(Upload on September 20 2020) [ 日本語 | English ]
Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily
HOME > Catalog > Glossary > Volcanology > Volcanoes
On mountain names, '-dake', '-take', '-san' and '-yama' mean 'mountain'. For example, Komagatake means Mount Koma.
| Hokkaido | Japan | World |
|---|---|---|
|
Mount
 |
|
Volcano World (Oregon State Univ.) Volcano Live (John Seach) |
|
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 rockTephra chronology and palynology:
Aso
Rs-Ac2: the apogee of coldness Toya |
 Viewing from Wakasakanai Coast on May 25 2015. |
|
Eniwa-dake (エニワダケ, 恵庭岳)
Eniwa: etymology = e-en-iwa [a sharp-pointed rock (or peak)] |
 1
 2
[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) |
 1 |
 2 |
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. |
|
stratovolcano with lava domes (2077 m elevation, tallest volcano of the Tokachi Volcanic Group) |
1670: lavaflow 1857 1887 1926: eruptions → debris avalanche and lahar 1962: eruptions |
|
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 |
Active stratovolcano grouped into Akan Volcanic Complex in Kurile arc
CAUTIONThis mountain is an active volcano.Please watch out for flaling rocks, smoke and poisonous gas. |
|
[succession, 遷移]
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 eruptionsYear (Era): M (magnitude if known), Eruption type(s)Damage 1640 (Kanei 17): M5.4, collapse, blast, plinian (Ko-d)
Kurumi-slope debris avalanche → 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) 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 → 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[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]
1
2
3
| 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) | 2.5 | trace | 0.11 | 0.28 | 0.35 | 0.003 | 0.001 | 0.09 | < 0.001 |
| Death | 5 | 103 | 1 | 1 | 3 | 0 |
There are two groups of craters: Konpira and Nishiyama.
11/10/01: From the former kindergarden to the 2nd lookout _________________________
Toyako Twon Office
| Prediction (Yokoyama et al. 1973) | 1977-1978 eruption | |
| Eruption point | Summit or north flank | Summit |
| 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 magma | Dacite | Dacite |
| 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. 1
 2
 3
[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 GeoparkShinzan-numaAfter 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. |
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. |
About 45 volcanic craters were created by the eruptions in Meiji 43 (1910).
|
2568 m elevation 1783.8.15: mudflow → killed ≈ 1,400 people |
|
1915 m elevation 1408-1410: formed Mount Chausu |
[succession, 遷移]
Recent eruptions1983: fissure eruption, and lavaflow2000: a caldera was created, and the eruptions were characterized by the production of enourmous volcanic gas (SO2) |
|
Elevation: 3776 m - active stratovolcano Coordinates: 35°21'29"N, 138°43'52" |
|
|
1684-90: Kyoho mega-eruption 1695-: Anei mega-eruption → Anei lava 1912-14: eruption 1950-51: producing Showa lava 1986: eruption |
|
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) |
The 7th crater (pink): 27°14.6'N, 140°52.7'EThe former Nishinoshima (green) Nishinoshima (gray) less than 1.5 km long from the crater (red circle) (2016.02.17. Japan Coast Guard) |
|
An active composite volcano (stratovolcano) Formerly it was an island in Kyushu The lava flows in 1914 connected the island with the Osumi Peninsula |
in early April 1985. |
The volcano Mount Kliuchevskoi (ca 4800 m) and Kamchatka River (a letter photo from Grishin S).
|
= 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-Junethe source of the Songhua, Tumen and Yalu River 12-14 km in perimeter, 213 m in averaged depth
on June 12 2017 
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 SeedbedsThe 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 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.
|
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 VegetationFederation Forest Stage ParkLowland 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 |
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
3
4
[1/2] lava flow. Lichens pathces sparsely establish on the lava. [3/4] forests develop on the island. (on January 31 1997)
