Question

why did most volcano and earthquakes in the world are located plate  margins

Answer 1

To a first approximation, Earth is a composite of elevated continents and deep ocean basins. We use the present-day sea level to reference topography and bathymetry and the average elevation of the continents is 840 meters, the average depth of the oceans is 3800 meters. The maximum continental elevation is about 8848 meters (Mt. Everest) and the deepest trench is about 10,000 meters (Mariana Trench).

Answer 2

The Himalayas or Rockis or Alps