Models of tsunami waves at the Institute of Ocean Sciences

Transcription

1 Models of tsunami waves at the Institute of Ocean Sciences Josef Cherniawsky and Isaac Fine Ocean Science Division, Fisheries & Oceans Canada, Sidney, BC Port Alberni, March 27, 2014

2 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!

3 Our tsunami web site: or just search for DFO tsunami research

4 An outline o Introduction o Models of submarine landslide tsunamis (4 min) o A model of a Cascadia earthquake tsunami (4 min) o Tsunami wave amplification in Alberni Inlet (4 min) o A model of the 2012 Haida Gwaii tsunami (4 min) o Questions

5 Examples of models of landslide generated tsunamis in Canada - some references - Fine, I.V., Rabinovich, A.B., Thomson, R.E. and E.A. Kulikov 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 Fine, I. V., A.B. Rabinovich, B. D. Bornhold, R.E. Thomson and E.A. Kulikov The Grand Banks landslide-generated tsunami of November 18, 1929: Preliminary analysis and numerical modeling. Marine Geology. 215: Fine, I.V., Rabinovich, A.B., Thomson, R.E., and Kulikov, E.A., 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 Rabinovich, A.B., Thomson, R.E., Bornhold, B.B., Fine, I.V. and E.A. Kulikov Numerical modelling of tsunamis generated by hypothetical landslides in the Strait of Georgia, British Columbia. Pure appl. Geophys. 160: Thomson, R., Fine, I., Krassovski, M., Cherniawsky, J., Conway, K. and Wills, P., 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.

6 Landslide-generated tsunami: sediments in Strait of Georgia Hypothetical failure of the Fraser River delta front Rabinovich et al Fine et al. 2003

7 Submarine Slide Tsunami Time to cross the strait ~7 min

8 Richmond Modeled wave heights for the case of a Case 1 slide: area = 7.3 km 2 volume = 0.75 km 3 Waves up to 18 m high hit Galiano and Main Islands; less than 5 m on the mainland side.

9 Historic landslides

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12 IOS models of earthquake generated tsunamis (some references) Cherniawsky, J.Y., Titov, V.V., Wang, K. and J.-Y. Li Numerical simulations of tsunami waves and currents for southern Vancouver Island from a Cascadia megathrust earthquake. Pure and Applied Geophysics. 164: Cherniawsky, J.Y., Preliminary results from a project Tsunami Modelling with Inundation: Sooke 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 Numerical Modeling and Observations of Tsunami Waves in Alberni Inlet and Barkley Sound, British Columbia. Pure and Applied Geophysics. 165: Titov, V.V. and Synolakis, C.E. (1997), Extreme inundation flows during the Hokkaido Nansei Oki tsunami, Geophys. Res. Lett. 24(11), [nested-grid MOST model]

13 An example of nested model grids grid size ~ 300 m Alberni Inlet grid size ~ 900 m grid size ~ 50 m

14 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).

15 Initial bottom deformation and wave propagation on a coarse (900 m) grid Scenario A (Wang et al. 2003) Cherniawsky et al. 2007

16 Maximum heights: Comparison of the two earthquake scenarios Scenario A without run-up (from CTWL2007) Scenario B with run-up

17 Esquimalt and Victoria Harbours 4.2 m Victoria Inner Harbour Esquimalt Victoria Esquimalt Harbour Maximum wave height for 12 hour duration

18 Esquimalt Sea level time series at various sites Site 5 Time (min) Victoria Site 1 Time (min)

19 Esquimalt Harbour Maximum water speed Victoria Harbour

20 Sea level time series at various sites Outer Coast: Ucluelet Inlet and vicinity Itatsoo Bay

21 Ucluelet Inlet Maximum water height Maximum water speed

22 1964 Great Alaska Earthquake tsunami waves travel times Vancouver Island (from NOAA web site)

23 Port Alberni tide gauge PST 4 m 1.7 hr 2.0 hr Port Alberni tide gauge March 28-29, 1964

24 Admittance functions for Bamfield and Port Alberni (relative to Tofino) from power spectra of background sea-level oscillations

25 Spectral response method 49.2N Alberni C5 C4 Numerical model details: Linear flux model (similar to a linear version of TUNAMI by Imamura) 49.0N C2 C3 grid size: 40x40 m (1213x1223 grids) time step: 0.43 sec duration: 240 hours 48.8N Bamfield C1 open boundary conditions: radiation + prescribed waves (from AR spectral function) 125.6W 125.4W 125.2W 125.0W 124.8W Results processed using standard spectral analysis

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27 16 14 Bamfield - Port Alberni response function 100 min 44 min 12 Amplitude Phase (degree) Data Model Frequency (cph) (from cross-spectra between Alberni and Bamfield)

28 The Haida Gwaii earth(sea)quake (from James et al. Eos 2013)

29 USGS finite fault model (G. Hayes 2012) n n n n n n NEIC hypocenter (Lon.= deg.; Lat.=52.7 deg.). M w = 7.46e+27 dyne.cm Nodal plane (strike=323.0 deg., dip=25.0 deg.). Nx (along-strike)=18; dx=14 km Ny (downdip)=10; dy=9 km Oblique trust faulting

30 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 1 st 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)

31 Nested grid tsunami model using the MOST3 code Initial surface deformation with its maximum on QCT (USGS/IOS source)

32 Tasu Sound 8.4 m Gowgaia Bay Maximum sea level on a medium grid (~130 m grid size)

33 A revised uplift model based on GPS data (from Kelin Wang)

34 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)

35 from HWF source (coarse grid)

36 Maximum tsunami waves (HWF)

37 Model bathymetry Seaquake/Davidson Inlet

38 Maximum tsunami wave and maximum speed (HWF)