Answer: Indonesia
Notes: Mount Ibu, an active stratovolcano on Halmahera Island, Indonesia, recently erupted, ejecting ash 4 km high with purple lightning around its crater. Indonesia, part of the Pacific "Ring of Fire" with 127 active volcanoes, often experiences such events. Stratovolcanoes, like Ibu, are characterized by conical shapes formed by layers of volcanic material. They rise sharply near the summit and are common in subduction zones, such as the Andes Mountains.
