Three more volcanoes—Mount Kerinci in West Sumatra, Mount Semeru in East Java and Mount Merapi in Central Java—showed elevated activity on Friday, on the same day that Anak Krakatau erupted.
The activity at the four mountains was unrelated to one another, as each volcano had a different magma chamber, according to the Volcanology and Geological Hazard Mitigation Center (PVMBG).
Volcanic and tectonic activity is the norm in Indonesia, which is located on the Pacific Ring of Fire, an area where many volcanoes and earthquakes are formed.
“Volcanic eruptions in Indonesia are a common thing as they happen every day,” PVMBG head Kasbani said on Saturday, adding that the eruptions did not happen simultaneously.
Anak Krakatau, a volcano that emerged from the remains of the biggest volcano blast recorded by the Krakatau volcano in 1883, erupted twice on Friday evening, spewing out a 500-meter-high column of ash during the second eruption, which lasted more than 38 minutes.
Mount Kerinci in Jambi, West Sumatra last erupted in March 2019, sending ash 600 m into the sky. On Friday, the Energy and Mineral Resources (ESDM) Ministry reported tremors and quakes at Mount Kerinci.
Mount Semeru, the tallest peak of Java Island, which is located in Lumajang, East Java, erupted on Friday with 42 explosion quakes and a 400-meter-high column of ash blowing north.
Mount Merapi, located between Yogyakarta and Central Java, erupted on March 29 with a 1,500-m-high ash column. Friday’s data show that the volcano is still experiencing quakes.
The PVMBG declared the waspada (caution) alert status for all four mountains on Saturday, the second-highest level.