Skip to content

Temporal recurrence rate estimation in distributed volcanic fields

Mark Bebbington 1, William Hackett2, Scott Hughes3, Shannon Kobs Nawotniak3, Michael Ort4

  • Affiliations: 1School of Agriculture and Environment, Massey University, Palmerston North, New Zealand; 2WRH Associates Inc, Ogden, UT, USA; 3Department of Geosciences, Idaho State University, Pocatello, ID, USA; 4Geology, School of Natural Sciences, Triniity College Dublin, Dublin, Ireland

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 51

  • Programme No: 6.3.10

  • Theme 6 > Session 3

Abstract

A critical element in hazard estimation from distributed volcanic fields, particularly in regulatory environments, is the estimation of temporal recurrence. The low temporal frequency of distributed volcanism means the historical record is commonly nonexistent or inadequate, and interpretation of the geological record is required. However, the geological record is incomplete, uncertain, and in multiple forms, subject to a variety of constraints. A holistic view of the temporal record can be assembled by generating age realizations via Monte Carlo simulation. Each realization is a random draw from all of the data available, where all of the constraints, such as stratigraphy, are satisfied, in contrast to their average, where constraints may be violated. We illustrate how Monte Carlo simulation can provide a basis for temporal recurrence estimates, including aleatory and epistemic uncertainty, using the example record of Quaternary volcanism in the eastern Snake River Plain. This consists of 617 vents, 156 with isotopic dates, 307 with paleomagnetic determinations, and 2644 stratigraphic relations. In addition, undated vents and their mapped lava fields have been subjectively assigned to age groups (0--200 ka, 200--400 ka, 400--780 ka, 780--2000 ka) based on their geomorphic features, paleomagnetic data, and stratigraphic relations relative to dated map units in contact. Age realizations are simulated from these with and without applying the age groups.  After disaggregating the record to derive homogeneous 'regions' in space and/or composition, various temporal models can be fit to these realizations, providing estimates of recurrence rates with quantified uncertainty.