Natural Catastrophic Events
Introduction
The major types of natural calamities are
- Volcanoes
- Earthquakes
- Tsunami
Volcanoes:
Volcanism and causes of volcanism aren’t random. The areas of high volcanic activity are of ocean – ocean convergence and ocean continent convergence.
One of the regions is the Pacific ring of fire located in the pacific ocean and consists of border areas of China, Philippines, Japan, rocky mountains, Mexico , Andes mountains, Indonesia, new Zealand, Tanzania.
The second reason for volcanoes is the ocean – ocean divergence which creates peaceful basaltic eruptions as mid ocean ridges are formed.
The third reason for volcanic eruptions is breaking up of plates into blocks. The andesitic eruptions are seen in this type.
Intrusive land – forms:
1.Sills – Horizontal
2.Dykes – vertical
3.Laccoliths – magma which couldn’t come out
4.Balolith – intrusive granite rock
5.Phacolith – shaped like waves
6.Lopolith – saucer shaped.