According to wikipedia scale an 8.8 magnitude earthquake has approximately the same energy release as a 288 megaton nuke. Since the largest nuclear bomb ever was 100 megaton and a 35km radius for the zone of total destruction, direct bombing is almost certainly more damaging.
I (morbidly) wonder if it would be possible to set off a tsunami with just the explosion, without necessarily the ground movement. It would seem to me that a lot of the earthquake's energy release would go into shaking the ground.
