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Estimating proximal hazards in a distributed volcanic field

Michael H. Ort1, Charles B. Connor2,3, Laura J. Connor3, Mark S. Bebbington4, William R. Hackett5, Shannon E. Kobs Nawotniak6, Scott S. Hughes6, M. Elise Rumpf7

  • Affiliations: 1Geology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland; 2University of South Florida, Tampa, FL, USA; 3Desperate Measures International, 113 1st Ave NW, Lutz FL USA; 4School of Agriculture and Environment, Massey University, Palmerston North, New Zealand; 5WRH Associates Inc, Ogden, UT, USA; 6Department of Geosciences, Idaho State University, Pocatello, ID, USA; 7Astrogeology Science Center, U.S. Geological Survey, Flagstaff, AZ USA 

  • Presentation type: Talk

  • Presentation time: Tuesday 16:00 - 16:15, Room R290

  • Programme No: 6.3.6

  • Theme 6 > Session 3

Abstract

Assessing volcanic hazards in distributed volcanic fields (DVFs) is complicated by their dispersed vents (spatial uncertainty), long irregular repose periods (temporal uncertainty) and diverse eruption styles (hazard uncertainty). The Probabilistic Volcanic Hazards Assessment of Idaho National Laboratory (INL) USA developed an approach to assess proximal hazards where the location and style of eruption are uncertain. In contrast to most volcanic hazards assessments, in which likely vent areas are known and hazard zones are then mapped, the sites for which the hazards assessment is needed are defined and the vent locations, timing, and style of eruption are not initially defined. The hazard assessment is split into distal (fallout and flows from distant volcanic areas; hazards vary little across INL) and proximal hazards. To develop the proximal hazards assessment, a hazard footprint for each type of volcano (low shield, scoria cone, spatter cone, dome, cryptodome, phreatomagmatic vent) was created. The hazards associated with each volcano type and their extent from a vent were determined, using ESRP and analog examples. Hazards include burial, ballistic projectiles, gas, pyroclastic currents of various types, and ground deformation. For each eruption style, the areal extent of each hazard was estimated and a combined footprint created using the probability-distance relations for all hazards, producing a circle or oval having generally decreasing probabilities with distance from vent. These footprints are centered on the sites of interest rather than vents. The spatio-temporal likelihood of future eruptions within the footprints was then evaluated to assess hazard probability at each site.