Volcano is a mountain with magma inside it. Most volcanoes are formed on land, but there are some volcanoes that are on the ocean floor. Mount Merapi and Mount Krakatau are the famous mount with their extrussive explotion in Indonesia. Remember that the Mount Krakatau is the phenomenal mount in the world which explode in 1883. The ash of this explode mount flow into U.S.A. Mount Merapi was erupt in October 2010. The eruptions are really massive and destructive.
Volcano eruptions divided into two, instrussive and extrussive. Based on its name, intrussive is the volcanoes explotion which not through the mouth of the mountain. But this eruptions can makes the plutonics stones like batholit, lakolit, sills, and others. Batholit is the stone which made in the kitchen of the magma. Batholits are big. Lakolit is the stones which made in the pipe of the magma. Lakolits are small but they are sharpen than the batholits. Their freezing proccess are faster than Batholits because lakolits are near with the mouth of the mount. Sills are the stones which made in some place between the kitchen and the pipe or the troughway of the magma.
The extrussive explotion is the volcanoes explotion which throught the mouth of the mountain. As we know, this explotion is the most destructive and ruined one. This explotion is the endogen power which donate all of the rock and the stones in the world. The stones and the rocks circulation happened because of this explotion. The proccess are first, the magma throughout of the mouth of the mountain. Next, the lava get down into the hills and freezed, well known as the freezed stones. After that, the exogen energy changes the freezed stones into the sedimentary stones which formed from the particle of the freezed rocks or stones. Then sometime and someday, the rocks will located in the near of the kitchen of magma, and the rocks changed tectonicly in their particle and shape. And the last, the stones be the part of the magma again.
There are several steps for mount to doing eruption. At first, the eruption begins when pressure on a magma chamber inside the volcano forcesmagma up through the conduit and out the volcano's vents. Then, when the magma chamber has been completely filled, the pressure is getting higher. Finally, the magma reaches up to the surface. When magma reaches earth's surface it is called lava. It may pour out in gentle streams called lava flows or erupt violently into the air. Rocks ripped loose from the inside of the volcano or torn apart by the gas. may be shot into the air with the lava. The lava destroys everything in its path because it is very hot. The big rocks can destroy anything because the sizes are super big. The thick black smoke can burn everything slowly and it’s suffocating.
There’s no doubt that volcano eruption is really dangerous. Many people were dead because of it. A big number of people had to abandon their homes and land forever. Even the whole world's climate was changed for a while as a result of an eruption. But volcano eruptions bring good effects too, because after a long time it can make the land fertile, the object for therapy, many mineral objects were found after the eruption, hot water resources, etc.
Created by : Andika Satria Pradana on 22nd January 2014
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Additional explanation about Types of Volcanoes
1.Shield Volcanoes
Shield volcanoes are the largest volcanoes on Earth that actually look like volcanoes (i.e. not counting flood basalt flows). The Hawaiian shield volcanoes are the most famous examples. Shield volcanoes are almost exclusively basalt, a type of lava that is very fluid when erupted. For this reason these volcanoes are not steep (you can't pile up a fluid that easily runs downhill). Eruptions at shield volcanoes are only explosive if water somehow gets into the vent, otherwise they are characterized by low-explosivity fountaining that forms cinder cones and spatter cones at the vent, however, 90% of the volcano is lava rather than pyroclastic material. Shield volcanoes are the result of high magma supply rates; the lava is hot and little-changed since the time it was generated. Shield volcanoes are the common product of hotspot volcanism but they can also be found along subduction-related volcanic arcs or all by themselves. Examples of shield volcanoes are Kilauea and Mauna Loa (and their Hawaiian friends), Fernandina (and its Galápagos friends), Karthala, Erta Ale, Tolbachik, Masaya, and many others.
Here are 4 of the volcanoes that comprise the big island of Hawai'i. They are Mauna Kea (MK), Mauna Loa (ML), Hualalai (H), and Kohala (K). The photo was taken from near the summit of East Maui volcano (EM). These are the largest volcanoes on Earth.
This is a vertical air photo of the summit caldera of Mauna Loa volcano (North is to the left). Notice that the caldera is composed of numerous smaller "cookie-cutter" collapses which have coalesced to form the main caldera. Notice also that many of the lava flows (dark and light are 'a'a and pahoehoe, respectively) have been truncated by the caldera margin. This is an indication that they erupted from the volcano summit when the caldera was full. Collapse since then has produced the present caldera. In this manner of collapsing and filling, calderas come and go throughout the active lifetime of a basaltic volcano.
2. Stratovolcanoes
Strato Volcanoes comprise the largest percentage (~60%) of the Earth's individual volcanoes and most are characterized by eruptions of andesite and dacite - lavas that are cooler and more viscous than basalt. These more viscous lavas allow gas pressures to build up to high levels (they are effective "plugs" in the plumbing), therefore these volcanoes often suffer explosive eruptions.
Strato volcanoes are usually about half-half lava and pyroclastic material, and the layering of these products gives them their other common name of composite volcanoes.
Left: This is a schematic diagram of a strato volcano, intended to illustrate the different layers of different materials that comprise them. The purple colors are meant to represent ash layers, either the products of fall-out from big eruption clouds or the products of pyroclastic flows. Notice that these ash layers tend to be thin but widespread. The orange colors represent lava flows, and note that some of them have cinder cones associated with them at thevent. The green colors are meant to represent lava domes, and notice that they do not flow very far. Each eruption, regardless of what it produces, is fed from the magma chamber by a dike. Most dikes come up through the center of the volcano and therefore most eruptions occur from at or near the summit. However, some dikes head off sideways to feed eruptions on the flanks.
Right: This is a pit that has been dug into the ground at Cotopaxi, a big strato volcano near Quito, the capital city of Ecuador. The pit is about 2 meters deep and in it you can clearly see a number of ash layers exposed. It is also easy to see that the layers are different - some are coarse and others are fine, some are dark-colored and others are light-colored
The lava at strato volcanoes occasionally forms 'a'a, but more commonly it barely flows at all, preferring to pile up in the vent to form volcanic domes. Some strato volcanoes are just a collection of domes piled up on each other. Strato volcanoes are commonly found along subduction-related volcanic arcs, and the magma supply rates to strato volcanoes are lower. This is the cause of the cooler and differentiated magma compositions and the reason for the usually long repose periods between eruptions. Examples of strato volcanoes include Mt. St. Helens, Mt. Rainier, Pinatubo, Mt. Fuji, Merapi, Galeras, Cotopaxi, and super plenty others.
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Although they are not as explosive as large silicic caldera complexes, strato volcanoes have caused by far the most casualties of any type of volcano. This is for many reasons. First is that there are so many more strato volcanoes than any of the other types. This means that there will also be lots of people who end up living on the flanks of these volcanoes. Additionally, strato volcanoes are steep piles of ash, lava, and domes that are often rained heavily on, shaken by earthquakes, or oversteepened by intruding blobs of magma (or all of these). This makes the likelihood of landslides, avalanches, and mudflows all very high. Occasionally as well, entire flanks of strato volcanoes collapse, in a process that has been termed "sector collapse". Of course the most famous example of this is Mt. St. Helens, the north flank of which failed during the first stages of the big 1980 eruption. Mt. St. Helens was certainly not the only volcano to have suffered an eruption such as this, however. Two other recent examples are Bezymianny (Kamchatka) in 1956, and Unzen (Japan) in 1792. The 1792 Unzen sector collapse dumped a flank of the volcano into a shallow inland sea, generating devastating tsunami that killed almost 15,000 people along the nearby coastlines.
Left: This is a photo of lahar deposits near Santa Maria volcano (Guatemala). This used to be a wide, deep river valley, and you can see the far wall of the valley where the trees are growing. The lahar deposits extend from that far wall to behind where this photo was taken. You can see that between lahar events the river cuts into the lahar deposits, but every time there is another event, it fills up again. The people give an idea of the size of stones that can be carried by a lahar.
Another very common and deadly hazard at most strato volcanoes is called a Lahar. Lahar is an Indonesian word for a mudflow, and most geologists use the term to mean a mudflow on an active volcano. Sometimes the word is reserved only for mudflows that are directly associated with an ongoing eruption (which are therefore usually hot), but that starts to make things confusing. It is probably simplest to just call any mudflow on a volcano a lahar. Lahars are so dangerous because they move quickly, and often times a small eruption or relatively small rainstorm can generate a huge lahar. The most recent huge volcanic disaster occurred at a Colombian volcano called Nevado del Ruiz in 1985. This disaster has been well-documented by numerous post-eruption studies. Nevado del Ruiz is a very tall volcano, and even though it lies only slightly above the equator it has a permanent snow and ice field on its summit. On November 13, 1985 a relatively small eruption occurred at the summit. Even though only a little bit of ash fell and only small pyroclastic flows were produced, they were able to melt and destabilize a good deal of the summit ice cap. The ice cap had already been weakened and fractured by a few months of pre-cursor seismic activity. The melted snow and ice, along with chunks of ice, surged down gullies that started high on the slopes, picking up water, water-saturated sediments, rocks, and vegetation along the way. The eruption occurred just after 9:00 pm, and about 2 and a half hours later lahars managed to travel the approximately 50 km down river valleys to the town of Armero. The lahar entered Armero at 11:30 pm as a wall of muddy water nearly 40 meters high, and roared into the city, producing an eventual thickness of 2-5 meters of mud. Somewhere around 23,000 people were almost instantly killed. The path of destruction almost exactly matches similar disasters that occurred in 1595 and 1845. It also almost exactly covered the highest lahar-designated area on the volcanic hazard map that had been prepared prior to the 1985 eruption. Unfortunately that map had not yet been distributed by the time of the 1985 eruption.
Another place that is starting to get really tired of lahars is Pinatubo, in the Philippines. The 1991 Pinatubo eruption was the second largest this century (after Katmai in 1912), and deposited a huge volume of relatively loose pyroclastic material on already-steep and gullied slopes. Additionally, the rainfall in the Philippines is very high. The combination of all this unconsolidated material and heavy rainfall has generated probably hundreds of lahars, some of which have been enormous. Timely evacuation meant that only a couple hundred people were killed directly by the 1991 eruption. Many times that many have been killed or injured by lahars since the 1991 eruption. These lahars will continue to be a problem for decades after the big eruption.
3. Rhyolite caldera complexes
Rhyolite caldera complexes are the most explosive of Earth's volcanoes but often don't even look like volcanoes. They are usually so explosive when they erupt that they end up collapsing in on themselves rather than building any tall structure (George Walker has termed such structures "inverse volcanoes"). The collapsed depressions are large calderas, and they indicate that the magma chambers associated with the eruptions are huge. In fact, layers of ash (either ash falls or ash flows) often extend over thousands of square kilometers in all directions from these calderas. Fortunately we haven't had to live through one of these since 83 AD when Taupo erupted. Many rhyolite caldera complexes, however, are the scenes of small-scale eruptions during the long reposes between big explosive events. The vents for these smaller eruptions sometimes follow the ring faults of the main caldera but most often they don't. The origin of these rhyolite complexes is still not well-understood. Many folks think that Yellowstone, for example, is associated with a hotspot. However, a hotspot origin for most other rhyolite calderas doesn't work; they occur in subduction-related arcs. Examples of rhyolite caldera complexes include Yellowstone, La Primavera, Rabaul, Taupo, Toba, and others.
This is an outcrop in the Los Chocoyos ignimbrite, the product of one of the most powerful eruptions known...
4. Monogenetic fields
Monogenetic fields don't look like "volcanoes", rather they are collections of sometimes hundreds to thousands of separate vents and flows. Monogenetic fields are the result of very low supply rates of magma. In fact, the supply rate is so spread out both temporally and spatially that no preferred "plumbing" ever gets established; the next batch of magma doesn't have a pre-existing pathway to the surface and it makes its own. A monogenetic field is kind of like taking a single volcano and spreading all its separate eruptions over a large area. There are numerous monogenetic fields in the American southwest and in México, including Michoacan-Guanajuato, San Martín Tuxtla, Pinacate, and the San Francisco volcanic field.
5. Flood Basalts
Flood basalts are yet another strange type of "volcano." Some parts of the world are covered by thousands of square kilometers of thick basalt lava flows - individual flows may be more than 50 meters thick, and individual flows extend for hundreds of kilometers. The old idea was that these flows went whooshing over the countryside at incredible velocities (e.g., like a flash flood). The new idea is that these flows are emplaced more like flows, namely slow moving with most of the great thickness being accomplished by injecting lava into the interior of an initially thin flow. The most famous US example of a flood basalt province is the Columbia River Basalt province, covering most of SE Washington State and extending all the way to the Pacific and into Oregon. The Deccan Traps of NW India are much larger and the Siberian Traps are even larger than that (but poorly understood). The Ontong Java plateau may be an oceanic example of a flood basalt province.
6.Mid-ocean ridges
This is a map of the major oceanic spreading centers. This is sometimes considered to be one ~70,000 km-long volcano. Here, the plates are pulled apart by convection in the upper mantle, and lava intrudes to the surface to fill in the space. Or, the lava intrudes to the surface and pushes the plates apart. Or, more likely, it is a combination of these two processes. Either way, this is how the oceanic plates are created.
The lava produced at the spreading centers is basalt, and is usually abbreviated MORB (for Mid-Ocean Ridge Basalt). MORB is by far the most common rock type on the Earth's surface, as the entire ocean floor consists of it. We know that spreading occurs along mid-ocean ridges by two main lines of evidence: 1) the MORB right at the ridge crest is very young, and it gets older on either side of the ridge as you move away; and 2) sediments are very thin (or non-existent) right near the ridge crest, and they thicken on either side of the ridge as you move away. Mid-ocean ridges are also the locations of many earthquakes, however, they are shallow and generally of smallmagnitude.
We have never witnessed an eruption along a mid-ocean ridge, although a few times earthquake swarms have been detected along them (mainly by secret US Navy listening devices). When scientists have investigated soon after, fresh-looking basalt, plumes of hot chemical-laden water, and recently-killed marine organisms have been observed, indicating that an eruption almost certainly had occurred.
Source for this additional information : http://volcano.oregonstate.edu/book/export/html/198
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a. Destructive explotion
b. Ruined explotion
c. Extrussive explotion
d. Intrussive explotion
e. Merapi explotion
2. What happen if the gas pressure is low when the mountain was explode?
a. Destructive explotion
b. Ruined explotion
c. Extrussive explotion
d. Intrussive explotion
e. Merapi explotion
3. What is the main factor of the rock's cycle?
a. Endogen energy
b. Exogen energy
c. Potential energy
d. Kintetical and Potential Energy
e. Endogen and Exogen energy
4. Freezed rock mainly came from the ....
a. Magma
b. Lava
c. Gloedwolk
d. Wedhus gembel
e. Batholit and Lakolit
5. How if the magma through the branch of the magma's throughway inside the mountain?
a. New Volcano Mountain
b. New Hole in the side of the mountain
c. New explotion
d. New Gloedwolk
e. New Batholit
6. What kind of mountain which explode the andecite and dacite material?
a. Shield Volcanoes
b. Strato Volcanoes
c. Rhyolite Caldera
d. Monogetic
e. Flat Volcanoes
7. The field which doesnt look like volcano is...
a. Shield Volcanoes
b. Strato Volcanoes
c. Rhyolite Caldera
d. Monogetic
e. Flat Volcanoes
8. The main material inside or at the base of the mountain is?
a. Freezed Rock
b. Basalt
c. Sedimentary Rock
d. Erosion Rock
e. Batholit and Lakolit
9. The most dangerous things (cold lava flood) happen when the lava meet the....
a. Water or rain
b. fire
c. rock
d. hot material
e. trashes
10. The main differences between magma and lava is?
a. Material
b. Water composition
c. Place or position
d. Volume
e. Colour
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