Philippines Tectonic Setting and Plate Tectonics Vocabulary

Twenty key vocabulary flashcards to review Philippine tectonics, plate movements, and related geological terms.

Pacific Plate

The large oceanic tectonic plate east of the Philippines; its movement over the Philippine Sea Plate forms trenches and drives frequent seismic activity.

Eurasian Plate

Massive continental plate west of the Philippines; subducts beneath Luzon at the Manila Trench and contributes to Philippine earthquakes.

Philippine Sea Plate

Oceanic plate east of the Philippines that subducts under the eastern islands at the Philippine Trench, generating deep earthquakes and volcanoes.

Ring of Fire

Circum-Pacific belt roughly 40,000 km long with 75 % of Earth’s volcanoes and 90 % of earthquakes; the Philippines is part of this zone.

Philippine Mobile Belt

Highly active tectonic region where the Philippine archipelago sits, squeezed between the Philippine Sea Plate and the Eurasian Plate.

Subduction Zone

Convergent boundary where one plate dives beneath another, forming trenches, earthquakes, and magma that feeds volcanoes.

Convergent Boundary

Plate margin where plates collide, producing mountains, trenches, strong earthquakes, and volcanic arcs.

Divergent Boundary

Plate margin where plates move apart, allowing magma to create new crust—seen at mid-ocean ridges and rift valleys.

Transform Boundary

Plate margin where plates slide sideways past each other, causing earthquakes without creating or destroying crust.

Philippine Fault System

Major left-lateral strike-slip fault running from Luzon to Mindanao; source of shallow, destructive earthquakes.

Philippine Trench

Deep trench east of Mindanao and Eastern Visayas formed by subduction of the Philippine Sea Plate; can trigger strong quakes and tsunamis.

Manila Trench

Subduction trench west of Luzon in the South China Sea where the Eurasian Plate descends beneath Luzon, generating seismic hazards.

East Luzon Trench

Subduction zone off northeastern Luzon where the Philippine Sea Plate dives under Luzon; less active but still a seismic threat.

Strike-Slip Fault

Fault in which blocks of crust move horizontally past each other; example: the Philippine Fault System.

Tectonic Plates

Huge slabs of Earth’s lithosphere that move slowly over the asthenosphere, shaping the surface via quakes, volcanoes, and mountain-building.

Asthenosphere

Plastic, partially molten layer of the upper mantle on which tectonic plates (lithosphere) float and move.

Lithosphere

Rigid outer shell of Earth comprising the crust and uppermost mantle; broken into tectonic plates.

Volcano

Surface opening through which magma, ash, and gases erupt; commonly forms above subduction zones like those around the Philippines.

Earthquake

Vibrations of Earth’s crust caused by sudden release of stress along faults or plate boundaries; the Philippines records ~1,000 felt events yearly.

PHIVOLCS

Philippine Institute of Volcanology and Seismology; government agency that monitors earthquakes and volcanic activity in the Philippines.