A map depicting all the worlds eartquakes since 1898. Notice how the Pacific "Ring" is most prominent. This demonstrates how active the Pacific region is tectonically.
It is generally accepted that the activity is down to the surface plates in the region moving. And the northern and western perimeter of the "Ring" is where one plate or plates are subducted under another. The Philippines is in there somewhere, covered in neon green.
http://www.ouramazingplanet.com/3114...uakes-map.html
