Explosive vent sites on Mercury: Commonplace multiple eruptions and their implications

International audience; Explosive volcanic vents are widespread on Mercury. Compound volcanic vents comprise multiple individual vents, and probably formed through multiple events. We demonstrate that ~70% of the volcanic vent sites on Mercury that have been imaged with sufficient resolution to resolve their internal features are compound vents that have probably undergone multiple eruptions. Interior characteristics of compound vents, such as crosscutting relationships, contrasts in small scale impact cratering, and other textural detail, as well as the asymmetry of surrounding faculae, suggest that activity occurred over a prolonged but so far unquantified period of time. We use multiple case studies to highlight the migration of eruption centres at these sites. At the Nathair Facula vent, small-scale interior pits suggest the location of the most recent activity.