It's events like this that the devil uses to make people say, "Why would God do this?" The devil wants to lead people away from the Lord and cause Christians to falter. But this can be used to God's glory.
Pray for the people lost to this disaster, the people affected by the devastation, and that their lives can be rebuilt on the foundation of God. Let's pull together as God's people and pray for healing, rebuilding, and the glory of God to shine through this all. Glorify God through your prayers for these people and with your actions. It may not be possible to go to Japan and help clean up, or go to the other nations hit and help rebuild, but just like Haiti, there will be orphaned children that need help, and there will be places to send funds to to get clean food and water, first aid and missionaries into the field to help those affected.
Dear Lord, please help all of those affected not only in Japan but also around the world. Please help them to rebuild their lives on the rock that is Christ, to heal after their losses, to rebuild their economies. You know more than we do what their needs are Lord, please help them and help us all to glorify your name Lord. In your holy name Jesus, Amen.
The prayer doesn't stop there. Keep praying, keep doing whatever we can to help.