Runup for tsunami versus non-tsunami earthquakes

Plots of runup from a tsunami, one plot shows average runup and the other maximum:

1. for a given earthquake magnitude, local runup is substantially greater for tsunami earthquakes than for non-tsunami earthquakes; and
2. the degree of scatter is critical for estimating local tsunami hazards—comparison of earthquakes of similar magnitude (1944 Tonankai and 1986 Aleutian, for example) illustrates the discrepancy of maximum runup that could occur.

It is also important to note that these observations pertain to local tsunamis. There is considerably less scatter in the scaling relationship for distant tsunamis because of the smoothing effect of tsunami propagation on small-scale variations of the earthquake rupture process.