There are many different types of volcanoes in the world we call Earth. However, there is one specific type we are focusing on today. They are known as the seamounts, or underwater volcanoes. More specifically, the focus will be on the Axial Seamount. Hidden below the Pacific ocean, about 300 miles off the coast of Oregon, lies the Axial Seamount. It is located on the plate boundary between the Pacific tectonic plate and the Juan de Fuca tectonic plate. The plate boundary is a divergent plate boundary, meaning that the two plates are slowly pulling away from each other. This causes a gap to be left behind in the ocean’s crust. Magma from deep below races to fill in the gap. Once the magma reaches the ocean water, it is cooled into a solid …show more content…
The closest landmass is the North American Continent. As stated before, the surrounding tectonic plates are the Juan de Fuca plate, the Pacific plate, and the North American Plate. It is also located on the Juan de Fuca ridge, or as before stated, a mid-ocean ridge.
Axial Seamount contains a caldera. A caldera is a large crater caused by an extreme and explosive volcanic eruption, or when a large volume of rock gives way into a large chamber underneath from years of wear from the flowing magma. The caldera of Axial Seamount covers an area of 3 x 8 km wide. A few interesting facts that I uncovered in my research are that Axial Seamount was the site of the first underwater research facility for seamounts called NeMo. Another interesting fact was that after the eruption of 2011, scientists believed that Axial would become dormant, but it proves to be active to this day.
In conclusion, Axial Seamount is an underwater volcano on the Juan de Fuca ridge, between the Juan de Fuca and the Pacific tectonic plates. It is one of the most active in the Northeastern Pacific region to this day. It has even been in the news on several occasions. Axial Seamount is fantastic example of how a mid-ocean ridge operates on a diverging plate boundary. However, we must remind ourselves that this is just one of the many interesting and unique volcano type on our home planet we call
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.
Over the centuries, the making of the Big Island as we know it today eventually entailed the growth and conjoining of six separate volcanoes, building all the way up from the seafloor, some 18,000 feet below the ocean’s surface. These volcanoes, from northwest to southeast, are named Mahukona, Kohala, Mauna Kea, Hualalai, Mauna Loa and Kilauea, and become younger as one moves north to south. Mahukona Volcano, just off the Big Island’s northwest coast, was the first volcano to start forming. Now submerged beneath the surface of the ocean because it is sinking into the Earth’s crust under its own vast weight, Mahukona is no longer visible. As the Pacific Plate slowly continued moving northwestward over the hotspot, the location of the rising magma moved relatively southeastward, and through time the rest of the Big Island volcanoes formed along that path.After Mahukona, Kohala Volcano, the precursor to today’s Kohala Mountain, erupted next. As Kohala Volcano emerged from the sea and joined with Mahukona, a much larger Big
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.
... used to be a sea (Beaumont,1978). As mountain-building forces continued for several million years it created a big fold or anticline as it squeezed the rocks. These same pressures continued and overturned the fold which eventually caused them to break along a great low-angle fault (Beaumont,1978). The western limb of the fold was driven upward and eastern placing older layers of rock on top of younger ones. The younger layers of rock include cretaceous shales and sandstones. The slice of crust has been moved more than 15 miles toward the east, the surface it moved through is called the Lewis Overthrust. (Dyson,1957). Years of erosion finally exposed the fault which was buried throughout its early years. Erosion then separated several remnants, Chief Mountain is the best known which consists of Altyn limestone, exposed on its base is the Lewis Overthrust fault.
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.
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 ...
About 20 million years ago the last part of the Farallon sea floor plate subducted under the North American plate. This put the North American plate and the Pacific plate into contact, but unlike the Farallon sea floor plate, the Pacific plate sheared against the side of the North American plate. Because there was no plate subducting, the North American plate was in direct contact with the mantle (Tierney, 29). Heat from the mantle made the continental crust more ductile, which allowed the crust to extend and thin.
First you might need to know definition of tectonics. It is a theory in geology. The lithosphere of the Earth is divided into a small number of plates which float on and travel independently over the mantle and much of the Earth’s seismic activity occurs at the boundaries of these plates. That is the official definition of Plate tectonics. secondly, this plate covers many parts of continents. plate boundaries don’t go according to Continents boundaries, they make their own boundaries. The North American plat...
It also stretches across some oceanic crust which “lies between the continent and various surrounding ocean ridges.” The African plate actually has 6 major other plates connected to it as well, but Mount Etna is located in the North, on the Eurasian
Super volcanoes are formed when magma rises from the mantle to create a scorching reservoir in the Earth's
Volcanoes can be one of the most destructive forces on Earth. It is estimated that some
The concurrent convective circulations in the mantle leads to some segments of the mantle moving on top of the outer core which is very hot and molten in nature. This kind of movement in different segments occurs as tectonic plates. These tectonic plates are basically seven on the earth surface as major ones, although, several small ones exist also. The plates motions are characterized by varying velocities, this variance results to sub sequential collision of two plates (leading to formation of a mountain in a convergent boundary), drift of two plates (leading to formation of rifts in a divergent boundary), or parallel movement in a transform boundary(Webcache 3).
inferred for the reservoir (4). The magma ascent to the surface occurred through a conduit of possibly 70 to 100 m in diameter (5). A thermal model predicts that such a reservoir should contain a core of partially molten magma (6) that can be detected by high-resolution seismic tomography.