(Upload on September 20 2020) [ 日本語 | English ]

Volcanoes (火山)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily


On mountain names, '-dake', '-take', '-san' and '-yama' mean 'mountain'. For example, Komagatake means Mount Koma.
volcanoes in Hokkaido
Volcanoes of Japan


Volcano World (Oregon State Univ.)
Volcano Live (John Seach)

Hokkaido (北海道)

Mount Rishiri (利尻山)

Quaternary stratovolcano (45°10'43"N, 141°14'31"E, 1721 m a.s.l.)

the nickname is Rishiri-Fuji

Late Pleistocene (130,000-18,000BP): alkali and non-alkali mafic volcanic rock
Tephra chronology and palynology:


Rs-Ac2: the apogee of coldness
Rs-Ac1: the beginning of coldness


Viewing from Wakasakanai Coast on May 25 2015.

The volcano Mount Eniwa (恵庭岳)

Eniwa-dake (エニワダケ, 恵庭岳)

Eniwa: etymology = e-en-iwa [a sharp-pointed rock (or peak)]
dake: = "mountain"

Mount Eniwa (1319.7 m elevation) is located near Lake Shikotsu in Hokkaido Island, Japan, and was assigned as Shikotsu-Toya National Park. The last magmatic eruption was recorded 2,000 years before now. From early 17th to 19th, a few phreatic explosions occurred.
V1 V2
[1] We can see fumarolic gas in the center of the photos. This mountain is an active volcano. [2] The dominant shrub is Salix reinii. (taken on May 29 1998)

Mount Esan (恵山)

Esan1 Esan2 Mount Esan (618.1 m elevation) is a small stratovolcano faced to Tsugaru Straits in Hokkaido Island, and was assigned as Esan Prefectural Natural Park in 1961 when I was born. A minor phreatic eruption in 1846 induced a mudflow. The last (small) eruption took place in 1874. Sulfur buring occurred in 1876 and 1962. Nowadays, fumaroles emerge from the upper-northwestern flank.
[1/2] famous to see ericaceous plants. Also, you should visit Sai-no-kawara (the Children's Limbo). (in early October, 1983. It was cold.) The grassland was dominated by Miscanthus sinensis.

Mount Tokachi (十勝岳)

stratovolcano with lava domes (2077 m elevation, tallest volcano of the Tokachi Volcanic Group)
1670: lavaflow
1926: eruptions → debris avalanche and lahar
1962: eruptions

Mount Tarumae (樽前山)

An active andesitic stratovolcano forming a lava dome (1041 m elevation)
1667: Ta-c1, Ta-c2
1739: plinian eruption of VEI 5
1909 (April 17-19): forming the present lava dome
1982: phreatic eruption,
and more

Mount Yotei (羊蹄山)

1898 m elevation (also called shiribeshi-yama or ezo-fuji → assigned as 100 nice mountains in Japan
southern Shiribeshi District (northwestern Iburi Province)
confical stratovolcano

2003 designated to active volcano (Meteorological Agency of Japan)

Yotei Yotei

Mount Meakan (雌阿寒岳)

Mount Meakan Active stratovolcano grouped into Akan Volcanic Complex in Kurile arc
This mountain is an active volcano.
Please watch out for flaling rocks, smoke and poisonous gas.
Mount Mashu Meakan

[succession, 遷移]

Mount Oshima-Koma (渡島駒ヶ岳)

What is KOMA?
Location = 42°03'48''N, 140°40'38''E. Elevation = ca 1140 m (1131 m)

O-numa Quasi-National Park

History of major eruptions

Year (Era): M (magnitude if known), Eruption type(s)


1640 (Kanei 17): M5.4, collapse, blast, plinian (Ko-d)

Kurumi-slope debris avalanche →
ca 700 persons killed by tsunami

1694 (Genroku 7): M2?, pumice fall, pyroclastic flow (Ko-c2)
1765? (Meiwa 2): small eructation (no detailed information)
1784 (Tenmei 4): M4.2, small eructation
Sept 25 1856 (Ansei 3): formed small lava dome and Ansei Crater →

pumice fall (eastern Hokkaido)
pyroclastic flow (Ko-c1)
created Ansei Crater and lava dome
2 killed by pumice fall, > 20 killed by pyroclastic flow

1888 (Meiji 21): small eructation
1905 (Meiji 38): small eructation (Ko-b) → formed Meiji Crater
1919 (Taisho 8): small eructation, ceased in 1924 (Taisho 13)
June 17 1929 (Showa 4): M4.5, pyroclastic flow, mudflow (Ko-a)

Showa-4 Crater
2 killed

1942 (Showa 17): phreatomagmatic eruption → ash fall, fissure

→ formed Showa-17 Crater and Showa Huge-rift (1.6 km long)

1996-2000 (Mori Climatological Observatory)

Eruption type = phreatic explosion, and damaged area = the summit

Date               Ejecta (ton)
Mar 5 1996    12,000
Oct 25 1998   > 1,000
Spt 4 2000     several 10,000
Spt 28 2000   < 1,000
Oct 28 2000   4,700-12,000
Nov 8 2000    < 1,000

[1] Showa huge-rift formed by the 1942 eruption (on November 21 2005).

→ The characteristics of revegetation patterns

What is USU? [ Usu | Flora | Showa-Shinzan | Yosomi ] [succession, 遷移]

Mount Usu (有珠山)


  1. Utah State University (ユタ州立大学), and many other universites
  2. Humic Soil Units (USu)
  3. Wheat caltivars USU-Apogee
  4. Of course, Mount Usu (有珠) located in Hokkaido Island, Japan!
    Research on Usu1 Research on Usu2 Research on Usu3
    [1] although volcanic eruption is one of the largest disturbances, the patterns of succession has not been generalized due to the varieties of eruption types and the responses of plant communities. Recently, Mount Usu erupted in 1977-1978 and in 2000. We are trying to clarify concretely the changes in plant communities by using permanent-plot survey. [2] on July 18, 2006. That means 29 years after the 1977-78 eruptions. [3] Mounts Usu and Showa-Shinzan, viewing from the eastern side of Mount Usu on July 25 2013
    References on the revegetation of Mount Usu
  5. mortar (usu) [in Japanese]
History of major eruptions after 1663
Year 1663 17C 1769 1822 1853 1910 1944-45 1977-78 2000
Spot Summit Summit Summit Summit North foot East foot Peak West foot
Construction Ko-Usu Ogari O-Usu Yosomi Showa-shinzan Usu-shinzan
Tephra (km³)2.5trace0.110.280.350.0030.0010.09< 0.001

2000 Craters

There are two groups of craters: Kompira and Nishiyama.

11/10/01: From the former kindergarden to the 2nd lookout _________________________

Instructions for Nishiyama Crater Walking Trail

  • This is NOT a circular trail.
  • Please do not cross over the rope fence and walk ONLY on the trail.
  • Please avoid walking on the trail in slip-ons or high heels
  • As the trail may become slippery after a rainfall, please be careful.
  • Toyako Twon does not bear responsibility for any accident that may occur.
  • This is Shikotsu Toya National Park. Please refrain from removing any items (stones, plants, etc.) from the park. Your co-operation is highly appreciated.

Toyako Twon Office

1977-78 eruptions

Table. The 1977-1978 eruption of Usu.
Prediction (Yokoyama et al. 1973)1977-1978 eruption
Eruption pointSummit or north flankSummit
Types of eruptions 30-50 years since 1945
Occurrence of forerunning shocks
Eruption may begin 3-10 days after the starting of earthquake
Eruption began 32 years after 1945
Forerunning earthquakes occurred
Eruption began 30 hours after the starting of earthquakes
Nature of magmaDaciteDacite
Eruption and associated phenomena Explosive eruptions
Ash fall deposits (thickness): several-several tens cm at the foot (3-5 m in case of major eruption)
Flying distance of volcanic blocks: 1.5-2.5 km in maximum
Occurrence of nuee ardente
Uplift of ground - Formation of cryptodome
Appearance of lava dome
Pumice eruption followed by phreatic-phreato-magmatic eruptions
Ash fall deposits: 30-50 cm at the foot
Flying distance of volcanic blocks: 2 km in maximum
No nuee occurred
Uplift of the summit caldera bottom - A cryptodome (Usu-Shinzan) was formed
Lava dome did not appear
Disasters caused by: 1) earthquake shocks, 2) crustal movements, 3) pyroclastic fall, 4) nuee ardente, and 5) mudflow 2) crustal movements, 3) pyroclastic fall, and 5) mudflow

Showa-Shinzan (昭和新山)

This mountain (398 m a.s.l.) is a volcanic lava dome close to Mount Usu, created during 1944 and 1945.
Showa-Shinzan1 Showa-Shinzan2 Showa-Shinzan3
[1] Mount Showa-Shinzan created by 1945 eruptions. Mimatsu diagram recorded the process of the development of this mountain. Mt. Showa-Shinzan is gropued into the volcanic clusuter of Usu volcanoes. The forest was dominated by Betula platyphylla var. japonica and Populus maximowiczii. on December 18 2004 by Uraguhi A. [2] viewing from Sobetsu Town on July 3 2009. [3] veiwing from the caldera rim of Mount Usu on July 17 2013.
Toya Caldera and Usu Volcano UNESCO Global Geopark


After about 6 months-long intensive earthquakes and uplift deformation, an eruption occurred on June 23, 1944 in the wheat field in the eastern flank of Mt. Usu. Early eruptions were steam explosions, but the following larger ones produced pyroclastic surges. Two years-long uplift resulted to the birth of lava dome called Showa-Shinzan, now designated as a special natural monument of Japan, attracting many visitors.

Shinzan-numa on August 13 2019

Settlement Fukaba was destroyed. Roads, railroad, and Sobetsu River were also thrusted up to the east, so people had to relocate them or to reduce the flooded water. This once a flooded site, “Shinzan-numa” pond tells you the amazement history between the nature and us.
Dammed lake is a common phenomenon among the world volcanoes. The mechanism is mostly a blocked river by entering lava flows or debris. However, this Shinzan-numa pond is a quite unique and rare one. Sobetsu River was dammed up by the successive ground upheaval (called crypto-dome or hidden dome) as a part of Showa-Shinzan lava dome formation. The 2000 eruptions of Mount Usu created “Nishi-Shinzan-numa” again by same mechanism.
Despite of the world war, challenging researchers were performed on Showa-Shinzan activity. A local postmaster Mr. Masao Mimatsu found a pattern of radial fissure, and Prof. Takeshi Minakami estimated hypocenters of shallow earthquakes clustered at that deformation center and increasing in number several days prior to the eruption. So, basic eruption forecasting “where” and “when” was a promising one.
If you have more interest, we recommend you to visit “Mimatsu Memorial Hall” in the Showa-Shinzan square, where abundant observational data are displaced.

Mount Yosomi (四十三山)

About 45 volcanic craters were created by the eruptions in Meiji 43 (1910).

Japan (except Hokkaido)

Asama (浅間)

2568 m elevation
1783.8.15: mudflow → killed ≈ 1,400 people

Nasu (那須)

1915 m elevation
1408-1410: formed Mount Chausu

Hakone (箱根)

Location 80 km SW of Tokyo (in Kanagawa Prefecture)
Volcano type: massive stratovolcano truncated by 2 overlapping calderas
[ geopark ]

[succession, 遷移]

Miyake Island (三宅島)

Recent eruptions
1983: fissure eruption, and lavaflow
2000: a caldera was created, and the eruptions were characterized by the production of enourmous volcanic gas (SO2)

Mount Fuji (富士山)

Elevation: 3776 m - active stratovolcano
Coordinates: 35°21'29"N, 138°43'52"

Mount Fuji
viewing from Mount Yatsu,
on March 5 2013

1707 Hoei eruption occurred on southeastern slope → completely destroyed the former vegetation

Izu-oshima (伊豆大島)

1684-90: Kyoho mega-eruption
1695-: Anei mega-eruption → Anei lava
1912-14: eruption
1950-51: producing Showa lava
1986: eruption

Nishinoshima (西之島)

2013.11.20: emerged
2013.11.26: 200 m long × 170-180 m wide
2013.12.24-25: 15 ha → connected with the former Nishinoshima Island (therefore called Nishinoshima Island because of the nomenclature)
Nishinoshima The 7th crater (pink): 27°14.6'N, 140°52.7'E
The former Nishinoshima (green)
Nishinoshima (gray)
less than 1.5 km long from the crater (red circle)
(2016.02.17. Japan Coast Guard)

Aso (阿蘇)

Caldera: 25 km north-south and 18 km east-west (rough estimation)
Central cone group of ASo volcano

Mount Neko
Mount Taka: peak: 1,592 m a.s.l.
Mount Naka(-dake)
Mount Eboshi
Mount Kishima

Sakurajima (桜島)

An active composite volcano (stratovolcano)
Formerly it was an island in Kyushu
The lava flows in 1914 connected the island with the Osumi Peninsula
Sakurajima Sakurajima
in early April 1985.


Kamchatka Volcanoes (カムチャッカ火山群)

large volcano active in Holocene
large volcano in Holocene caldera
  Holocene monogenetic volcano (cinder cone, maar, crater or lava dome)
▇▇▇ late Pliocene-Holocene volcanic fields
Holocene Volcanoes in Kamchatka
Mount Kliuchevskoi
The volcano Mount Kliuchevskoi (ca 4800 m) and Kamchatka River (a letter photo from Grishin S).
Volcano Bezymianny (ベズイミアニ)
stratovolcano (≈ 2882 m a.s.l.)
1955 eruption → 1956 sector collapse
2022/05/28 ≈17:00: eruption

Changbai Mountain (長白山), northeastern China

= Paektu Mountain (白頭山)
stratovolcano, 2744 m elevation (41°41'-42°51'N, 127°43'-128°16'E)
946AD (prob.): VEI = 7
Changbaishan Tianchi (長白山天池)
caldera lake, frozen from mid-October to mid-June

the source of the Songhua, Tumen and Yalu River

12-14 km in perimeter, 213 m in averaged depth
Tianchi Tianchi
on June 12 2017
Tianchi Mudflows frequently occur in this area. We saw many plates that show the attention.
Keep away! Debris flow region!

The Dell forest

"Dell Forest" is alos called the underground forest. The ground subsided and formed the valley during the volcanicity and orogenetic movements. The depth of valley is 60 meters and the width is about 3000 meters. Such spectacle of the nature! Thick forest, stones and fresh air in the valley bottom. Standing on the edge of the dell forest, you can see the whole scene. Rare plants and animals lives here. It is a really valuable land.
Fallen Trees - Forest Seedbeds
The betula ermanii, spruce-fir forest in the Changbai Mountain is one of the rare forest vegetations of the subalipine in north China. The understory has a large number of fallen trees. Due to the competitions from herbaceous plants on seedlings and the threats from rainy season moistures on seeds and seedlings, the fallen trees serve as main seedbdes in the forest. Although fallen trees cover an area of only 7.21% of the forest, the number of seedlings growing of the total number of seedlings in the forest. At the same time, the fallen trees constitute the main habitat of microorganisms. Artificial removal of fallen trees will deprive the decomposers (microorganisms) of decomposition objects the food chain, making it impossible for such nutirents as C, N, P and others to return to nature, and breaking the original sustainable material cycle and energy transffer processes, so the fallen trees in virgin forests cannot be cleared away!

(nothing has changed on the board. on June 12 2017.)

[succession, 遷移]

Mount St. Helens (セントへレンズ山), USA

Mount St. Helens made catastrophic eruption on May 18, 1980. By the creation of horseshoe crater, the elevation changed from 2950 m to 2550 m. Before the eruption of Mount Pinatubo, Philippines, this eruption was the largest in 20th century. A massive debris avalanche derived from the eruption.

Rainier Beer

Mount Rainier, USA

A volcano Active during 1820 and 1854
Highest mountain (4,392 m a.s.l.) in the Cascades that are a part of the Pacific Ring of Fire
Mount Rainier National Park established on March 2 1899


Federation Forest Stage Park

Lowland old-growth vegetation on the Natches Trail (Tsuga heterophylla zone)
Trees-Shrubs: Tsuga heterophylla-Acer circinatum. Pseudotsuga menziesii-Oplopanax horridum. Pinus contorta-Rosa nootkatensis. Picea sitchensis-Vaccinium parvifolium. Thuja plicata-Gaulteria shallon. Abies grandis-Berberis nervosa. Alnus rubra-Holodiscus discolor. Acer macrophyllum-Salix sp. Taxus brevifolia. Lonicera ciliata
Herbs: Achlys triphylla. Adenocaulon bicolor. Athyrium flix-femina. Blechnum spicant. Clintonia uniflora. Coralorhiza sp. Cornus unalaschkensis. Goodyera oblongifolia. Hieracium albiflorum, Lactuca muralis. Linnaea borealis. Lysichitum americanum. Polystichum munitum. Prunella vulgaris, Pteridium aquilinum. Rubus ursinus. Smilacina stellata. Streptopus roseus, Tiarella trifoliata, Trientalis latifolia. Trillium ovatum, Viola spp.

Silver Fir Campground (elevation ca 650 m)

Old growth Tsuga heterophylla zone forest at upper near limit. Soils are derived from various volcanic activities.
Trees-Shrubs-Herbs: Tsuga heterophylla-Acer circinatum-Achlys triphylla, Pseudotsuga menziesii-A. glabrum-Asarum caudatum, Thuja plicata-Aruncus sylvestre-Athyrium flix-femina, Abies grandis-Berberis nervosa-Blechnum spicant, Pinus contorta-Gaulteria shallon-Clintonia uniflora, Alnus rubra-Chimaphila umbellata-Cornus unalaschkensis, Populus trichocarpa-Linnaea borealis-Fragaria virginiana, Oplopanax horridum-Galium triflorum, Rosa gymnocarpa-Gymnocarpium dryopteris, Rubus parviflorus-Hieracium albiflorum, Salix sp.-Maianthemum dilatatum, Sambucus racemosa-Petisites frigida, Taxus brevifolia-Polygonum munitum, Vaccinium parvifolium-Prunella vulgaris, Pteridium aquilinum. Rubus ursinus. Smilacina stellata. Tiarella trifoliata. Trientalis latifolia. Viola glabella. Streptopus sp.

White River Road (1200 m)

Vegetation in this area falls into the Abies amabilis zone.
Trees-Shrubs-Herbs: Abies amabilis-Alnus sinuata-Anaphalis margaritacea. Abies lasiocarpa-Gaulteria shallon-Asarum caudatum.
Abies procera-Mensiesia ferruginea-Chimaphylla umbellatum. Rubus parvifolia. Chamaecyparis nootkatensis-Gaultheria humifusa. Pinus monticola-Rubus spectabilis-Linnaea borealis. Populus trichocarpa-Salix hookeri-Pyrola secunda. Pseudotsuga menziesii-Sorbus sitchensis-Viola spp. Thuja plicata-Vaccinium membranaceum. Tsuga heterophylla-Vaccinium alaskense. Tsuga mertensiana. Sambucus racemosa. Taxus brevifolia. Vaccinium parvifolium

Sourdough Ridge (1800 m)

Vegetation here begins to resemble that of the Abies lasiocarpa zone.It is too dry for a Tsuga mertensiana zone, though this species occur in favorable sites.
Trees-Shrubs-Herbs: Abies lasiocarpa-Alnus sinuata-Anapaahlis margaritacea. Tsuga mertensiana-Juniperus communis-Arnica diversifolia. Abies amabilis-Sorbus sitchensis-Aster foliosus. Chamaecyparis nootkatensis-Spirea densiflora-Castilleja miniata. Pinus albicaulis-Cassiope mertensiana-Luetkea pectinata. Picea engelmannii-Vaccinium membranaceum-Luina stricta. Lupinus latifolius. Luzula sp. Polemonium pulchellemum. Sitanion hystrix. Veratrum viride. Vaccinium deliciosum

Sunrise (1900 m)

This is a dry subalpine meadow complex, with isolated tree groups. The substrate is a recent pumice. Disturbance easily destroys the vegetation and recovery is very slow. We will view a 40 years old disturbance to determine the degree of recovery.
Trees-Herbs: Pinus albicaulis-Lupinus latifolius. Abies lasiocarpa-Potentilla flabellifolia. Picea engelmannii-Anemone occidentale. Chamaecyparis nootkatensis-Antennaria lanata. Aster alpigenus
Shrubs: Aster foliosus. Cassiope mertensiana-Carex mertensiana. Phyllodoce empetriformis - Castilleja parviflora. Juniperus communis-Hieracium gracile. Sorbus sitchesis-Juncus parryi. Vaccinium myrtillus-Agoseris sp. Ligusticum grayii
Herbs: Phlox diffusa. Festuca viridula-Polygonum bistortoides. Sitanion hyxtrix-Polygonum newberryi. Pedicularis contorta. Veronica cusickii

Rangitoto Island, NZ

A volcanic island in the Hauraki Gulf near Auckland, New Zealand
It is an iconic landmark of Auckland as its distinctive symmetrical 260 meter high shield volcano cone is visible from much of the city. It is the most recent and the largest (2311 hectares) of the approximately 48 volcanoes of the Auckland Volcanic Field.
This island is also covered with weeds and/or exotic plants. (Clarkson 1990)

[1/2] lava flow. Lichens pathces sparsely establish on the lava. [3/4] forests develop on the island. (on January 31 1997)