Give a geographical reason for each of the following:

(i) Most earthquakes occur on account of plate movements.

(ii) Primary waves are the first earthquake waves to be recorded on a seismogram.

(iii) Volcanic activity and earthquakes occur in the same belt.

(i) Most earthquakes occur on account of plate movements because when two plates slip past each other or collide against each other, their edges produce faults along the lines of weakness.

(ii) Primary waves are the first earthquake waves to be recorded on a seismogram because they travel at the greatest speed and can pass through solids, liquids and gases.

(iii) Volcanic activity and earthquakes occur in the same belt because earthquakes and volcanoes are formed along faults between tectonic plates, where the crust is weakest.