Chilean volcano Calbuco, which erupted twice spectacularly last week, began erupting again on Thursday, sending a fresh cloud of ash and gas high into the sky, local TV pictures showed.Calbuco spewed over 200 million tonnes of ash last week, coating nearby towns, wrecking the local salmon industry, and forcing the cancellation of flights as far as Buenos Aires, some 1,400 km (870 miles) away.The volcano had gone quiet, but geological officials had warned it was still unstable and could erupt again.Calbuco, one of the most active along a chain of around 2,000 in Chile, is in the scenic Los Lagos region around 1,000 km (620 miles) south of the capital, Santiago.