Indonesia's volcanology authorities have limited access to the popular Mount Ijen after its alert status was raised to level 3, just one below the highest.
Surono, the head of the Volcanology and Geological Disaster Mitigation Center (PVMBG), told the Jakarta Globe that Ijen's volcanic activities began increasing on Wednesday, March 27.
“With the increasing volcanic quakes, we are issuing an alert status. People are banned to go within one kilometer [of the crater] because it is dangerous,” he said over the phone.
Smoke has been observed rising from the crater, a highly popular desination for tourists for its turquoise yet highly acidic crater lake. But Surono said they had yet to confirm whether the smoke was poisonous gas.
News website Metrotvnews.com reported on Monday that the West Java PVMBG dispatched an emergency team to Mount Ijen to install a new seismograph to replace the old one that was hit by lightning. The team also installed a Close Circuit Television (CCTV) camera.
Hendra, from the PVMBG's Western Area Volcanic Monitoring Division, said that based on the team’s report, the water in the crater was now murky.
All climbing routes have been closed since Friday as the volcanic activities increased, Detik.com reported.
Wiyono, head of the Banyuwangi Disaster Mitigation Agency (BBPD), said the agency has activated all alert posts, including for three subdistricts surrounding the volcano, Licin, Glagah and Wongsorejo.
All related agencies were also tasked with warnings tourists and tourism services that organize trips to the mountain, either from Bondowoso or Banyuwangi.
The agency also asked Banyuwangi’s Industry, Trade and Mining Office to warn the sulfur mining companies in the area. Hundreds of sulfur miners eke out a dangerous living in the mountain, known as a source of high-grade sulfur.
Mount Ijen has four known eruptions, the last one in 1936.