what do you mean by shadow zone? what is its significance?
Answers
Answer:
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.
Answer:
,Definition
Seismic waves are produced by the energy released from an earthquake. As one side of a fault slips past the other, the pressure that had been stored is released and travels radially away from the focus of the earthquake in the form of primary waves and secondary waves. A seismic shadow zone is an area that receives only one type of seismic wave or, in some places, no seismic activity.
There are two main types of seismic waves:
Primary waves or P-waves are compressional waves that move in a forward and backward motion. They are the first seismic wave to be felt or recorded during an earthquake. If you have ever experienced an earthquake, you may remember the first jolt, this is the P wave.
Secondary waves or S-waves are lateral waves that move as a sine wave perpendicular to the forward movement (propagation) of the wave. They are the second seismic wave to be felt or recorded during an earthquake after the primary wave. When compared to P-waves, S-waves are the more destructive of the seismic waves.