# What happens in a shadow zone?

## What happens in a shadow zone?

The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves. The shadow zone results from S waves being stopped entirely by the liquid core and P waves being bent (refracted) by the liquid core.

What happens to secondary waves when they reach the outer core?

What happens when S waves reach Earth’s outer core? S waves cannot travel through liquids, and since Earth’s core is liquid, S waves do not travel directly through Earth. P waves can travel through a liquid and solid, but can be reflected off of the “surface” layer.

Where does the secondary waves can travel?

solids
Secondary waves S-waves can travel only through solids, as fluids (liquids and gases) do not support shear stresses. S-waves are slower than P-waves, and speeds are typically around 60% of that of P-waves in any given material.

### What is the predicted shadow zone for secondary waves that do not travel through a liquid?

The secondary seismic waves cannot pass through the liquid outer core and are not detected more than 104° (approximately 11,570 km or 7,190 mi) from the epicenter.

What happens to S waves when they reach the outer core and what does this indicate about this layer?

S waves cannot pass through the liquid outer core, but P waves can. The waves are refracted as they travel through the Earth due to a change in density of the medium. This causes the waves to travel in curved paths.

Why do secondary waves disappear?

Data from many earthquakes has shown that S-waves disappear when they encounter the liquid outer core. As seismic waves pass from one type of material into another, they are refracted (or bent slightly). As a result of these two observations, scientists have determined that all earthquakes have shadow zones.

#### What is the motion of secondary wave?

The S-wave (secondary or shear wave) follows more slowly, with a swaying, rolling motion that shakes the ground back and forth perpendicular to the direction of the wave.

What happens to the secondary waves S waves when it is approaching to areas with liquid composition?

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.

Why are there no S waves in the Shadow Zone?

The area beyond 105 degrees of distance forms a shadow zone. At larger distances, some P waves that travel through the liquid core would arrive, but still no S waves. The Earth has to have a molten, fluid core to explain the lack of S waves in the shadow zone, and the bending of P waves to form their shadow zone.

## What happens in the Shadow Zone of an earthquake?

shadow zone The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves. The shadow zone results from S waves being stopped entirely by the liquid core and P waves being bent (refracted) by the liquid core.

Which is the best definition of a shadow zone?

Seismic Shadow Zones: P wave. The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves.

When was the Shadow Zone of the Earth discovered?

Through measuring how P and S waves travel through the earth and out the other side, a seismic wave shadow zone was discovered in about 1910. From the lack of S waves and a great slowing of the P wave velocity (by about 40%) it was deduced that the outer core is made of liquid. The shadow zone also defined the diameter of the core.