The whole staff community is now being informed about this incident and the admins and Sop are working hard to have everyone unbanned and the security of the server improved.
If the grief happened a little while ago, they can do an area roll back. Which technically means, any changes in the past couple hours will be removed including the huge explosion that it sounds happened. If im not mistaken, the server has a backup ever 1-5 hours or so.
UPDATE: Most of, if not all, of the hackers have been banned and anyone who was banned by them has been unbanned. As far as I know the most likely solution to the griefing, would be to load a backup. This will probably delete everything that was built today but we are still having the admins and Sop discuss and think about what would be the best possible solution to this event. Please be patient for this may take a day or two because some of our admins are on the opposite side of the world. An announcement thread will be posted shortly.