A powerful quake of magnitude 6.4 on Thursday struck Southern California near the city of Ridgecrest, some 200 miles (320 km) northeast of Los Angeles, the U.S. Geological Survey said. The depth is reported at 8 km (5 miles) causing significant shaking. Preliminary magnitude was reported at 6.6. A 4.2 pre-shock was recorded 30-minutes prior to the 6.4 event. A 4.7 aftershock has also been recorded, with over 25 aftershocks recorded within an hour…