Watch for falling Guams!

Hank Johnson, Georgia Democrat in the U.S. House of Representatives, is obviously very concerned with the Marine presence in Guam.  His main concern is that the island will tip over and fall into the ocean killing thousands.  Global warming doesn't appear to help the matter.  Yes, global warming and over population are going to decimate the entire island of Guam.  But what I really can't understand is, how big is Guam really?  20, 7, 24 miles across?  Apparently, the only people who know don't share with Congressmen...