"Do you not fear me? declares the Lord.
Do you not tremble before me?
I placed the sand as the boundary for the sea,
a perpetual barrier that it cannot pass;
though the waves toss, they cannot prevail;
though they roar, they cannot pass over it."
Quote Source: Bible Gateway
This is actually a good point, in fact, of the 20 or 30 atheist quotes I've responded to here, this is so far, by far, the best. In answer I would only offer what will most likely be an unpopular answer. The atheist tends to criticize the Bible in a far too literal sense. Tsunamis are rare, and for the most part Jehovah's Earthly creation is remarkable.
What a Bible student such as myself thinks of these sorts of problems is that Jehovah created a paradise which was protected for man to subdue. That was his purpose for us, and natural disasters we see in this imperfect sinful inheritance could actually be prevented had we not rejected and continue rejecting his guidance and protection, and not only that, but truth be told, the devastating effects of these events could easily be prevented.
Excellent point though.