HOME



picture info

Mount Oakan
is a stratovolcano located in Akan National Park in Hokkaidō, Japan. Geography and geology Mount Oakan sits in the Akan caldera northeast of Lake Akan. The volcano rises some above the surrounding terrain. The top of the volcano is above sea level. The volcanic cone is some in diameter. There are three explosion craters at the summit. At at about , there is a fumarole. The volcano is made mostly from non-alkali mafic volcanic rock. The main rock type is andesite and dacite. History Mount Oakan emerged in the Late Pleistocene dropping pumice on Minamishikata. After that, continuous lava flows formed the bulk of the volcano. In the final stages of its life, a parasitic volcano formed a lava dome In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions ... at the summit. According to ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  




List Of Mountains And Hills Of Japan By Height
The following is a list of the mountains and hills of Japan, ordered by height. Mountains over 1000 meters Mountains under 1000 metres As the generally accepted definition of a mountain (versus a hill) is 1000 m of height and 500 m of prominence, the following list is provided for convenience only. See also *List of Japanese prefectures by highest mountain References External links Mt. Nakanodake:Hiking route|Snow Country* * Japan 100 Mountains
{{DEFAULTSORT:List Of Mountains And Hills Of Japan By Height Mountains of Japan Lists of mountains of Japan, Height ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Akan National Park
is a national park located on the island of Hokkaidō, Japan. Along with Daisetsuzan National Park, these are the two oldest national parks in Hokkaidō. The park was established December 4, 1934. Akan is an area of volcanic craters and forests, covering . The park is famous for its crystal clear lakes, its hot springs, and its large marimo. It is the only place where marimo of appreciable size form naturally in Japan. Sites The park can be divided into two general areas, Kawayu and Akan. Kawayu Mount Iō and the Kawayu Onsen offer natural hotsprings and sulphur fumarole A fumarole (or fumerole) is a vent in the surface of the Earth or another rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...s. Around Lake Kussharo, a caldera lake, are Bihoro Pass, Mount Mokoto, and Mount Nishibetsu. At the lake, Wakoto Peninsula is an area with high ground temp ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Mount Meakan
is an active stratovolcano located in Akan National Park in Hokkaidō, Japan. It is the tallest mountain in the Akan Volcanic Complex. The volcano consists of nine overlapping cones that grew out of the Akan caldera, on the shores of Lake Akan. Mount Meakan has a triple crater at its summit. According to its name and local legend, Mount Meakan is the female counterpart to Mount Oakan on the other side of Lake Akan. Geography There are two ponds in the crater, 赤沼 (Sekinuma, ''Red Pond'') and 青沼 (Aonuma, ''Blue Pond''). Gallery File:Akan Caldera Relief Map, SRTM.jpg, Akan CalderaMe-Akan (bottom left)O-Akan (center right) File:Mount Meakan seen from the NE (2005).jpg, Seen from the NE File:Meakandake funka.jpg, March 2006 eruption See also *List of volcanoes in Japan This is a list of active and extinct volcanoes in Japan. An Orange background indicates a volcano considered active by the Japan Meteorological Agency. Hokkaido Honshū Izu Islands Oga ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Lava Dome
In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on Earth form lava domes. The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day). The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite. Existence of lava domes has been suggested for some domed structures on the ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Dacite
Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz. Dacite is relatively common, occurring in many tectonic settings. It is associated with andesite and rhyolite as part of the subalkaline tholeiitic and calc-alkaline magma series. Etymology The word ''dacite'' comes from Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains (now modern Romania and Moldova) where the rock was first described. The term ''dacite'' was used for the first time in the scientific literature in the book ''Geologie Siebenbürgens'' (''The Geology of Transylvania'') by Austrian geologists Franz Ritter von Hauer and Guido Stache. Dacite was originally defined as a new rock type to separate calc-alkaline ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Andesite
Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predominantly of sodium-rich plagioclase plus pyroxene or hornblende. Andesite is the extrusive equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs. The average composition of the continental crust is andesitic. Along with basalts, andesites are a component of the Geology of Mars, Martian crust. The name ''andesite'' is derived from the Andes mountain range, where this rock type is found in abundance. It was first applied by Christian Leopold von Buch in 1826. Description Andesite is an aphanitic (fine-grained) to porphyritic (coarse-grained) igneous rock that is intermediate in its content of silica and low in alkali metals. It has less than 20% quartz and 10% feldspa ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Mafic
A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, diabase and gabbro. Mafic rocks often also contain calcium-rich varieties of plagioclase feldspar. Mafic materials can also be described as ferromagnesian. History The term ''mafic'' is a portmanteau of "magnesium" and "ferric" and was coined by Charles Whitman Cross, Joseph P. Iddings, Louis V. Pirsson, and Henry Stephens Washington in 1912. Cross' group had previously divided the major rock-forming minerals found in igneous rocks into ''salic'' minerals, such as quartz, feldspars, or feldspathoids, and ''femic'' minerals, such as olivine and pyroxene. However, micas and aluminium-rich amphiboles were excluded, while some calcium minerals containing little iron or magnesium, such as wollastonite or apatite, were included in t ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Fumarole
A fumarole (or fumerole) is a vent in the surface of the Earth or another rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcanic activity, but fumarole activity can also precede a volcanic eruption and has been used for eruption prediction. Most fumaroles die down within a few days or weeks of the end of an eruption, but a few are persistent, lasting for decades or longer. An area containing fumaroles is known as a fumarole field. The predominant vapor emitted by fumaroles is steam, formed by the circulation of groundwater through heated rock. This is typically accompanied by volcanic gases given off by magma cooling deep below the surface. These volcanic gases include sulfur compounds, such as various sulfur oxides and hydrogen sulfide, and sometimes hydrogen chloride, hydrogen fluoride, and other gases. A fumarole that emits significant sulfur compounds is some ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  




Lake Akan
is a lake in Kushiro, Hokkaidō, Japan. It is located in Akan National Park and is a Ramsar Site. History Volcanic activity formed the lake some 6,000 years ago, when a lava dam was formed. The lake used to have a clarity of 8–9 meters in the 1930s. Pollution from local hotspring resorts has decreased the transparency to 3–4 meters. Flora and fauna The lake is famous for its marimo (''Aegagropila linnaei''), aggregations of algae that form into spherical shapes 2–30 cm in diameter. Other flora of the lake include the following: * Phragmites communis *'' Nuphar'' sp. *Potamogeton crispus * Hydrilla verticillata * Myriophyllum verticillatum * Vallisneria gigantea * Melosira italica * Asterionella formosa * Synedra Kokanee salmon (''Oncorhynchus nerka'') are native to Lake Akan. Other fauna of the lake include the following: *Zooplankton: **'' Daphnia longiremis'' **'' Bosmina coregoni'' **'' Eurytemora affinis'' *Bottom: **''Chironomus plumosus'' **'' Tubificidae'' ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Stratovolcano
A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and explosive eruptions. Some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and solidifies before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high to intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less viscous mafic magma. Extensive felsic lava flows are uncommon, but can travel as far as 8 km (5 mi). The term ''composite volcano'' is used because strata are usually mixed and uneven instead of neat layers. They are among the most common types of volcanoes; more than 700 stratovolcanoes have erupted lava during the Holocene Epoch (the last 11,700 years), and many ol ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Hokkaidō
is the second-largest island of Japan and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by railway via the Seikan Tunnel. The largest city on Hokkaido is its capital, Sapporo, which is also its only ordinance-designated city. Sakhalin lies about to the north of Hokkaidō, and to the east and northeast are the Kuril Islands, which are administered by Russia, though the four most southerly are claimed by Japan. The position of the island on the northern end of the archipelago results in a colder climate, with the island seeing significant snowfall each winter. Despite the harsher climate, it serves as an agricultural breadbasket for many crops. Hokkaido was formerly known as '' Ezo'', ''Yezo'', ''Yeso'', or ''Yesso''. Nussbaum, Louis-Frédéric. (2005). "Hokkaidō" in Although Japanese settlers ruled the southern tip of the island since the 16th century, Hok ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]