Summary Of The Earth Science Journal Geology '

The cataclysmic eruption which caused the collapse of the caldera and the deposition of the Bishop Tuff was an explosive, fast event. It ejected coarsely porphyritic biotite rhyolitic ash and viscous lava with an approximate silica content of 76 percent. The total ejecta came to about 600

Analyse the factors that causes differences in the hazards posed by volcanoes around the world (40 marks)

the lateral blast, and the large mudflow of this eruption have led to the reassessment

A hazard is a situation that poses a level of threat tolife, health, property or environment. The level of hazard posed by different volcanoes can very greatly, from a weak eruption with minimal impact that causes little damage, to a voilent and life threatening explosion. Most of the sixty-plus volcanoes that erupt each year are low risk, however a combination of factors can cause a volcano to be a serious hazard. The factors causing these variations will be explained in this essay.

A human factor that would cause differences in the hazards posed by volcanoes is settlement, which includes where people chose to live in relation to a volcano. For example, in Indonesia many people settle near Mount Merapi because of the rich and fertile soil favoured for farming. As Indonesia is a poor country many people rely on subsistence farming, therefore are willing to risk everything by settling beside a volcano. Furthermore, in the last eruption in 2010 360,000 people were displaced from their homes, meaning not only did they lose their home but also their livelihood; hundreds also lost their lives. Therefore, the hazards posed could have been minimalised if people chose to settle elsewhere.

A volcano is an earth hazard that occurs on faults between tectonic plates on a destructive boundary and an eruption is a natural disaster. A primary impact happens immediately after the disaster and before any response like death or collapsing or destruction of buildings. A secondary impact occurs later after the disaster, such less farm produce or a reduction in tourism. The severity of these impacts will differ considerably in a MEDC and LEDC where volcanic eruptions have taken place. These may be seen in the Mount St. Helen volcano eruption as well as in the Iceland volcanic eruption. They may also

Austin, Steven A. 1994. Grand Canyon: Monument to Catastrophe. Santee, California: Institute for Creation Research.

However, scientists have discovered that there is a tear underneath Vesuvius. The lower part of the subducting African plate is torn and detached from the upper plate, forming a “slab window.” Vesuvius rest right above that slab window. This makes the rocks of Vesuvius chemically different from the other volcanoes in the Campanian arc (Ball). The tear allows heat from the Earth’s mantle to melt the plate, which builds up pressure and causes more violent and explosive eruptions (Bagley). Stratovolcanos like Vesuvius are usually formed from alternating layers of pyroclastic debris and lava flows. The magma present at Mount Vesuvius is andesitic, making it an intermediate composition (Sabatino). The force of the eruption was almost 100,000 times greater than the force of the nuclear bomb in Hiroshima (Cartwright). Because of the magma composition, the gases present in volcanoes could not escape. As more gas was trapped, it eventually leads to the deadly eruption when the volcano could no longer contain the amount of gas in the mountain. The volcano has erupted more than 50 times since the eruption of 79 C.E. Originally, Vesuvius was thought to have a 20-year eruption cycle. However, the last explosion was in 1944, making another catastrophic eruption long overdue (Bagley).

An arc which spreads from New Zealand all the way to the west coast of North and South America where three-quarters of world’s volcanoes are found is called the Ring of Fire. According to the scientists in the video plate tectonics play a very important role in forming of all the volcanoes. The Ring of Fire is also famous for the earthquakes which takes place here. Ninety percent of the world’s earthquakes occur around the Pacific Rim, which is also an aftermath of shifting of plates. The process that moves the rocks and the seawater into the Earth is called subduction. The scientists explained the process of subduction through a 3D picture of the

In 79 CE, a disastrous eruption from Mt. Vesuvius occurred. This eruption affected many towns, but one famous town affected was one that was located about five miles from the volcano. This ancient Roman area was known as Pompeii. After the eruption, it was abandoned for many years, until explorers rediscovered Pompeii in 1748. Below the dust and debris, was a town that once lively; mostly everything remained intact. For a long time, people thought that the Pompeiians had suffocated, but now many historians believe that those who perished in Pompeii died after being hit by an explosion and hot debris. Evidence has been collected to prove this theory including body casts which captured villagers in their last living moments, skeletons in nearby towns and facts about volcanic behaviour.

This paper will provide information on the volcanoes of Hawaii, where it is known to be the home of one of the world’s largest volcanic islands, merely second to Iceland. It is not just the beautiful landscapes and wildlife that spark the interest to this particular area, but the uniqueness of the Hawaiian volcanoes and islands themselves are what make the area so significant. There will be information spanning from the history of the origin of the islands to how Hawaii must adjust to the volcanic hazards in order to keep the area livable. With these ideas in mind, I will first address background information on the area and set the scene as to what makes this area so special. Then I will transition to the history of how the

Part 1 Earth's Mantle, Crust, etc. The physical geology of the earth consists of a Core (inner and outer), the mantle, the asthenosphere and the lithosphere. The inner core is primarily a solid ball about 70% the size of the moon and thought to consist of an iron-nickel alloy with a temperature about the same as the sun. The outer core is a liquid layer about 1500 mils thick that is composed of iron and nickel, just below the mantle. The mantle is divided into layers, and is a rocky shell surrounding the core of the earth with about 84% of the total volume of the planet. It is primarily solid and encloses the iron rich hot core and was formed by numerous past incidents of volcanism. Two main zones are in the upper mantle of the earth. The inner asthenosphere that is composed of flowing rock about 200 km thick and the lithosphere which is composed of rigid rock about 50-120 km thick. There is also a thick crust which is the upper part of the lithosphere that surrounds the mantle, anywhere from 5-75 km thick. Additionally, the asthenosphere may be described as being highly viscous that is crucial to the plate tectonic theory in that in spite of its high temperature, pressures keep it malleable and at a relatively low density. The lithosphere is the crust and upper mantle of the earth that is the hard and rigid layer in which humans live. This portion of the earth reacts to the atmosphere, hydrosphere and biosphere through erosion and weathering, resulting the soil forming

The media has engendered the critical opprobrium of volcanoes with their triumphant essays at delineating volcanic eruptions so as to give the impression that they are devastating and precarious. As a result, the negative stigma encompassing volcanoes and their concomitants permeates all walks of life. Under the nourishment of ignorance and fear, which are constituents of the human condition, antipathy multiplies. Ergo, Homo sapiens, possessing complex cognitive neural processes, are predisposed to the fallacious notion that assumes volcanoes have deleterious effects on the progression of humankind. The precise definition of the term volcano is profoundly convoluted, as a myriad of labyrinthine systems engage in volcanic activity. On loci where

Living in the shadow of a volcano can be a dangerous proposition. A volcanic eruption, and there have been hundreds in the history of the United States, can range from slowly oozing lava to massive eruptions and explosions causing devastation over hundreds of square miles of territory. While many people associate volcanic activity with the flowing of lava, as is common in the Hawaiian Islands, lava is rarely associated with being hazardous to humans. Lava simply moves too slowly for people to be caught by it. However, there are many other types of activities associated with volcanic eruptions that are more hazardous to human beings. The enormous heat that comes from material from deep inside the Earth is a more common cause of death than lava, as too is the suffocating cloud of ash and debris that is often blown out from the volcano during violent, explosive eruptions. This cloud of ash and debris is often carried by toxic and deadly gasses, including carbon dioxide, sulfur dioxide, as well as "chlorine, hydrogen, and argon." (Lutgen, 2011, p. 213) And the force of the blast that can come from an exploding volcano can hurl people long distances to their deaths.

Kieffer et al., (2004) studied the petrology, geochemistry, and isotopic compositions of the large shield volcanoes, compared their compositions with those of the flood volcanic and also traced the variations in eruption style and magma flux of lavas with ages ranging from 30 to ~10 Ma, (from the peak of flood volcanism to the onset of major rifting in the northern part of the volcanic plateau).