Indonesia’s Anak Krakatau, Mount Ibu Erupt Hours Apart
Anak Krakatau and Mount Ibu erupted hours apart, prompting 2-kilometer crater restrictions and an added northern exclusion zone at Mount Ibu.
PANGKALPINANG, Indonesia — Two Indonesian volcanoes erupted within hours of each other on Monday, Oct. 5, prompting authorities to warn residents and visitors to stay clear of their active craters. The Geological Agency set a 2-kilometer exclusion radius at both Anak Krakatau, in the Sunda Strait between Java and Sumatra, and Mount Ibu, in West Halmahera, North Maluku.
The restrictions have immediate implications for people near the volcanoes: at Mount Ibu, the warning also covers a 3.5-kilometer sector extending toward the crater opening on the north side. The agency urged residents, tourists, visitors and climbers to keep away from the restricted areas.
Separate eruptions, hours apart
Anak Krakatau erupted at 8:28 p.m. Western Indonesia Time, according to a report by CNBC Indonesia citing the Geological Agency. The eruption was recorded by a seismograph with a maximum amplitude of 33 millimeters and lasted 61 seconds.
Mount Ibu followed at 11:09 p.m. Eastern Indonesia Time. Its eruption sent an ash column about 500 meters above the summit, while the seismograph recorded a maximum amplitude of 28 millimeters over 45 seconds, the agency said.
The ash plume adds a practical concern for people nearby. The Geological Agency advised residents to wear masks to protect their noses and mouths, as well as glasses to protect their eyes, if ash falls while they are outdoors. It also told the public to follow local government instructions and avoid the designated hazard zones.
Reports differ on Anak Krakatau measurements
Accounts of Anak Krakatau’s activity did not agree. CNBC Indonesia reported an eruption at 8:28 p.m., with a maximum amplitude of 33 millimeters and a duration of 61 seconds. Detik News gave a different time, 8:13 p.m., and reported a maximum amplitude of 55 millimeters and a duration of about 6 minutes and 29 seconds.
Because the published figures differ, this dispatch follows the CNBC Indonesia account, which attributed its details to the Geological Agency. The available information does not establish that the accounts describe the same recording, so their measurements should not be combined.
Bisnis.com also reported the 33-millimeter amplitude and a 2-kilometer restriction at Anak Krakatau, but said the volcano erupted twice that night. The source material does not detail those two events, so that claim is not merged with the single time-and-duration record cited above.
The Geological Agency urged people not to circulate information from unclear sources and called for calm. It asked the West Halmahera regency government to coordinate with the Center for Volcanology and Geological Hazard Mitigation in Bandung and the Mount Ibu observation post in Gam Ici to obtain updates on the volcano’s activity.
For Mount Ibu, the agency’s warning covers the 2-kilometer crater radius and the additional northern sector extending 3.5 kilometers toward the crater opening.
