Tectonic Dynamics and Seismicity in Arc-Continent Collision Zones

Arc-continent collision zones form where an oceanic plate bearing an island arc converges with and is thrust beneath a continental margin, generating complex deformation, uplift and seismicity. These regions are characterised by double-vergence structures, sutures that mark former ocean basins, accretionary wedges built of scraped-off sediments and crustal slices, and basement uplift in adjacent mountain belts. Interactions between thrust, strike-slip and normal fault systems control the distribution of earthquakes from shallow crustal levels to deeper seismogenic zones. Ongoing convergence produces transpressional deformation and stress transfer between adjacent fault segments, influencing earthquake clustering and recurrence intervals. Surface uplift, erosion and sediment dispersal feed back on tectonic loading and help to trace the evolution of orogenic systems. The global significance lies in understanding seismic hazards and landscape evolution from Taiwan to the Mediterranean; practical applications include refining time-dependent hazard models, informing infrastructure design and guiding land-use planning in densely populated collision belts.

Research from Nature Portfolio

Recent studies have combined high-resolution geodesy with detailed field mapping to reveal how interacting faults within a double-vergence suture accommodate seismic and aseismic slip. In eastern Taiwan, coseismic rupture on a north-trending, west-dipping range-bounding fault dynamically triggered shallow slip on an east-dipping valley fault. Overlapping seismic and creeping behaviour demonstrated mutual stress suppression, producing out-of-phase seismic bursts and underscoring a need for time-dependent hazard reassessment in complex, poly-fault systems.

Investigations of the 2022 Mw7.0 earthquake sequence further substantiated the existence of a previously unrecognised west-dipping boundary fault beneath the Longitudinal Valley. Joint source inversions showed that rupture nucleated on this fault, propagated northwards at ~2.5 km/s, and passively triggered slip on the known east-dipping valley fault. This finding reshapes models of strain partitioning and highlights concealed seismogenic structures beneath accretionary sutures.

Tectonic Dynamics and Seismicity in Arc-Continent Collision Zones publication trend

The graph below shows the total number of articles in tectonic dynamics and seismicity in arc-continent collision zones across all publications each year (not limited to Nature Index journals).

Technical terms

Suture: A zone of former oceanic crust welded between colliding plates, now marked by complex faulting.

Double vergence: Opposing directional thrusting on either side of an orogenic core, producing two vergent fold-thrust systems.

Accretionary wedge: A pile of sediments and tectonic slices scraped off a subducting plate and thrust landward.

Coulomb stress: A measure of how changes in shear and normal stress on a fault influence its failure potential.

Forearc basin: A sedimentary basin forming between an island arc and its associated trench or accretionary prism.

b-value: A statistical index from the earthquake magnitude–frequency distribution indicating relative proportions of small to large events.

References

1. Fast-eroding Taiwan and transfer of orogenic sediment to forearc basins and trenches in the Philippine and South China seas. Earth-Science Reviews (2023).
2. Nearby fault interaction within the double-vergence suture in eastern Taiwan during the 2022 Chihshang earthquake sequence. Communications Earth & Environment (2023).
3. Spatiotemporal seismicity pattern of the Taiwan orogen. Natural Hazards and Earth System Science (2023).
4. The role of the west-dipping collision boundary fault in the Taiwan 2022 Chihshang earthquake sequence. Scientific Reports (2023).
5. Seismogenic structure beneath the northern Longitudinal Valley revealed by the 2018–2021 Hualien earthquake sequences and 3-D velocity model. Terrestrial Atmospheric and Oceanic Sciences (2022).