Jakarta. Mount Semeru in Lumajang, East Java, erupted with volcanic ash reaching a height of 900 meters on Saturday. The Center for Volcanology and Geological Disaster Mitigation has urged people living around the slopes of the mountain to stay alert and maintain a safe distance.

Footage from a surveillance camera in Supiturang Village, Pronojiwo District, shows volcanic activities at 7:50 a.m., with the eruption heading toward the east and northeast.

“The ash column was observed to be white to gray with heavy intensity toward the northeast and east. The eruption was recorded on a seismograph with a maximum amplitude of 21 millimeters and lasted for 115 seconds,” explained Sigit Rian Alfian, an observer at the Semeru observation post, in a written report.

Although no damage or significant impacts have been reported, the status of Mount Semeru remains at level II (Alert). People are prohibited from engaging in any activities within a 13-kilometer radius of the summit, especially in the southeastern sector along Besuk Kobokan.

“Outside of this distance, people are also advised not to engage in activities within a 500-meter radius from riverbanks due to the potential for hot ash flows and lava,” Sigit added.

Additionally, the public should be on alert for potential lava and cold lava flows, especially in areas where rivers originate from the summit of Mount Semeru.a