Why do earthquakes occur only in some parts of the world?

The map shows where earthquakes have happened . These occur near the edges of the Rearth's Crustal plates.

The plates are slowly moving together or apart. For instance , one zone encircles the Pacific. Here , the floor of the Pasific is being pushed down under the continents, and this gradual movement of Pacific plates agaist the continental plates causes earthquakes. Other zones are in the Mediterranean and the Atlantic.