LOS ANGELES (Reuters) - A powerful earthquake jolted Southern California on Thursday, touching off house fires and damaging buildings in a desert town northeast of Los Angeles, but authorities said it has caused only minor injuries. The 6.4 magnitude quake, the largest in two decades in the area, struck about 113 miles (182 km) northeast of Los Angeles near the city of Ridgecrest at around 1:30 pm EDT (1730 GMT), according to the U.S. Geological Survey (USGS). The Kern County Fire Department said it was dealing with “multiple injuries,” two house fires, small brush fires and gas leaks.