Give reasons for the following:

Earthquake can be proved to be helpful for Navigation.

Give reasons for the following:

Japan is an earthquake and Tsunami prone area.

The magnitude of an earthquake is measured by

1. Mercelli scale
2. Seismograph
3. Richter scale
4. None of the above

Which of the following statements related to earthquake focus is not true?

1. It is situated on the surface of the earth & from here the earthquake waves spread horizontally on the earth surface.
2. It is the point of origin of earthquake wave.
3. It is situated below the earths crust
4. Effect of earthquake will be greater if focus is situated near the surface