Journal
Journalof
ofCoastal
CoastalResearch
Research
SI 64
pg -- pg
1195
1199
ICS2011
ICS2011 (Proceedings)
Poland
ISSN 0749-0208
STUDY OF TSUNAMI ATTACKS ON NEIGHBORING COUNTRIES
OF CASPIAN SEA CAUSED BY A PROBABLE SUBMARINE
LANDSLIDE
M. Soltanpour† and E. Rastgoftar‡
† Dept. Civil Eng.
K. N. Toosi University
of Technology, Tehran
19967-15433, Iran
[email protected]
‡ Dept. Civil Eng.
K. N. Toosi University of
Technology, Tehran
19967-15433,Iran
[email protected]
ABSTRACT
Soltanpour, M. and Rastgoftar, E., 2011. Study of tsunami attacks on neighboring countries of Caspian Sea
caused by a probable submarine landslide. Journal of Coastal Research, SI 64 (Proceedings of the 11th
International Coastal Symposium), 1195 – 1199. Szczecin, Poland, ISSN 0749-0208
Subduction zone earthquakes have been considered as the tsunami source in most of the previous studies of
Caspian Sea tsunamis and the result of a submarine landslide has been less investigated. A probable tsunami
generated by a submarine landslide, located in Derbent Basin of the middle part of Caspian Sea, is studied in this
research. The effect of tsunami on surrounding countries is simulated using GEOWAVE, a combination of
TOPICS and FUNWAVE models. Numerical results show that tsunami waves, propagating out from landslide
location in circular rings, are first amplified approaching the coasts of close neighboring countries; but damp
rapidly when they travel to far distances. The high tsunami waves are observed only along the coastlines of
countries in the vicinity of the landslide and the probability of tsunami attack on other coasts of Caspian Sea
countries is relatively low. This can be attributed to the limited far-field effect of submarine landslides tsunamis
due to their radial damping and dispersion. Future studies to determine other probable landslide locations in
Caspian Sea are important for the risk assessment of generated tsunamis on neighboring countries.
ADDITIONAL INDEX WORDS: Tsunami Simulation, risk assessment, GEOWAVE, Derbent Basin
INTRODUCTION
The public awareness of tsunamis has been intensified
following the destructive Indian Ocean tsunami caused
widespread damage and more than 225,000 fatalities. Similar to
the other coastal regions around the world, the increase of the
population along the coasts of Caspian Sea highlights the urgent
need to assess tsunami hazards in the region. There have been a
number of investigations on Caspian earthquake tsunamis during
past years. The collected information achieved by historical
events, regional seismicity and numerical models shows that
coseismic tsunamis in the Caspian Sea have repeatedly happened
in the past and their occurrence in future are probable. Although
the past historical tsunamis have not been destructive (Dotsenko et
al., 2002), seismic activity is not the only possible cause of
tsunami generation in the Caspian Sea. Underwater landslides,
explosions of mud volcanoes and other factors can probably
produce locally destructive tsunamis. These non-earthquake
sources of locally destructive tsunamis have been less studied due
to limited existence of reliable information and low recurrence of
these events in the region.
In the autumn of 2004, using a super high-resolution narrowbeam parametric profiler, the fine structure of the uppermost
sediments of the Caspian Sea was studied for the first time.
Analyzing the data of profiling across the western slope of
Derbent Basin, located in the middle part of Caspian Sea and in
the vicinity of the Dagestan coast, indicated that submarine
landslide processes proceeded on the region during the
Neopleistocene–Holocene, which may have been kept their
activity up to present (Levchenko et al., 2008).
Most submarine slopes are inherently stable. Elevated pore
pressures (leading to decreased frictional resistance to sliding) and
specific weak layers within stratified sequences appear to be the
key factors influencing landslide occurrence. Elevated pore
pressures can result from processes such as rapid sedimentation,
earthquake shaking or possibly due to melting of gas hydrates
contained within the sediments. Historical evidences suggest that
the majority of large submarine landslides are triggered by
earthquakes (Masson et al., 2006). Seismological analysis and
historical events show Derbent Basin has highest seismic activity
among the regions of Caspian Sea (Dotsenko et al., 2002). The
existence of the transient factor to make a submarine landslide
reveals the relatively high probability of occurrence of a
submarine landslide in the region.
GEOWAVE, a combination of TOPICS and FUNWAVE
models, is an integrated tsunami simulation numerical model.
Using GEOWAVE model, the probable tsunami caused by a
submarine landslide in Derbent Basin is simulated in this study to
assess tsunami hazards on the coasts of Caspian Sea. Tsunami
generation is first simulated by TOPICS model. The propagation
of tsunami will then be investigated employing FUNWAVE.
SUBMARINE LANDSLIDES
Submarine landslides, or submarine mass failures, are one of the
main agents through which sediments derived from land (mainly
Journal of Coastal Research, Special Issue 64, 2011
1195
1
1
Coastal Modelling
Coastal Modelling
carried by rivers) and from the continental shelf (e.g. through
erosion
andrivers)
transport
by ocean
currents shelf
and (e.g.
storms),
are
carried by
and from
the continental
through
transferred
across
the continental
slopecurrents
to the deep
erosion and
transport
by ocean
andocean.
storms), are
Althoughacross
subduction
zone earthquakes
are the
commonest
transferred
the continental
slope to the deep
ocean.
source
of tsunamis
around
theearthquakes
world, submarine
failures
Although
subduction
zone
are themass
commonest
have
resulted toaround
considerable
tsunamis.
While
earthquake
sourcealso
of tsunamis
the world,
submarine
mass
failures
tsunamis,
last 50 years,
are now
relatively
well
have also studied
resultedfor
to the
considerable
tsunamis.
While
earthquake
understood,
knowledge
of
tsunamis, studied
for theoflastthe50generation
years, are and
now propagation
relatively well
submarine
failure tsunamis
is instead still
understood,mass
knowledge
of the generation
andfragmentary.
propagationThe
of
importance
of tsunamis
generatedisbyinstead
submarine
mass failure The
was
submarine mass
failure tsunamis
still fragmentary.
only
recognized
following
the 1998
Newmass
Guinea
terrible
importance
of tsunamis
generated
by Papua
submarine
failure
was
tsunami,
where waves
up tothe
15 1998
m high
affected
km segment
only recognized
following
Papua
Newa 20
Guinea
terrible
of
coast and
killed
2200uppeople
et al.,
2000).
tsunami,
where
waves
to 15 (McSaveney
m high affected
a 20
km segment
generated
by subduction
or
of Tsunamis
coast and killed
2200 people
(McSaveneyzone
et al.,earthquakes
2000).
submarine
failures by
havesubduction
fundamentalzone
differences.
Rapture
Tsunamismass
generated
earthquakes
or
dimensions
determine
thehave
source
areas for earthquake
submarine mass
failures
fundamental
differences. tsunamis
Rapture
resulting
to determine
vast sourcethe
areas,
compared
to the
areas affected
by
dimensions
source
areas for
earthquake
tsunamis
landslide
tsunamis.
On areas,
the other
hand, totsunamis
resulting to
vast source
compared
the areasgenerated
affected by
subduction
zone earthquakes
have ahand,
lineartsunamis
source and
propagate
landslide tsunamis.
On the other
generated
by
perpendicular
to the
source fault
buta landslide
tsunamis
subduction zone
earthquakes
have
linear source
and propagate
radial
due to their
point
source.
source
area ofpropagate
landslide
perpendicular
to the
source
faultThe
butsmall
landslide
tsunamis
tsunamis
leads
the generation
of shorter
in
radial due also
to their
pointtosource.
The small source
area ofwaves
landslide
comparison
to the
waves
caused
by earthquakes
tsunamis.
tsunamis also
leads
to the
generation
of shorter
wavesThe
in
dispersion
alsobyradial
spreadingtsunamis.
decrease The
the
comparisonoftoshort
the waves and
caused
earthquakes
far-field
of landslide
in contrast
to decrease
tsunamis the
of
dispersioneffects
of short
waves andtsunamis
also radial
spreading
seismic
shorter
wavesinare
more prone
to coastal
far-fieldorigins.
effects However,
of landslide
tsunamis
contrast
to tsunamis
of
amplification
with
higher local
effects.
tsunamis
seismic origins.
However,
shorter
wavesUnlike
are more
prone generated
to coastal
by
earthquakes,
tsunamis
generated
in
amplification
with submarine
higher local landslide
effects. Unlike
tsunamis
generated
shallow
waters aresubmarine
more destructive
compared
to those
generated
by earthquakes,
landslide
tsunamis
generated
in
in
deep waters
water. are
This
is destructive
due to the compared
higher energy
thatgenerated
can be
shallow
more
to those
converted
from the
slide
shallow
areas.that
Moreover,
in deep water.
This
is to
duethetowater
the in
higher
energy
can be
shallower
areslide
usually
closer
to the
coasts and
thusMoreover,
a shorter
converted waters
from the
to the
water
in shallow
areas.
available
exists
for radial
The and
timethus
of the
initial
shallowerdistance
waters are
usually
closerdamping.
to the coasts
a shorter
wave
generations
alsofor
different
in these two
tsunamis.
available
distance are
exists
radial damping.
Thetypes
time of the
initial
Earthquake
tsunamis
are different
generatedininstantaneously,
so tsunamis.
the final
wave generations
are also
these two types of
seabed
vertical
displacements
are instantaneously,
immediately transferred
to
Earthquake
tsunamis
are generated
so the final
initial
surfacedisplacements
elevations. However,
since the movements
seabedsea
vertical
are immediately
transferred of
to
landslides
normally
sub critical,
a landslide
tsunami
leaves the
initial sea are
surface
elevations.
However,
since the
movements
of
generation
region
moresub
rapidly
than
the duration
of leaves
landslide
landslides are
normally
critical,
a landslide
tsunami
the
motion.
Thus,
the more
timingrapidly
of thethan
landslide
movement
becomes
generation
region
the duration
of landslide
important
for thethe
generation
of submarine
landslide
waves.becomes
motion. Thus,
timing of
the landslide
movement
important for the generation of submarine landslide waves.
TSUNAMI GENERATION
TOPICS, tsunami
generator GENERATION
model of GEOWAVE, can simulate
TSUNAMI
multiple
tsunami
sources
withmodel
different
generation mechanisms.
TOPICS,
tsunami
generator
of GEOWAVE,
can simulate
For
submarine
the initial
freegeneration
surface elevation
and
multiple
tsunamilandslides,
sources with
different
mechanisms.
water
velocities landslides,
in TOPICSthe
areinitial
derived
from
multivariate,
For submarine
free
surface
elevationsemiand
empirical
curve fits
as a function
of non-dimensional
parameters
water velocities
in TOPICS
are derived
from multivariate,
semicharacterizing
(e.g., density,
geometry, etc.)
and the
empirical curvethefitslandslide
as a function
of non-dimensional
parameters
local
bathymetry
(e.g., slope,
depth, geometry,
etc.). Relevant
characterizing
the landslide
(e.g., density,
etc.) andnonthe
dimensional
parameters
selected
the numerical
local bathymetry
(e.g., are
slope,
depth,based
etc.).on Relevant
nonexperiments,
first carried are
out selected
with 2D based
fully nonlinear
potential
dimensional parameters
on the numerical
flow
model offirst
Grilli
and Watts
(1999).
fits were
later
experiments,
carried
out with
2D The
fullycurve
nonlinear
potential
modified
based
on the
the more
3D were
model
of
flow model
of Grilli
andresults
Watts of
(1999).
The recent
curve fits
later
Grilli
et al.based
(2002).
modified
on the results of the more recent 3D model of
Twoet idealized
Grilli
al. (2002).types of submarine mass failures moving over
plane
are types
considered
in thesemass
models,
representing
the
Twoslopes
idealized
of submarine
failures
moving over
extreme
casesareof considered
a general in
probable
submarine
mass failure
plane slopes
these models,
representing
the
motion.
are underwater
slides, i.e. mass
translational
extreme These
cases two
of atypes
general
probable submarine
failure
failures,
and slumps,
i.e. rotational
failures.slides,
For underwater
slides,
motion. These
two types
are underwater
i.e. translational
which
submarine
landslidefailures.
in Derbent
Basin of Caspian
failures,probable
and slumps,
i.e. rotational
For underwater
slides,
Sea
appears
to submarine
be similar landslide
to it, theinlandslide
is idealized
as a
which
probable
Derbent Basin
of Caspian
mound
with to
elliptical
cross-section
a straight
Sea appears
be similar
to it, the translating
landslide isalong
idealized
as a
slope
(Figure
1). The
mound istranslating
specified along
with maximum
moundθ with
elliptical
cross-section
a straight
slope θ (Figure 1). The mound is specified with maximum
Figure 1. Definition sketch of the simulation domain for
underwater
(Wattssketch
et al., 2003).
Figure 1. slides
Definition
of the simulation domain for
underwater slides (Watts et al., 2003).
thickness T in the middle, total length b along the down-slope
axis,
totalTwidth
along total
the cross-slope
axis, the
anddown-slope
an initial
thickness
in thewmiddle,
length b along
submergence
d at the
of the
landslide. axis, and an initial
axis, total width
w middle
along the
cross-slope
Expressing dthe
Newton’s
first
by the balance of existent
submergence
at the
middle of
thelaw
landslide.
forces
for the
of first
masslaw
motion
performing
32
Expressing
the center
Newton’s
by theand
balance
of existent
underwater
numerical
by and
Grilliperforming
et al. (2005),
forces for slide
the center
of simulations
mass motion
32
covering a slide
wide numerical
range of governing
led to
underwater
simulationsparameter
by Grilli values,
et al. (2005),
construct
for 2D
tsunami
amplitude,
covering a predictive
wide rangeequations
of governing
parameter
values,
led to
minimum
depression
abovefor
the 2D
middle
of the initial
slide
construct surface
predictive
equations
tsunami
amplitude,
position,
characteristic
based ofonthecurve
minimum and
surface
depression wavelength
above the middle
initialfitting
slide
results.
more than half
of all tsunamigenic
submarine
position,Since
and characteristic
wavelength
based on curve
fitting
landslides
do not
satisfy
2D criteria
in 2D
model,
results. Since
more
thanthehalf
of all established
tsunamigenic
submarine
3D
simulation
were
performed
Grilli etestablished
al. (2002) in
to propose
an
landslides
do not
satisfy
the 2Dbycriteria
2D model,
analytical
method
specify initial
3D tsunami
elevations.
It was
3D simulation
weretoperformed
by Grilli
et al. (2002)
to propose
an
concluded
that underwater
tsunami
features
are primarily
analytical method
to specifyslide
initial
3D tsunami
elevations.
It wasa
function
of that
submarine
mass slide
failuretsunami
volumefeatures
(b,w,T),are
angle
of slope,a
concluded
underwater
primarily
and
initial
submergence
thesevolume
models.(b,w,T),
Table angle
1 shows
the
function
of submarine
massinfailure
of slope,
required
TOPICS
parameters
simulate
tsunami
generation
and initial
submergence
in to
these
models.
Table
1 showsbased
the
on
landslide
characteristic
andtolocal
bathymetry.
required
TOPICS
parameters
simulate
tsunami generation based
reported
from typical
of the past landslides around
onData
landslide
characteristic
andwidths
local bathymetry.
theData
world
(e.g., McAdoo
et al.,
2000;ofHutton
and
Syvitski,around
2004)
reported
from typical
widths
the past
landslides
show
that (e.g.,
underwater
slides
are2000;
oftenHutton
narrowand
compared
their
the world
McAdoo
et al.,
Syvitski,to2004)
length,
with
typical slides
width are
w often
=0.25b
(Grilli
et al., to2005).
show that
underwater
narrow
compared
their
Unfortunately,
there iswidth
not anwaccurate
total
length, with typical
=0.25b estimation
(Grilli et for
al.,the2005).
width
of the landslide
parameter
Unfortunately,
there is in
notthe
an region.
accurateThis
estimation
for has
the been
total
considered
as landslide
a variable inin the
this region.
study assuming
1,000, 2,000
and
width of the
This parameter
has been
3,000
metersasfor
the total in
width
the landslide.
initial
wave’s
considered
a variable
thisof
study
assuming The
1,000,
2,000
and
amplitude
is linearly
proportional
as illustrated
3,000 meters
for the total
width of to
thelandslide
landslide.width,
The initial
wave’s
in
Figure is2.linearly
Despite
the differences
of initial
surface
amplitude
proportional
to landslide
width, free
as illustrated
elevations,
wavelengths,
to thesurface
Table
in Figure the
2. calculated
Despite the
differencescorresponding
of initial free
1elevations,
landslide,the
arecalculated
about 30 kilometers
for corresponding
all three cases.toThis
due
wavelengths,
the is
Table
to
the fact are
thatabout
the wavelength,
the travel
1 landslide,
30 kilometersdetermined
for all threebycases.
This istime
due
which
is athe
function
of initial
submergence
andtravel
landslide
to the itself
fact that
wavelength,
determined
by the
time
length,
is independent
of landslide
width.
which itself
is a function
of initial
submergence and landslide
The assumed
widthsofoflandslide
the landslide
length,
is independent
width.and other parameters were
introduced
to TOPICS
Consequently,
TOPICS
provided
The assumed
widths ofmodel.
the landslide
and other
parameters
were
the
initial free
surface of
the landslide
tsunami
at characteristic
introduced
to TOPICS
model.
Consequently,
TOPICS
provided
after thatofthe
starts
its motion
(Figure 3).
time
(t0= 484s),
the initial
free surface
thelandslide
landslide
tsunami
at characteristic
time (t0= 484s), after that the landslide starts its motion (Figure 3).
Table 1: Parameters of the Caspian Sea probable submarine
landslide.
Table 1: Parameters of the Caspian Sea probable submarine
landslide.
Estimated parameter
Value
Estimated
Slopeparameter
(θ)
Slope
(θ)
Initial submergence
Initial Length
submergence
Length
Maximum thickness
Maximum thickness
Journal of Coastal Research, Special Issue 64, 2011
Journal of Coastal Research, Special Issue 64, 2011
1196
Value
2°
2° m
415
415 m
5300
m
5300
m
1100 m
1100 m
2
2
Soltanpour and Rastgoftar
Soltanpour and Rastgoftar
Figure 2. Variation of initial free surface elevation with width of
the
landslide
(w), corresponding
to surface
the Tableelevation
1 landslide.
Figure
2. Variation
of initial free
with width of
the landslide (w), corresponding to the Table 1 landslide.
TSUNAMI PROPAGATION AND INUNDATION
The outputs PROPAGATION
calculated from TOPICS
model
are introduced as
TSUNAMI
AND
INUNDATION
theThe
initial
conditions
to thefrom
tsunami
propagation
In the case
outputs
calculated
TOPICS
model model.
are introduced
as
of
landslide
tsunami,
generated
outputsmodel.
are free
surface
the ainitial
conditions
to thethe
tsunami
propagation
In the
case
elevation
and tsunami,
water horizontal
velocities,
no surface
initial
of a landslide
the generated
outputs while
are free
horizontal
velocities
assumed for
the tsunamis
by
elevation and
waterarehorizontal
velocities,
while resulted
no initial
earthquakes.
horizontal velocities are assumed for the tsunamis resulted by
earthquakes.
Figure 3. Initial free surface elevation corresponding to the Table
1
landslide
with an
of 2,000 m.
Figure
3. Initial
freeassumed
surfacelandslide
elevationwidth
corresponding
to the Table
1 landslide with an assumed landslide width of 2,000 m.
Earthquake tsunamis are most commonly described by the
shallow
water equations,
i.e. the
simplest
type ofdescribed
depth integrated
Earthquake
tsunamis are
most
commonly
by the
long
wave
equations,
since
their
wavelengths,
in theintegrated
order of
shallow
water
equations,
i.e. the
simplest
type of depth
hundreds
kilometers,since
are much
than the in
ocean
in
long waveof equations,
their larger
wavelengths,
the depth,
order of
the
order of few
kilometers.
Assuming
thethan
vertical
acceleration
hundreds
kilometers,
are much
larger
the ocean
depth, of
in
water
particles
be negligible
compared
to theacceleration
gravitational
the order
of few to
kilometers.
Assuming
the vertical
of
acceleration,
thetohydrostatic
pressure
approximation
is used in
water particles
be negligible
compared
to the gravitational
long
wave theory.
Moreover,
the shallow
water isequations
acceleration,
the hydrostatic
pressure
approximation
used in
disregard
frequency
spiteshallow
of thesewater
simplifications,
long wave
theory. dispersion.
Moreover, Inthe
equations
these
equations
are generally
enough
accurate
for the
modeling of
disregard
frequency
dispersion.
In spite
of these
simplifications,
earthquake
tsunamis.
However,
shorter
these equations
are generally
enoughlandslides
accurate forproduce
the modeling
of
tsunami
waves
in comparison
to those
generated
by earthquake
earthquake
tsunamis.
However,
landslides
produce
shorter
tsunamis,
as mentioned
before.toThese
are nontsunami waves
in comparison
those tsunami
generatedwaves
by earthquake
hydrostatic
the vertical
velocities
cannot be
neglected,
in
tsunamis, asand
mentioned
before.
These tsunami
waves
are noncontrast
the thewaves
generated
earthquake
tsunamis.
hydrostaticto and
vertical
velocitiesbycannot
be neglected,
in
Moreover,
shorter
wavelength
the necessity
of the
contrast tothethe
waves
generatedindicates
by earthquake
tsunamis.
dispersive
application.
A different
is necessary
Moreover, model
the shorter
wavelength
indicatesapproach
the necessity
of the
for
the numerical
of landslide
tsunamis.
dispersive
model modeling
application.
A different
approach is necessary
propagation
forGEOWAVE
the numericalsimulates
modeling tsunami
of landslide
tsunamis. and inundation
using
the long wave
propagation
FUNWAVE
based on
GEOWAVE
simulates
tsunami model
propagation
and inundation
fully
Boussinesq
equations
developed
by Wei
et al.
using nonlinear
the long wave
propagation
model
FUNWAVE
based
on
(1995),
considering
the effects
of nonlinearity
frequency
fully nonlinear
Boussinesq
equations
developed and
by Wei
et al.
dispersion.
Another advantage
a Boussinesq
wave
(1995), considering
the effectsofofchoosing
nonlinearity
and frequency
propagation
model isadvantage
that the horizontal
velocities
are no longer
dispersion. Another
of choosing
a Boussinesq
wave
constrained
have isa constant
value overvelocities
the water are
depth
propagation to
model
that the horizontal
no (Watts
longer
et
al., 2003).to Since
equations
become
in the
constrained
have aBoussinesq
constant value
over the
waterinvalid
depth (Watts
surf
of not including
the wave
breaking,
et al.,zone,
2003).because
Since Boussinesq
equations become
invalid
in the
FUNWAVE
simple
viscosity-type
formulation
to
surf zone, applies
because a of
not eddy
including
the wave
breaking,
model
the turbulent
and dissipation
caused
by wave
FUNWAVE
applies a mixing
simple eddy
viscosity-type
formulation
to
breaking.
additional
eddyand
viscosity
terms caused
are introduced
to
model theSome
turbulent
mixing
dissipation
by wave
momentum
conservation
equations.
Onset
cessation of
breaking. Some
additional eddy
viscosity
termsand
are introduced
to
breaking
in each
point of equations.
model domain
determined
by ηoft,
momentum
conservation
Onsetis and
cessation
variation
respect
to time,is which
is calculated
breaking of
in free
eachsurface
point with
of model
domain
determined
by ηt,
from
massofconservation
variation
free surfaceequation.
with respect to time, which is calculated
Formass
simulation
of wave
run-up, the model uses the “slot”
from
conservation
equation.
method
of Tao (1983,
1984). run-up,
This technique
assumes
is
For simulation
of wave
the model
usesthe
thebeach
“slot”
porous,
or Tao
it contains
slots.technique
The porous
beachthe
allows
method of
(1983, narrow
1984). This
assumes
beachthe
is
water
be belownarrow
the beach
and beach
propagate
within
porous,level
or ittocontains
slots.elevation
The porous
allows
the
the
land.
occursthe
when
theelevation
elevationand
of propagate
the groundwater
water
levelRun-up
to be below
beach
within
rises
above
that ofoccurs
the land.
Slotthe
method
calculates
maximum
the land.
Run-up
when
elevation
of thethe
groundwater
run-up
height
with
a 10%
error. This
arises
rises above
that
of about
the land.
Slotdiminution
method calculates
theerror
maximum
because
first the
slot
should
be filled
beforeerror.
waterThis
coulderror
cover
the
run-up height
with
about
a 10%
diminution
arises
dry
land.first
A slightly
formulation
in slot
method,
proposed
because
the slotdifferent
should be
filled before
water
could cover
the
by
et al. different
(2000), isformulation
applied byinFUNWAVE
reduce
dry Kennedy
land. A slightly
slot method,to
proposed
water
mass losses.
slotbymethod
leads to
small
by Kennedy
et al. However,
(2000), is using
applied
FUNWAVE
to areduce
alteration
in losses.
mass conservation.
water mass
However, using slot method leads to a small
Using finite
technique and a composite 4th-order
alteration
in massdifference
conservation.
Adams-Bashforth-Moultan
scheme, the
equations
are
Using finite difference technique
andgoverning
a composite
4th-order
solved
in the modeling domain
area the
(UTM
coordinates).
Surface
Adams-Bashforth-Moultan
scheme,
governing
equations
are
elevation
horizontaldomain
velocities
are(UTM
calculated
at 427,200
(800
solved in and
the modeling
area
coordinates).
Surface
×534)
gridand
points
for all time
steps are
of simulation.
Considering
the
elevation
horizontal
velocities
calculated at
427,200 (800
size
thepoints
mesh,fori.e.
decimal
degree, the
time step the
of
×534)ofgrid
all 0.014
time steps
of simulation.
Considering
dt=3.65s
wasmesh,
determined
by the
model
to satisfy
the stability
size of the
i.e. 0.014
decimal
degree,
the time
step of
conditions.
dt=3.65s was determined by the model to satisfy the stability
Figure 4 displays the propagating tsunami waves computed by
conditions.
FUNWAVE
model. the
It ispropagating
observed that
tsunami
waves
propagate
Figure 4 displays
tsunami
waves
computed
by
out
from themodel.
landslide
waves
FUNWAVE
It is location
observed inthatcircular
tsunamirings.
wavesThe
propagate
amplify
the coast
of landslide
neighbouring
countries
out fromapproaching
the landslide
location
in circular
rings. The
waves
but
theyapproaching
highly damp
more neighbouring
distances to reach
far
amplify
thepropagating
coast of landslide
countries
countries.
In orderdamp
to have
a better view
of distances
waveformstoatreach
different
but they highly
propagating
more
far
locations,
point
defined
the Caspian
Sea
countries. In
orderstations
to have were
a better
view ofalong
waveforms
at different
coastline.
5 shows were
the location
assumed
get
locations, Figure
point stations
definedof along
the stations
Caspianto Sea
the
time series
of5tsunami,
where
the calculated
wave
heights
coastline.
Figure
shows the
location
of assumed
stations
to are
get
presented
in Figure
6.
the time series
of tsunami,
where the calculated wave heights are
presented in Figure 6.
Journal of Coastal Research, Special Issue 64, 2011
Journal of Coastal Research, Special Issue 64, 2011
1197
3
3
Coastal Modelling
Coastal Modelling
Figure 4. Computed tsunami waves propagating at (a) 0.5, (b) 1,
(c) 2, and
3 hours tsunami
after the waves
landslide
motion. at (a) 0.5, (b) 1,
Figure
4. (d)
Computed
propagating
(c) 2, and (d) 3 hours after the landslide motion.
Figure 5. Location of numerical wave stations (A-K).
Figure 5. Location of numerical wave stations (A-K).
Journal of Coastal Research, Special Issue 64, 2011
Journal of Coastal Research, Special Issue 64, 2011
1198
4
4
Soltanpour and Rastgoftar
Soltanpour and Rastgoftar
part of Dagestan, north of Azerbaijan, and near the regions of
Aqtau
Kazakhstan,
other
of Caspian
Sea are
against
part ofinDagestan,
north
of coasts
Azerbaijan,
and near
thesafe
regions
of
the
mentioned
landslide
forare
ansafe
integrated
Aqtau
in Kazakhstan,
othertsunami.
coasts ofHowever,
Caspian Sea
against
assessment
of Caspian
Seatsunami.
tsunami hazards,
possibility
of the
the mentioned
landslide
However,thefor
an integrated
occurrence
in other parts
of Caspian
assessment of submarine
Caspian Sealandslides
tsunami hazards,
the possibility
of Sea
the
should
be investigated.
occurrence
of submarine landslides in other parts of Caspian Sea
should be investigated.
LITERATURE CITED
Figure 6. Wave height time series for numerical wave stations; w
(width of
the landslide)
= 1,000
meter
(...), 2,000wave
meterstations;
(---), and
Figure
6. Wave
height time
series
for numerical
w
3,000
(widthmeter
of the(—).
landslide) = 1,000 meter (...), 2,000 meter (---), and
3,000 meter (—).
It is observed that the increase of the landslide width results to
higher
wave heights
coastlines,
expected.width
Moreover,
It is observed
that at
thethe
increase
of theaslandslide
resultsthe
to
stations
closerheights
to the landslide
receive relatively
higher
waves. the
higher wave
at the coastlines,
as expected.
Moreover,
Figurecloser
6 reveals
that thereceive
generated
tsunami
canwaves.
cause a
stations
to the landslide
relatively
higher
considerable
of adjacent
sucha
Figure 6 run-up
revealsalong
that the
thecoastlines
generated
tsunami countries
can cause
as
southern part
of Dagestan,
north of Azerbaijan,
and Aqtau
of
considerable
run-up
along the coastlines
of adjacent countries
such
Kazakhstan.
Northern
parts of north
Azerbaijan
are first hit
tsunami
as southern part
of Dagestan,
of Azerbaijan,
andbyAqtau
of
waves,
just after
aboutparts
35 minutes.
Considering
thathitthe
Kazakhstan.
Northern
of Azerbaijan
are first
bylandslide
tsunami
movement
towards
direction Considering
and the trough
thelandslide
tsunami
waves, justisafter
abouteast
35 minutes.
thatofthe
wave
is created
behindeast
the direction
landslide,and
falling
movement
is towards
the water
troughisoffirst
theobserved
tsunami
along
coastlines
west falling
of the water
tsunami
source,
i.e.
wave isthe
created
behindlocating
the landslide,
is first
observed
stations
D, coastlines
F and J. This
can be west
trustedofasthe
a useful
natural
warning
along the
locating
tsunami
source,
i.e.
sign
to the
communities.
However,
coastlines
locating
stations
D, Flocal
and J.
This can be trusted
as a the
useful
natural warning
east
first experience
the rising
tsunami waves.
It
sign of
to tsunami
the localsource
communities.
However,
the coastlines
locating
should
also besource
mentioned
that station
located
in waves.
west of
east of tsunami
first experience
the G,
rising
tsunami
It
Caspian
Sea, is
behind thethat
landslide
will firstinexperience
should also
benot
mentioned
stationand
G,it located
west of
aCaspian
high tsunami
wave.
It can
also be observed
tsunami
Sea, is not
behind
the landslide
and it willthat
firstthe
experience
waves
the wave.
coastlines
of the
far from
a high along
tsunami
It can
alsocountries
be observed
that the
thelandslide
tsunami
location
are small
even for of
thethe
case
of w=3,000
m. Therefore,
the
waves along
the coastlines
countries
far from
the landslide
danger
tsunami
of Iran,m.
southern
partthe
of
locationofarethis
small
even at
forthe
thecoastlines
case of w=3,000
Therefore,
Turkmenistan
Azerbaijan,
and North
Kazakhstan
is not
danger of this and
tsunami
at the coastlines
of of
Iran,
southern part
of
high
and these coasts
will not experience
a remarkable
inundation.
Turkmenistan
and Azerbaijan,
and North
of Kazakhstan
is not
high and these coasts will not experience a remarkable inundation.
CONCLUSIONS
A probable tsunamiCONCLUSIONS
generated by submarine landslide, located
at A
theprobable
middle part
of Caspian
Seaby
in submarine
the vicinitylandslide,
of the Dagestan
tsunami
generated
located
coast,
was simulated
to investigate
on the
at the middle
part of Caspian
Sea in thetsunami
vicinity hazards
of the Dagestan
neighbouring
countries.to GEOWAVE
numerical
modelon was
coast, was simulated
investigate tsunami
hazards
the
employed
to simulate
tsunami
generationnumerical
and propagation.
neighbouring
countries.
GEOWAVE
model The
was
required
inputstsunami
were generation
estimated and
based
on landslide
employed model
to simulate
propagation.
The
characteristic
and local
Since there
is not
accurate
required model
inputsbathymetry.
were estimated
based
onan landslide
estimation
forand
the local
total width
of the Since
landslide,
parameter
was
characteristic
bathymetry.
therethis
is not
an accurate
considered
as athevariable
basedof on
typical this
widths
of the past
estimation for
total width
thethe
landslide,
parameter
was
landslides.
considered as a variable based on the typical widths of the past
Model results revealed that this probable landslide tsunami is
landslides.
capable
generating
highthat
waves
considerable
run-ups
along
Modelofresults
revealed
thisand
probable
landslide
tsunami
is
the
coasts
countrieshigh
in the
vicinity
landslide. run-ups
However,
the
capable
of of
generating
waves
and the
considerable
along
danger
of aofmajor
tsunami
on the other
coasts
due to this
the coasts
countries
in theattack
vicinity
landslide.
However,
the
landslide,
Iran,tsunami
is veryattack
low and
there
willcoasts
not be
major
danger of ae.g.
major
on the
other
duea to
this
inundation.
ThisIran,
can is
be very
attributed
to thethere
limited
of
landslide, e.g.
low and
willfar-field
not be effect
a major
the
submarine
landslides
tsunamis,
of theireffect
radial
inundation.
This can
be attributed
to thebecause
limited far-field
of
the submarine
landslides
tsunamis,
because of
theirsouthern
radial
. In summary,
except
damping
and frequency
dispersion
damping and frequency dispersion. In summary, except southern
Dotsenko, S.F.; Kuzin,
I.P.; Levin, B.V.,
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