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

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/tsunamis/index-eng.htm

… or just search for “DFO tsunami research”

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

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, British Columbia. 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.

Hypothetical failure of the Fraser River delta front

Landslide-generated tsunami: sediments in Strait of Georgia

Rabinovich et al. 2003 Fine et al. 2003

Submarine Slide Tsunami

Time to cross the strait ~7 min

Richmond

Modeled wave heights 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 Vancouver 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: 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. 2009. Numerical Modeling and Observations of Tsunami Waves in Alberni Inlet and Barkley Sound, 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]

grid size ~ 900 m

An example of nested model grids grid size ~ 300 m

grid size ~ 50 m

Alberni Inlet

Some plausible sea-bottom uplift scenarios for a CSZ earthquake

Scenario A (Satake et al., JGR 2003; Wang et al., JGR 2003). Scenario B (Wang and He, BSSA 2008).

A B

Initial bottom deformation and wave propagation on a coarse

(900 m) grid

Scenario A

(Wang et al. 2003)

Cherniawsky et al. 2007

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

Maximum heights: Comparison of the two earthquake scenarios

Esquimalt and Victoria Harbours

Victoria Inner Harbour

Esquimalt Harbour

Victoria Esquimalt

Maximum wave height for 12 hour duration

4.2 m

Esquimalt

Victoria

Sea level time series at various sites

Time (min)

Time (min)

Site 5

Site 1

Maximum water speed Esquimalt Harbour Victoria Harbour

Outer Coast: Ucluelet Inlet and vicinity

Sea level time series at various sites

Itatsoo Bay

Ucluelet Inlet

Maximum water height Maximum water speed

1964 Great Alaska Earthquake tsunami waves travel times

(from NOAA web site)

Vancouver Island

Port Alberni tide gauge March 28-29, 1964

4 m

PST

1.7 hr

2.0 hr

Port Alberni tide gauge

Admittance functions for Bamfield and Port Alberni (relative to Tofino)

from power spectra of background sea-level oscillations

125.6W 125.4W 125.2W 125.0W 124.8W

48.8N

49.0N

49.2N

C1

C2C3

C5C4

Bamfield

Alberni

Spectral response method Numerical model details: Linear “flux” model (similar to a linear version of TUNAMI by Imamura) grid size: 40x40 m (1213x1223 grids) time step: 0.43 sec duration: 240 hours open boundary conditions: radiation + prescribed waves (from AR spectral function) Results processed using standard spectral analysis

0

2

4

6

8

10

12

14

16

Ampl

itude

Bamfield - Port Alberni response function

0 1 2 3Frequency (cph)

0100200

300400500600700

800900

Pha

se(d

egre

e)

DataModel

100 min 44 min

(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

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)

1000 m

Original Shifted

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

Nested grid tsunami model using the MOST3 code

Maximum sea level on a medium grid (~130 m grid size)

8.4 m

Tasu Sound

Gowgaia Bay

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

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

Two possible initial deformation scenarios

(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)