Western Hellenic Subduction Zone: deep earthquake activity 2000 - 2017, plate interface geometry and thermal model

It is debated, however, whether fluids and earthquakes are directly related. By combining seismic observations and geodynamic models from western Greece, and comparing across other subduction zones, we find that earthquakes effectively track the flow of fluids from their slab source at >80 km depth to their sink at shallow (<40 km) depth.

Between source and sink, the fluids flow updip under a sealed interface, facilitating intraslab earthquakes. In some locations, the seal breaks and fluids escape through vents into the mantle wedge, thereby reducing the fluid supply and seismicity updip in the slab. The vents themselves may represent nucleation sites for larger damaging earthquakes.