At slower-spreading ridges, plate separation is often partly accommodated by slip on long-lived detachment faults, commonly forming corrugated domes called oceanic core complexes. However, the mechanics of this process, and the subsurface structure and connectivity of oceanic detachments, remain uncertain. I will present the results of repeat passive microearthquake surveys conducted in 2014 and 2016 over a pair of oceanic detachments on the Mid-Atlantic Ridge near 13°N. The two ocean bottom seismograph networks provided dense spatial coverage of the two adjacent detachment faults, and the intervening ridge axis. Although both detachments exhibited high levels of seismicity, they are separated by a ~8–10 km wide aseismic zone, indicating that they are mechanically decoupled. Significant changes in the patterns of seismicity between the two surveys are observed implying that stress accumulation and release varies on years-long cycles.
Meeting ID: 845 8663 6933