Volcano Assessment Noel Pd 2

The given statement is false because although the likelihood of being killed by a volcano has decreased significantly due to advances in technology and early warning systems, it is still possible for people to be killed by volcanic eruptions. Volcanic eruptions can cause direct hazards such as pyroclastic flows, lava flows, and volcanic gases, as well as indirect hazards like lahars and tsunamis. Therefore, while the risk has been reduced, it is not accurate to say that people are never likely to be killed by a volcano.

Volcanoes can form on the ocean floor because of the movement of tectonic plates. When two plates separate or collide, magma rises to the surface, creating underwater volcanic activity. This process is known as seafloor spreading or subduction. The volcanic eruptions on the ocean floor can lead to the formation of new islands or underwater mountain ranges. These underwater volcanoes, also known as seamounts, play a crucial role in shaping the Earth's surface and have a significant impact on the marine ecosystem.

The statement that there is no relationship between plate tectonics and volcanoes is false. Plate tectonics is the theory that explains how the Earth's lithosphere is divided into several large and small plates that move and interact with each other. Volcanoes are often formed at plate boundaries, where the plates either converge, diverge, or slide past each other. This movement and interaction of the plates can lead to the formation of magma chambers beneath the Earth's surface, which can then erupt as volcanoes. Therefore, plate tectonics and volcanoes are closely related.

Gas trapped in magma under high pressure can cause explosive eruptions. When magma rises to the surface during a volcanic eruption, the decrease in pressure allows the dissolved gases to expand rapidly and form bubbles. If the magma contains a high concentration of gas and the pressure is intense, these bubbles can expand quickly and violently, leading to an explosive eruption. The force of the expanding gas can fragment the magma into ash, rock fragments, and volcanic bombs, creating a hazardous eruption column and pyroclastic flows. Therefore, the statement is true.

Cinder cone volcanoes actually produce explosive eruptions, not quiet ones. These eruptions occur when gas-rich magma is ejected from the volcano, resulting in a violent explosion. The explosive nature of cinder cone volcanoes is due to the high gas content in the magma, which builds up pressure until it is released in a powerful eruption. This is in contrast to other types of volcanoes, such as shield volcanoes, which typically have less gas content and therefore produce quieter eruptions.

A batholith is formed when magma cools and solidifies underground before reaching the surface. This process takes place over a long period of time, allowing the magma to slowly cool and harden into a large, intrusive igneous rock mass. As the surrounding rock erodes away, the batholith is exposed at the surface. Batholiths are typically composed of coarse-grained rocks, such as granite, and can cover extensive areas.

A volcano is an opening in the Earth's surface that erupts gases, ash, and lava. It is formed when molten rock, called magma, rises to the surface through cracks in the Earth's crust. As the magma reaches the surface, it erupts, releasing gases, ash, and lava. Volcanoes can have different shapes and sizes, and their eruptions can vary in intensity. They are found in areas where tectonic plates meet and are associated with volcanic activity.

Kilauea in Hawaii is considered the world's most active volcano because it has been continuously erupting since 1983. It is known for its frequent lava flows and has been a popular tourist attraction. The volcano exhibits constant activity, making it the correct answer choice.

The amount of water vapor and other trapped gases in the magma is a factor that determines whether a volcanic eruption will be quiet or explosive. When magma contains a high amount of water vapor and gases, it creates pressure within the volcano. If this pressure is released slowly, it results in a quiet eruption. However, if the pressure builds up rapidly, it leads to an explosive eruption. The trapped gases and water vapor play a crucial role in determining the intensity and type of volcanic activity.

Devil's Tower in Wyoming is an example of a volcanic neck. A volcanic neck is formed when magma solidifies inside the vent of an extinct volcano. Over time, the surrounding rock erodes away, leaving behind a tall, cylindrical structure made of solidified magma. Devil's Tower is a prominent example of a volcanic neck, with its distinct columnar shape and height, making it a popular landmark and rock climbing destination.

In 1990, lava from Kilauea covered most of a town in Hawaii. Kilauea is an active shield volcano located on the Big Island of Hawaii. It is one of the most active volcanoes in the world and has been continuously erupting since 1983. The eruption in 1990 resulted in the destruction of the town of Kalapana, with lava flowing over and engulfing homes and infrastructure. This event serves as a reminder of the power and destructive force of volcanic eruptions.

Approximately 600 of Earth's volcanoes are currently active. This means that these volcanoes have erupted at least once in the past 10,000 years and have the potential to erupt again in the future. Active volcanoes are monitored closely by scientists to track any signs of volcanic activity and to ensure the safety of nearby communities. The number of active volcanoes can vary over time as new ones form and others become dormant or extinct.

Magma forms deep inside Earth because of a rise in temperature and increase in pressure. As heat is generated from the Earth's core, it causes the surrounding rocks to heat up and melt, forming magma. Additionally, the increase in pressure from the overlying rocks helps to keep the magma in a liquid state. This combination of rising temperature and increasing pressure creates the conditions necessary for magma formation deep within the Earth.

Volcanoes form islands when lava flows from the rifts in the seafloor and accumulates to a point where it emerges above the ocean's surface. This molten rock, known as lava, is responsible for the formation of volcanic islands.

A sill is a type of magma that intrudes into a horizontal crack between rock layers and solidifies. Unlike a dike, which cuts across the rock layers, a sill is parallel to the layers. It is similar to a batholith, which is a large mass of igneous rock, but sills are smaller in size. A volcanic neck, on the other hand, is formed when magma solidifies in the vent of an extinct volcano. Therefore, the correct answer in this case is sill.

A dike is formed when magma is forced into a crack that cuts across rock layers and then hardens. This process typically occurs vertically, resulting in a vertical sheet-like intrusion of hardened magma. Unlike a batholith or a sill, which are larger and more horizontal in nature, a dike is a relatively narrow and vertical feature. A volcanic neck, on the other hand, is formed when magma solidifies in the neck of a volcano, and is not directly related to cracks in rock layers.

After an eruption, if the top of a volcano collapses down, a caldera forms. A caldera is a large, basin-shaped depression that is formed when the magma chamber beneath a volcano is emptied during an eruption, causing the volcano to collapse inward. This results in a large, circular depression on the Earth's surface. Calderas can be several kilometers in diameter and are often filled with water or subsequent volcanic activity.

The correct answer is resistance to erosion. When a volcano erupts, it releases magma from beneath the Earth's surface. Over time, the surrounding rocks and sediment erode away, but the volcanic neck, which is made of more resistant material, remains. This resistance to erosion allows the volcanic neck to stand tall even after the surrounding area has been worn away.

Most of the rock in Yosemite National Park is an exposed batholith. A batholith is a large mass of intrusive igneous rock that forms deep beneath the Earth's surface. Over time, erosion and uplift have exposed the batholith in Yosemite, creating the stunning granite cliffs and domes that the park is famous for. This explanation fits with the information provided in the question and accurately describes the geological features found in Yosemite National Park.

A steep-walled depression around a volcano's vent is called a crater. Craters are formed when volcanic material is ejected during eruptions, creating a bowl-shaped cavity. These depressions can vary in size and depth and are typically found at the summit or on the flanks of a volcano. Craters are important features that provide insights into the volcanic activity and can also serve as vents for releasing gases and steam.

Parcutin, located in Mexico, is classified as a cinder cone volcano. Cinder cone volcanoes are characterized by their steep sides and conical shape, formed by the accumulation of volcanic debris, such as cinders and ash, around the vent. They are typically small in size and have short-lived eruptions. Parcutin is a well-known example of a cinder cone volcano, as it formed in 1943 and erupted for almost a decade, leaving behind a cone-shaped volcanic structure.

A composite volcano, also known as a stratovolcano, is formed by alternating layers of lava flows and pyroclastic material. These volcanoes are characterized by their steep slopes and explosive eruptions. Soufriere Hills volcano in Montserrat fits this description as it has a composite structure, with layers of both lava and pyroclastic deposits. Its explosive eruptions and steep slopes are further evidence of its composite nature.

The correct answer is "all the possibilities." Silica-rich magma can form at subduction zones, as the subducting oceanic plate melts and mixes with the mantle. This type of magma also produces explosive eruptions because it is thick and viscous, which allows gas to get trapped and build up pressure. Therefore, all of the given possibilities are true for silica-rich magma.

Basaltic magma is silica poor, meaning it has a low silica content. This low silica content results in quiet, nonexplosive eruptions. Basaltic magma has a lower viscosity compared to magmas with higher silica content, allowing gases to escape more easily. This prevents the build-up of pressure that leads to explosive eruptions. Therefore, basaltic magma is the correct answer for the given statement.

Andesitic magma has a moderate amount of silica, which is why it can create composite cone volcanoes. Composite cone volcanoes, also known as stratovolcanoes, are formed when viscous magma, like andesitic magma, erupts. This type of magma has a moderate silica content, which means it is more viscous than basaltic magma but less viscous than granitic magma. The moderate silica content allows andesitic magma to trap gas bubbles, leading to explosive eruptions and the formation of composite cone volcanoes.

Pahoehoe is the correct answer because it is a type of lava that pours freely from volcanic vents of a shield volcano. Pahoehoe lava has a smooth, rope-like texture and can flow for long distances before solidifying. This type of lava is typically low in viscosity and high in temperature, allowing it to flow easily and form smooth, undulating surfaces. Pahoehoe lava is commonly found in shield volcanoes, which are characterized by their broad, gently sloping shape.

The figure represents a cinder cone volcano because it has a steep, conical shape with a symmetrical slope. Cinder cone volcanoes are formed by eruptions of gas-rich lava that eject cinders, ash, and other volcanic materials into the air. These materials fall back to the ground and accumulate around the vent, creating a cone-shaped structure. The figure does not show the characteristics of a composite cone or shield volcano, which have different shapes and eruption patterns.

The figure represents a composite cone volcano. Composite cone volcanoes, also known as stratovolcanoes, are tall and steep-sided volcanoes formed by alternating layers of lava flows and pyroclastic materials such as ash, cinders, and volcanic bombs. They are characterized by explosive eruptions and are typically found at subduction zones where one tectonic plate is forced beneath another. The figure likely shows a volcano with a conical shape and layers of both lava and pyroclastic materials, indicating that it is a composite cone volcano.

The figure represents a shield volcano because it has a broad, gently sloping cone shape, which is characteristic of shield volcanoes. Shield volcanoes are formed by the accumulation of low-viscosity lava flows that spread out in all directions from a central vent. They are typically large in size and have a relatively gentle slope due to the runny nature of the lava.

Magma, which is molten rock beneath the Earth's surface, can rise to the surface through an opening called a vent. This vent acts as a pathway for the magma to escape, allowing it to flow out onto the surface as lava during volcanic eruptions. Vents can vary in size and shape, ranging from small cracks to large openings like volcanic craters.

Pahoehoe and AA lavas are both basaltic. Basaltic lavas are characterized by their low viscosity and fluid-like texture, which allows them to flow easily. Pahoehoe lava is a type of basaltic lava that has a smooth, ropy texture, while AA lava is a more jagged and rough type of basaltic lava. Both types of lavas are commonly associated with volcanic activity and can be found in volcanic regions around the world.

Basaltic magma is known for its low viscosity and low gas content, which leads to nonexplosive eruptions. Kilauea is a shield volcano located in Hawaii, and it is characterized by basaltic magma eruptions that are typically gentle and nonexplosive. This is due to the low silica content and high temperature of the magma, allowing it to flow easily and release gases without building up pressure. Mount St. Helens and Mount Pinatubo, on the other hand, are known for explosive eruptions caused by more viscous and gas-rich magma. Paracutin is a cinder cone volcano, which can have both explosive and nonexplosive eruptions depending on the type of magma.