Volcano Watch: Deciphering explosive behavior at Mauna Loa

USGS map Map of explosive deposits at the edge of Moku‘aweoweo, the summit caldera of Mauna Loa. Map showing the size distribution of ejecta, sorted by maximum length in centimeters (one inch is about 2.5 cm). The colors indicate the different size fractions in centimeters. The largest blocks were found closest to the rim. In general, clast size diminished with increasing distance, but medium-sized blocks were found nearly at the distal extent of fan limits. The dark flows in the image outside the caldera are the youngest ‘a‘a flows.

Mauna Loa is known for its effusive eruptions that produce spectacular lava flows. However, some of the volcanic products found on Mauna Loa are pyroclastic or explosive in character.