Forecasting transitions in monogenetic eruptions using the geologic record

Abstract

Spatial forecasting of volcanism and associated hazards in intraplate monogenetic volcanic fields is subject to large uncertainties in both data and models. We demonstrate a novel logistic regression method for mapping phreatomagmatic-magmatic eruption transition susceptibility using near-surface hydrologic, topographic, and geologic data. The method is illustrated on the Auckland volcanic field, the location of New Zealand’s largest city, Auckland. Environmental factors examined for possible influence included the thickness of water-saturated and porous sediments, substrate type and geology, vent elevation, and distance from the nearest fault. By comparing these factors with the volumes and styles of past eruption sequences, a location-specific eruption sequence forecasting model was constructed, recognizing that larger and/or longer eruptions are more likely to exhaust vent-area sources of water. Estimating volcanic hazard susceptibility in this way allows more effective planning and improved preeruption preparedness between eruptions and during future volcanic crises.