I hesitate to post this observation because I don't wish to diminish the tragic aspect of this event, but others have commented on that better than I can, so I will mention the following as an addition to what has already been posted:

I find it interesting from a survival standpoint that some accounts reported that the sea receeded before the main wave hit. I read some reports that hundreds of feet of sea bed were exposed that had never been exposed before. People had no idea what it meant and it actually drew onlookers to the beach where they were exposed to more danger. Some people were gathering fish that were left stranded by the receeding water. I don't know how much time this kind of "warning" would provide, but I guess that would be a good time to run for it. Even 30 seconds or a minute head-start could improve your chances if you were able to reach higher ground or a protected area. I don't recall hearing about this kind of effect before.