why most volcanoes around the world are reawakening?any idea or explanation?
446878
Only a few and that is dictated by pure chance. All over the world are many extinct and dormant volcanoes. We have an extinct one near us, and I just hope it will keep to the rules.
585860
there is a hot core in the center of the earth, this escapes from fissures in the earths crust,finding its way up and out of the earth surface through fractures in the platelets. on these platelets the lava flows and when cooled becomes rock hard. when this happens in a volcano type of environment the pressure builds up over time, and the result is the "Blowing of the top/side" of the volcano, causing molten lava to flow, often causing damage to human, and plant life, that is around the base of the volcano..
133677
This question, as worded, could yield multiple answers.\n\nVesuvius, as an example, has erupted more than 50 times since 79 AD.  This, technically, fits within the parameters of the question.
872859
Most earthquake happens around the edge of the Pacific Ocean. Namely Japan, Alaska, California, etc. Its been called the Ring of Fire, because numerous volcano eruptions have been caused by earthquakes in these areas. The cause of the earthquake is due to the movement of 2 or more underground plates rubbing against each other either in a vertical or horizontal movement. Usually these movement goes smoothly without anyone noticing, but when a big shift - slippage occur we observe this as a major earthquake. Just like rubbing your hands together, most of the time it will go smoothly, but once in a while you will catch and cause a big jerk.
844151
I can see Mt. Hood out my window and I haven"t heard of any explosions. We keep a close watch on our volcanoes around here since Mt St. Helens erupted 25 years ago. Mt. Hood will erupt again in the future but hasn't since 1781. Check the link below.
1162848
That depends on your definition.\n\nThe Etna, in Sicily, which has been erupting for 3,500 years, is considered to be the most active volcano in the world.\n\nThe following 4 volcanoes emit the most lava: Kilauea (Hawaii), Mt Etna (Italy), Piton de la Fournaise, (Réunion), Nyamuragira, (D.R. Congo)\n\nHere is a list of volcanoes that have been in continuous eruption for decades:\nhttp://www.volcanolive.com/active2.html
924713
Volcanism at Nyiragongo is caused by the rifting of the Earth's crust where two parts of the African Plate are breaking apart. >>> breaking apart = divergent = constructive !!!!
597381
Geologists generally group volcanoes into four main kinds--cinder cones, composite volcanoes, shield volcanoes, and lava domes. \n\nIn regard to your question, Cinder cones are the simplest type of volcano. They are built from particles and blobs of congealed lava ejected from a single vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as cinders around the vent to form a circular or oval cone. Most cinder cones have a bowl-shaped crater at the summit and rarely rise more than a thousand feet or so above their surroundings. Cinder cones are numerous in western North America as well as throughout other volcanic terrains of the world.\n\nShield volcanoes are built almost entirely of fluid lava flows. Flow after flow pours out in all directions from a central summit vent, or group of vents, building a broad, gently sloping cone of flat, domical shape, with a profile much like that of a warrior's shield. They are built up slowly by the accretion of thousands of highly fluid lava flows called basalt lava that spread widely over great distances, and then cool as thin, gently dipping sheets. Lavas also commonly erupt from vents along fractures (rift zones) that develop on the flanks of the cone. Some of the largest volcanoes in the world are shield volcanoes. In northern California and Oregon, many shield volcanoes have diameters of 3 or 4 miles and heights of 1,500 to 2,000 feet. The Hawaiian Islands are composed of linear chains of these volcanoes including Kilauea and Mauna Loa on the island of Hawaii-- two of the world's most active volcanoes. The floor of the ocean is more than 15,000 feet deep at the bases of the islands. As Mauna Loa, the largest of the shield volcanoes (and also the world's largest active volcano), projects 13,677 feet above sea level, its top is over 28,000 feet above the deep ocean floor.
755153
start from here:http://en.wikipedia.org/wiki/Volcano\nthan click here:\nhttp://rds.yahoo.com/_ylt=A0geupc15FRFTXQBUXpXNyoA;_ylu=X3oDMTE2ZGhvZmh2BGNvbG8DZQRsA1dTMQRwb3MDMQRzZWMDc3IEdnRpZANERlg1XzMw/SIG=19tfhms70/EXP=1163277749/**http%3a//rdre1.yahoo.com/click%3fu=http%3a//www.volcanolive.com/%26y=04D6D45EA8332C5A9E%26i=680%26c=21908%26q=02%255ESSHPM%255BL7sviz%253Fips%257C%7eqpzl6%26e=utf-8%26r=0%26d=wow%7eDFX5-en-us%26n=0IHKK1KQNHA4BU6E%26s=12%26t=%26m=4554E436%26o=01C888B21CE6710E36%26x=052DFE91D28B9E0A83349375261B2BB2A1\nhttp://rds.yahoo.com/_ylt=A0geupc15FRFTXQBXHpXNyoA;_ylu=X3oDMTE2aXBvZDkwBGNvbG8DZQRsA1dTMQRwb3MDMwRzZWMDc3IEdnRpZANERlg1XzMw/SIG=12fj2lehe/EXP=1163277749/**http%3a//www.geo.mtu.edu/volcanoes/west.indies/soufriere/govt\nhttp://rds.yahoo.com/_ylt=A0geupc15FRFTXQBaXpXNyoA;_ylu=X3oDMTE2bTQybGs2BGNvbG8DZQRsA1dTMQRwb3MDNQRzZWMDc3IEdnRpZANERlg1XzMw/SIG=13154364e/EXP=1163277749/**http%3a//interactive2.usgs.gov/learningweb/explorer/topic_hazards_volcanoes.asp\nhttp://rds.yahoo.com/_ylt=A0geupc15FRFTXQBV3pXNyoA;_ylu=X3oDMTE2MWFla2V2BGNvbG8DZQRsA1dTMQRwb3MDMgRzZWMDc3IEdnRpZANERlg1XzMw/SIG=1aaavi8gn/EXP=1163277749/**http%3a//rdre1.yahoo.com/click%3fu=http%3a//www.volcanolive.com/contents.html%26y=04BF5322B24FA45313%26i=680%26c=15685%26q=02%255ESSHPM%255BL7sviz%253Fips%257C%7eqpzl6%26e=utf-8%26r=1%26d=wow%7eDFX5-en-us%26n=0IHKK1KQNHA4BU6E%26s=12%26t=%26m=4554E436%26o=018610364A2BA0082E%26x=05679277237FEB7DFC07236F0AED3006C9
705501
Composite volcanoes typically form along subduction zones (ocean - continent plate boundaries).  They tend to have higher viscosity magma (andesite and dacite) which allows for more gas pressure to develop.  This produces more explosive eruptions.\n\nSome examples of subduction zones are the western coast of the USA and South America.  The Cascades and the Andes were and are currently being formed by subduction related processes.
54493
Volcanoes are usually situated either at the boundaries between tectonic plates or over geology hotspots. Volcanoes may be either dormant (having no activity) or active (near constant expulsion and occasional eruptions), and change state unpredictably.\n\nSurprisingly, there is no consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes meaningless when compared to the lifespans of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing signs of activity. Given the long lifespan of such volcanoes, they are very active. By our lifespans, however, they are not. Complicating the definition are volcanoes that become restless but do not actually erupt. Are these volcanoes active?
29535
...And the ring of fire is located around the Pacific.  \n\nVolcanoes can also be found in Iceland, where it lies above a hot spot and a Mid Ocean Ridge.  They also tend to coincide with mantle plumes surging from the core mantle boundary as well as plate convergent (subduction) and divergent (rifts and MOR) settings, but further details can be found in various websites --> search on google.\n\nWikipedia or the United States Geologic Survey (usgs.gov?) websites may have some useful info about volcanoes.
1084414
Dormant volcanoes are those that are not currently active (as defined above), but could become restless or erupt again. Confusion however, can arise because many volcanoes which scientists consider to be active are referred to as dormant by laypersons or in the media.\n\nExtinct volcanoes are those that scientists consider unlikely to erupt again. Whether a volcano is truly extinct is often difficult to determine. Since "supervolcano" calderas can have eruptive lifespans sometimes measured in millions of years, a caldera that has not produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct.\n\nFor example, the Yellowstone Caldera in Yellowstone National Park is at least 2 million years old and hasn't erupted violently for approximately 640,000 years, although there has been some minor activity relatively recently, with hydrothermal eruptions less than 10,000 years ago and lava flows about 70,000 years ago. For this reason, scientists do not consider the Yellowstone Caldera extinct. In fact, because the caldera has frequent earthquakes, a very active geothermal system (i.e., the entirety of the geothermal activity found in Yellowstone National Park), and rapid rates of ground uplift, many scientists consider it to be an active volcano.
651917
A volcano is a geological landform usually generated by the eruption through a planet's surface of magma, molten rock welling up from the planet's interior. Other forms of volcano include ice volcanoes (particularly on some moons of Jupiter, Saturn and Neptune) and mud volcanoes. On Earth, volcanoes tend to occur near the boundaries of crustal plates. There are Diff types of volcanoes:\n1)Extinct--lowest possible chance of erupting.Whether a volcano is truly extinct is often difficult to determine. Since "supervolcano" calderas can have eruptive lifespans sometimes measured in millions of years, a caldera that has not produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct.\n\n2)Dormant --those that are not currently active but could become restless or erupt again. Confusion however, can arise because many volcanoes which scientists consider to be active are referred to as dormant by laypersons or in the media.\n3)Active--it is currently erupting or showing signs of unrest, such as unusual earthquake activity or significant new gas emissions. Many scientists also consider a volcano active if it has erupted in historic time.\n  \nIt is important to note that the span of recorded history differs from region to region; in the Mediterranean, recorded history reaches back more than 3,000 years but in the Pacific Northwest of the United States, it reaches back less than 300 years, and in Hawaii, little more than 200 years. The Smithsonian Global Volcanism Program's definition of 'active' is having erupted within the last 10,000 years.So A volcano may occur anytime as earthquakes do.
819640
The most common place to find shield volcanoes is over hotspots (such as Hawai'i, the Galapagos, etc.). This is because hotspot magmas are almost always hot basalts and therefore the erupted lavas have low viscosities. Low viscosity lavas cannot be piled up very steeply so they form shield volcanoes.\nSubduction-zone magmas are almost always cooler and they are higher in silica, both qualities that make the lavas more viscous. These magmas are able to pile up into steep domes and additionally make the volcanoes more explosive so that they have a greater percentage of ash. This makes the volcanoes steep strato-cones instead of shields. It isn't impossible to find shield volcanoes along lines of arc volcanoes (for example Masaya in Nicaragua), but it is rare.
1049359
There are explosions in and on the surface of the sun, but as for volcanoes like here on earth no there are none. Since the surface of the sun is molten (which means not solid) there are no mountains on the sun.
995032
It may gas off or have some activity,but the conditions that created it will probably not happen again.No one should be ramping up fear of the super volcanoes as there is not even a scintilla of enough earth heating to make them blow.