How Volcanoes Work

 Image Described in Caption
 Strombolian scoria-fall deposit -- Airfall deposits of basalt scoria are typical of Strombolian eruptions. The deposit shown here is from Bandera, New Mexico. It is composed of lapilli-size scoria fragments which have a cindery appearance with a light, frothy texture. The pyroclasts are sharp and angular. The deposit is very near the scoria cone from which it erupted. Typically, scoria-fall deposits are localized in this manner because of the low height of the Strombolian eruptive column, which is generally only a few hundred meters above the vent. Courtesy of Peter Francis.