History of the Planet & Plate Tectonics

The outer layer of the earth's rocky bits is fractured like a cracked egg shell. These pieces, called plates, are not stationary. The plates are moving away or across or crashing into one another. This movement results in geological activity, like volcanic eruptions, earthquakes, and continental drift.

There are three main types of volcanic islands:

1. Islands created along mid-ocean ridges such as Ascension Island
2. Islands created over hot spots like the Hawaiian Islands
3. Islands created by plate convergences like the Aleutian Islands