Q. With reference to the shadow zone of the seismic waves, consider the following statements:
Which of the statements given above is/are correct?
Q. With reference to the shadow zone of the seismic waves, consider the following statements:
Which of the statements given above is/are correct?
The correct option is B 3 only
Explanation:
There are two types of body waves: P-waves and S-waves which are generated at the focus of the earthquake. The shadow zones for these waves are:
Figure: Shadow Zone of P and S waves.
Statement 1 is incorrect: The seismic shadow zone is the area of the Earth's surface where seismographs cannot detect an earthquake after the waves have passed through the earth.
Statement 2 is incorrect: P-waves are not detected between 105° and 145° from the epicentre, as these waves, while passing through the liquid outer core, are refracted by this layer.
S-waves can not pass through the liquid outer core and are not detected beyond 105°.
Statement 3 is correct: The Shadow zone of S-waves is larger than that of P-waves. As the S-waves are not able to pass through the liquid outer core. Whereas, the P-waves are able to pass through them with refraction, creating a smaller shadow zone.
Explanation:
There are two types of body waves: P-waves and S-waves which are generated at the focus of the earthquake. The shadow zones for these waves are:
Figure: Shadow Zone of P and S waves.
Statement 1 is incorrect: The seismic shadow zone is the area of the Earth's surface where seismographs cannot detect an earthquake after the waves have passed through the earth.
Statement 2 is incorrect: P-waves are not detected between 105° and 145° from the epicentre, as these waves, while passing through the liquid outer core, are refracted by this layer.
S-waves can not pass through the liquid outer core and are not detected beyond 105°.
Statement 3 is correct: The Shadow zone of S-waves is larger than that of P-waves. As the S-waves are not able to pass through the liquid outer core. Whereas, the P-waves are able to pass through them with refraction, creating a smaller shadow zone.
