Volcanic terrain

Volcanic skeleton 

 When volcanic activity ceased, the erosion of the role of then forthcoming, weak sediments are corrosion, and the remaining is to do some hard igneous veins standing surface, the volcanic terrain skeleton known as the volcano (Volcanic skeletons). Volcanic formation, first of all persons shall be eroded volcanic cone (Volcanic cones), cone contains many large volcanic quality, easy-permeable of these substances, it could enhance its corrosion resistance, and the volcanic cone for radial water system, as a result of Hill Cone considerable slope, rivers easy to cut, can form small canyon. After a long-term erosion of the volcanic cone, only a small number of hard rock residues, these remnants of the terrain to volcanic neck and dyke-feng (Dike ridges) is most common for the lava rock wall in the vertical by condensation into a rock, if the intrusion of the large number of magmatic material , the Diagenetic also has strength and corrosion resistance dyke generally weak, they can form mountain dyke; But Hill is not very rock wall and has a number of vertical tilt, then in appearance back Cliff like pig (Hog backs) , the difference between the two, mainly from the nature of the rocks on the start for the volcanic rock formed by the wall, pigs back is by the side of cliffs and steep rock formation. Dyke can not form a peak, if the rock wall of stone weaker than the surrounding rock, it vulnerable to erosion by weathering depression. 

 Low-lying volcanic terrain 

 Volcanic eruptions and fall, can be found in the crater area of the formation of low-lying land, the Composite Williams (Howel Williams) and search Algabid (TA Jaggar)'s classification of the two laws, these low-lying land can be divided into three categories: 

 

 Crater (Craters) 

 Volcano eruptions (Explosion craters) 

 There are side crater (Crater within constructed rims) 

 Fall crater (Collapse craters) 

 Volcanic acetabular (Calderas) 

 Acetabular volcanic eruption (Explorsion calderas) 

 Subsidence volcano acetabular (Subsidence calderas) 

 Composite volcano acetabular (Composite calderas) 

 Volcanic tectonic depressions (Volcanic-tectonic depressions) 

 Acetabular crater and volcanic eruptions are the mouth, but both of different shapes, so the names are different, their differences are as follows: 

 a. crater size, often less than a mile in diameter, volcanic area of the acetabulum, and a few miles in diameter to tens of miles. 

 b. crater shape such as bowl, crater precipice down to the central relief; volcanic acetabular as surrounded steep precipice. As follows: 

 Crater 

 Usually in the mountain crater Central, will be known as the main crater (Main crater), formed in the side of a volcano crater called the Deputy (Pareasitic crater), a result of a volcanic eruption in the number of different locations each exhaled not identical, it is often a volcanic crater several months. Peltate in Hawaii volcano, there are many Xiaowa pool crater called Point (Volcanic sinks), this crater is mainly low-chu from the underground magma caused the collapse, it is the fall of the crater. If a volcano crater in another form, called the nest-shaped crater (Nested crater), this crater is the first generation to generation in a volcanic eruption in the mouth, so that the expansion of the original crater, and in the old fire Yamaguchi caused new crater and volcanic cone, and then on another part of continue to form a nest-shaped. Nest-shaped volcanoes and volcanic parasitic different, if the body in a volcanic cone that is the side of the slope have volcanic eruptions, the formation of a new volcanic body, then this new body is parasitic volcano volcano; for example, on Yangmingshan Mountain Shamao Tatun Mountain is a parasitic volcano, and the nest-shaped volcano in the re-eruption of the crater formed.

Volcanic acetabular 

 Acetabular past volcanic formation, is generally believed that due to the role of violent volcanic eruptions formed, but now that its main reason for the fall. William's view that some pot-shaped crater is separate from the role of the formation of the outbreak, although it said this little pot-shaped crater, the percent of area is also small. Regardless of the shape of a volcano, the first generation to start by the eruption of the role, but due to the bottom of a large number of cone after the eruption, leading to the bottom of emptiness, causing cone roof fall, forcing extended crater, which had been preceded by a number of volcanic acetabular by the eruption, after the fall into the dual role, Kirton also think that Williams and 10000 Milan (Vam Bemmelan) and others advocated by the fall of pot-shaped crater that should be called the outbreak of the fall, said (Explosion-collapse theory) a small number of volcanic acetabular? role may be purely made before or at the same time, there is no role with see eruption. Large volcanic depression, such as the Hawaiian Islands on crater and the crater are purely as a result of magma column lower down, causing the fall from the upper, resulting crater around often associated fault precipice gradually so that the expansion of the volcanic crater cave wall to form a large pot-shaped crater. fire in the pot-shaped mouth, there is a special form for the pot-shaped settlement (Cauldron subsidence). If a nearly circular block, subsidence in the lava cave in, so that by the extrusion of magma along the vertical cracks increased, resulting in ring-dyke, so in the pot-shaped crater area can be found to be corroded ring dyke with the same structure exists. 

 Volcano tectonic depression 

 Emitted by a volcanic eruption of pumice and lava material for the volume of a great accumulation of these substances in the surrounding volcanic and increase the pressure formation in the region, and the formation because of the large number of magma beneath the smoke, after this pressure was more prone to faults or folds fall, caused by depression. Indonesia's Sumatra island has a low-lying land, William style that is because a large number of pumice smoke caused by the formation of large-scale fall into, one of them? Stubble j flurried the pools of stagnant water to form the Palestinian territories Lake (Lake Toba). In the volcanic cone on the slopes, often many deep depressions, known as the Graben area (Sector Grabens), presumably because of the underground magma is empty, causing the top block down from faulting occurred, because faulting regard to the flank the movement of a larger formation of wide groove, then known as the volcanic groove (Volcanic rents). 

 

 The volcanic plateau and the plains 

 If the volcanic eruption in the region will have become flat lava plains (Lava plains), the majority of the lava plateau and plain, are all composed of mafic lava, only Yellowstone plateau and Ignatius plateau of lava and volcanic-rich acidic tuff. If the lava from a central volcano eruption outward flow, then it should by into cone and cereal-like lava flows, it is not easy sharing into a large, this lava outflows should be very calm along the spillover from many cracks before they can piled up into a plain or plateau. a region that volcanic eruptions can cause plain or plateau, depending on the volcanic cracks be persistent, if the rock cracks in the open ductus straight, then the person into a cone or volcanic fornix; if the closure of the old sewing sewing again opened a new, long-term outflow of lava pulp but not the accumulation of the same ground, then by becoming lava plateau or plateau; a wide range of lava plateau requires a large amount of cracks can only be formed, and the shield-shaped volcano (Shield volcano) the generation, you do not need so many crater.