Seismic waves from an earthquake’s focus travel
through the earth along bent paths
and are eventually recorded by distant seismograph stations. The character of the waves and the time it takes for them to reach a particular location reveals important clues as to the nature of the earth’s interior.
How do seismic waves form and travel?
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.
Which wave travels out of the focus?
Body waves
. Body waves radiate outward from the focus in all directions and travel through solid rock.
How do seismic waves behave as they travel?
Seismic waves travel
a curving path through the earth due to changes in composition, pressure, and temperature within the layers of the Earth
. 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.
Where do seismic waves come from?
The point within the earth along the rupturing geological fault where an earthquake originates is called the
focus, or hypocenter
. The point on the earth’s surface directly above the focus is called the epicenter. Earthquake waves begin to radiate out from the focus and subsequently form along the fault rupture.
Where do seismic waves travel fastest?
Surface waves travel along the surface. There are two types of body waves:
P-waves travel fastest
and through solids, liquids, and gases; S-waves only travel through solids. Surface waves are the slowest, but they do the most damage in an earthquake.
What do seismic waves tell us?
Knowing how the waves behave as they move through different materials enables us to learn about the layers that make up the Earth. 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
.
How far do seismic waves travel?
In the Earth, P waves travel at speeds from about 6 km (3.7 miles) per second in surface rock to about 10.4 km (6.5 miles) per second near the Earth’s core some 2,900 km (1,800 miles) below the surface. As the waves enter the core, the velocity drops to about 8 km (5 miles) per second.
What do waves carry from place to place?
A wave is a disturbance that transfers energy from one place to another without transferring matter. Waves transfer
energy away from the source, or starting place, of the energy
.
How do seismic waves radiate outward from their point of origin?
During an earthquake, energy is released in waves that travel from the earthquake’s focus or point of origin, in the form of seismic waves. The seismic waves radiate from the focus like
ripples on the surface of a pond moving outward from where a stone is thrown into the water
.
Which seismic wave stay on earths surface?
S waves are called secondary waves because they always arrive after P waves at seismic recording stations. Unlike P waves, S waves can travel only through solid materials. After both P and S waves have moved through the body of Earth, they are followed by
surface waves
, which travel along Earth’s surface.
What kind of seismic wave travels in the mantle of the Earth?
4. Figure 19.2a:
P-waves
generally bend outward as they travel through the mantle due to the increased density of mantle rocks with depth. When P-waves strike the outer core, however, they bend downward when traveling through the outer core and bend again when they leave.
Why do seismic waves speed up as they travel deeper into the crust?
The density of the mantle also increases at greater depth, which has the effect of reducing the speed of seismic waves, but
the increase in rigidity is much greater than the increase in density
, so S-waves speed up as they get deeper in the mantle, in spite of the increased density.
Why do seismic waves refract?
If it passes across a boundary to a lower velocity layer, the wave will be refracted downward and slow down. Because velocity generally increases with depth in the mantle, the wave paths get bent until they reach a critical angle at which point, the waves return to the surface following a curved path upward.
What is created during an earthquake that travels from the focus to the interior and surface of the Earth?
Explain to students that earthquake energy travels in the form of waves. These waves are called
seismic or earthquake waves
. There are different kinds of earthquake waves: body waves and surface waves. Body waves pass through the interior of the Earth whereas surface waves travel along the Earth’s surface.
When seismic waves travel deeper into the crust the quake will?
Answer. Answer: Seismic stations located at increasing distances from the earthquake epicenter will record seismic waves that have traveled through increasing depths in the Earth. … Molten areas within the Earth slow down P waves and
stop S waves
because their shearing motion cannot be transmitted through a liquid.
Why are seismic waves important?
The importance of seismic wave research lies
not only in our ability to understand and predict earthquakes and tsunamis
, it also reveals information on the Earth’s composition and features in much the same way as it led to the discovery of Mohorovicic’s discontinuity.
How does studying the seismic waves make scientists infer that the Earth’s outer core is liquid?
For example, we know that Earth’s outer core is liquid
because s-waves are not able to pass through it
; when an earthquake occurs there is a “shadow zone” on the opposite side of the earth where no s-waves arrive.
