A Look Into Volcanoes
I. Introduction Volcano: defined is a mountain or hill formed by the accumulation of materials erupted through one or more openings (called volcanic vents) in the earth's surface. The term volcano can also refer to the vents themselves. Most volcanoes have steep sides, but some can be gently sloping mountains or even flat tablelands, plateaus, or plains. The volcanoes above sea level are the best known, but the vast majority of the world's volcanoes lie beneath the sea, formed along the global oceanic ridge systems that crisscross the deep ocean floor. According to the Smithsonian Institution, 1511 above-sea volcanoes have been active during the past 10,000 years, 539 of them erupting one or more times during written history. On average, 50 to 60 above-sea volcanoes worldwide are active in any given year; about half of these are continuations of eruptions from previous years, and the rest are new. Mount St. Helen Volcanic eruptions in populated regions are a significant threat to people, property, and agriculture. The danger is mostly from fast-moving, hot flows of explosively erupted materials, falling ash, and highly destructive lava flows and volcanic debris flows. In addition, explosive eruptions, even from volcanoes in unpopulated regions, can eject ash high into the atmosphere, creating drifting volcanic ash clouds that pose a serious hazard to airplanes. II. Volcano Formation All volcanoes are formed by the accumulation of magma which is molten rock that forms below the earth's surface. Magma can erupt through one or more volcanic vents, which can be a single opening, a cluster of openings, or a long crack, called a fissure vent. It forms deep within the earth, generally within the upper part of the mantle which is one of the layers of the earth's crust, or less commonly, within the base of the earth's crust. High temperatures and pressures are needed to form magma. The solid mantle or crustal rock must be melted under conditions typically reached at depths of 50 to 60 mi. (80 to 100 km) below the earth's surface. Once tiny droplets of magma are formed, they begin to rise because the magma is less dense than the solid rock surrounding it. The processes that cause the magma to rise are poorly understood, but it generally moves upward toward lower pressure regions, squeezing into spaces between minerals within the soli...
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...the first blobs of melt. As melting continues other minerals start to melt as well, and the chemistry of the magma changes. From studies like this geologists have determined that the early stages of a Hawaiian volcano's life is generated by magmas derived from only small degrees of partial melting (such as only 5% of the source melting and the rest staying behind). On the other hand, when the volcano really gets going (such as at Kilauea and Mauna Loa), the percentage of source rock that melts to produce the magma is perhaps as high as 20%. There are many other ways in which chemistry is used in volcanology, including the studies of volcanic gases, crater lakes, and trying to determine the temperatures that lava had at the time they were erupted even long after the eruption has ended.
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...e than 30 volcanoes that have erupted over the past 300,000 years in the Lassen Peak volcanic area.
Mud volcanoes of the Orinoco Delta, Eastern Venezuela. Retrieved November 13, 2013, from http://pubs.er.usgs.gov/publication/70023450 World Atlas. n.d. - n.d. - n.d. Lake Maracaibo. Retrieved November 19, 2013, from http://www.worldatlas.com/aatlas/infopage/lakemaracaibo.htm.
Mount Vesuvius is one of history’s most recognizable Volcanoes, as each of its eruptions have gone down as a significant event in geologic history. The events that transpired during and after these eruptions have shaped the way scientists and people view the sheer power that these volcanoes possessed. This report will take a look at Vesuvius’ most prolific eruption in 79 AD. The geologic setting of the mountain, precursor activity, and the impact the eruption had on the surrounding populations and towns will all be detailed. Along with these details, this report will also look at the further history of Vesuvius’s explosive past by detailing its eruption cycle. Finally, the current state of Vesuvius and the possible danger the current population living near the mountain could face should it erupt explosively again.
The first time I saw Mt. Rainier for myself, was last summer when my boyfriend and I drove to Washington. It was the most beautiful, peaceful looking mountain I have ever seen. However, underneath it's great beauty, it hides a deadly secret. Mt. Rainier is one of the most dangerous volcanoes that we have here in the United States. One of the reasons it is so dangerous is because of it's great beauty. People enjoy looking at it, and the area that surrounds it, so they have made their homes here. Mt Rainier is not the only volcano I am interested in, in fact this last summer I also went to Mt. St. Helens and Crater Lake. But it is the volcano I chose to research for this paper because it does have so much beauty and at the same time so much power. I already know the basics about volcanoes, how they form, the different types, etc., but I wanted to find out more about what would happen if this great volcano were to erupt, what type of eruption would it be, and how would it affect the people that live around it.
Wood and Kienle, 1990, Volcanoes of North America: United States and Canada: Cambridge University Press, 354 p., p. 158-160, Contribution by Patrick Pringle.
Miesse, Willian C. "Mount Shasta Geology and History." USGS: Volcano Hazards Program - Mount Shasta Geology and History. College of the Siskiyous Library, n.d. Web. 01 May 2014.
Basalt forms due to the partial melting of the layer of the mantle called the asthenosphere. The asthenosphere is the plastic zone of the mantle beneath the rigid lithosphere. Mantle plumes coming from the mesosphere can cause the asthenosphere to melt with heat or even if pressure decreases, which is called decompression melting (Richard 2011). The magma that forms from this melting is mafic magma that solidifies once it reaches the earth’s surface and cools quickly. The above process mainly occurs mainly during intraplate igneous activity which is the main explanation for volcanic activity that occurs a long distance away from a plate boundary. If the tectonic plate above the mantle plume is moving it can create a string of volcanic activity such as in Hawaii. See Fig 2.
These differences are in the makeup of the volcano, the impact on society, and the eruption itself. Mount Saint Helens, used to be a wonder of the world, but now a damage site of what happened on May 18, 1980. Mauna Loa is a tourist destination and one of the most active dispensers of lava and magma in the world. As shown, these volcanoes can’t be more different. Yet, each volcano has been a culprit to destruction, and have similarities within themselves. This report has expressed many similarities and differences and brought facts and knowledge to the historical eruptions by these impressive and ancient structures of
Stories about volcanoes are captivating. Myths come in different versions, but all of them are capable of capturing yours, and everybody’s imagination.
Magma is a hot liquid made of melted minerals. Minerals can form crystals when they are cool. Igneous rock can form underground, where the magma cools. slowly. Or, igneous rock can form above ground, where the magma cools.
Volcanoes are one of natures most interesting and dangerous phenomenons. The way volcanoes operate can be understood, on a basic level, by just some simple physics and chemistry, this paper will investigate and explain some of the basic physics that govern the behavior of volcanoes.
Volcanoes are one of the most destructive forces on Earth. It is estimated that some 500 million people live near active volcanoes (Lutgens and Tarbuck, 2013). Of the Earth's known volcanoes, 70 are expected to erupt each year with at least one large eruption each decade (Lutgens & Tarbuck, 2013). As populations continue to increase and more people are attracted to the beauty surrounding these areas, the immediate threat to humans from these sometimes sleeping giants grows. Due to this, the study of volcanoes and the service that volcanologists provide to the public by way of information and predictions on activity is immeasurable.
Digging up the dirt on Mauna Loa. (Hawaiian volcano studied) Science News v144, n25-26 December 18th, 1993 414 (1 page)
The earliest outcropping volcanic deposits date back to about 25,000 years ago. The lavas observed at a -1125 m bore-hole are about 0,3-0,5 million years old. It is known for the first eruption of which an eyewitness account is preserved, in 79 AD. Geologically, Vesuvio is unique for its unusual versatility. Its activity ranging from Hawaiian-style release of liquid lava, fountaining and lava lakes, over Strombolian and Vulcanian activity to violently explosive, plinian events that produce pyroclastic flows and surges.