Aftershocks of the 2011 Tohoku-Oki great earthquake have a wide range of focal depths and fault plane mechanisms. We constrain the focal depths and focal mechanisms of 69 aftershocks with Mw [ 5.4 by modeling the waveforms of teleseismic P and its trailing near-surface reflections pP and sP. We find that the ‘‘thrust events' ' are within 10 km from the plate interface. The dip angles of these thrust events increase with depth from *5° to *25°. The ‘‘non-thrust events' ' vary from 60 km above to 40 km below the plate interface. Normal and strike-slip events within the overriding plate point to redistribution of stress following the primary great earthquake; however, due to the spatially variable stress change in the Tohoku-Oki earthquake, an understanding of how the mainshock affected the stresses that led to the aftershocks requires accurate knowledge of the aftershock location.
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