The M7.1 Japan aftershock is on a moderately-dipping fault: much steeper than the mainshock. If the quake is on the nodal plane that dips WNW, then there might be strong ground motion near the coast (but over a much smaller area). Just now I checked and there is no tsunami advisory but it is certainly possible to have a small local one for a quake like this. With a steeper fault there can be more vertical motion of the sea floor for a given amount of slip. But, maybe much of the vertical motion will be onshore. Maybe some areas that subsided 1 m in the mainshock will uplift 10 cm in this one.....

It was 1 hour 20 minutes after a M6.5 deep quake in southern Mexico.

Chris

• M7.1 Japan