Destruction of the First Nations Village of Kwalate by a
Rock Avalanche-generated Tsunami
Brian D. Bornhold1, John R. Harper1, Duncan McLaren2 and Richard E. Thomson3,*
1School
of Earth and Ocean Sciences, University of Victoria, Victoria BC
of Anthropology, University of Victoria, Victoria BC
3Department of Fisheries and Oceans, Institute of Ocean Sciences, Sidney BC V8L 4B2
2Department
[Original manuscript received 15 January 2007; in revised form 22 March 2007]
The First Nations (Da’naxda’xw) village of Kwalate, Knight Inlet, British Columbia was located
along the shore of a funnel-shaped bay. Archaeological investigations show that this was a major village that
stretched 90 m along the shoreline and was home to possibly 100 or more inhabitants. Oral stories indicate that
the village was completely swept away by a tsunami that formed when an 840-m high rock avalanche descended
into the water on the opposite side of the fjord. Shipboard geological mapping, combined with empirical tsunami modelling, indicate that the tsunami was likely 2 to 6 m high prior to run-up into the village. Radiocarbon dates
reveal that the village was occupied from the late 1300s CE until the late 1500s CE when it was destroyed by the
tsunami.
ABSTRACT
RÉSUMÉ [Traduit par la rédaction] Le village de la première nation Da’naxda’xw de la région de Kwalate, dans
l’inlet Knight, en Colombie-Britannique, était situé sur le rivage d’une baie en forme d’entonnoir. Les recherches
archéologiques montrent qu’il s’agissait d’un village important s’étendant sur 90 m le long du rivage et pouvant
regrouper 100 habitants ou plus. Les récits oraux indiquent que le village a été complètement balayé par un
tsunami qui s’est formé lorsqu’une avalanche de pierres de 840 m de hauteur a atteint l’eau du côté opposé du
fjord. La cartographie géologique embarquée, de pair avec la modélisation empirique du tsunami, indique que le
tsunami avait sans doute une hauteur de 2 à 6 m au moment où il a atteint le village. Des datations par le
radiocarbone révèlent que le village a été occupé de la fin des années 1300 de l’ère chrétienne jusqu’à la fin des
années 1500, moment où il a été détruit par le tsunami.
1 Introduction
Landslide-generated tsunamis represent major natural hazards for coastal communities and waterways in the fjord
regions of British Columbia (Murty, 1979; Prior et al., 1982),
Alaska (Miller, 1960; Kulikov et al., 1996), Norway (Longva
et al., 2003; Blikra et al., 2002), and Greenland (Dahl-Jensen
et al., 2004). Because of sparse populations, most accounts of
historical coastal tsunamis have been anecdotal and related to
the stories of First Nations peoples, sailors’ experiences and
the effects on forestry operations. While oral histories and
stories of First Nations peoples living along the coasts of
British Columbia and Alaska are clearly an important source
of information about catastrophic natural events, such as
landslide-generated tsunamis, they are often problematic
because of the absence of a clear chronology and uncertainties with respect to precise locations. Thus, in attempts to elucidate such past events it is important to bring several lines of
evidence – archaeological, geological and oceanographic – to
the investigations. This paper describes our efforts to merge
field studies with several types of analyses to understand better a devastating tsunami generated by a rock avalanche in
Knight Inlet, British Columbia.
The First Nations village of Kwalate was located at the
mouth of the Kwalate River in Knight Inlet on the central
coast of mainland British Columbia (Fig. 1). According to
Kwakwaka’wakw oral narratives of the A’wa’etlala and
Da’naxda’xw peoples, a devastating landslide-generated
tsunami destroyed the village: “About three generations ago,
or possibly at an earlier date, a large portion of the mountain
opposite Kwalate Point slid into the inlet causing a huge tidal
wave which wiped out all of the inhabitants of the village
opposite…and the vast slide is noticeable today” (Boas,
1910). “Kwalate was the site of a big village at one time. The
story I was told is that a big part of the mountain across the
inlet fell into the sea and created a tidal wave that rolled
across the inlet and drowned most of the village” (Proctor and
Maximchuk, 2003).
*Corresponding author’s e-mail: [email protected]
ATMOSPHERE-OCEAN 45 (2) 2007, 123–128 doi:10.3137/ao.450205
Canadian Meteorological and Oceanographic Society
124 / Brian D. Bornhold et al.
Kw
a la
te
Ri
ve
r
t.
eP
an
e
Ad
Glendale Cove
Fig. 1
Map of Knight Inlet, the former First Nations village of Kwalate
and the large landslide areas opposite the village site. Water
depths are in metres.
Guided by these narratives, we examined physical evidence for the events surrounding this tragedy. Our multidisciplinary approach includes detailed shipboard bathymetric
charting of the inlet, remotely operated vehicle surveys of the
landslide debris on the seafloor, empirical modelling of the
tsunami generation, archaeological surveys to locate and test
the remains of the village, archival research of ethnographic
and historical documents, and interviews with William
Glendale II, hereditary chief of the Da’naxda’xw-A’wa’etlala
Nation. These findings have implications for understanding
tsunamis generated by rock avalanches and their historical
and future effects on settlements on the Pacific coasts of
British Columbia and Alaska.
2 Observations
Knight Inlet (Fig. 1) is 120 km long, 3–4 km wide and attains
a maximum depth of roughly 540 m. For the most part, the
fjord is bounded by rugged, steep terrain, comprised of sheer
bedrock cliffs of plutonic and metamorphic rocks that generally rise to more than 500 m above sea level. The Kwalate
tsunami was generated by a rock avalanche from an 840-m
high cliff face just north-east of Adeane Point (Figs 1 and 2)
that rapidly plunges to water depths of more than 530 m.
The mouth of the Kwalate River, situated about 5 km
across the inlet from the landslide site (Figs 1 and 3), is a
funnel-shaped bay bounded by bedrock on its north and south
sides. Along the northern edge of the estuary lies a beach of
pebbles and sand and a wetland complex. Behind this beach
rises a 10–15 m wide, 120-m long platform about 5 m above
high water, starting 10 to 15 m landward of the high water
line. It was on this platform that the former village of Kwalate
was rediscovered through archaeological investigations
(McLaren, 2005). Archaeological investigations at the village
site included: (1) surface inspection of the site for cultural
evidence; (2) short auger probes to determine the spatial
extent of the midden (shell debris indicative of human habitation) that would determine the limits of the village site;
(3) two 50 cm × 50 cm controlled excavation units and a
trench (2 m long, 0.3 m wide, 1 m deep) through the village
platform deposits; (4) mapping the edge of the platform; and
(5) collection of samples for radiocarbon dating.
Investigations by McLaren (2005) revealed that the shell
midden associated with the village extends at least 90 m along
the northern edge of the bay and reaches a thickness of at least
60–70 cm beneath 10–20 cm of forest soil cover. This cultural unit includes many hearth features, fragments of mussels
are predominant with a lesser abundance of fish bones, clams,
animal bones (dog, deer, seal and porcupine) and scarce tools
(e.g., harpoon valves and a bone barb from a composite fishhook). No cultural materials of European origin were found at
the site. Culturally modified trees (cedars logged and stripped
by aboriginal peoples) and a rock shelter were also found in
the vicinity. The midden is capped by a layer of clean, light
brown medium to coarse sand 1 to 5 cm thick. From the soils
that overlie this layer of sand, very little in the way of cultural remains were encountered, confirming that the site was
abandoned following the deposition of sand.
It is difficult to estimate the number of individuals that perished in this event. The pictographs at Naena Point have four
crests that were placed in “memory of the chiefs who lost
their lives in this cataclysm” (Barrow, 1935). This indicates
that people from at least four numayms – a social division that
traces its crest through a supernatural ancestor (Boas, 1966) –
died as a result of the tsunami. According to Boas (1966), the
earliest dependable population estimates, for the year 1835,
yield an average numaym membership of 75. For the
A’wa’etlala, there were four recorded numayms. The census
of 1835 listed 300 A’wa’etlala people (Galois, 1994). This
population would most likely have been spread throughout
the territory over at least three main village locations including Kwalate. If the population estimates from 1835 reflect
those from the late 1500s, then it is possible that about 100,
or possibly more, people occupied the site destroyed by the
tsunami. In fact, populations in the 1500s were probably
greater than in the 1800s as this predates the time of depopulation due to epidemic disease following the arrival of
Europeans (Boyd, 1991).
a Time of the Event
Some sources suggest that this event occurred some time
before the mid-nineteenth century. “In the mid 1800s they
ATMOSPHERE-OCEAN 45 (2) 2007, 123–128 doi:10.3137/ao.450205
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Rock Avalanche-generated Tsunami, Knight Inlet, BC / 125
Fig. 2
Rock-avalanche area north of Adeane Point, Knight Inlet (right); the source of the Kwalate tsunami.
[A’wa’etlala and Da’naxda’xw] joined together after two of
their villages were destroyed. One by fire and the other by a
landslide” (Willie, 2004; italics added). The date given refers
to this amalgamation which is indicated as occurring after the
landslide (this is a sequencing reference, commonly used in
oral history which simply tells the order of events). The present hereditary chief, William Glendale, confirmed that the
latter referred to the landslide-generated tsunami described in
this paper. According to Galois (1994) the event occurred
“about three generations ago or possibly at an earlier date…”.
The author William Proctor (personal communication, 2005)
was told the story by his father and estimated that the slide
and tsunami took place about 150 years previously (i.e., midnineteenth century).
Three Accelerator Mass Spectrometer (AMS) radiocarbon
samples for plant macrofossils from sedimentary deposits at
the abandoned village yield calibrated dates of 1540 ±70,
1570 ±70 and 1520 ±50 CE, very much earlier than the above
accounts from oral history. Thus, the tsunami and the abandonment of the village took place sometime in the mid- to late
sixteenth century or nearly three centuries before it was previously thought to have occurred. The sixteenth century timing is much more consistent with the archaeological evidence
because of the absence of any archaeological material reflecting trade with Europeans. Virtually all sites in the region that
post-date the arrival of Europeans contain articles such as
glass, buttons or metal implements. A single radiocarbon date
of 1390 ±50 CE from the base of the cultural unit suggests
that the village may have been occupied for about 180 years
before the tsunami.
b Failure Mass Estimation
The landslide scar at Adeane Point is still visible across the
inlet from the archaeological remains of Kwalate Village.
Because of glacial and early post-glacial modifications to the
terrain it is impossible to know precisely what the pre-slide
shape of the failure zone was in order to compute the failure
volume; earlier failure masses would either have been swept
away by glaciers or buried on the fjord floor by Holocene sediments. To determine the maximum extent and volume of the
failed bedrock material, a multibeam bathymetric survey was
undertaken in May 2005 using a Simrad EM 1002 system
onboard the Canadian Coast Guard Ship (CCGS) Vector, a
Department of Fisheries and Oceans (DFO) research vessel.
A prominent cone of coarse debris extending about 800 m
from the shoreline is evident at the base of the landslide
(Fig. 3). The diameter of the cone at its terminus is about
400 m and the estimated volume of the debris is 4 × 106 m3.
Visual observations of the debris in July 2005 using the
Canadian Remotely Operated Platform for Oceans Science
(ROPOS) from the research ship CCGS John P. Tully
revealed a steep (>35°) disorganized pile of angular bedrock
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Fig. 3
Multibeam echo-sound image of the failure mass cone just north of Adeane Point, the likely source of the Kwalate tsunami. The maximum water
depth (purple) is about 535 m; the shoreline is in mauve above the red band. The slide volume is estimated to be about 4 × 106 m3.
blocks rising to a height greater than 175 m. Individual blocks
were up to 5 m in length. Unfilled porosity was estimated
visually at about 25%, yielding an approximate initial failure
volume of 3–4 × 106 m3 assuming that all of the material in
the debris fan is related to this single failure event. There was
little infilling matrix within the blocks and little surface
veneer of muddy sediments on the blocks.
3 Estimate of the tsunami height
The estimated rock avalanche volume and morphology of the
inlet between the slide and the village can be used to determine the deep water wave height of the tsunami which inundated the village. A recent investigation (Pararas-Carayannis,
1999) of the massive tsunami and 520 m run-up in Lituya
Bay, Alaska suggests that the giant waves were generated by
an enormous 30 × 106 m3 subaerial rock avalanche into
Gilbert Inlet. The effect of this event was analogous to that of
an asteroid or meteor impact. The volume of the Knight Inlet
rock avalanche was roughly 10% of that for the Lituya Bay
rock avalanche and therefore its effect was less likely to have
resembled that of a meteor impact. Our empirical model is
therefore based on assumptions that relate the potential energy in the rock avalanche prior to failure to the total energy
imparted to the ensuing tsunami wave field, similar to the
approach used by Murty (1979) to examine the 1975 tsunami
generated by a submarine landslide in Kitimat Inlet, British
Columbia.
Let Ek be the kinetic energy of the failure as it enters the
sea. Ignoring frictional, acoustic and other energy loss terms,
the kinetic energy of the failure is roughly equal to the potential energy, Ep, of the rock mass prior to failure;
Z
Ek ≈ E p = ρr g ′X ( z )Y ( z ) zdz
∫
(1)
0
where ρr is the mean density of the rock avalanche, X, Y and
Z are, respectively, the cross-shore extent, alongshore width,
and vertical elevation of the rock fall prior to failure, and
ATMOSPHERE-OCEAN 45 (2) 2007, 123–128 doi:10.3137/ao.450205
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Rock Avalanche-generated Tsunami, Knight Inlet, BC / 127
g ′ = g ( sin α − µ cos α )
(2)
is the effective acceleration of gravity for a rock avalanche
zone of slope α (relative to the horizontal) and friction coefficient µ. The total energy (kinetic plus potential) of the
tsunami’s waves per unit area is (LeBlond and Mysak, 1978)
Ew′ = ρw gη2
(3)
where ρw is the water density and η is the wave height relative to the undisturbed sea level. We next assume that the
waves generated by the rock avalanche radiate symmetrically
into the inlet from the base of the rock avalanche such that the
total energy, Ew, of the waves can be expressed in polar coordinates as
Ew =
∫∫
A
Ew′ dA ≈
π r2
2
∫ ∫ ρw gη (θ, r ) rd θdr
(4)
0 r1
where A is the area of the inlet surface occupied by the waves,
r is the radial distance along the direction of wave propagation, and θ is the azimuthal direction normal to the direction
of propagation. We further assume that the initial outward
propagating wave energy is concentrated in a single dominant
wave of amplitude η ≈ ηo occupying the surface annulus
r1 ≤ r ≤ r2 . Here, r1 is the radial distance to the toe of the rock
face prior to failure and
r2 = ∆t gD = 2 H / g ′ gD ≈ 2 DH
(5)
is the distance that the leading edge of the tsunami has travelled across the inlet at the shallow water wave phase speed,
c = gD , over the time, ∆t needed for the top of the rock
avalanche (elevation H) to reach the ocean surface; D is the
water depth immediately seaward of the rock avalanche base.
For the rock avalanche elevation H = 840 m, we find that
∆t = 2 H / g ′ = 13.1 sec.
Following Murty (1979), we assume that only a small fraction, δ << 1, of the rock avalanche kinetic energy is converted into tsunami wave energy. The square of the initial tsunami
height, ηo, is then
η2o ≈
H
2δ  g ′   ρr   1 
X ( z )Y ( z ) zdz.


π  g   ρw   r 2 − r 2 
2
1
∫
(6)
0
For a wedge-shaped rock avalanche that tapers upward
toward the mountain peak,
( X ( z ) ,Y ( z )) = ( Xo ,Yo )(1 − z / H )
(7)
our estimate, Eq. (6), becomes
η2o ≈
δ  g ′   ρr   1 

 VH
2π  g   ρw   r 2 − r 2 
2
1
(8)
where we have used the fact that the total volume of the
wedge-shaped rock avalanche is
V=
1
X Y H
3 o o
(9)
where Xo and Yo are, respectively, the slide thickness and
width at the toe of the rock face prior to failure.
The next step is to estimate the maximum height of the
tsunami just before the waves struck Kwalate Village.
Assuming that the tsunami wavelength (and therefore the lateral scales of the slide impact region) exceeds the local water
depth, D, the tsunami energy and height will decay through
geometrical spreading as r–1 and r–1/2, respectively (cf. Ward
and Asphaug, 2000). (If the scale of impact is comparable to
or less than that of the local water depth, then wave dispersion
effects can be important and energy and wave height decay
rates would be closer to r–2 and r–1, respectively.) Assuming
that the maximum wave is formed near the mean radial dis1
tance ro = –2 (r1 + r2) and that the waves are non-dispersive
(i.e., the width of the advancing wave band does not increase
significantly in the time it takes the waves to cross the inlet),
the wave height offshore of Kwalate Village (KV) at distance
rKV from the source region becomes
 r 
ηKV ≈ ηo  o 
 rKV 
1/ 2
.
(10)
This relationship follows directly from Eq. (3) and the conservation of wave energy, η2A = constant, for a local water
surface area, A. For a radially symmetric wave field generated by a wedge-shaped rock failure that thins to near zero at its
maximum elevation, H, above the water surface, the initial
tsunami height, ηo, is estimated from Eq. (8) where, in the
present case, α ~ 90°. Table 1 presents derived values of the
initial tsunami height for a fractional energy coefficient δ = 1
and 10% for known physical parameters.
As indicated by Eq. (10), the height, η, of the tsunami
decreased as r–1/2 as it propagated toward Kwalate Village
from the source region (the spatial decay rates of r-1 for wave
energy and r–1/2 for wave amplitude follow from simple twodimensional radial wave spreading). Noting that the water
depth at the base of the rock avalanche is in the range of 100
to 500 m, the height of the waves striking the shores of
Kwalate Village would have been on the order of 1–2 m for a
low rock avalanche–wave energy conversion coefficient of
1% and 4–6 m for a moderate coefficient of 10% (column 5,
Table 1). Such waves, amplified by the run-up into the
Kwalate River basin, would have been more than capable of
destroying the entire village. Waves would have traversed the
inlet in just over one minute, leaving little time for the villagers to flee to higher ground.
4 Summary and conclusions
This study documents a devastating rock avalanche and associated tsunami that likely destroyed a large aboriginal community and forever altered the history of First Nations
ATMOSPHERE-OCEAN 45 (2) 2007, 123–128 doi:10.3137/ao.450205
Canadian Meteorological and Oceanographic Society
128 / Brian D. Bornhold et al.
TABLE 1. Tsunami height estimates for different fractional energy conversion coefficients, δ. Known parameter values used in the estimates are:
g′ (≈g) = 9.81 m s–2, (ρr, ρw) = (2700, 1000) kg m–3, D = 500 m, H = 840 m and V = 3 × 106 m3. The radius of the leading tsunami wave at the end
of the rock avalanche event is r2. The Kwalate Village site is 5 km from the rock avalanche site.
Water depth at
failure
D (m)
Radius of
leading edge
r2 (m)
Efficiency
coefficient
δ
Initial wave
height
ηo (m)
Wave height at
Village
ηKV (m)
100
410
410
0.01
0.10
8.0
25.2
1.8
5.7
250
650
650
0.01
0.10
5.0
15.9
1.4
4.4
500
917
917
0.01
0.10
3.6
11.2
1.1
3.6
peoples in the Knight Inlet area of British Columbia. In North
America, occupation of these regions by non-aboriginal people has been short, in many instances less than a century. As
the pace of development in such coastal settings increases, the
occurrence of these rare but devastating events, now being
increasingly recognized through a combination of ethnographic, archaeological and geological investigations, should
prompt more serious consideration of this natural hazard.
While seismogenic tsunamis have been the focus of countless
global investigations, the assessment of potentially catastrophic tsunamis generated by landslides and rock avalanches in coastal areas of British Columbia, Alaska, and other
fjord regions is rarely undertaken. We believe that such studies are critical prior to habitation and infrastructure development in these regions.
Acknowledgements
We thank Chief William Glendale II, Hereditary Chief of the
Da’naxda’xw-Aw’a’etlala Nation for his invaluable assis-
tance in our studies at Kwalate and his enthusiasm for learning the details of this important event in the history of his people. His wife Anne and grandsons Billy and Harry assisted
with field investigations. William Proctor provided additional background material to the report of this event contained in
his book (Proctor and Maximchuk, 2003). The Department of
Fisheries and Oceans (DFO) and the Natural Sciences and
Engineering Research Council of Canada (NSERC)
Continental Slope Stability (COSTA)-Canada project provided funding for the research. The crews of the DFO research
ships CCGS Vector and CCGS John P. Tully, as well as the
ROPOS team, are thanked for their help in the collection of
multibeam bathymetric data and underwater video imagery in
the underwater areas of the slide. We thank the two anonymous reviewers for their comments and the journal editor,
Patrick Cummins (DFO), for his comments on the analysis in
Section 3.
References
1935. Barrow catalogues/pictographs (complete), Book No. 2
No. EgSj – DiRx1, Report on File at the Royal British Columbia Museum,
Victoria, British Columbia, Canada.
BLIKRA, L.H.; A. BRAATHEN, E. ANDA, K. STALSBERG and O. LONGVA. 2002. Rock
avalanches, gravitational bedrock fractures and neotectonic faults onshore
northern West Norway: examples, regional distribution and triggering
mechanism, Report 2002.016, Norwegian Geotechnical Institute, 53 pp.
BOAS, F. 1910. Kwakiutl Tales, Volume II. Columbia University Press, New
York, NY, 495 pp.
BOAS, F. 1966. Kwakiutl Ethnography. H. Codere (Ed.), The University of
Chicago Press, Chicago and London, 439 pp.
BOYD R. 1991. Demographic history 1774–1874. In: Handbook of North
American Indians, Vol. 7, Northwest Coast. W. Suttles (Ed.), Smithsonian
Institution Press, pp. 135–140.
BARROW, F.J.
DAHL-JENSEN, T.; L.M. LARSEN, S.A.S. PEDERSEN, J. PEDERSEN, H.F. JEPSEN, G.K.
and W.
2004. Landslide and tsunami 21 November 2000 in Paatut, West
Greenland. Natural Hazards, 31: 277–287.
GALOIS, R. 1994. Kwakwaka’wakw Settlements 1775-1920: A Geographical
Analysis and Gazetteer. University of British Columbia Press, Vancouver,
465 pp.
KULIKOV, E.A.; A.B. RABINOVICH, R.E. THOMSON and B.D. BORNHOLD. 1996. The
landslide tsunami of November 3, 1994, Skagway Harbour, Alaska. J.
Geophys. Res. 101: 6609–6615.
PEDERSEN, T. NIELSEN, A.K. PEDERSEN, F. VON PLATEN-HALLERMUND
WENG.
and L.A.
Amsterdam, 602 pp.
LEBLOND, P.H.
MYSAK.
1978. Waves in the Ocean, Elsevier,
and R. BOE. 2003. The 1996 Finneidfjord
slide; seafloor failure and slide dynamics. In: Submarine Mass Movements
and their Consequences. J. Locat and J. Mienert (Eds), Kluwer Academic
Publishers, Dordrecht, The Netherlands, pp. 531–538.
MCLAREN, D. 2005. Archeological and oral history evidence of an ancient
tsunami event at Kwalate, Knight Inlet. Report to the Archeological
Branch, British Columbia, Permit 2004-211, 46 pp.
MILLER, D.J. 1960. The Alaska earthquake of July 10, 1958: giant wave in
Lituya Bay. Bull. Seismol. Soc. Am. 50: 253–266.
MURTY, T.S. 1979. Submarine slide-generated water waves in Kitimat, British
Columbia. J. Geophys. Res. 84 (C12): 7777–7779.
PARARAS-CARAYANNIS, G. 1999. Analysis of mechanism of tsunami generation in Lituya Bay. Sci. Tsunami Hazards, 17: 193–206.
PRIOR, D.B.; B.D. BORNHOLD, J. M. COLEMAN and W.R. BRYANT. 1982. Morphology
of a submarine slide, Kitimat Arm, British Columbia. Geol. 10: 588–592.
PROCTOR, W. and Y MAXIMCHUK. 2003. Full Moon Tide: Bill Proctor’s
Raincoast. Harbour Publishing, Vancouver, British Columbia, 288 pp.
WARD, S.N. and E. ASPHAUG. 2000. Asteroid impact tsunami: a probabilistic
hazard assessment. Icarus, 145: 64–78.
WILLIE, P. 2004. Repatriation of T’sadzis’nukame – A Vision Becomes Reality.
Da’naxda’xw Nation, Alert Bay, British Columbia Canada, 24 pp.
LONGVA, O.; N. JANBU, L.H. BLIKRA
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