Geology of The Philippines

The Philippines are part of the ring of volcanoes around the Pacific Ocean. The Pacific Plate is surrounded by convergent rims, where one plated submerges under another plate. This collision produces a sort of accumulation of volcanic rocks, which form a rim of islands along the plate rim. So the islands of the Philippines are of volcanic origin, and the obvious guess would be that caves are most likely lava tubes. Actually the sediments on top of the plates ar also uplifted by the convergent movement, and so there is a large amount of sedimentary rocks including limestone.

The longest cave of the Philippines is currently Puerto Princesa Subterranean River, which is 32 km long. A famous karst area are the Chocolate Hills on Bohol, the tenth-largest island. The dome-shaped limestone hills are a typical tropic ExplainTower Karst. The name is a result of the grass which covers the hills. It dries up and turns brown under the sun in dry season.