How does multiscale modelling and inclusion of realistic palaeobathymetry affect numerical simulation of the Storegga Slide tsunami

Abstract The ∼8.15 ka Storegga submarine slide was a large (∼3000 km3), tsunamigenic slide off the coast of Norway. The resulting tsunami had run-up heights of around 10–20 m on the Norwegian coast, over 12 m in Shetland, 3–6 m on the Scottish mainland coast and reached as far as Greenland. Accurate numerical simulations of Storegga require high spatial resolution near the coasts, particularly near tsunami run-up observations, and also in the slide region. However, as the computational domain must span the whole of the Norwegian-Greenland sea, employing uniformly high spatial resolution is computationally prohibitive. To overcome this problem, we present a multiscale numerical model of the Storegga slide-generated tsunami where spatial resolution varies from 500 m to 50 km across the entire Norwegian-Greenland sea domain to optimally resolve the slide region, important coastlines and bathymetric changes. We compare results from our multiscale model to previous results using constant-resolution models and show that accounting for changes in bathymetry since 8.15 ka, neglected in previous numerical studies of the Storegga slide-tsunami, improves the agreement between the model and inferred run-up heights in specific locations, especially in the Shetlands, where maximum run-up height increased from 8 m (modern bathymetry) to 13 m (palaeobathymetry). By tracking the Storegga tsunami as far south as the southern North sea, we also found that wave heights were high enough to inundate Doggerland, an island in the southern North Sea prior to sea level rise over the last 8 ka.

[1]  David A. Ham,et al.  On the performance of a generic length scale turbulence model within an adaptive finite element ocean model , 2012 .

[2]  M. Piggott,et al.  Eastern Mediterranean tectonics and tsunami hazard inferred from the AD 365 earthquake , 2008 .

[3]  S. Björck,et al.  Storegga tsunami deposits in a coastal lake on Suouroy, the Faroe Islands , 2001 .

[4]  Stephan T. Grilli,et al.  Dispersive tsunami waves in the ocean: Model equations and sensitivity to dispersion and Coriolis effects , 2013 .

[5]  M. Piggott,et al.  Three‐dimensional tsunami propagation simulations using an unstructured mesh finite element model , 2013 .

[6]  Stephan T. Grilli,et al.  Source Constraints and Model Simulation of the December 26 , 2007 .

[7]  Stephan T. Grilli,et al.  Experimental Study of Tsunami Generation by Three-Dimensional Rigid Underwater Landslides , 2007 .

[8]  Colin J. Cotter,et al.  LBB stability of a mixed Galerkin finite element pair for fluid flow simulations , 2009, J. Comput. Phys..

[9]  David E. Smith,et al.  Relative sea-level change and evidence for the Holocene Storegga Slide tsunami from a high-energy coastal environment: Cocklemill Burn, Fife, Scotland, UK , 2005 .

[10]  C. Amante,et al.  ETOPO1 arc-minute global relief model : procedures, data sources and analysis , 2009 .

[11]  Christopher C. Pain,et al.  Modelling ancient tides: the Upper Carboniferous epi‐continental seaway of Northwest Europe , 2005 .

[12]  Walter H. F. Smith,et al.  A global, self‐consistent, hierarchical, high‐resolution shoreline database , 1996 .

[13]  M. J. Tooleya,et al.  Relative sea-level change and evidence for the Holocene Storegga Slide tsunami from a high-energy coastal environment : Cocklemill Burn , Fife , Scotland , UK , 2005 .

[14]  R. Lien,et al.  The dating and morphometry of the Storegga Slide , 2005 .

[15]  David E. Smith,et al.  A Holocene tsunami deposit in eastern Scotland , 2010 .

[16]  Christopher C. Pain,et al.  Modelling tidal current‐induced bed shear stress and palaeocirculation in an epicontinental seaway: the Bohemian Cretaceous Basin, Central Europe , 2010 .

[17]  Colin J. Cotter,et al.  Numerical wave propagation for the triangular P1DG-P2 finite element pair , 2010, J. Comput. Phys..

[18]  Jean-François Remacle,et al.  Multiscale mesh generation on the sphere , 2008 .

[19]  Finn Løvholt,et al.  Fundamental mechanisms for tsunami generation by submarine mass flows in idealised geometries , 2005 .

[20]  Christophe Geuzaine,et al.  Gmsh: A 3‐D finite element mesh generator with built‐in pre‐ and post‐processing facilities , 2009 .

[21]  N. C. Flemming,et al.  The scope of Strategic Environmental Assessment of North Sea area SEA4 in regard to prehistoric archaeological remains , 2003 .

[22]  Matthew D. Piggott,et al.  The impact of mesh adaptivity on the gravity current front speed in a two-dimensional lock-exchange , 2011 .

[23]  I. Shennan,et al.  An improved glacial isostatic adjustment model for the British Isles , 2011 .

[24]  T. Bernhardsen.  Geographic Information Systems: An Introduction , 1999 .

[25]  Christopher C. Pain,et al.  Tidal Modeling of an Ancient Tide-Dominated Seaway, Part 1: Model Validation and Application to Global Early Cretaceous (Aptian) Tides , 2010 .

[26]  O. Bennike,et al.  First indication of Storegga tsunami deposits from East Greenland , 2007 .

[27]  J. Wiseman,et al.  The general bathymetric chart of the oceans , 1955 .

[28]  David E. Smith,et al.  The Storegga Slides: Evidence from eastern Scotland for a possible tsunami , 1988 .

[29]  Christopher C. Pain,et al.  A wetting and drying algorithm with a combined pressure/free-surface formulation for non-hydrostatic models , 2011 .

[30]  Carl B. Harbitz,et al.  The Storegga Slide tsunami—comparing field observations with numerical simulations , 2005 .

[31]  P. Sabatier,et al.  Numerical Modelling of a Landslide-generated Tsunami: The 1979 Nice Event , 2000 .

[32]  C. C. Pain,et al.  A mixed discontinuous/continuous finite element pair for shallow-water ocean modelling , 2008, 0805.4380.

[33]  Sylfest Glimsdal,et al.  Dispersion of tsunamis: does it really matter? , 2013 .

[34]  Stephan T. Grilli,et al.  Numerical modeling of tsunami waves generated by the flank collapse of the Cumbre Vieja Volcano (La Palma, Canary Islands): Tsunami source and near field effects , 2012 .

[35]  Gangfeng Ma,et al.  Numerical simulation of tsunami waves generated by deformable submarine landslides , 2013 .

[36]  I. Boomer,et al.  Holocene coastal change and geoarchaeology at Howick, Northumberland, UK , 2007 .

[37]  G. Pedersen,et al.  Submarine landslides: processes, triggers and hazard prediction , 2006, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[38]  R. Wynn,et al.  Large Landslides on Passive Continental Margins: Processes, Hypotheses and Outstanding Questions , 2010 .

[39]  Bernd Wagner,et al.  The catastrophic final flooding of Doggerland by the Storegga Slide Tsunami. , 2008 .

[40]  G. Pedersen,et al.  Mechanisms of tsunami generation by submarine landslides - a short review , 2006 .

[41]  R. Musson,et al.  Impact of a Lisbon‐type tsunami on the U.K. coastline and the implications for tsunami propagation over broad continental shelves , 2008 .

[42]  H. Hébert,et al.  The 1755 Lisbon Tsunami in Guadeloupe Archipelago: Source Sensitivity and Investigation of Resonance Effects , 2010 .

[43]  David A. Wood,et al.  What a performance , 2004 .

[44]  A. Nesje,et al.  Evidence for Storegga tsunami run‐up at the head of Nordfjord, western Norway , 2013 .

[45]  David E. Smith,et al.  The sedimentology of Middle Holocene tsunami facies in northern Sutherland, Scotland, UK , 2000 .

[46]  I. Foster,et al.  The Holocene Storegga Slide tsunami in the United Kingdom , 2004 .

[47]  R. Madariaga,et al.  Could a 1755-Like Tsunami Reach the French Atlantic Coastline? Constraints from Twentieth Century Observations and Numerical Modeling , 2012, Pure and Applied Geophysics.

[48]  Christopher C. Pain,et al.  A new computational framework for multi‐scale ocean modelling based on adapting unstructured meshes , 2008 .

[49]  V. Gaffney,et al.  Late Pleistocene and Holocene depositional systems and the palaeogeography of the Dogger Bank, North Sea , 2005, Quaternary Research.

[50]  K. Haugen,et al.  A parametric study of tsunamis generated by submarine slides in the Ormen Lange/Storegga area off western Norway , 2005 .

[51]  Carl B. Harbitz,et al.  Model simulations of tsunamis generated by the Storegga Slides , 1992 .

[52]  J. Mangerud,et al.  Sea-level changes and pollen stratigraphy on the outer coast of Sunnmøre, western Norway , 1990 .

[53]  Gangfeng Ma,et al.  Shock-capturing non-hydrostatic model for fully dispersive surface wave processes , 2012 .

[54]  S. Bondevik.  Storegga tsunami sand in peat below the Tapes beach ridge at Harøy, western Norway, and its possible relation to an early Stone Age settlement , 2003 .