JOEL - How about , "Who made you God?" or ""Judge not that ye be not judged"(Matt 1:7).
God does not normally cause these things to happen; they just happen. How about all the little children who died? Were they wicked?
When the Teton dam broke in Idaho and washed away many houses and caused much hardship for the residents there, President Spencer W. Kimball was asked the question, "Why did this flood happen to us?" They were no doubt expecting some great prophetic God involved reason for it. His response was. "Because the dam broke."
The prophets don't make any judgments on why these things happen, but they express their sorrow and concern for those affected and immediately get to work doing all they can that will provide as much help as the Church can give.
God created this earth and set it in motion. After that everything that happens on this earth follows a natural course according to the laws of physics. According to the laws of physics it was time for an earthquake to happen, which in turn caused the tsunami. These things are in fulfilment of prophesies that were made about our days. (D&C 45:26–27, 31, 33)
As terrible as these things are, God allows them to happen because they do give us the opportunity to have the works of God be mannifest as we help those who have suffered (John 9:2-3). He is watching us and hoping we will choose to help.
I have never heard a church authority claim that events such as this is God's way of cleansing the earth of the wicked. There are only a few instances of this recorded in the scriptures and the only time it will happen again is at the Second Coming of Christ.