Hi Beth,
I posted below on bathymetry and Crescent City tsunamis. Yes, the bathymetry of the deep Pacific Ocean has an effect on focusing or defocusing of the tsunami as it approaches the west coast. The local bathymetry you mention, like the canyons, likely has a strong effect on whether some point or some harbor will have a larger wave.

OK, I TA-ed Geology 4 at UCSB a couple of times: that is an Oceanography class. We looked at refraction of waves at Campus Point.

Lets say that there is an offshore canyon that is perpendicular to the coast, and the tsunami is arriving parallel to the canyon. Tsunamis are everywhere shallow water waves. That means that the deeper the water, the faster they travel. So, over a canyon the wave will be faster. Let's say there is a Bay at the head of the Canyon (Monterey Bay for example). you would expect the wavefront to be convex towards the coast.

Ok, now my Physics 1 is failing me: whether a convex towards coast wavefront would focus or defocus the energy I'm having some trouble with

Offshore Ridges leading towards headlands should slow the wave and make a concave towards the coast wavefront.

Between the headland and the bay there should be an inflection point: would that have larger energy?

But, that is not all that is going on: I believe that shallow water will disappate some of the energy. For example, a wide continental shelf like on a passive margin would be less likely to have a large tsunami if everything else was equal (which it is not).

Chris