Renewed eruptions from a remote Indonesian volcano have triggered fresh evacuation orders and sparked flight cancellations and airport closures this week with smoke, lava and volcanic gasses spewing out of the fiery mountain. Mount Ruang, a 725-meter (2,400-foot) volcano on Ruang Island, North Sulawesi, has been erupting in spectacular fashion on and off since mid-April, posing a growing threat to those living nearby and to air traffic in the region. The volcano erupted three times on Tuesday, sending lava and ash clouds into the sky and prompting Indonesia's national PVMBG volcanology agency to issue its highest alert, warning that a tsunami could be triggered by "volcanic material collapsing into the ocean." Ruang lies just off the coast of the larger Tagulandang island, where authorities have called on more than 12,000 people to evacuate, according to Reuters. Footage released by the National Disaster Management Authority (BNPB) on Thursday showed huge crowds of people awaiting evacuation at ports and towering ash plumes. PVMBG raised alert levels on Tuesday, warning of "new eruptions and continuous earthquakes" while advising the public to wear protective masks and exercise caution. The latest eruptions have also forced closures of at least seven airports in the vicinity, including the Sam Ratulangi International Airport that serves the city of Manado, capital of North Sulawesi province and a well-known scuba diving destination. Nearby schools have also been shut to protect children from volcanic ash, BNPB said. Dramatic footage shared by the BNPB on Thursday showed ash cascading into the air. Mount Ruang is a stratovolcano, which are typically conical and relatively steep-sided due to the formation of viscous, sticky lava that does not flow easily. Stratovolcanoes often produce explosive eruptions due to gas build-up in the magma, according to volcanologists. Volcanic ash from Ruang has reached eastern Malaysian airspace, Malaysia's meteorological department said. "We are monitoring the volcanic dust movements continuously and will update the information and issue aviation weather warnings if necessary," said Met Malaysia chief Muhammad Helmi Abdullah Regional carrier Air Asia said it canceled 21 flights following Mount Ruang's latest eruption. "Guests traveling to and from affected destinations (between Malaysia and Indonesia) are encouraged to check their email and phones for cancelation notifications," the airline said Wednesday. "Air Asia is continuing to monitor the situation closely and will provide more information on the latest developments." Malaysia's national carrier Malaysia Airlines also issued similar travel advisories on Wednesday, following the cancelation of several flights in the area. Indonesia, a Southeast Asian archipelago of 270 million people, sits along the Ring of Fire and has more than 120 active volcanoes – more than anywhere else in the world. Mount Ruang previously erupted in April, disrupting more than 200 flights on April 18 and 19 and affecting tens of thousands of passengers, officials said. Hundreds living in the volcano's vicinity were evacuated due to fears it could partially collapse into the sea and cause a tsunami as it did in 1871. — CNN
