A strong 6.3 magnitude earthquake hit off the Pacific island nation of Tonga today, the US Geological Survey said, but there was no tsunami alert and no immediate reports of damage. The quake hit at 3:34 pm (0234 GMT) 96 kilometres (60 miles) south-southeast of the capital Nukualofa at a relatively shallow depth of 10 kilometres, the USGS said. Nine people died in September when a tsunami hit the northern Tongan island of Niuatoputapu following an 8.0-magnitude earthquake. The tsunami also killed 143 people in Samoa and another 34 in neighbouring American Samoa. Earthquakes are common on the Pacific Ring of Fire where continental plates in the Earths crust meet.