JAKARTA, Feb 20 (Reuters) - The U.S. Geological Survey revised down the magnitude of an earthquake that struck eastern Indonesia on Tuesday to 6.5 from 6.9. The USGS on its Web site (http://earthquake.usgs.gov) said the quake occurred at a depth of 31 km (19 miles), with the epicentre 315 km north north-west of Ambon in the Moluccas. The Hong Kong Observatory also put the quake's magnitude at 6.5. (Editing by David Fogarty; Reuters Messaging; ahmad.pathoni.reuters.com@reuters.net; tel +6221 384 6364))
