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MODELING TSUNAMI INUNDATION AND ASSESSING TSUNAMI HAZARDS FOR THE U.S. EAST COAST. Presented by : James T. Kirby Center for Applied Coastal Research University of Delaware Stephan T. Grilli Department of Ocean Engineering University of Rhode Island.
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MODELING TSUNAMI INUNDATION AND ASSESSING TSUNAMI HAZARDS FOR THE U.S. EAST COAST Presented by: James T. Kirby Center for Applied Coastal Research University of Delaware Stephan T. Grilli Department of Ocean Engineering University of Rhode Island Report to National Tsunami Hazard Mitigation ProgramFebruary 8, 2012
Project Personnel: University of Delaware: James T. Kirby (PI, inundation and propagation modeling, project coordination) John Callahan (Scientist, Del. Geological Soc., GIS/DEM database development, inundation map development) Fengyan Shi (Res. Asst. Prof, inundation and propagation modeling) BabakTehranirad (Graduate Research Assistant, inundation modeling and mapping)) University of Rhode Island: Stephan Grilli (co-PI, coordination of URI tasks), Chris Baxter (Assoc. Prof., MC simulations of SMF sources). Jeff Harris (postdoc, integration of source simulations and propagation modeling), StephaneAbadie (Visiting prof., Fulbright Scholar, CumbreVieja, SMF source modeling), Teresa Kraus and Tamara Eggeling (Graduate Research Assistants, MC simulations of SMF sources)
University of Delaware and University of Rhode Island2010-2011 (FY10-11) Accomplishments$393,855 (Total Funding Received, 8/1/10-7/31/12) Subtasks 1.1-1.3 Completion 100% - Report published 75% - Final evaluation of sources underway 100% • Literature Review • MC modeling of East Coast SMF • Simulation of co-seismic sources and flank collapse of CumbreVieja Volcano using 3D multi-fluid VOF model
University of Delaware and University of Rhode Island2010-2011 (FY10-11) Accomplishments$393,855 (Total Funding Received, 8/1/10-7/31/12) Milestones for Tasks 1.4 - 1.5 Completion 20% - Work limited to DEM and GIS development 20% - • Inundation modeling for high risk East Coast communities • Construct inundation maps for modeled East Coast communities
Issues Encountered: Task 1.2 • Questions about appropriateness of SMF events from a geological standpoint • Estimated sources are being examined by USGS personnel working with the UD/URI team. • This effort is expected to be completed (summer) • Questions about whether it is appropriate to use probabilistic results for slides, or whether whether worst-case scenarios based on historical input should form the basis of results for mapping. • UD/URI feel that there should be input from the NTHMP program on this question. • Guidance on this question could be improved after the planned workshop on probabilistic hazard analysis. (enough guidance to proceed obtained during MMS meeting) Both of these situations lead to Task 1.2 extending into FY12, beyond the planned completion in the original proposal
Task 1.1: Literature review established large selection of potential sources
Task 1.3: An Overview of Distant Sources I: Flank collapse of CumbreVieja Volcano using 3D multi-fluid VOF model • 2D slope stability computations (with 2 different models) on various cross sections. Geotechnical parameters are progressively reduced (mimicking hydrothermal alteration) until unstable state. • 3D slide volumes are inferred using a 3D ellipsoid shape, based on the 2D failure contours and geological considerations for lateral extent. • Slide volumes range from 40 to 70 km3, depending on the scenario. [Vizualisation of the quasi elliptic failure contour (Drucker-Prager failure criterion) calculated with the finite element code ADELI]
Set-up of 3D tsunami generation model (THETIS) Geometry of THETIS domain Nested within larger scale domain for propagation model 3-D view of THETIS domain
CVV impact on East Coast: South-East(Georgia – South Carolina)
Overview of Distant Sources II: Caribbean subduction zone tsunamigenic earthquakes Summary SIFT sources (Gica et al 2008) used in CSZ simulation • Historical examples include 1867 (7.7 near US Virgin Islands); 1918 (7.3 from PR); 2010 (7.0 from PR) • Tsunami risk studied by many (e.g., Zahibo and Pelinovsky 2001) • NOAA Forecast Source Database (Gica et al. 2008) modeled series of potential sources • Potential high risk to particular communities (e.g., S. Carolina)
Puerto Rico trench example Distribution of maximum surface displacements in Mid-Atlantic due to CSZ simulations • Location: 19.674° N 65.806° W • Direction: 92° • Dip: 165° • Rake: 50° • Magnitude: 9.0 • Slip: 1.0 m • Depth: 40 km • Length: 600 km • Width: 150 km • Shear modulus: 4.2x1010 kg/m s2 • Radius: 200 km • Depth of slip: 400 m • Water depth: 7000 m
Overview of distant sources III: Azores-Gibraltar convergence zone Summary Sources considered for East Coast Inundation Studies • Region best known for 1755 Lisbon earthquake (8.5-9.0 magnitude; 100,000 deaths) • Earthquake extensively studied (e.g., Johston 1996; Baptista et al. 1998; Gutscher et al. 2006; Grandin et al. 2007) • Source of 1755 quake not known; Barkan et al. 2009 simulated possibilities based on far-field effect • Not included in NOAA Forecast Source Database
Azores-Gibraltar convergence zone example Lisbon 1755-like source • Location: 36.015° N 11.467° W • Direction: 345° • Dip: 40° • Rake: 90° • Magnitude: 9.0 • Slip: 13.1 m • Depth: 30 km • Length: 200 km • Width: 80 km • Shear modulus: 6.5x1010 kg/ms2 • Radius: 300 km • Depth of slip: 40 km • Water depth: 4709 m
Status of Task 1.2: Probabilistic analysis of coastal hazards associated with submarine mass failures (SMF) Summary • Past tsunamis caused by Grand Banks (1929) and Currituck (24-50,000 years ago) • 33% of US East Coast continental slope covered by landslide scars and deposits (Twichell et al. 2009) • Large number of submarine mass failures have been analyzed using Monte Carlo analysis in addition to historical examples Grand Banks source
Basis of MC analysis • Compiling surficial sediment data for the study area and enter into the GIS [Continental Margin Mapping (CONMAP) sediments grain size distribution for the United States East Coast Continental Margin]
Generation of cross-shelf/slope transects for slope stability analyses [Idealized coastline and transects for the upper east coast of the U.S., Grilli et al 2009]
Simplified tsunami propagation, runup, inundation in MC model => source selection for actual propagation with FUNWAVE • [Tsunami propagation picked within an angular spread from the failed transect direction, with insert of Gaussian distribution of coastal runup(Grilli et al., 2009)].
Simplified coastline with names of corresponding coastal states, ranges of indices of studied coastal points, numbered N-S (Baxter et al., 2011; Krauss, 2011). Points 1-899 correspond to the upper East Coast already studied in Grilli et al. (2009).
Right panel: MC estimates of runupsfor Mid-Atlantic. Left panel: SMF transects (blue lines) used in MC analysis and location and size of underwater landslides causing 500 year runup (red ellipses).
Events identified in MC analysis and chosen for use in inundation mapping: Ongoing Task 1.2 evaluation
Tsunami elevation computed with NHWAVE (up to 15 mins.) and FUNWAVE-TVD, in a 500 m regional grid, for the first SMF source. (a) instantaneous elevation after 75 mins of propagation; (b) maximum envelope of elevation
University of Delaware and University of Rhode IslandFY 12 Funding Plan