A strong 6.3 magnitude earthquake hit off the Pacific island nation of Tonga today. The US Geological Survey said there was no tsunami alert and no immediate reports of damage. The quake hit 96 kilometres south south-east of the capital Nuku'alofa at a relatively shallow depth of 10 kilometres. Nine people died in September when a tsunami hit the northern Tongan island of Niuatoputapu following an 8.0 magnitude earthquake.