Tsunami Runup Simulations

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Tsunami Runup Simulations

• Jim Kirby
• Center for Applied Coastal Research
• Department of Civil and Environmental
  Engineering, UD
• NEES Training and Tsunami Modeling Workshop
• July 28, 2006
• With Stephan Grilli, Phil Watts, Mansour
  Ioualalen, Jack Asavanant,
• Fengyan Shi

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Contexts for runup calculations

• As landward boundary of a propagation model
  calculation (NSW, Boussinesq)
• More detailed, Navier Stokes calculations to
  examine forces on structures, transport and
  impact of debris
• -- VOF, other grid-based schemes
• -- SPH, lagrangian particle techniques
• Hybrid methods coupling these apparoaches

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Boussinesq model assumptions

• ? h/L ltlt 1
• d a/h ltlt 1 (this restriction often
  neglected now)
• ? / ?2 O(1)

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Boussinesq Model Equations (Wei et al, 1995)

• Mass Conservation
• Momentum Equation

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Methodologies for runup calculations

• Slot methods (Tao, Kennedy et al 2000, Chen et
  al 2000)
• Thin film methods (Wei, 1997 Long, Delguzzo and
  Kirby (2006)
• Wetting-drying methods (Lynett and Liu)

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Slot method (Kennedy et al, 2000)
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Slot method testing I
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Slot method testing II
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• Maximum runup (Chen et al, 2000)

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Thin film method (Long et al, 2006)

• Maintain a minimum water depth over entire grid
  area
• Increase bottom friction in region above
  instantaneous shoreline

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Testing thin film method

• Data Synolakis (1985)

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Geological Setting
3.244º N, 95.825º E Bottom Displacement 1000
km long 100 km wide 2 m high
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High Resolution Runup simulations on coast of
Thailand

• High resolution grid 0.25 resolution
  corresponds to a grid spacing of about 450m
• Higher resolution local bathymetry data merged
  into ETOPO2 data set.
• Runup data obtained and reported independently by
  Tsuji et al (2006)

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Bathymetry data from local surveys
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High resolution grid coverage
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Maximum computed surface displacement values (m).
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Model vs. Meas-ured runup

• Simulation on 0.25 grid

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Degradation of results with decreasing grid
resolution
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Runup statistics I
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Runup Statistics II lognormal runup
distribution(after Choi et al, 2006)
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Java, July 06
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