How Volcanoes Work

 Image Described in Caption
Parasitic cones -- There are nearly 100 parasitic scoria cones on the flanks of Mauna Kea volcano, Hawaii. Shown here are some of the larger ones near the snow-covered summit of the volcano. Most of the cones erupted between 65,000 and 14,000 years ago. Courtesy of Don Swanson, USGS.