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Philippines Tectonics |
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My Blogs (olelog) are mainly based on my daily
reading of earth science news.
Here on whatonearth.olehnielsen.dk I try to weave
some of the pieces together to a greater whole with added background info.
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On a world
scale the Philippine Plate is usually mapped a bit like the drawing to
the right.
Indeed the plate is squeezed in between the Eurasian plate and the Pacific Plate, but the situation is more complex than that. The Philippine Islands are surrounded by complex plate boundaries, and the Philippines Plate rather consists of several micro-plates - squeezed in between two convergent plate margins. Please find below a simplified map of the larger tectonic structures.
The lines with black triangles are active subduction zones with teeth on the over-riding plate. Lines with white triangles are passive subduction zones with teeth on the over-riding plate. The major Philippine fault zone is shown as a black line with arrows showing the movement direction. The volcanoes Pinatubo and Mayon are shown as red dots.
The volcanoes of the Philippines are probably the most deadly in world. They are concentrated in a northern volcanic arc above and east of the north-western subduction zone (Manila Trench) and in a southern volcanic ar above and west of the south-eastern subduction zone (Philippine trench).The Sulu trench also produce a (discontinuous) line of active volcanoes. The Mayon volcano may be associated with the transform fault that connects the eastern and the western subduction zones. This transform fault is offset by the younger north-south directed Philippine Fault.
The Eurasian Plate is being subducted along the western side of Luzon and Mindoro at a rate of 3cm/year. The Philippine Fault Zone decouples the northwestward motion of the Pacific with the southwestward motion of the Eurasian Plate. Movements along other active faults are responsible for the present-day high seismicity of the Philippine Archipelago.
For the last 35 years, the Philippines have been affected by 10 earthquakes with magnitude greater than 7.0.
Map of Philippine Plate from USGS marking one of the many eartquakes in the area. Major Tectonic Boundaries: Subduction Zones -purple and Transform Faults -green |
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22 august 2006 Mayon Volcano
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