CONSTRAINING THE SIZE AND SHAPE OF TERRESTRIAL MAAR VOLCANOES THROUGH THE EXPANDED MAARVLS DATABASE: PREPARATION FOR REMOTE IDENTIFICATION OF MAARS ON MARS

A maar is a volcanic crater formed from subsurface phreatomagmatic explosions which produce a distinctive landform for remote morphometric analysis. Ninety one percent of maars with published compositional data are mafic. There is evidence for water and ice on Mars along with volcanic landforms that reflect probable interactions between magma and water, suggesting the possibility of maars on Mars. The remote identification of volcanic landforms such as maars on other planetary bodies requires an understanding of their typical morphometry characteristics on Earth.

We expanded the global MaarVLS (Maar Volcano Location and Shape) database to be more inclusive of features from volcanic regions with fewer published studies to constrain the size and shape of terrestrial maars. The updated MaarVLS database includes 455 features, an increase of 90% (n = 216). The range of sizes of craters did not change, and exceptional size populations were determined to be less common than previously suggested. The updated database reinforced the common elongation of maar craters and recognized a greater percentage (9.66%) of maars containing a division between multiple connected depressions. This elongation and increased population of septa suggests that most maars experience lateral migration of their eruption loci during formation. This lateral migration requires more dynamic hazard plans, but also results in more distinctive morphometry for remote recognition. The updated dataset provides a better understanding of maar characteristics globally, with 119 volcanic fields represented. This also more accurately reflects the distribution of maars, with only 31 volcanic fields having more than five maars, and with maar-dominated volcanic fields most commonly occurring in the East African Rift. These data will be incorporated into the Global Volcanism Program (GVP) to update the number and location of small features in the catalog available for public use. In MaarVLS, 65% of maars lack published composition data and 62% lack published age data. Future integration of this data into MaarVLS is crucial for determining the effect of magma composition or age on crater size and shape. Future research will integrate this data into comparative morphometric studies of Martian landforms to remotely identify potential maars on Mars.