese Quaternary Volcanoes database, RIODB, http://riodb02.ibase.aist.go.jp/strata/VOL_JP/EN/index.htm and Geol Surv Japan, AIST, http://www.gsj.jp/).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. 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.

Hasenaka T, Ui T, Nakamura Y, Hayashi S, 1992. Traverse of Quaternary volcanoes in Japan. 29th Internatl Geol Cong, Kyoto, Field Trip A06, 74 p.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Ichimura T, 1951. Geological investigations on the Zao volcanoes. 1. Goshikidake, a central cone of the Zao proper. Bull Earthq Res Inst, Univ Tokyo, 39: 327-339.

Ishikawa H, Ohba T, Fujimaki H, 2007. Sr isotope diversity of hot spring and volcanic lake waters from Zao volcano, Japan. J Volc Geotherm Res, 166: 7-16.

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.

Kudo T, Hoshizumi H, 2006-. Catalog of eruptive events within the last 10,000 years in Japan, database of Japanese active volcanoes. Geol Surv Japan, AIST, http://riodb02.ibase.aist.go.jp/db099/eruption/index.html.

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

Miura K, Ban M, Yagi H, 2008. The tephra layers distributed around the eastern foot of the Zao volcano--ages and volumes of the Za-To 1 to 4 tephras. Bull Volc Soc Japan (Kazan), 53: 151-157.

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/.

Volcano Types

Complex

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Andesite / Basaltic Andesite
Basalt / Picro-Basalt
Dacite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
632
4,681
550,409
4,956,958

Affiliated Databases

Large Eruptions of Zaozan Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.