A powerful earthquake struck the southern Philippines on Thursday, killing at least five people and sparking searches of seriously damaged buildings that had already been rattled by two previous deadly tremors in recent weeks. The 6.5 magnitude quake hit the island of Mindanao, the US Geological Survey said, causing locals to run to safety in the same area where a strong tremor killed eight people on Tuesday.The powerful shaking caused serious damage to a condominium building in the