A 5.8-magnitude quake hit Puerto Rico before dawn today, unleashing small landslides, causing power outages and severely cracking some homes. There were no immediate reports of casualties. <br />'' <br />'' According to the U.S. Geological Survey, the quake struck just south of the island at a relatively shallow depth of 10 kilometres.<br />'' <br />''It was one of the strongest quakes yet to hit the U.S. territory that has been shaking for the past week.