Spreading rate dependence of morphological characteristics in global oceanic transform faults

We quantified the systematic variations in global transform fault morphology, revealing a first-order dependence on the spreading rate. (1) The average age offset of both the full transform and transform sub-segments decrease with increasing spreading rate. (2) The average depth of both the transform valley and adjacent ridges are smaller in the fast compared to the slow systems, reflecting possibly density anomalies associated with warmer mantle at the fast systems and rifting at the slow ridges. However, the average depth difference between the transform valley and adjacent ridges is relatively constant from the fast to slow systems. (3) The nodal basin at a ridge-transform intersection is deeper and dominant at the ultraslow and slow systems, possibly reflecting a lower magma supply and stronger viscous resistance to mantle upwelling near a colder transform wall. In contrast, the nodal high, is most prominent in the fast, intermediate, and hotspot-influenced systems, where robust axial volcanic ridges extend toward the ridge-transform intersection. (4) Statistically, the average transform valley is wider at a transform system of larger age offset, reflecting thicker deforming plates flanking the transform fault. (5) The maximum magnitude of the transform earthquakes increases with age offset owing to an increase in the seismogenic area. Individual transform faults also exhibit significant anomalies owing to the complex local tectonic and magmatic processes.