GEOLOGY

Detailed explanation-1: -The spot underground where the rock first breaks is called the focus, or hypocenter of the earthquake. The place right above the focus (at the ground surface) is called the epicenter of the earthquake. Cutaway view of the reverse fault. The earthquake starts at the focus, with slip continuing along the fault.

Detailed explanation-2: -The point on a fault at which the first movement or break occurs during an earthquake is called the earthquakes hypocenter (focus) (figure 1). In the case of a large earthquake, a section of a fault that is many kilometers long may slip, but there is always a point at which the first movement occurred.

Detailed explanation-3: -Earthquakes occur along faults, which are fractures between blocks of rock that allow the blocks to move relative to one another. Faults are caused by the bumping and sliding that plates do and are more common near the edges of the plates.

Detailed explanation-4: -The point at the surface directly above the focus is called the earthquake epicentre. Intense vibrations, or seismic waves, spread out from the initial point of rupture (the focus) like ripples on a pond. These waves are what makes the ground shake and can travel large distances in all directions.

Detailed explanation-5: -Explain to students that earthquake energy travels in the form of waves. These waves are called seismic or earthquake waves. There are different kinds of earthquake waves: body waves and surface waves. Body waves pass through the interior of the Earth whereas surface waves travel along the Earth’s surface.