<p>New field work, combined with analysis of aerial photographs, high resolution, digital elevation models, and satellite imagery has identified an active fault that is traceable for ∼ 90 km across the Seymchan Basin, and is part of the Ulakhan fault system, which is believed to form the Okhtotsk-North America plate boundary. Age dating of alluvial fan sediments in a channel system that is disturbed by and abandoned due to fault activity, suggest the current scarp is a result of a series of large earthquakes (≥ M<sub>w</sub> 7.5) that have occurred since ∼11.5 ka. A possible offset channel edge associated with these sediments yields a slip rate of ∼ 5–6 mm yr<sup>−1</sup>, in broad agreement with rates suggested from global plate tectonics and other theoretical studies. Our results clearly identify the Ulakhan fault as the Okhotsk-North America plate boundary, and show that tectonic strain release is strongly concentrated on the boundaries of Okhotsk. In the light of our results, the likelihood of recurrence of M<sub>w</sub> 7.5 earthquakes is high, raising serious questions of seismic hazard across the region.</p>