The North Luzon Trough formed as a result of the oblique convergence between the Eurasian and Philippine Sea plates.
This oblique convergence creates a complex tectonic setting, with both compressional and extensional forces acting on the crust.
The trough itself is a forearc basin, which is a depression that develops in front of an island arc system.
[2] The subducting plate releases fluids and sediments, which accumulate in the forearc basin.
Multi-channel seismic data suggests that the basin's sedimentary deposits resulted from multiple periods of emplacement and erosion.