At least it's not as bad as Aceh in the Boxing Day tsunami a few years back.
Wikipedia tells us that:
Earthquakes, volcanic eruptions and other underwater explosions (detonations of nuclear devices at sea), landslides and other mass movements, bolide impacts, and other disturbances above or below water all have the potential to generate a tsunami.
Ocean levels have been rising for a while, as predicted, and scientists expect the trend to continue. Not sure how much difference it makes but you'd imagine it would tend to make the effect of tsunamis worse. As we clear more land near the sea you'd also expect more landslides.