Quake rattles Kadena Published Feb. 26, 2010 By 18th Wing Public Affairs KADENA AIR BASE, Japan -- An earthquake struck this morning around 5:30 a.m. off the coast of Okinawa, 50 miles east-southeast of Naha. There were no reports of damage or injuries on base, nor any impact on the base's mission. The U.S. Geological Survey assessed the magnitude of the quake at 7.0 while the Japan Meteorological Agency calculated a magnitude at 6.9. Japan issued a warning of a small tsunami with a height of one to two meters, but that warning was cancelled around 6:30 a.m. and downgraded to an advisory. According to the U.S. National Weather Service, advisories are issued to coastal populations within areas not currently in either warning or watch status when a tsunami warning has been issued for another region of the same ocean. An advisory indicates that an area is either outside the current warning and watch regions or that a tsunami poses no danger to that area.