Part 5: Convergent Boundaries & Subduction
Where Plates Collide
Convergent boundaries are destructive margins where oceanic lithosphere descends into the mantle. Subduction zones produce the deepest earthquakes, the most explosive volcanism, and the largest tsunamis on Earth. From accretionary wedges to back-arc basins, these margins display an extraordinary range of tectonic processes.
~55,000 km
Global Trench Length
3.3×10¹³ N/m
Slab Pull Force
~670 km
Max Slab Penetration Depth
Topics in This Part
5.1 Subduction Zone Mechanics
Slab dynamics, Wadati-Benioff zones, and the forces driving subduction
5.2 Accretionary Wedges
Critical taper theory, the bulldozer analogy, and sediment accretion
5.3 Volcanic Arcs
Flux melting, arc spacing, and ignimbrite flareups
5.4 Back-Arc Basins
Trench rollback, extensional arc systems, and back-arc spreading