Residents in Karo regency on Sumatra island were on edge yesterday, with a rumbling Mount Sinabung spewing volcanic ash that reached as high as 1km. The volcano, which began erupting on Sunday, has prompted the authorities to bar tourists from entering a radius of 6km from the crater, volcanologist Nia Hairani said. Sinabung roared back to life in 2010 for the first time in 400 years. After another period of inactivity, it erupted once more in 2013. It has been highly active since. It is one of 129 active volcanos in Indonesia sitting on a quake-prone zone called the Pacific Ring of Fire.