The intensity scale (range varies from 1-12) takes into account the visible damage caused by the event and is named after Mercalli, an Italian seismologist.

In the Permian Period, reptiles dominated and replaced amphibians.

Eon > era > period > epoch

These volcanoes outpour highly fluid lava that flows for long distances. There can be a series of flows with some flows attaining thickness of more than 50 m. Individual flows may extend for hundreds of kilometres.

The near horizontal bodies of the intrusive igneous rocks are called sill or sheet. The thinner ones are called sheets while the thick horizontal deposits are called sills.

Core is made up of very heavy material mostly constituted by nickel and iron. That is why, it is sometimes referred to as nife layer.

The transfer of heat through horizontal movement of air is called advection.

S-waves (secondary waves) arrive at the surface with some time lag. An important fact about S-waves is that they can travel only through solid materials.

India is supposed to have started her northward journey about 200 million years ago at the time when Pangaea broke.

Caroline plate is located between Philippine and Indian plates (North of New Guinea). Nazca plate lies between South America and Pacific plates.

Barrier bar, which gets keyed up to the headland of a bay is called a spit.

Slump is slipping of one or several units of rock debris with a backward rotation with respect to the slope over which the movement takes place.

Half of the earth’s crust is composed of feldspar.

Seif is similar to barchan but it has only one wing or point.

Anticyclone: Anticlockwise pattern in the Southern Hemisphere and Clockwise in the Northern Hemisphere.