The aftershock pattern suggests that perhaps two perpendicular faults ruptured at once, which is not uncommon. The sense of motion for the M=6.1 mainshock includes both strike-slip (horizontal) and thrust (vertical) slip, consistent with an inference of a two-fault rupture.

The aftershock pattern suggests that perhaps two perpendicular faults ruptured at once, which is not uncommon. The sense of motion for the M=6.1 mainshock includes both strike-slip (horizontal) and thrust (vertical) slip, consistent with an inference of a two-fault rupture.

The aftershock pattern suggests that perhaps two perpendicular faults ruptured at once, which is not uncommon. The sense of motion for the M=6.1 mainshock includes both strike-slip (horizontal) and thrust (vertical) slip, consistent with an inference of a two-fault rupture.