Fault-controlled magma pathways driving seismicity and eruption risk in Eastern Turkey

Many oceanic and some continental transform faults host coupled tectonic shear and magmatism, complicating seismic and volcanic hazards. Here we integrate high-resolution seismic tomography and three-dimensional finite-element modelling to investigate fault–magma interactions along the eastern North Anatolian Fault Zone. Tomography reveals two shallow magma reservoirs beneath the Erzincan Basin and the Karlıova Triple Junction, characterised by high Vp/Vs (>1.85). The western reservoir is largely aseismic while the eastern reservoir has persistent seismicity. Time-dependent models demonstrate that right-lateral shear focuses tensile stresses around both reservoirs that encourage reservoir rupture and dyke injection. This stress concentration occurs even when the initial magma-generated excess pressure is zero, and may gradually expand towards the surface. Upward stress transfer is enhanced within the fractured damage zone, facilitating dyke propagation. The results may apply to many transform faults and are of great importance for evaluating the coupled earthquake–volcano hazards in such fault zones.