Understanding volcanoes require our understanding of planet Earth’s structure. Earth is a ball of rocks divided into four layers; crust, mantle, outer core and inner core. The Crust is the outermost layer. It comprised of continental and oceanic crust. The second layer is the mantle and it makes up about 80% of the Earth’s total volume. The outer core is liquid consisting of iron and nickel and it is the third layer. The Forth layer, inner core is the solid iron and nickel alloy. The temperature and density of these layers differs. Inner core has the highest temperature and density with the crust having the lowest temperature and density in comparison. The extreme pressure and temperature within the earth causes the hot magma (also known …show more content…
Their eruptions are mixtures of hot stream, ash, rock and dust (pyroclastic flow) rather than lava flow (BBC, n.d.). Composite volcano has crater at the summit which have one or more vents. Its conduit system through is an essential feature as it contribute to the size of the volcano as lava, cinders, bombs and ash are added to its slope. In addition, silica content has direct effect on the fluidity of the magma. An increase in silica concentration results in an increase in magma resistance to flow (viscosity). Andesite magma which have high content of silica compared to basalt magma make up most of the composite volcanoes fragmental materials. This silica-and volatile-rich magma is what separate composite volcanoes from shield volcanoes. Although, andesite magma dominate fragmental debris, some magma intrudes the cones such as sills or dikes. Due to this multiple intrusions, the strength of the structural framework is obtained and therefore composite volcanoes stand higher than those composed solely of the fragment materials. Sigurdsson (2000) observed that there are at least two factors that promote the formation of composite volcanoes. First the composition of erupted magma and second the eruption style. Magma composition varies depending the site of eruption. Magma Eruptions at convergent plate are results of differentiation and volatile concentrations. The style of eruptions is
It is believed that this volcanic area was caused by a localised hot spot within the Pacific plate. A concentration of radioactive elements inside of the mantle may have caused this hot spot to develop. The hot spot is stationary so as the Pacific plate moves over it a line of volcanoes are made. This is more proof that the Earth’s crust is moving as suggested by Wegener.
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
Anpother factor that can have an impact on the level of hazard posed by a volcano is the type of plate margin on which it occurs. Volcanoes occuring at constructive plate boundaries are usually much less violent than those occuring at destructive plate boundaries. This is because the magma produced by plates moving apart is Basic, and therefoe has a low viscosity, allowing it to flow easily. The lava is produced from a central vent or fissure and erupts regularly but not usually violently. Also,constructive plate boundaries are often found under the sea and create submarine volcanoes, such as along the Mid-Atalntic ridge, so pose few threats to humans. As a result, the hazards posed by volcanoes at constructive plat eboundaries is relatively low. However, the subduction of one plate under another at destrctive plat eboundaries can form an acidic magma chamber, due to the build up of intense heat. Acidic magma is very viscous and resisitant to flow, meaning that there is often a huge build up of pressure, which can result in very violent and dangerous eruptions involving ash and pyroclastic flow. This can pose a a serious hazard. Pyroclastic flowsa are extremely dense, containing toxic gases at very high temperatures, and can move at speeds over 100km/h. The consequences of such an unpredictable hazard can be extremely seruous
The volcanoes are located where there is a divergence or convergence in the tectonic plates and bring their lava from the deepest of the terrestrial mantle. The materials and explosions of these ginates represent a constant risk in the places inhabited by the human being, nevertheless the people ususually live in these areas no matter the risk. On the other hand the volcanos can change the geology of an impressive form, or to cool the temperature of the earth, or to darken the sky. The scientific community increases its efforts to try to understand better what happens in volcanoes, however it is impossible to predict these conditions.
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
Volcanoes are one of the most destructive, yet, most beautiful things on Earth. They can make a famous city choke in its own ashes in one day, like Pompeii. Or they can turn a once damaging mountain into a graceful and peaceful home for new life, like Mount St. Helen’s. All volcanoes are unique, and no two are the same. Some erupt differently than others, some look different than others, and all are located in different spots all over the world. I learned this while completing the project and the five volcanoes I researched are examples of my discoveries. The five volcanoes I researched were Mount Hood, Mount Mageik, Long Island, Mount Muria, and Las Pilas.
One physical factor which causes differences in a volcanic hazard is the steepness of the volcano. If the volcanoes sides are of a steep gradient then the
The Earth’s outer crust is made up many tectonic plates that move over the surface of the planet. When the plates come collide, volcanoes will form sometime (National Ocean Service). Volcanoes can also form in the middle of a plate, where magma rises upward until it erupts on the sea floor, at what is called a “hot spot” (National Ocean Service). A hot spot is a plume of magma or molten rock that rises from within the Earth then reaches the surface forming underwater volcanoes which may grow tall enough to
The mythology of the Aztec peoples, which dominated central Mexico in the 1400’s and early 1500’s, described a universe of greatness and fear. In this Mexica civilization, volcanoes had a deep spiritual as well as strategic military importance. The legend of the volcanoes, Popocatepetl and Iztaccihuatl, is no different. The Aztec mythological explanation for the two volcanoes is a story of love and war. In this paper, I will describe the legend behind these two natural locations and its correlation with the spiritual and social importance of volcanoes to the Mexica people at the time.
The active volcano that I chose to research is Popocatepetl volcano. Popocatepetl volcano is an active volcano located in Mexico. The volcano is oftentimes referred to as “El Popo” by many Mexicans. El Popo is a composite cone volcano. Being a composite cone volcano, El Popo is characterized by a steep cone shape, which was created by many composite layers of material pouring out over numerous eruptions. The lava that comes out of El Popo is extremely viscous. The highly viscous lava does not travel very far, and typically cools down rapidly. Scientists believe that El Popo is about 730,000 years old. It has erupted more than 15 times since 1519. In 1994 El Popo produced gas and ash, which caused nearby towns to evacuate. The toxic
First there are tectonic plates that collide together that will cause an earthquake which can make the volcano erupt.
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 pyroclastic flows are clouds of ash, stones etc that move down the side of volcanoes and carry any debris in its way. A famous pyroclastic flow occurred when Mt Pinatubo erupted in 1991. Mud volcanoes, which may form where hot water mixes with mud and surface deposits. Solfataras, that are created when mainly sulphurous gases escape onto the surface. Geysers, occuring when water in the lower crust is heated by rocks and turns to steam, pressure increases and the steam and water explode onto the surface.
Ash plumes and steam rose into the bright blue sky as the underground earthquake shook the land and rattled windows all across the eighteen mile town. As the jet circled the island, in view of lovely beaches and emerald water, looming over this lush paradise was the screaming volcano. Volcanos erupt when the pressure inside of them becomes so great that the magma surges up and forces its way out. An exploding volcano can rip apart a mountain in just seconds, when the eruption is over, a landscape is changed forever. The united states is home to more volcanos than any other country except Indonesia, and Japan. The majority of these volcanoes are in Alaska. Until recently, there was no way to predict when a volcano would blow, although volcanoes give off many warning signs before they erupt. Including smaller earthquakes beneath the volcano, slight inflation, or swelling. The rising magma eventually causes the solid rock to break, sending earthquake signals. Most volcanoes give warning signs beginning weeks or months before they blow (Lindop).
In these eruptions, instead of the mixture of gas and ash flowing upwards, it flows outwards and hugs the ground. These eruptions are extremely dangerous.