Pu’u ‘Ō’ō

Pu’u ‘Ō’ō is a cinder and spatter cone in Kilauea’s east rift zone. It began erupting on January 3, 1983; a summary of its eruption can be found here. This image shows the result of the largest of the collapse pits that began to appear around 1993.

Cinder cones (otherwise known as scoria cones) are the most common type of volcano on Earth. They’re also one of the smallest. They can often be found growing on larger volcanoes, in which case they’re dubbed as ‘parasitic.’ Cinder cones form when gaseous, fragmented volcano ejecta—called tephra or ‘cinder’—accumulates around the vent and welds together. They usually have a bowl-shaped crater at their summit.

While cinder cones abound on Earth, they have been harder to find on Mars. At least, they’re not as easily identified as the massive shield volcanoes such as Olympus Mons. Several structures might resemble cinder cones but with further investigation prove to be something different. Identifying a cinder cone on Mars is not just a matter of morphology. One should ask, for example, whether the structure is in an area of volcanic activity or has evidence of lava flows.