WASHINGTON - A strong earthquake of magnitude 6.4 struck near the Nicaraguan capital, Managua, on Thursday, the US Geological Survey said. It said the quake, very shallow at a depth of 6.2 miles (10 km) and therefore more powerful, struck at 2327 GMT north of Managua, 14 miles (22.5 km) northeast of the town of Nagarote. A magnitude 6.4 quake is capable of causing severe damage. The quake was initially reported as having a 6.2 magnitude.