 GEOG: The impact off Cape Hatteras forms a tsunami that we are told  washes inland as far as the Ohio River valley. Given what we are  told about its height, it actually could reach no farther than the  Appalachian Mountains. If any part of the tsunami reached the land  north or south of the mountains, either by a direct route across  land or by diffraction around the end of Florida and then moving  north, it would be too attenuated by this to continue as far as the  Ohio River.