Global Volcanism Program | Image GVP-00673
Merapi (left) and Merbabu (right) volcanoes tower above the lowlands between the cities of Yogyakarta and Surakarta in this aerial view from the SE. Both have erupted during historical time, but Merapi is by far the more vigorous of the two. Activity at Merapi frequently includes lava dome and collapse that produces pyroclastic flows and lahars that travel down the valleys, often with catastrophic results.
Photo by Jeff Post, 1991 (Smithsonian Institution).