, Volume 10, Issue 2, pp 179200
First online:
Probabilistic model for eruptions and associated flood events in the Katla caldera, Iceland
 Jonas EliassonAffiliated withEngineering Research Institute, University of Iceland Email author
 , Gudrun LarsenAffiliated withInstitute of Earth Sciences, University of Iceland
 , Magnus Tumi GudmundssonAffiliated withInstitute of Earth Sciences, University of Iceland
 , Freysteinn SigmundssonAffiliated withNordic Volcanological Centre, Institute of Earth Sciences
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Get AccessEruptions in the subglacial Katla caldera, South Iceland, release catastrophic jokulhlaups (meltwater floods). The ice surface topography divides the caldera into three drainage sectors (Ko, So and En sectors) that drain onto Myrdalssandur, Solheimasandur and Markarfljot plains, respectively. In historical times, floods from the Ko sector have been dominant, with only two recorded So events. Geological records indicate that floods from the En sector occur every 500–800 years. A probabilistic model for an eruption is formulated in general terms by a stochastic parameter that simulates a series giving the time interval in years between two consecutive events. The model also contains a Markovian matrix that controls the location of the event and thereby what watercourse is hit by the flood. A record of Katla eruptions since the 8th and the 9th century a.d., and geological information of volcanogenic floods towards the west over the last 8,000 years is used to calibrate the model. The model is then used to find the probabilities for floods from the three sectors: Ko, So and En. The simulations predict that the most probable eruption interval for the En sector and the So sector is several times smaller than the average time interval, implying infrequent periods of high activity in these sectors. A correlation is found between the magnitude of eruptions and the following time intervals. Using the statistical approach and considering this magnitude–time interval correlation, the probability of an eruption in Katla volcano is considered to be 20% within the next 10 years. This compares to a probability of 93% if only a simple average is considered. These probabilities do not take account of longterm eruption precursors and should therefore be regarded as minimum values.
Keywords
Katla volcano volcanic eruptions jokulhlaups catastrophic floods probabilistic modeling simulations Markov processes eruption probabilities Title
 Probabilistic model for eruptions and associated flood events in the Katla caldera, Iceland
 Journal

Computational Geosciences
Volume 10, Issue 2 , pp 179200
 Cover Date
 200606
 DOI
 10.1007/s105960059018y
 Print ISSN
 14200597
 Online ISSN
 15731499
 Publisher
 Springer Netherlands
 Additional Links
 Topics
 Keywords

 Katla volcano
 volcanic eruptions
 jokulhlaups
 catastrophic floods
 probabilistic modeling
 simulations
 Markov processes
 eruption probabilities
 Industry Sectors
 Authors

 Jonas Eliasson ^{(1)}
 Gudrun Larsen ^{(2)}
 Magnus Tumi Gudmundsson ^{(2)}
 Freysteinn Sigmundsson ^{(3)}
 Author Affiliations

 1. Engineering Research Institute, University of Iceland, Hjardarhaga 6, IS107, Reykjavik, Iceland
 2. Institute of Earth Sciences, University of Iceland, Sturlugata 7, IS101, Reykjavik, Iceland
 3. Nordic Volcanological Centre, Institute of Earth Sciences, Sturlugata 7, IS101, Reykjavik, Iceland