The area where seismic energy is concentrated is at the edges of the shadow
zone - about 102-107 degrees and 142-146 degrees from the mainshock. Little
seismic energy is available within the shadow zone which is where it got it's
name from - there's a shadow in the seismic arrivals at these distances. Little
triggering (except possibly at 127-129 degrees where a cusp occurs) is likely
in this zone.