Late Quaternary Eruption Record and Probability of Future Volcanic Eruptions in the Long Valley Volcanic Region (CA, USA)

The Long Valley volcanic region, eastern California, has been characterized by recurrent and
generally explosive eruptions in the past 180,000 years, originating from a N/S elongated area ~50 km in
extent, including the Mammoth Mountain lava dome complex, the Mono-Inyo volcanic chain, and their
peripheries. Several temporal clusters of activity have been observed in a relatively well-preserved
time-stratigraphic record, which is nevertheless affected by uncertainties. This study has two main objectives:
(1) to fully describe the past eruption record by using a stochastic model capable of combining radiometric
ages and stratigraphic constraints and, (2) based on the uncertainty assessment, to develop a doubly
stochastic, long-term temporal model based on the current situation. Multiple approaches are described and
compared, and multimodel forecasts are also presented. Our findings provide fundamental information for
hazard assessment and forecasting of the next eruption in the Long Valley volcanic region, of which the mean
probability of occurrence is estimated to be ~2.5% in the next 10 years and ~22.5% in the next 100 years.