Indonesia’s ‘Ring of Fire’: Key facts about the world's most volcanic nation

Indonesia, home to over 17,000 islands, is the world's most volcanic nation, with more than 100 active volcanoes scattered across its territory, according to the country's volcanology agency. The archipelago's location on the Pacific "Ring of Fire" contributes to the frequency of volcanic eruptions and earthquakes. Indonesia boasts 500 volcanoes in total, with 127 of them being active.

The agency monitors 69 of these active volcanoes closely through a network of 74 observation points. Globally, only the United States and Japan have more active volcanoes than Indonesia, as reported by the Washington-based Smithsonian Institution's Global Volcanism Program. Currently, five of Indonesia's active volcanoes are at the second-highest alert status, including Mount Anak Krakatau, Mount Lewotobi Laki-laki, Mount Merapi, Mount Semeru, and Mount Sinabung.

The latest eruptions of Anak Krakatau, the most severe in terms of ash emissions, disrupted air travel and affected more than 270,000 people. The ash plume reached a height of 50,000 feet (15,240 meters), spreading up to 400 kilometers (250 miles), including reaching Jakarta, approximately 150 kilometers away. In 2008, the volcano triggered a tsunami, resulting in over 400 fatalities on Java and Sumatra islands, marking it as the deadliest volcanic disaster in recent Indonesian history.

However, no deaths were reported from the latest eruptions. The eruption of Mount Semeru on September 5, 2026, sent ash up to 1 kilometer above the summit but did not cause any evacuations or flight disruptions.