Here is a quote from

http://www.tsunami.org/faq.htm

"Boats are safer from tsunami damage while in the deep ocean rather than moored in a harbor. U.S. Coast Guard guidelines suggest deployment to water depths of at least 1,200 feet (200 fathoms). However, do NOT risk your life and attempt to get underway if it is too close to the first wave arrival time. Anticipate slowdowns caused by traffic gridlock and hundreds of other boaters heading out to sea."

This tells me that if you have adequate warning your best bet may be to go towards the wave if you have access to a boat.

Any comments?