Earthquake is the sudden shaking of ground due tothe breaking and movement of large sections (tectonicrocks) in the crust of the earth.

A tsunami is a largeocean ware that is caused bysudden motion on the ocean floor.

The word 'Tsunami' in Japanese mean 'harbor wave'that refers to a seriesof largeocean waves that hitsthe shoreline.

Richer scale is the scale that measures themagnitudeor intensity of energy released by anearthquake.

Hypocenter is the place of origin of an earthquakewhich is always hidden inside the earth at the depthof 20 km to 700 km.

Epicenter is the place on the ground surface thatis perpendicular to the hypocenter which records thefirst quake.

Seismic waves are the wavesgenerated by anearthquake.

Seismology is the branch of science that dealswith the seismicwaves.

Earthquake is caused because of various differentinternal and external disorder in the surface ofthe earth. It is also caused when the tectonicplates collide each other during its movement. A smallearthquake is caused due to the nuclearexplosion.Volcanic eruption also plays an role tooccurrenceof the earthquake. It is also caused as the effect ofother disaster like derbies flow, tsunami, etc.

The effects of Tsunami are:
-Huge less of propertiessuch as destruction houses,bridges, dams, buildings and other constructions.
-Brings destruction inwayof life, arisesfinancialand economiccrises, etc.
-Increase the risk for rising and sinking the earth'ssurface.
-It also cause the other calamities as its effect.
- It compel us to face the huge loss of life andproperty.

Any three seismic belts are:
- Circum-Pacific Belt.
- Mid-continental Belt.
-Mid-Atlantic Ridge Belt.

The safety measures to be adopted during anearthquake are:
-We shouldn't panic and run about here and there.
-Stay away from windows and big furniture.
- Turn off the electricswitches and gas.
- If possible, we should heat to safe andopen places.
-We should sit under the tables or bed.

a. Hypocenter and Epicenter.

b. Earthquake and Volcano.