Tsunami wave modelling at the Institute of Ocean Sciences

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.
Landslide-generated tsunami: sediments in Strait of Georgia
Hypothetical
failure of the
Fraser River
delta front
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]
An example of nested model grids
grid size ~ 300 m
Alberni Inlet
grid size ~ 900 m
grid size ~ 50 m
Some plausible sea-bottom uplift scenarios for a CSZ earthquake
A
Scenario A (Satake et al., JGR 2003; Wang et al., JGR 2003).
B
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
Esquimalt and Victoria Harbours
4.2 m
Victoria Inner Harbour
Esquimalt
Esquimalt Harbour
Victoria
Maximum wave height
for 12 hour duration
Esquimalt
Sea level time series at
various sites
Site 5
Time (min)
Victoria
Time (min)
Site 1
Maximum water speed
Esquimalt Harbour
Victoria Harbour
Sea level time series at
various sites
Outer Coast:
Ucluelet Inlet and vicinity
Itatsoo Bay
Ucluelet Inlet
Maximum water height
Maximum water speed
1964 Great Alaska Earthquake
tsunami waves travel times
Vancouver
Island
(from NOAA web site)
Port Alberni tide gauge
PST
4m
1.7 hr
2.0 hr
Port Alberni tide gauge March 28-29, 1964
Admittance functions for Bamfield and Port Alberni (relative to Tofino)
from power spectra of background sea-level oscillations
Spectral response method
Alberni
49.2N
C5
C4
grid size: 40x40 m
(1213x1223 grids)
time step: 0.43 sec
duration: 240 hours
C3
49.0N
C2
C1
open boundary conditions:
radiation + prescribed waves
(from AR spectral function)
Bamfield
48.8N
125.6W
125.4W
125.2W
Numerical model details:
Linear “flux” model
(similar to a linear version of
TUNAMI by Imamura)
125.0W
124.8W
Results processed using
standard spectral analysis
Bamfield - Port Alberni response function
16
100 min
44 min
14
Amplitude
12
10
8
6
4
2
0
900
Phase (degree)
800
Data
Model
700
600
500
400
300
200
100
0
0
1
Frequency (cph)
2
(from cross-spectra between Alberni and Bamfield)
3
The Haida Gwaii earth(sea)quake (from James et al. Eos 2013)
USGS finite fault model (G. Hayes 2012)
n 
n 
n 
n 
n 
n 
NEIC hypocenter (Lon.=-132.1 deg.; Lat.=52.7 deg.).
Mw= 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
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)