With reference to the shadow zones of Earthquakes which of the following statements is are correct 1...........

Geography and Environment (RAS) World Physical Aspects

With reference to the shadow zones of Earthquakes, which of the following statements is/are correct?

1. The shadow zone of the primary waves is larger than that of the secondary waves because of their early origination.

2. The shadow zone of primary waves appears as a band around the earth between 105° and 145° away from the epicentre.

3. One can draw the shadow zone for any earthquake even if the location of the epicentre is not provided.

Select the correct answer using the code given below:

1 only

1 and 2 only

2 only

1 and 3 only

Earthquake waves get recorded in seismographs located at far off locations. However, there exist some specific areas where the waves are not reported. Such a zone is called the ‘shadow zone’. The study of different events reveals that for each earthquake, there exists an altogether different shadow zone. Statement 1 is not correct:
The shadow zone of S-wave is much larger than that of the Pwaves.
Statement 2 is correct:
The shadow zone of P-waves appears as a band around the earth between 105° and 145° away from the epicentre. The shadow zone of S-waves is not only larger in extent but it is also a little over 40 percent of the earth's surface.
Statement 3 is not correct:
One can draw the shadow zone for any earthquake provided that one knows the location of the epicentre.