What is Plate Tectonics as Earthquake Terminology? What are Aseismic and Seismic Deformation?

Dear reader we have discussed about continental drift in the very beginning posts of our blog. We have also learnt about formation of Mount Everest and Andes earlier. This theory shows us that the massive continents are pushing across ocean floor and through seas by some forces.

Plate tectonic is involved with above theory. Here earth surface is considered as coalition of number of intact blocks termed as plate. These large plates move past each other by a driving force. These plates are

1. African plate

2. American plate

3. Antarctica plate

4. Australia-Indian plate

5. Eurasian plate

6. Pacific plate

Major tectonic plates with direction of movement showing other details as in legend

There have also 14 subcontinental plate also like

1. Caribbean

2. Cocos

3. Nazca

4. Philippine etc

These are also called microplates.

Microplates were broken from large plates (major plates) near boundaries of many plates. The deformations generated between plates are found to occur near narrow zones of their boundaries, some deformations are continuous and slow and some are sudden.

The slow and continuous deformation will not produce earthquake i.e. aseismic deformation and the sudden deformation produce earthquakes i.e. seismic deformation.

Seismic activity over the world showing epicenters of significant earthquake

According to this theory, as deformations mainly occur at plate boundaries, it is also expected to found epicenters of earthquake near plate boundaries. The figure provided above showing earthquake epicenters also supports this theory.