Terrestrial Analogs to Planetary Volcanic Phenomena

Abstract More than 50 years of solar system exploration have revealed the great diversity of volcanic landscapes beyond Earth, be they formed by molten rock, liquid water, or other volatile species. Classic examples of giant shield volcanoes, solidified lava flows, extensive ash deposits, and volcanic vents can all be identified, but except for eruptions seen on the Jovian moon Io, no planetary volcanoes have been observed in eruption. Consequently, the details of the processes that created these landscapes must be inferred from the available spacecraft data. Despite the increasing improvement in the spatial, temporal, compositional, and topographic characteristics of the data for planetary volcanoes, details of the way they formed are not clear. However, terrestrial eruptions can provide numerous insights into planetary eruptions, whether they are effusive eruptions resulting in the emplacement of lava flows or explosive eruptions due to either volatiles in the magma or the interaction between hot lava and water or ice. In recent decades, growing attention has been placed on the use of terrestrial analogs to help interpret volcanic landforms and processes on the rocky planets (Mercury, Venus, the Moon, and Mars) and in the outer solar system (the moons of Jupiter and Saturn, and the larger asteroids). In addition, terrestrial analogs not only provide insights into the geologic processes associated with volcanism but also can serve as test sites for the development of instrumentation to be sent to other worlds, as well as provide a training ground for crewed and uncrewed missions seeking to better understand volcanism throughout the solar system.