This is an extremely complicated tectonic area where the Pacific, Australian, Asian
and Indian Ocean plates all collide. There are many microplates in this general
vicinity as well. The answer to your question is best left to the experts on this
region, and I do not fall in that category. This is probably one of the most complicated
tectonic zones in the world.
Perhaps Don in Hollister can find something on the web that will help out -- help Don!!!