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Home , Alberni Inlet, Bamfield, Esquimalt, Port Alberni, Tofino

Models of waves at the Institute of Ocean Sciences

Josef Cherniawsky and Isaac Fine

Ocean Science Division, Fisheries & Oceans , Sidney, BC

Port Alberni, March 27, 2014 Acknowledgements:

Richard Thomson Alexander Rabinovich Kelin Wang Kim Conway Vasily Titov Jing Yang Li Brian Bornhold Maxim Krassovski Fred Stephenson Bill Crawford Pete Wills Denny Sinnott … and others!

Our tsunami web site: http://www.pac.dfo-mpo.gc.ca/science/oceans//index-eng.htm

… or just search for “DFO tsunami research” An outline … oIntroduction oModels of submarine landslide tsunamis (4 min) oA model of a Cascadia tsunami (4 min) oTsunami wave amplification in (4 min) oA model of the 2012 Haida Gwaii tsunami (4 min) oQuestions Examples of models of landslide generated tsunamis in Canada - some references - Fine, I.V., Rabinovich, A.B., Thomson, R.E. and E.A. Kulikov. 2003. Numerical Modeling of Tsunami Generation by Submarine and Subaerial Landslides. In: Ahmet C. et al. [Eds.]. NATO Science Series, Underwater Ground Failures On Tsunami Generation, Modeling, Risk and Mitigation. Kluwer. 69-88. Fine, I. V., A.B. Rabinovich, B. D. Bornhold, R.E. Thomson and E.A. Kulikov. 2005. The Grand Banks landslide-generated tsunami of November 18, 1929: Preliminary analysis and numerical modeling. Marine Geology. 215: 45-57. Fine, I.V., Rabinovich, A.B., Thomson, R.E., and Kulikov, E.A., 2003. Numerical modeling of tsunami generation by submarine and subaerial landslides, in: Submarine Landslides and Tsunamis, edited by Yalciner, A.C., Pelinovsky, E.N., Synolakis, C.E., and Okal, E., NATO Adv. Series, Kluwer Acad. Publ., Dorderecht, pp 69–88.

Rabinovich, A.B., Thomson, R.E., Bornhold, B.B., Fine, I.V. and E.A. Kulikov. 2003. Numerical modelling of tsunamis generated by hypothetical landslides in the Strait of Georgia, . Pure appl. Geophys. 160: 1273-1313. Thomson, R., Fine, I., Krassovski, M., Cherniawsky, J., Conway, K. and Wills, P., 2012. Numerical simulation of tsunamis generated by submarine slope failures in Douglas Channel, British Columbia. DFO Can. Sci. Advis. Sec. Res. Doc. 2012/115. v + 38p. Landslide-generated tsunami: sediments in Strait of Georgia

Hypothetical failure of the delta front

Rabinovich et al. 2003 Fine et al. 2003 Submarine Slide Tsunami

Time to cross the strait ~7 min Modeled wave heights Richmond for the case of a “Case 1” slide:

area = 7.3 km2 volume = 0.75 km3

Waves up to 18 m high hit Galiano and Main Islands; less than 5 m on the mainland side.

Historic landslides

IOS models of earthquake generated tsunamis (some references) Cherniawsky, J.Y., Titov, V.V., Wang, K. and J.-Y. Li. 2007. Numerical simulations of tsunami waves and currents for southern Island from a Cascadia megathrust earthquake. Pure and Applied Geophysics. 164:465-492. Cherniawsky, J.Y., 2007. Preliminary results from a project “Tsunami Modelling with Inundation: Harbour and Sooke Basin”. Unpublished Report for the Municipality of Sooke (can be requested from the author). Fine, I., J.Y. Cherniawsky, A.B. Rabinovich and F. Stephenson. 2009. Numerical Modeling and Observations of Tsunami Waves in Alberni Inlet and , British Columbia. Pure and Applied Geophysics. 165:1019-2044. Titov, V.V. and Synolakis, C.E. (1997), Extreme inundation flows during the Hokkaido– Nansei–Oki tsunami, Geophys. Res. Lett. 24(11), 1315–1318. [nested-grid MOST model]

An example of nested model grids grid size ~ 300 m

Alberni Inlet

grid size ~ 50 m grid size ~ 900 m Some plausible sea-bottom uplift scenarios for a CSZ earthquake

A B

Scenario A (Satake et al., JGR 2003; Wang et al., JGR 2003). Scenario B (Wang and He, BSSA 2008). Initial bottom deformation and wave propagation on a coarse (900 m) grid

Scenario A (Wang et al. 2003)

Cherniawsky et al. 2007 Maximum heights: Comparison of the two earthquake scenarios

Scenario A without run-up (from CTWL2007) Scenario B with run-up and Victoria Harbours

4.2 m

Victoria Inner Harbour Esquimalt Victoria

Maximum wave height for 12 hour duration Esquimalt Sea level time series at various sites

Site 5

Time (min)

Victoria Site 1

Time (min) Maximum water speed Esquimalt Harbour Victoria Harbour Sea level time series at Outer Coast: various sites Inlet and vicinity

Itatsoo Bay Ucluelet Inlet

Maximum water height Maximum water speed 1964 Great Earthquake tsunami waves travel times

Vancouver Island

(from NOAA web site) tide gauge

PST

4 m 1.7 hr

2.0 hr

Port Alberni tide gauge March 28-29, 1964 Admittance functions for and Port Alberni (relative to )

from power spectra of background sea-level oscillations Spectral response method Alberni 49.2N Numerical model details: C5 Linear “flux” model C4 (similar to a linear version of TUNAMI by Imamura)

grid size: 40x40 m

49.0N C3 (1213x1223 grids) C2 time step: 0.43 sec duration: 240 hours

C1 open boundary conditions: radiation + prescribed waves Bamfield (from AR spectral function) 48.8N Results processed using 125.6W 125.4W 125.2W 125.0W 124.8W standard spectral analysis

Bamfield - Port Alberni response function 16 100 min 44 min 14 12

e 10 d u t i l

p 8 m A 6 4

2

0

900

800 Data

) 700 Model e e r

g 600 e d ( 500 e s

a 400 h

P 300 200 100 0 0 1 2 3 Frequency (cph)

(from cross-spectra between Alberni and Bamfield) The Haida Gwaii earth(sea)quake (from James et al. Eos 2013) USGS finite fault model (G. Hayes 2012) n NEIC hypocenter (Lon.=-132.1 deg.; Lat.=52.7 deg.). n Mw= 7.46e+27 dyne.cm n Nodal plane (strike=323.0 deg., dip=25.0 deg.). n Nx (along-strike)=18; dx=14 km n Ny (downdip)=10; dy=9 km n Oblique trust faulting Correcting the USGS source position using inverse travel times to the 4 nearest DARTs

Original Shifted

1000 m

Isochrones: black – for tsunami arrival times (first rise ± 1 min); red – for 1st tsunami maximum Shadow zone: grey area Source function (smoothed): thick yellow line – 10 cm contour; thick red – 100 cm contour (Fine et al. 2013a,b) Nested grid tsunami model using the MOST3 code

Initial surface deformation with its maximum on QCT (USGS/IOS source) Tasu Sound

8.4 m

Gowgaia Bay

Maximum sea level on a medium grid (~130 m grid size) A revised uplift model based on GPS data (from Kelin Wang) Two possible initial deformation scenarios

Hayes – Wang – Fine (HWF) Lay et al. – Wang – Fine (LWF)

(the last “seabed to sea surface” transformation was done as in Fine and Kulikov 2011) from HWF source (coarse grid) Maximum tsunami waves (HWF) Seaquake/Davidson Inlet

Model bathymetry Maximum tsunami wave and maximum speed (HWF)