Volcanoes have played a key role in forming the face of the earth as we know it today. Some of the most well known landmarks and locations in the world are volcanoes. From the Hawaiian Islands to Mount Vesuvius, the Earth is populated with hundreds of active and dormant volcanoes. Among these volcanoes there are multiple different types. Stratovolcanoes, the most dangerous type of volcanoes, are built by multiple eruptions over many years. Shield Volcanoes, the largest recognizable volcanoes, are characterized by being short but very broad with low sloping sides. Cinder cones, the most common type of volcano in the world, are composed of large amounts of tephra, or pyroclastic debris. The last type of volcano is supervolcanoes. Supervolcanoes …show more content…
Shield volcanoes are very broad, but do not grow very tall. The slope on shield volcanoes is typically around 2-3 degrees at the edges and flat on the top. About halfway up the volcanoes the slope can reach about 10 degrees. The reason for these very low angle inclines is that the lava erupted from shield volcanoes is basaltic. Basaltic lava has a very low viscosity and high temperature. This causes it to flow for great distances before cooling and solidifying. Because of the great distances that the lava can flow these the height of these volcanoes winds up being only a fraction of what the width is. They range from a few kilometers in diameter to well over 100 …show more content…
The most notable shield volcanoes in the world are the Hawaiian islands. The 8 main Hawaiian islands are composed of 15 shield volcanoes. The biggest of these volcanoes is Mauna Loa. Mauna Loa is also the largest active volcano in the world. It is 48.3 kilometers wide and 96.5 kilometers long and makes up half of the Big Island of Hawaii. In contrast to it’s massive horizontal size, the mountain is only about 9 kilometers tall from the seafloor. Another famous chain of shield volcanoes is the Galapagos Islands. The main island of the chain, Isabela Island, is composed of coalesced shield volcanoes. Since Charles Darwin’s first visit to the islands in 1835, scientists have recorded over 60 eruptions across 6 of the volcanoes. Another distinguishing feature of shield volcanoes is the frequent formation of calderas at their summits. Calderas are formed when volcanoes empty magma chambers near their surface. The surface above the caldera may collapse into the voided magma chamber resulting in a bowl shaped depression. The two most well known shields in the hawaiian islands, Kilauea and Mauna Loa, both have summit
Mauna Loa is located on a hot spot in the Pacific Ocean. It is not near a plate boundary, in fact it is 3,200 km from the nearest plate boundary, and is situated in the middle of the Pacific tectonic plate. This is actually a rarity, as 90% of volcanoes are along a tectonic plate boundary. A hot spot occurs where long, stationary vertical pools of magma rise up and towards the plate. Movement of the tectonic plates above the hot spot created Mauna Loa, along with the other Hawaiian volcanoes. The older Hawaiian Islands were once above this stationary hot spot, but have been carried northwest by the slowly moving Pacific plate. As the plate moves, it carries the previously formed, older, volcanoes with it, creating a trail of younger, new volcanoes behind. The islands are lined up along the Hawaiian Ridge-Emperor Seamounts chain, which is 3,750 miles and includes Kauai, Maui, Oahu and Hawai’i, from north to south, respectively. There are around 80 volcanoes in this chain; most of them underwater, consequently the term seamount refer to submarine volcanoes. Three volcanoes of Hawai’i, Mauna Loa, Kilauea and Loihi seamount, are all currently sharing the Hawaiian hot spot. Although, recent evidence has shown that all three volcanoes use have separate plumbing systems to expel the lava from the pool of magma deep below them. It has also been suggested that Loihi is slowly moving Mauna Loa from the center of the island, thus shifting directly over the hot spot. The closer to the hot spot a volcano is, the more active it will be. The Hawaiian hot spot has laid down layers of lava, building up enormous islands from the ocean floor.
The most iconic volcanic eruption in history was the eruption of Mt. Vesuvius in 79 A.D. Mt. Vesuvius is located on the west coast side of Italy. Pompeii was the ancient town five miles from Mt. Vesuvius where people would flock to the area in 79 AD to be near the Bay of Naples. Little did they know that the volcano would erupt into the most destructive volcano in history. Mt. Vesuvius has erupted about three dozen times and was the most disastrous due to the large population around the area. The volcano, which is still active today, is a stratovolcano. A stratovolcano has pyroclastic flows and erupt explosively and violently. Pyroclastic flows don't necessarily look exactly like “flowing eruptions”. These eruptions are not the “flowing” type of eruptions because they are eruptions with explosions and blowing clouds that fill the air. These clouds are usually dark clouds that are made up of ash. Pompeii had some signs of the volcano erupting, but the technology was not like the technology of today where scientists can monitor the volcanic activity.
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.
Like most of the other volcanoes in the Cascade Range, St. Helens is a great cone of rubble, consisting of lava rock interlayered with ash, pumice and other deposits. Volcanic cones of this internal structure are called composite cones or stratovolcanoes. Mount St. Helens includes layers of basalt and andesite through which several domes of dacite lava have erupted. The largest of the dacite domes formed the previous summit; another formed Goat Rocks dome on the northern flank. These were destroyed in St. Helens' 1980 eruption.
Volcanoes have always been a mysterious wonder of the world. Volcanoes have shaped the landscape and the very ground that we all live on. People have written stories of their disastrous eruptions, and painted their marvelous shapes on canvas. The essay will outline some of the more famous volcanoes and how they have impacted are history. Mount Vesuvius that destroy the great city of Pompeii, Krakatoa they spewed deadly ash on small village town, and Mount St. Helen, the only volcano in my own country to every erupt during my own time period.
Stories about volcanoes are captivating. Myths come in different versions, but all of them are capable of capturing yours, and everybody’s imagination.
Volcanism is a major part of the Galapagos and their formation. The island chain is positioned on the Nazca Plate, which is subducting beneath the South American Plate at a geologically rapid pace of 2.5 inches per year. In addition, this Nazca Plate is located directly on top of the Galapagos Hotspot. It is here that mantle plumes melt Earth’s crust, creating volcanoes as a product. The oldest island was first shaped by this ...
The Hawaii Volcanoes National Park is about 30 miles southwest of Hilo. It is on the big island of Hawaii. This park is the home of Kilauea Volcano. Kilauea is one of the most active volcanoes on earth. The chance to see this creation and destruction makes this park one of the most visited National Parks in the United States.
Volcanic plateau: volcanic plateau or "shielded" as a result of outflows lava and accumulation on the main nozzle and the low-rise look for the large area occupied by the rules. And look peaks like convex plateaus with convexity weak and from this it renamed volcanoes Plateau These cones originated from the flow of molten severe lava heat and great liquidity, which has spread over large areas and is this volcanic plateau best representation in the volcanoes of the Hawaiian volcano Mauna Loa Islands, which has a height of 4100 m, which seems more like a spacious dome descend steeper easy and fragile.
The Mauna Loa volcano is located in Hawaii and means "Long Mountain" in Hawaiian. It is a giant, basaltic shield volcano. It is one of the largest volcanoes and mountains in the world and has been called the "monarch of mountains". It has an estimated volume of 9,600 cubic miles and takes up half the land of Hawaii. It extends about 120 km starting from the southern tip of the island to the northern region. It is 97 km (60 miles) long, 48 km (30 miles) wide, and is 8,742 km (28,680 miles) high from the base on the sea floor to the top. The slopes are steeper than 12 degrees and about 4 degrees at the top of the volcano. Mauna Loa formed about half a million years ago and in the middle stages of forming into a shield volcano where lava flows to form a sloped and broad flat domed volcanic cone. Along with Mauna Kea, the Mauna Loa volcano is responsible for the creation of the Hawaiian Islands. Mauna Loa has erupted thirty-three times since 1843 and is known as one of the most active volcanoes in the world today. The last eruption was 1984 and lava flowed within 4 miles of the city of Hilo. This shows that it is dangerous to live anywhere near Mauna Loa and that it poses as a threat to anyone living near it because it has a very high possibility of erupting within a very short span of time. Below is a picture of Mauna Loa taken from a bird's eye view.
A volcano is a large hill, with a crater or vent for lava to flow through. Volcanoes can have a lifespan of a couple months to a couple million years. They are one of the most dangerous natural disasters. An erupting volcano can cause other natural disasters. Such as tsunamis, flash floods, and earthquakes.
Volcanoes can be one of the most destructive forces on Earth. It is estimated that some
Our Earth was formed 4.6 Billion years ago. This formation is partly due to the colliding of tectonic plates found under the Earth’s crust. These plates have greatly impacted the way in which the Earth’s outer layer looks and the type of terrain found across its vast surface. One example of these plates at work are volcanoes. Volcanoes are formed through the process of volcanism. This process occurs when “magma- a mixture of molten rock, suspended mineral grains, and dissolved gases formed in Earth 's interior — is forced to the surface.” (Reed,2013) The concept of isostacy is the “ideal theoretical balance of all portions of Earth’s lithosphere as though they were floating on the denser underlying layer is isostacy.” (Reed, 2013) When considering
The process of forming volcanoes is quite simple. Over time, many parts of a volcano such as a sill and summit form on top of one another. All the while, magma from the underground reservoir builds up and eventually makes it's way through the throat of the volcano up to the surface, which is called an eruption. Once magma reaches the surface it is considered lava ("How do volcanoes form?"). Magma can come in different forms. These can range from basalt that is very fluid to andesite that has more resistance, or viscosity ("Volcanoes - Me...