A theory in Geology. Explains the large scale motions of the Earth's crust. It tells us that it is not only the continents that are in motion but the oceans as well.

The top crust of the Earth, is not single shell of granite and basalt, but a mosaic of several rigid segments called Plates.

The denser mantle below the earth's crust is called so. It carries the continents and oceans on their backs like a mammoth rafts.

100 Kms.

At the rate of about 20 cms a year.

1. Constructive    2. Destructive   and   3. Conservative.

Movement is well illustrated in the Atlantic oceans. At the mid ocean ridge, new ocean floor is continuously being produced, as the Americas move further apart from Europe and Africa.

Found on all sides of Pacific ocean, on the various plates slide down beneath the surrounding Lithosphere.

It arises where adjacent plates slide past one another along transform faults. This type of movement can cause the most destructive earthquakes.

Are geological fault - planar rock fractures which show evidence of relative movement.

Occurs where plates slide, or, perhaps more accurately, grind past each other along transform faults.

Occur where two plates slide apart from each other.

The plates cannot simply glide past each other because of friction. Thus, stress builds up in both plates and when the stress exceeds, potential energy is released as strain. The energy thus released results in earthquakes.

Transform boundaries.

Conservative plate movements.

It is the shaking of the ground, caused by the movement of earth's crust, causing land slides, destruction of buildings and so on. Technically, it is the sudden release of energy in the Earth's crust, creating the seismic waves.

A wave of energy that travel through the Earth, most often by an earthquake and sometimes by powerful explosions.

Earthquake's underground point of origin.

The point of the earthquake on the earth's surface vertically above the underground point.

An erroneous crack or break in the rock strata of the earth's crust caused by vertical or horizontal movement.

Seismology - professionals involved in this are called Seismologists.

Richter Scale - invented by Charles Richter in 1935. Measures the energy released by the earthquakes. Mercalli Scale - a modified version and widely used for the measurement of the intensity of earthquakes.

Nine - the maximum so far recorded is only 8.9.

SHAN XI in China in 1556, which killed more than 8 lakh people.

28.7.1976 TANG SHAN, China - killing over 2.25 lakh people. (Earlier in May 2008 an earthquake occured in Chichuan province of china, 35000 people).

1. 30.9.1993 - Lattur, Maharashtra - 7600 deaths. 26.1.2001 - Bhuj Dt., Maharashtra - 30000 deaths.

2. 08.10.2005 - Jammu and Kashmir NW region 79000 deaths. Most of the deaths have occured in the Pakistan occupied Kashmir.

Chile.

It is a Japanese word meaning - TSU-Harbour and NAMI - waves. It is the underwater earthquake in deep oceans because of which high tidal waves occur over the oceans and entering into the coastal regions.

26.12.2004 - at Sumatra in Indonesia in the Indian Ocean. It affected the coastal region/districts of Tamilnadu like Nagapattinam, Cuddalore,Chennai, Andamans.

India, Sri Lanka, Indonesia, and Thailand. The casualty of this Tsunami was nearly 2.5 lakh.

Aceh Province.