How does the structure of Earth’s interior affect seismic waves quizlet?
How does the structure of Earth's interior affect seismic waves. The direction and speed of waves change as they travel through different density materials. P waves can travel through solids and liquids. S waves can only travel through solids.
How is seismic waves related to Earth’s interior?
Seismic waves tell us that the Earth's interior consists of a series of concentric shells, with a thin outer crust, a mantle, a liquid outer core, and a solid inner core. P waves, meaning primary waves, travel fastest and thus arrive first at seismic stations. The S, or secondary, waves arrive after the P waves.
How do seismic waves affect the interior and exterior part of the Earth?
Seismic waves travel at varying speeds when they pass through different types of matter. The composition of earth's different layers is different. Therefore when the seismic waves reach boundaries of rocks of the earth's different layers their speed and direction will change accordingly.
How does seismic waves reveal the structure of Earth?
By measuring the time it takes for seismic waves to travel along many different paths through the earth, we can figure out the velocity structure of the earth. Abrupt changes in velocity with depth correspond to boundaries between different layers of the Earth composed of different materials.
How seismic waves are created and how they help scientists understand Earth’s structure?
Scientists can tell by observing the seismic waves that are recorded all over the surface of the earth from distant earthquakes. The seismic waves are reflected (bounced off) layers of different density, and they are refracted (bent) when they enter layers of different density.
What type of seismic waves move through Earth’s interior by compressing and expanding rocks?
P waves cause the ground to compress and expand, that is, to move back and forth, in the direction of travel. They are called primary waves because they are the first type of wave to arrive at seismic recording stations. P waves can travel through solids, liquids, and even gases.
What is the main cause of seismic waves?
Seismic waves are caused by the sudden movement of materials within the Earth, such as slip along a fault during an earthquake. Volcanic eruptions, explosions, landslides, avalanches, and even rushing rivers can also cause seismic waves.
Which seismic waves travel through the interior layer of the Earth?
P-waves and S-waves are known as body waves because they move through the solid body of the Earth. P-waves travel through solids, liquids, and gases. S-waves only move through solids (Figure 1).
How does the structure of the Earth affect the seismic wave speed and direction?
Seismic waves move more slowly through a liquid than a solid. Molten areas within the Earth slow down P waves and stop S waves because their shearing motion cannot be transmitted through a liquid. Partially molten areas may slow down the P waves and attenuate or weaken S waves.
What does the bending of seismic waves imply about the composition structure of the Earth?
This indicates that P-waves slow down in the outer core, suggesting that this layer has a significantly different composition from the mantle and may actually be liquid. This bending in the outer core creates a P-wave shadow zone where no P-waves are detected. 5. The bending of seismic waves is called refraction.
How are seismic waves used to determine the position and thickness of Earth’s interior layers?
How are seismic waves used to determine the position and thickness of Earth's interior layers? Dense rock layers will slow the velocity of seismic waves and allow them to pass straight through with no deflection. Dense rock layers will allow seismic waves to pass straight through them.
What happen when seismic waves travel deeper into the crust?
2. Figure 19.7: Beneath the crust, seismic waves increase abruptly indicating a sharp boundary between the crust and upper mantle. This is due to the compositional change from granite, or basalt, to peridotite that comprises the upper mantle. The boundary between the crust and upper mantle is called the Moho.
Which seismic waves stay on Earth’s surface?
There are different types of seismic waves based on the movement . The two major types are body waves ( S and P waves ) and surface waves. Body waves can travel through earth inner layers while surface waves can travel only on the surface of the land.
What seismic waves only travel through Earth’s interior explain why?
S-waves can only move through solids. This is because liquids and gases don't resist changing shape. P-waves and S-waves are the two types of body waves.
What does the bending of seismic waves imply about the composition structure of the earth?
This indicates that P-waves slow down in the outer core, suggesting that this layer has a significantly different composition from the mantle and may actually be liquid. This bending in the outer core creates a P-wave shadow zone where no P-waves are detected. 5. The bending of seismic waves is called refraction.
What causes seismic waves?
Seismic waves are usually generated by movements of the Earth's tectonic plates but may also be caused by explosions, volcanoes and landslides. When an earthquake occurs shockwaves of energy, called seismic waves, are released from the earthquake focus.
How do waves behave differently in Earth’s interior?
Seismic waves travel at different speeds through different materials. In this 2-layer model two wave fronts leave an impact at the same time but the lower layer is faster. Seismic waves travel a curving path through the earth due to changes in composition, pressure, and temperature within the layers of the Earth.
Which type of seismic waves generally cause the most structural damage as they travel through Earth?
S waves arrive next and cause a structure to vibrate from side to side. They are the most damaging waves, because buildings are more easily damaged from horizontal motion than from vertical motion.
How do seismic waves affect large structures?
Large structures or high rise buildings are more affected by long period, or slow shaking. For instance, an ocean liner will experience little disturbance by short waves in quick succession. However, a large swell will significantly affect the ship.
What are the seismic effects on structures?
Earthquake causes shaking of the ground. So a building resting on it will experience motion at its base. From Newton's First Law of Motion, even though the base of the building moves with the ground, the roof has a tendency to stay in its original position.
How are structures affected by earthquakes?
They may sustain structural damage but are designed to remain standing. The stronger the earthquake, the more the building moves in response. If the building shakes too much, structural elements, including beams, columns, walls and braces, can be damaged, rendering the building nonfunctional.
What is seismic effect?
Seismic effects means direct and indirect effects caused by an earthquake or an underground nuclear detonation.
Why do seismic waves bend as they travel in the interior of the earth?
2. Figure 19.2: The earth, however, is compositionally layered and the density of rocks, particularly in the mantle, generally increases with depth. As a result, seismic waves bend and reflect as they travel through the earth.
How does seismic structure affect?
Earthquake causes shaking of the ground. So a building resting on it will experience motion at its base. From Newton's First Law of Motion, even though the base of the building moves with the ground, the roof has a tendency to stay in its original position.