Pure and Applied Geophysics

, Volume 172, Issue 12, pp 3589–3616

Far-Field Tsunami Impact in the North Atlantic Basin from Large Scale Flank Collapses of the Cumbre Vieja Volcano, La Palma

  • Babak Tehranirad
  • Jeffrey C. Harris
  • Annette R. Grilli
  • Stephan T. Grilli
  • Stéphane Abadie
  • James T. Kirby
  • Fengyan Shi
Article

Abstract

In their pioneering work, Ward and Day suggested that a large scale flank collapse of the Cumbre Vieja Volcano (CVV) on La Palma (Canary Islands) could trigger a mega-tsunami throughout the North Atlantic Ocean basin, causing major coastal impact in the far-field. While more recent studies indicate that near-field waves from such a collapse would be more moderate than originally predicted by Ward and Day [Løvholt et al. (J Geophy Res 113:C09026, 2008); Abadie et al. (J Geophy Res 117:C05030, 2012)], these would still be formidable and devastate the Canary Island, while causing major impact in the far-field at many locations along the western European, African, and the US east coasts. Abadie et al. (J Geophy Res 117:C05030, 2012) simulated tsunami generation and near-field tsunami impact from a few CVV subaerial slide scenarios, with volumes ranging from 20 to 450 km\(^3\); the latter representing the most extreme scenario proposed by Ward and Day. They modeled tsunami generation, i.e., the tsunami source, using THETIS, a 3D Navier-Stokes (NS) multi-fluid VOF model, in which slide material was considered as a nearly inviscid heavy fluid. Near-field tsunami impact was then simulated for each source using FUNWAVE-TVD, a dispersive and fully nonlinear long wave Boussinesq model [Shi et al. (Ocean Modell 43–44:36–51, 2012); Kirby et al. (Ocean Modeling, 62:39–55, 2013)]. Here, using FUNWAVE-TVD for a series of nested grids of increasingly fine resolution, we model and analyze far-field tsunami impact from two of Abadie et al.’s extreme CVV flank collapse scenarios: (i) that deemed the most “credible worst case scenario” based on a slope stability analysis, with a 80 km\(^3\) volume; and (ii) the most extreme scenario, similar to Ward and Day’s, with a 450 km\(^3\) volume. Simulations are performed using a one-way coupling scheme in between two given levels of nested grids. Based on the simulation results, the overall tsunami impact is first assessed in terms of maximum surface elevation computed along the western European and African, and US east coasts (USEC). Strong wave elevation decay is predicted over the wide USEC shelf, which is shown to be essentially due to bottom friction effects. We then show more detailed results for the USEC, which is the object of high-resolution tsunami inundation mapping under the auspices of the US National Tsunami Hazard Mitigation Program. In this context, we compare the maximum surface elevation predicted along the coastline for each CVV scenario and show that, besides the initial directionality of the sources, coastal impact is mostly controlled by focusing/defocusing effects resulting from the shelf bathymetric features. A simplified ray-tracing analysis confirms this controlling effect of the wide USEC shelf for incident long waves. Finally, we perform high-resolution (10 m) inundation mapping for the most extreme CVV scenario and show results at one of the most vulnerable and exposed communities in the mid-Atlantic US states, in and around Ocean City, Maryland. Such maps are being generated for all exposed areas of the USEC, to be used in tsunami hazard assessment and mitigation work.

Keywords

Tsunami propagation coastal geohazard subaerial landslide navier-stokes VOF model boussinesq wave models volcano collapse Cumbre Vieja La Palma 

Copyright information

© Springer Basel 2015

Authors and Affiliations

  • Babak Tehranirad
    • 1
  • Jeffrey C. Harris
    • 2
    • 4
  • Annette R. Grilli
    • 2
  • Stephan T. Grilli
    • 2
  • Stéphane Abadie
    • 3
  • James T. Kirby
    • 1
  • Fengyan Shi
    • 1
  1. 1.Center for Applied Coastal Research, Department of Civil and Environmental EngineeringUniversity of DelawareNewarkUSA
  2. 2.Department of Ocean EngineeringUniversity of Rhode IslandNarragansettUSA
  3. 3.Laboratoire SIAMEUniversité de Pau et des Pays de l’AdourAngletFrance
  4. 4.Saint-Venant Laboratory for HydraulicsUniversité Paris-EstChatouFrance

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