The USS O'Kane makes its way out of Pearl Harbor as the state of Hawaii prepares for a possible tsunami generated by an 8.8-magnitude earthquake near Chile. The U.S. Navy ordered four ships based at Pearl Harbor to move out of harm's way as a precautionary measure, but the warning was later canceled, and the ships returned. U.S. Navy photo by Petty Officer 1st Class Mark Logico

U.S. Navy Adm. Mike Mullen, center, chairman of the Joint Chiefs of Staff, walks with U.S. soldiers in a devastated area of downtown Port-au-Prince, Haiti, Feb. 26, 2010. U.S. servicemembers are conducting humanitarian missions in the wake of the Jan. 12 earthquake that devastated the Caribbean nation. DoD photo by U.S. Navy Petty Officer 1st Class Chad J. McNeeley

U.S. Navy Adm. Mike Mullen, left, chairman of the Joint Chiefs of Staff, meets with Haitian President Rene Garcia Preval during a visit to Port-au-Prince, Haiti, Feb. 26, 2010. U.S. forces are conducting humanitarian missions in Haiti in the wake of the Jan. 12 earthquake that devastated the Caribbean nation. DoD photo by U.S. Navy Petty Officer 1st Class Chad J. McNeeley

Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, meets with local citizens in Port-au-Prince, Haiti, on Feb. 26, 2010. Mullen is visiting Haiti to observe humanitarian missions being performed by U.S. servicemembers. DoD photo by U.S. Navy Petty Officer 1st Class Chad J. McNeeley

A U.S. Marine crosses a canal near Marja, Afghanistan, Feb. 21, 2010. Marines have to cross many canals and drainage ditches while conducting patrols in the area. The Marine is assigned to Charlie Company, 1st Battalion, 3rd Marine Regiment. U.S. Marine Corps photo by Cpl. Albert F. Hunt

U.S. Marines, bottom, talk to a British soldier near Marja, Afghanistan, Feb. 21, 2010. The Marines, assigned to Charlie Company, 1st Battalion, 3rd Marine Regiment, and British soldiers are working together to clear the area of Taliban forces. U.S. Marine Corps photo by Cpl. Albert F. Hunt

U.S. Marines and Afghan soldiers conduct a patrol near Marja, Afghanistan, Feb. 21, 2010. The Marines are assigned to Charlie Company, 1st Battalion, 3rd Marine Regiment. U.S. Marine Corps photo by Cpl. Albert F. Hunt

U.S. Army Sgt. Jose Gonzalez gives snacks to Afghan children during a patrol in Dagyan village in Helmand province, Afghanistan, Feb. 21, 2010. Gonzalez is assigned to Company C, 4th Battalion, 23rd Infantry Regiment. U.S. Air Force photo by Staff Sgt. Christine Jones