An earthquake measuring 5.9 on the Richter scale jolted offshore Valparaiso in central Chile, the US Geological Survey said Wednesday. The quake, which struck at 0703 GMT, was centered 38 km north of the port city of Valparaiso with a depth of 19 km. There were no reports of damage and tsunami warning. Chile has been on edge since a devastating 8.8-magnitude quake last year unleashed a tsunami and killed more than 500 people.