Bulletin
of
the
Seismological
Society
of
America,
Vol.
75,
No.
5,
pp.
1455-1460,
October
1985
POSSIBLE
TSUNAMI
ALONG
THE
NORTHWESTERN
COAST
OF
THE
UNITED
STATES
INFERRED
FROM
INDIAN
TRADITIONS
BY
THOMAS
H.
HEATON
AND
PARKED.
SNAVELY,
JR.
Subduction
of
the
Juan
de
Fuca
and
Gorda
plates
beneath
western
North
America
presents
a
paradox;
despite
the
fact
that
there
is
good
evidence
of
3
to
4
cm/yr
of
ongoing
convergence,
there
is
a
remarkable
paucity
of
either
historic
or
instrumen-
tally
recorded
shallow
subduction
earthquakes.
Steady
aseismic
slip
along
the
entire
Cascadia
subduction
zone
provides
one
explanation
for
this
seismic
quiescence.
However,
the
Cascadia
subduction
zone
shares
many
features,
including
temporal
quiescence,
with
other
subduction
zones
that
have
experienced
very
large
shallow
subduction
earthquakes
(Heaton
and
Kanamori,
1984).
Yet,
there
is
no
direct
geologic
or
historical
evidence
presently
available
to
confirm
that
great
shallow
subduction
earthquakes
have
occurred
along
the
coast
of
Washington,
Oregon,
and
northern
California.
However,
there
are
reports
describing
Indian
legends
of
great
sea-level
disturbances
that
may
be
related
to
large
nearby
earth-
quakes.
In
this
letter,
we
briefly
review
the
history
of
exploration
and
settlement
of
this
region
by
nonnative
people
and
then
discuss
legends
from
Indians
in
northern
Washington
and
northern
California.
The
coastline
of
Washington
was
first
explored
by
Captain
Bruno
Heceta
of
Spain
in
1775,
and
a
Spanish
settlement
was
briefly
occupied
(5
months)
in
1792
at
Neah
Bay
(see
Figure
2).
This
coastline
was
also
explored
by
Captain
James
Cook
(England)
in
1778
and
Captain
Robert
Gray
(United
States)
in
1792.
Fur
trading
settlements
were
established
by
Canadians
in
1810
and
1811
at
Spokane,
Astoria,
and
Fort
Okanogan.
Permanent,
but
sparse,
settlement
of
the
region
persisted
until
the
1850's
when
a
major
wave
of
immigration
occurred.
It
seems
certain
that
great
coastal
subduction
earthquakes
have
not
occurred
since
the
1850's
and
highly
probable
that
they
have
not
occurred
since
the
1790's.
However,
Judge
James
Swan
has
reported
curious
Indian
"traditions"
that
suggest
effects
that
could
have
resulted
from
a
great
shallow
subduction
earthquake.
Swan
was
a
renowned
student
of
Indian
lore,
writing
several
fascinating
accounts
of
his
experiences
with
coastal
Indians
from
Washington,
Oregon,
and
British
Columbia
during
the
1850's
through
1870's
(Swan,
1857,
1868,
1874).
The
following
excerpts
are
from
Swan's
1868
publication,
"The
Indians
of
Cape
Flattery."
Although
it
is
useful
to
study
a
large
quantity
of
Swan's
writings
in
order
to
better
understand
the
context
of
the
"traditions"
of
a
large
sea-level
disturbance,
the
first
excerpt
indicates
Swan's
impressions
of
the
reliability
of
Indian
legends.
History,
Traditions,
Etc.--The
history
of
this
tribe
(Makah),
as
far
as
their
knowledge
extends,
is
a
confused
mass
of
fables,
legends,
myths,
and
allegories.
Nothing
that
they
can
state
prior
to
the
existence
of
a
few
generations
back
is
clear
or
wholly
to
be
relied
upon.
There
are
a
few
prominent
events
that
have
been
remembered
as
having
occurred;
but
the
detail
is
confused,
and
it
is
very
rare
that
two
Indians
tell
the
same
story
alike,
unless
it
may
be
some
wild
and
improbable
legend,
like
the
fairy
tales
related
in
nurseries,
which
are
remembered
in
after
life.
A
notable
instance
of
this
unreliability
is
in
their
version
of
the
account
of
the
1455
1456
LETTERS
TO
THE
EDITOR
Spanish
settlement
attempted
at
Neeah
Bay
by
Lieut.
Quimper,
in
1792
by
order
of
the
commandant
of
the
Spanish
forces
at
Nootka.
All
they
really
know
about
it,
is
that
they
have
been
told
by
their
fathers
that
the
Spaniards
were
here,
and
they
can
point
out
the
locality
where
yet
may
be
found
pieces
of
tile
used
by
the
Spaniards
in
building.
But
although
that
occurrence
was
only
seventy-three
years
ago,
there
is
but
one
man
living
in
the
tribe
who
remembers
the
circumstances,
and
he
is
in
his
dotage.
Almost
every
Indian
I
have
questioned
upon
the
subject
gives
a
different
version
of
the
detail.
Now,
as
they
cannot
relate
correctly
matters
given
in
our
history,
and
of
a
comparatively
recent
date,
but
little
dependence
can
be
placed
upon
the
tales
of
their
origin,
which
are
interesting
only
for
their
fabulous
and
superstitious
nature.
More
recent
events,
such
as
the
murder
of
the
crews
of
the
ship
Boston,
in
1803,
and
of
the
Tonquin,
in
1811,
and
the
captivity
of
Jewett
among
the
Nootkans,
they
remember
hearing
about,
and
relate
with
tolerable
accuracy.
As
events
recede
in
years,
however,
they
become
obscured
with
legends
and
fables,
so
that
the
truth
is
exceedingly
difficult
to
discover.
Keeping
these
strong
caveats
in
mind,
we
now
reprint
Swan's
(1868)
account
of
Indian
"traditions"
of
a
great
sea
level
disturbance
along
the
coast
of
Washington.
Geographic
locations
of
tribes
and
places
mentioned
in
this
account
are
shown
in
Figures
I
and
2
(modern
spelling
of
some
words
may
differ
from
that
in
the
account).
In
addition,
the
word,
Makah,
is
used
by
eastern
inland
Indians
and
nonnative
people;
the
word,
Classet,
is
used
by
northern
Coastal
Indians,
and
the
word
Kwenaitchechat
is
used
by
Cape
Flattery
Indians
(Makahs).
All
of
these
words
have
the
same
meaning:
"people
who
live
on
a
point
of
land
projecting
into
the
sea
(i.e.
Cape
Flattery)."
The
only
tradition
that
I
have
heard
respecting
any
migratory
movement
among
the
Makahs,
is
relative
to
a
deluge
or
flood
which
occurred
many
years
ago,
but
seems
to
have
been
local,
and
to
have
had
no
connection
with
the
Noachic
deluge
which
they
know
nothing
about,
as
a
casual
visitor
might
suppose
they
did,
on
hearing
them
relate
the
story
of
their
flood.
This
I
give
as
stated
to
me
by
an
intelligent
chief;
and
the
statement
was
repeated
on
different
occasions
by
several
others,
with
a
slight
variation
in
detail.
"A
long
time
ago,"
said
by
informant,
"but
not
at
a
very
remote
period,
the
water
of
the
Pacific
flowed
through
what
is
now
the
swamp
and
prairie
between
Waatch
village
and
Neeah
Bay,
making
an
island
of
Cape
Flattery.
The
water
suddenly
receded
leaving
Neeah
Bay
perfectly
dry.
It
was
four
days
reaching
its
lowest
ebb,
and
then
rose
again
without
any
waves
or
breakers,
till
it
had
submerged
the
Cape,
and
in
fact
the
whole
country,
excepting
the
tops
of
the
mountains
at
Clyoquot.
The
water
on
its
rise
became
very
warm,
and
as
it
came
up
to
the
houses,
those
who
had
canoes
put
their
effects
into
them,
and
floated
off
with
the
current,
which
set
very
strongly
to
the
north.
Some
drifted
one
way,
some
another;
and
when
the
waters
assumed
their
accustomed
level,
a
portion
of
the
tribe
found
themselves
beyond
Nootka,
where
their
descendants
now
reside,
and
are
known
by
the
same
name
as
the
Makahs
in
Classett,
or
Kwenaitchechat.
Many
canoes
came
down
in
the
trees
and
were
destroyed,
and
numerous
lives
were
lost.
The
water
was
four
days
regaining
its
accustomed
level."
LETTERS
TO
THE
EDITOR
1457
The
same
tradition
was
related
to
be
by
the
Kwilleyutes,
who
stated
that
a
portion
of
that
tribe
made
their
way
to
the
region
in
the
vicinity
of
Port
Townsend,
where
their
descendants
are
known
as
the
Chemakum
tribe.
I
have
also
received
the
same
tradition
from
the
Chemakum
Indians,
who
claim
to
have
originally
sprung
from
the
Kwilleyutes.
There
is
no
doubt
in
my
mind
of
the
truth
of
this
tradition.
The
Waatch
prairie
shows
conclu-
sively
that
the
water
of
the
Pacific
once
flowed
through
it;
and
on
cutting
through
the
turf
at
any
place
between
Neeah
Bay
and
Waatch,
the
whole
50
°
45
°
4A
3A
/
4A
"%
~,~
".°
"%
:f,2
-..
Makah
IA
3A
'-.ay
3A
Chemokum
•
Indlon$
2
/
_
jj
•
~
;
2A
J
/
/I/
/
:
.
_
!
~
2,
Mendocmo
F..Z.
L
"..
(
•
40
°
t
J
i
i
--i-
~--i----x~
i
t
I
-130
°
-125
o
FIG.
1.
Approximate
location
of
Indian
tribes
and
place
names
mentioned
in
this
report.
Approximate
locations
of
sea-floor
magnetic
lineations
and
Quaternary
volcanoes
(triangles)
are
also
shown.
substratum
is
found
to
be
pure
beach
sand.
In
some
places
the
turf
is
not
more
than
a
foot
thick;
at
others
the
alluvial
deposit
is
two
or
three
feet.
As
this
portion
of
the
country
shows
conclusive
evidence
of
volcanic
action,
there
is
every
reason
to
believe
that
there
was
a
gradual
depression
and
subsequent
upheaval
of
the
earth's
crust,
which
made
the
waters
rise
and
recede
as
the
Indians
stated.
Fossil
remains
of
whales
are
said
by
the
Indians
to
be
found
around
a
lake
near
Clyoquot,
which
were
possibly
deposited
at
the
time
of
this
flood.
I
have
not
seen
these
remains,
but
I
1458
LETTERS
TO
THE
EDITOR
o
+i +!++++i~+~++ii+++++il
+
"~.
c.,.
+
+
++
•
....
+.
.+ ,,,.,,,,,m,,.
%,,-~++
I
'
(:
... +~++I
"II
-
/
m
-+
j
J
O
II
+;
-
~+++
....
-
;
+,
~')
++
+ I
++
26
IS
| '...S
lC
R
ÂĄ/
q
+/
,%
-
.+~.
T
I
i
'
y
:+~
s
i
/
FIG.
2.
Topographic
map
of
the
Cape
Flattery
region
(U.S.
Geological
Survey
Cape
Flattery
Quad-
rangle,
15-rain
series).
have
been told
of
their
existence
by
so
many
different
Indians
who
professed
to
have
seen
them,
that
I think
the
story
probably
correct.
The
Indians
do
no
think
they
got
there by
means
of
the
flood,
but
that,
as
before
stated,
they
are
the remains
of
the feasts
of
the
T'hlukloots,
or
thunder
bird,
who
carried
the
whales
there in
his
claws,
and
devoured
them
LETTERS
TO
THE
EDITOR
1459
at
his
leisure.
With
the
single
exception
of
this
legend
of
the
flood,
I
have
never
learned
from
them
that
they
have
any
tradition
respecting
the
tribe
coming
to
or
going
from
the
place
where
they
now
reside,
and
this
is
the
only
one
which
they
relate
of
ancient
times
that
is
corroborated
by
geological
or
other
evidence.
Could
this
be
an
account
of
a
great
tsunami?
Although
there
are
many
features
of
this
report
that
seem
exaggerated,
apparently
Swan
was
convinced
that
some
remarkable
sea-level
disturbance
had
occurred.
He
clearly
segregates
this
report
from
the
majority
of
legends
which
he
feels
are
of
a
more
mythical
nature.
The
words,
"a
long
time
ago,
but
not
at
a
very
remote
period,"
indicate
that
the
alleged
disturbance
predates
the
lifetimes
of
the
reporting
Indians,
but
was
not
to
be
confused
with
an
ancient
time
which
was
associated
with
the
great
majority
of
their
mythical
legends.
If
this
is
an
account
of
an
ancient
tsunami,
then
what
can
be
deduced
about
its
nature
and
origin?
Great
tsunamis
may
have
periods
of
tens
of
minutes
to
hours,
but
4
days
is
without
percedent.
If
we
are
to
believe
that
this
is
an
account
of
a
through
the
years.
If
the
event
is
real,
then
it
is
apparent
that
the
effects
must
have
been
substantial.
However,
it
seems
incredulous
that
any
tsunami
could
have
overtopped
the
entire
Cape
Flattery
region
since
the
highest
elevation
of
the
cape
exceeds
400
m.
Furthermore,
one
is
hard
pressed
to
explain
why
the
water
would
become
warm.
Nevertheless,
the
description
of
water
receding
from
Neah
Bay
and
then
returning
in
a
strong
current
is
clearly
suggestive
of
a
tsunami.
If
this
is
a
tsunami
description,
could
the
sea
wave
have
originated
from
a
great
earthquake
at
a
distant
location?
Since
there
is
no
mention
of
any
ground
shaking,
this
might
be
a
logical
conclusion.
However,
large
historical
earthquakes
along
the
Pacific
rim
have
not
generated
large
tsunamis
at
Neah
Bay.
The
Mw
9.2
Alaskan
earthquake
in
1964
caused
a
tsunami
of
only
about
1.3
m
at
Neah
Bay
(Cloud
and
Scott,
1972).
Furthermore,
the
story
indicates
that
Cape
Flattery
was
an
island
before
this
legendary
event.
This
may
be
plausible
since
a
low
marshy
area
between
Waatch
and
Neah
Bay
is
the
only
thing
that
currently
prevents
Cape
Flattery
from
being
an
island.
If
there
was
permanent
uplift
of
the
Waatch
lowland
associated
with
the
event
described
in
the
legend,
then
crustal
deformation
associated
with
a
nearby
subduction
earthquake
could
explain
the
uplift.
However,
this
and
any
other
conjectures
about
the
significance
of
this
legend
are
purely
speculative.
There
are
enough
inconsistencies
in
the
legend
that
one
must
seriously
consider
the
interpre-
tation
that
this
Indian
tradition
may
be
entirely
fictional.
Nevertheless,
it
is
noteworthy
that
such
a
report
exists
for
a
region
for
which
there
is
growing
con-
cern
that
large
subduction
earthquakes
and
subsequent
tsunamis
may
be
a
real
possibility.
We
have
mentioned
this
report
by
Swan
to
several
colleagues
and
this
resulted
in
the
rediscovery
of
other
Indian
legends
of
earthquake
activity
along
the
north-
western
coastal
United
States.
Gary
Carver
(Department
of
Geology,
Humbolt
State
University,
Arcata,
California)
informed
us
of
myths
of
the
Yurok
Indians
in
which
earthquakes
seem
to
play
a
prominent
role.
These
myths
were
recorded
by
A.
L.
Kroeber
(1976)
between
1900
and
1907.
Yurok
Indians
inhabited
the
region
that
roughly
coincides
with
Redwood
National
Park
in
northernmost
coastal
California
(see
Figure
1).
According
to
Yurok
mythology,
the
god,
Earthquake,
was
a
very
powerful
being
that
ran
over
the
earth,
shaking
and
tearing
the
ground,
breaking
trees,
and
disturbing
the
rivers
and
ocean.
However,
the
Yurok
stories
are
very
1460
LETTERS
TO
THE
EDITOR
allegorical
and
seem
to
be
correctly
classified
as
myths.
We
do
not
reproduce
these
myths
here
since
they
are
somewhat
lengthy,
difficult
to
interpret,
and
their
factual
basis
is
unknown.
CONCLUSIONS
We
thank
Gary
Carver
for
generously
providing
materials
relating
to
Yurok
Indian
mythology.
We
also
thank
Joseph
Ziony
and
Robert
Wallace
for
thoughtful
reviews
of
the
manuscript.
This
work
is
supported,
in
part,
by
the
U.S.
Nuclear
Regulatory
Commission.
REFERENCES
Cloud,
W.
K.
and
N.
H.
Scott
(1982).
Distribution
of
intensity,
in
The
Great
Alaska
Earthquake
o/1964,
Seismology
and
Geodesy,
National
Academy
of
Sciences,
Washington,
D.C.,
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U.S.
GEOLOGICAL
SURVEY
SEISMOLOGICAL
LABORATORY
CALIFORNIA
INSTITUTE
OF
TECHNOLOGY
PASADENA,
CALIFORNIA
91125
(T.H.)
U.S.
GEOLOGICAL
SURVEY
345
MIDDLEFIELD
ROAD
MENLO
PARK,
CALIFORNIA
94025
(P.S.)
Manuscript
received
8
May
1985