tsunami threat to'port alberni · 2010-07-09 · port alberni. the size of maximum tsunami...
TRANSCRIPT
TSUNAMI THREAT TO' PORT ALBERNI
Prepared for
Allan M. McCraeConsulting Civil Engineer
Victoria, B.C.
and
Reid,.. Crowther- & Partners LimitedConsulting Engineers and Planners
Vancouver, B.C.
by
Sydney o. Wigen, P.Eng.4053 Nelthorpe Street
Victoria, B.C.
February 1977
IIii
-~
Contents
Abstact
Alternative Approaches
Numerical For~casting
Historical Forecasting
Source Data
Data Extraction
Port Alberni - Tofino Relationship
Tsunami Hazard, by Zone of Or~gin
Tsunami Frequency at Tofino and Port Alberni
Characteristics of the 1964 Tsunami at Port A1berni
Contribution of Tide to Tsunamis at Port A1berni
Tsunami Threat to Lugrin- Creek Site
Mitigation of Tsunami Damage
Acknowledgement
Ref.er.enc.es
Appendix: A
Page
5
6
6
7
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10
12
15
19
21
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23
25
Illustrations and Tables
Page
Figure 1 Tsunami wave heights 10
Figure 2 Alaska - Aleutian Islands. Earthquake
epicenters and magnitudes; and maximum
tsunami wave 'produced at Tofino.
Figure 3 Kamchatka Peninsula, Kuril Islands, and Japan.
Earthquake epicenters and magnitudes, and
max.lmumctsunamj, ',wave produced at Tofino.·
Figure 4 Number of tsunamis recorded at Tofino, ,with
maximum. wave equal or larger than value'give
in ordinate.
Figl.-rre'- 5 Tsunami of March 27, 1964 as recorded' at
-To fino and Port Alberni.
16
17
18
20
Table 1
Table·-2
.Summary of earthquakes studied, and tsunamis
identified at Tofino and Port Alberni.
Maximum tsunami waves at Tofino and Port
Alberni.
\ ..
9
II
/
5
Abstract
A historical approach has been undertaken in this report to
evaluate the threat of tsunamis to Port Alberni. From catalogues
of tsunamis, a list was compiled by area of more than 100 major
tsunamigenic events occurring throughout the Pacific since 1900.
Availab~eTofino and Port Alberni analogue tide records were
studied to find evidence of the waves reaching the Coast. Twenty-one
of 70 events examined showed a tsunami at 'I'ofLno, and 5 of 19 at
Port Alberni.
The size of maximum tsunami waves at Port Alberni was found
to b~approximately double that at Tofino, where both stations had'
recoTded the same tsunami. It was concluded that Tofino records.
could..be used to estimate the. frequency of tsunamis at Port Alberni,
and the probable maximum waves that would have been recorded •
.;., '~..- .
Of' the 21 tsunamis known·to have reached the coast, 15 came
from:::the region ,between Gulf of Alaska and northern Japan. In the
half century of records studied, the 1964'tsunami was.highly
destructive in Alberni Inlet; the 1960 event was moderately damaging;.
and 3~more...tsunamis may have been close to the point of doing
damage.
In designing for a one-in-200 year event in Port Alberni,
at least one tsunami of the 1964 size must be anticipated.
TSUNAMI THREAT TO PORT ALBEmTI
Alternative Approaches'to Forecasting. Tsunami Hazard
~vo alternative procedures·canbe·applied to forecast the
runup of tsunamis in Alberni Inlet, one numerical, and the other
his t.o'r.Lca.L,
Numerical Forecasting
A hydrodynamic numerical modelof'Albernilnlet and approaches
would be developed. The accuracy of the model would be calibrated
by· applying normal· tides at the entrance to.the model, and
COIDp-ar±n.g simulated tides .produced·at check points in the model. .
agains-t. those occur-r.tng dn the prototype., Simulated ·.tsunamis from
various· sources in the Pacific Ocean could ·then ·beapplied to the
mode'l-centrranee., and ·the response at the head" of the Inlet, or at
any-other location within the model could.be calculated.
Numerical forecasting has the advantage that as many different·
source conditions as required may be tested, and the probable most
criticaL events may vbe determined. However, scientists engaged in
this type of·study·advise that the·investigation of a waterway as
complex as Alberni Inlet and Barkley Sound would probably require
at least six months ·of research time. The cost of such a study,
including computer support, appears to be prohibitive for Lugrin
Creek planning, but might be feasible as a research project
correlated with overall planning for the head of Alberni Inlet.
A limitation of the numerical modelling technique must be
recognized, that the precise nature of the delta area becomes
critical in the Tunup interpretation. Simu~ated response of the
model might be changed significantly by slight changes in the
assumptions regarding the delta.
7
Historical Forecasting .
The historical approach requires a review of tsunamis known to
have occurred thr~ughout the Pacific Ocean. Records and publications
are examined to find which of these tsunamis reached' the" British Columbia
coast. For a study of Albemi Inlet and approaches~ the principal rec
ords are the analogue diagrams from tide gauge s~ations at Port Alberni
and Tofino. From such a study it becomes possible to identify which
zones of the Pacific represent a potential tsunami source~ and to make
some estimate of the frequency with which tsunamis may reach the Coast.
Such a study has been undertaken for .this report, and from the data col
lected and summarized we can draw some conclusions on the tsunami threat
to Port Alberni.
Source.. Data
For this study, available catalogues of tsunamis at the Inter
nationaL'Tsunami Information Center in Honolulu were reviewed. More
than.lOO earthqu~kes with Richter magnitudes between·7.5 and 8.6, oCcur
ring since 2900 were tabulated by" area. Some known exceptionally large
earthquakes of earlier years were also listed. Approximate travel times
for:waves from each epicenter to reach Tofino or Port Alberni were ex
tracted.from tsunami travel time· charts.
Through the co-operation of the Tidal and Current Section, Canadian
Hydrographic Service t in Victoria, and Marine Environment Data Service~
Ottawa~ analogue tide gauge records from Tofino and Port Alberni were
made available. The records were scanned at the estimated arrival times~
and any evidence of a tsunami was listed. Port Alberni original gauge
records were available from 1963 to 1976~ but with interruptions. The
Tofino tide gauge has been operated fairly continuously by the Government
of Canada since 1906, and for most of. these years~ the original records
were also available. However, there are some years of Tofino tide
8
records that now exist only on microfilm, and only a few prints from
these records have been available in time for use in the preparation of
this report.
Detail on the original records is sufficiently clear that generally
a tsunami registering a wave of 2 em or more at Tofino can be identified.
On the m~crofilm, whether similar tsunami oscillations can be recognized
is dependent on the quality of the' original record.
Data Extraction
Appendix A contains a listi;ng of the' tsunamigenic events of the
past' century that was prepared for this s tudy, grouped: by areas, the
Richter magnitude of the earthquake, and its depth of focus in kilometers s
where-available. The arrival time of the initial wave at Tofino and its
height in centimeters is listed, followed by R or Fto indicate whether
the wave was rising or EaLl.Lng ; The time of commencement and height of
th~~umwave for each tsunami, as recorded at Tofino, is also listed.
AlL_t±mes are gi~en in Universal Time (U.T.). A similar extraction of
tsunamis was made for Port Alberni. Table 1 summarizes the number of
events' by area and by magnitude, the number of these for which tide
r ecozds were available for scannfng , and the number of tsunamis identi
fied on 'Tofino and Port Alberni tide diagrams~ Twenty-one of 70 events
showed a tsunami at Tofino, and 5 of 19 at Port Alberni.
In past tsunami data extraction it has been cornman practice to
measure the height of a wave f;rom trough to crest, with the inf~uence
of the tide included. For this study, intercomparison of the 'waves at
Tofino and Port Alberni was required, so the contribution of the tide
has been deleted. This has been done by measuring each trough or crest
as the maximum displacement from an assumed tide that would have occurred
had there been no tsunami.
Tidal Records Scanned andNumber of Events by Magnitude Visible Tsunami Identified
Area >7.9 7.5-7.9 <7.5 UnknoWn Total Tofino Port Alberni
1. Chile - Peru 4 10 2 16 8/2 5/0
2. Ecuador - Mexico 2- 8 1 11 7/0 I/O
3. Baja California -Alaska Peninsula 2 .1 3 6· 3/0 1/0
4. Gulf of Alaska - Aleutians 1 3 10 6/5. 3/1
5. Kamch~tka - Kurils 7 3 ·1 11 9/7 4/2
6. Mariana - Japan Trench 4 9 13 10/3 2/1
7. .Ryukyu - Philippine Trench 5 8 13 9/0 2/0
8. S. China - Sulu - Celebes Sea 3 3 6 3/0 0/0
9. Java Trench - Banda Sea 1 3 1 5 3/0 a/a
10. N. Guinea - Bismarck Archipelago 2 2· 1/0 .0/0
II. Solomon Sea - New Hebrides 4 9 13 6/1 0/0
12. Tasman Sea 2 2 2/0 0/0
13. Kermadec - Tonga Trench '4 1 5 2/2 a/a
14. Hawaii i 1 1/1 1/1
.43 59 9 3 114 70/21 19/5
Table 1. Summary' of earthquakes studied,. and
tsunamis identified at tofino and Port Albern!
'.
In a typical case,
as shown in Figure 1, the
height of the initial wave
is taken as X-B, and not
X-A. Similarly the maximum
wave is not Y-Z, but (Y-~)
+ (D-Z).
(Right) Figure 1.
Tsunami Wave Heights
Port Alberni - Tofino Relationship
10
y
II
I
r :ei
z
To establish the frequency and hazard of tsunamis at Port Alberni
from...the very limited data would require an extrapolation that would have
little validity. However, Tofi~o, only "lOO kilometers ~way, offers a much
longer-history. The question comes up of whether. the response of the two
ports-·-is sufficiently similar that one can make any assumptions about tsu
namfs.cat; Port .AJ.berni from those recorded at Tofino. Although the char
acteristics of the waves are markedly different, we can attempt a correla
tion of the maximum waves of tsunamis observed at both locations. The
first comparison ~s for the 1960 tsunami from Chile which produced the
Lar-gestrwave ~ecorded to that time at Tofino. No gauge wa? operat.Lng at
Port Alberni, but the waves were reported to be large enough. to damage
log booms; one rise of about 2 meters was described at the paper loading
dock; and offices at MacMillan Bloedel Limited were sufficiently con
cerned that the Company agreed to co-operate with the Canadian Hydro
graphic Service in the installation and.operation of a pennanent tidal
station, principally to have its records available in the possible event
of a future tsunami.I
This fortuitous decision has made possible the data for this study,
and even though the disastrous 1964 tsunami did exceed the gauge range
11
and put it out of action briefly, the record none-the-less has been
invaluable.
Subsequent to 1960, five tsunamis were registered on both the
Tofino and Port Alberni tide gauges. Table 2 gives a comparison of the
maximum waves for which recorded or estimated h~ights can b~ given.
MaximUm Wave Maximum WaveDate Tsunami Source Magnitude Tofino " Port Alberni
May 22, 1960 Chile 8.5 126 200 (estimate)
Oct 13, 1963 S. Kuril Is. 8.2 16 27
Mar 28, 1964 Alaska 8.4 240 800 (estimate)
May l6, 1968 N. Japan 8.2 12 24
AugIl., 1969 S. Kuril Is. 7.8 6 4
Nov 29, 1975 Hawaii 7.2 9 10
--Tab.le 2.. Maximum Tsunami Waves at Tofino and Port Alberni
For the larger tsunamis there is a reasonable correlation between
the-,::two ports, with the maximum at Port Alberni averaging ab-out twice
the~"height" of the maximum at Tofino. In addition there were several
examples of both ports having no response to "a tsunami~ and no occasion
onrecord:when one responsed and the other did not.
On the strength of this evidence we conclude that the frequency of
tsunamis occurring at Tofino from various sources establishes the fre
quency for Port Alberni, but "that larger size waves must be expected
at Port Alberni than Tofino for major events.
12
Tsunami Hazard, by Zone of Origin
Less than one hundred years of systematic seismic and tidal
records are available for tsunami studies. Regi~nswith tsunamQgenic
potential may exist in the Pacific that have produced no major earth
quakes in the past century. Understanding of the plate tectonic move
ments producing most of these earthquakes is very recent. It is not
known whether seismic zones are alternately active and quiescent 'over
decades or centuries, or whether the frequency of earthquakes and
tsunamis is fairly constant. Of necessity then the history of activ
ity during the past century becomes the' criterion we must use to
estimate future threat.
Peru-Chile Trench
Tofino.tide'records were available for 8 major earthquakes of
the past 60 years. Only 2 showed evidence of a. t.sunami., but one' of
these~ in 1960, was the second largest wave registered at'Tofino.
The tsunami from this earthquake was one of the most severe on
record in the Pacific, and caused severe damage and casualties in
South.America, Hawaii, and Japan.
Ecuador-Nexico
The subduction zone of the Middle America Trench has produced
a number of tsunamis, but these appeal:" to be directed away from the
Canadian west coast. Tofino tide records showed no 'evidence 'of
tsunamis resulting from any of seven earthquakes in this areae
Baja California - Alaska Panhandle
Earthquake movements tend to be strike slip, having hori
zontal rather than vertical displacement, and therefore, are
generally non~tsunamigenic. Two records examined showed no tsunami.
13
The most recent of these, with~a magnitude of 6.7, occurred on
Dec. 20, 1976, 200 kilometers west of Tofino. A subduction zone
lies off Vancouver Island and Wash~ngton, associated with local sea
floor spre~dingo The Earth Physics Branch of Energy, }lines' and Re
sources Canada does not rule out the possibility of a tsunami from
this source, but indicates that if any occur here they are suffi
ciently rare that the last wa~ generated before the time of recorded
history on the Coast.
Gulf of Alaska~Aleutian'Islands
Five of six large earthquakes'produced'tsunamis at Tofino; two
additional earthquakes in the western Aleutians, for which Port
Alberni but not Tofino records were available,' did not. The 1964
earthquake, near Anchor.age,'produced the'l~rgest' tsunami on record
at Tofino and Port Alberni.
Kamchatka Peninsu1a~Kuti1 'Islands
Of nine events examined seven earthquakes produced tsunamis at
Tofino. Of these, the magnitude 8.2 earthquake off Kamchatka regis
tered the largest maximum wave at ,Tofino from this area, 58 em.
Mariana-Japan Trench
Tofino tide records were available for the time of 10 major
earthquakes, and of these 3 showed tsunamis. Epicenters of these
were all ,off Hokkaido and northern Ronshu~ The largest maximum
wave at Tofino from this area, of 23 em, was produced by the Great
Showa Sanriku Tsunami of 1933, that killed thousands of people in
Japan.
14
Ryukyu Trench-New Guinea
In areas 7 - lO.on Table 1, from southern Honshu to the
Philippines, Indonesia and New Guinea, Tofino records were examined
for 16 earthquakes, and none of these showed evidence ofa tsunami.
Solomon Sea-New Hebrides .
One earthquake on the northeast shore of the Solomon.Islands
produced a 6 em maximum Wave at Tofino. No other tsunamis from
this area showed on the records examined.
Tasman Sea
Two records examined showed no evidence of a tsunami at
Tofino •.
Kermadec-Tonga Trench
-~¥o earthquakes studied, of magnitudes 8.0 and 8.3, generated
tsunamis at Tofino with maximum waves of 12 and 9 em respectively.
Generally, the southwest Pacific would appear from the foregoing
results, and from the location of tsunami generating areas relative
to Tofino and to intervening island arcs, to offer no significant
tsunami threat to the British Columbia coast.
Hawaii
The magnitude 7.2 earthquake of November 1975 is the only
tsunamigenic event from this area on record at Tofino. It registered
a maximum wave of 9 em. The previous significant earthquake in
Hawaii occurred in 1868. Whether a major Pacific-wide tsunami could
originate from this area is unknown.
15
Tsunami Frequency at Tofino and Port Alberni
The region from Gulf of Alaska.to Japan, areas 4,5, and 6 in
Table 1, clearly provides the most significant tsunami threat to
Port Alberni. At least 34 tsunamigenic earthquakes occ.urred in 80
years, and of' 25 of these for which' Tofino tide records wexe avail
able at :the time of the study, 15 sho'i1 clear evidence of a tsunami.
·Locations of epicenters for this region are shown on Figures 2 and
3. With 'each-is shown the magnitude of the earthquake, and the
height of the maximum wave generated at Tofino from the event.
Eighteen of the earthquakes from the region registered a magnitude. -
of 8.0 or larger, a size for whichaPaeific-wide tsunami warning is
autqmatically issued from the Honolulu Observatory.
In the. p~riod of record '. six tsunamis reached Tofino from the
rest of the Pacific, the one in 1960 being-large enough to cause
damage. Figure 4 shows the number of tsunamis recorded at Tofino ,
with maximum wave height larger than any given value. Plotted
logarithmically, the result is approximately ·linear. The signifi
cance of this relationship is not clear, _since the sample is an in
complete record of the number of tsunamigenic events_that occurred,
and_furthermore, .it groups all tsunamis regardless of the area of
origin•.
Seismologists who have studied. earthquake frequencies, and who
were queried during the preparation of this report·, warned _against. .
attempting to extrapolate .tsunami frequencies from the presently
known history. In particular they cautioned .against identifying the
frequency with which the rlisastrous tsunami of 1964 would be equalled
or .exceeded. It was felt that mathematical expressions of probability
and frequency_ had little relevance to the data, since the mechanisms
producing tsunamis, or focusing their direction of travel from sourc.e
are not well understood.
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Figure 3. Kamchatka Peninsula, Kuril Islands and Japan
Earthquake Epicenters and Magnitudes, andHaximum Tsunami Wave Produced at Tofino
18
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Figure 4. Number of tsunamis recorded at Tofino, withmaximum wave equal or larger than value given in ordinate.
19
Notwithstanding the validity of this point of view, some con-
,- elusion on tsunami hazard is a specified requirement of the Lugrin
Creek Study, and the material here compiled is the most comprehen
sive set of data on tsunami impact on Tofino and Alberni Inlet yet
assembled. From these data it is apparent that tsunamis reaching
the British Columbia coast, and specifically Alberni Inlet, are a
much mor.e common phenomenon than had generally been recognized. In
the past half century, one tsunami has been highiy destructive, and
another moderately damaging. Assuming an amplification on waves
recorded at, Tofino,as evidenced by the data in Table 2, 'three more
tsunamis in this same period may have been close to the' point of
being moderately damaging. Earlier tide records back to 1906, may
give some further indication on tsunami freque~cies when the micro
films are studied. Newspapers prior to .-1906 may also provide in
fo rmatri.on if events comparable, to the 1964 tsunami occurred subse
quent to the development of Alberni as a port~
On ~resent knowledge, for a design criterion based 'on a one in
200 year event, at'least one tsunami of the 1964 size must be expected.
Characteristics of the 1964 Tsunami at Port A1berni
Figure 5 (taken from Marine Sciences Directorate ~illnuscript Re
port Series, No. 36)" shows the analogue trace of 'the 1964 tsunami at
Tofino and Port Al.be'rnd., For the first 8 hours the 'Port Alberni gauge
was for the most part out of service, and waves exceeded the range of
the gauge. However, parts of the first and second rise were recorned,
and the maximum crest was identified with accuracy by the water level
mark on the gauge house wall, at 20.9 feet (6.4 m). The first three
crests were recorded also on the Soroass River gauge, and helped in
recreating some of the missing record. The second or maximum crest
reached an elevation of 19.6 feet (5.6 m) on the Somass River gauge,
showing a drop in tsunami height beyond the end of the harbour.
TSUNA~I WEST COAST OF CANADA MARCH 27 -29 1964
20 U \0 12 ,~ ..I. '? \3 20 22 0 4 10, eure lIJoIfitUg TI I
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31Figure 5. Tsunami of March 27, 1964
as recorded at Tofino and Port Alberni
21
Of the 5 tsunamis at Port Alberni for which analogue records. .
are available only the 1964 event shows dominant waves with a period
of about 90 minutes. This is also the apparent period of a natural
seiche in the Inlet, and corresponds closely with one of the natural
frequencies of Alberni Inlet calculated. by Murty and Henry (1972).
Contribut:Lon of Tide to Tsunamis at Port Alberni
In the 1964 tsunami the first waves came in vThen the tide was
cresting at about 10 feet (3.0. in), very close to the 10.4 feet (3.2 m)
level of higher high water mean tide.;
Since the elevation of higher high water, large tide is 12.2 feet
(3.7m) and the all time extreme tide (non tsunamis) is 14.3 feet
(4.4m), in a once in 200 years tsunami the prospect of a higher tide
contributing substantially to a tsunami flood crest is small. It is
more likely that a minor variation in the s t rengfh of inlet response
to a.particular tsunami would have more impact than tide on the flood
crest ·reached.
Tsunami Threat to the Lugrin Creek Site
Unless exceptionally high dikes can be provided. in any Lugrin
Creek development, the possibility that a tsunami' will flood the area
has to be accepted.
With the present capabilities of the Tsunami Warning System in
the Pacific, and of Civil Defense authorities in Canada, it is probable
that at least 2 hours warning of an impending tsunami can be given, and
that evacuation of people ~ivin~, working, or enjoying recreational
facilities in the area can be effected. This potential need for evac
uation needs to be recognized in designing roads leading from the low
lying ·area.
The remote .threat of a severe tsunami generated near the coast
probably does not warrant undue concern for the proposed Lugrin Creek
development, but could be a significant factor in siting an atomic
power plant, or major oil terminal in Port Alberni.
As an additional but hidden cost of development, periodic evac
uation for tsunamis, that could, but do not actually flood the area
must be anticipated. Such false alarm evacuations may be anticipated
once per decade, or oftener, based on the history of tsunamis in the
Pacific.
Mitigation of Tsunami Damage
Damage from tsunamis may result from flooding.when the water is
raised to abnormal levels, and from the very strong currents asso
ciated wi.th the rapid changes in water level. Dikes will be scoured,
log booms destroyed, and vessels driven ashore.o!, overturned. Damage
or destruction may occur from the dynamic pressures and pressure dif
ferentials on the faces of structures, and by excessive'erosion of
the foundations. Logs and floating debris become damaging or destruc
tive missi.les.
Experience in parts of the Pacific has shown that trees, closely
spaced, reduce some of these hazards. Retention or enhancement of
natural vegetation should be encouraged during any development.··
Acknowledgement
Of many people who have advised or assisted with aspects of thisstudy I would like to acknowledge in particular the support and interestof G. Pararas-Carayannis and M. Ching, International Tsunami InformationCenter; G. Miller (deceased) and H. Loomis, Joint Tsunami ResearchEffort; w. Rapatz and J. Manson, Tidal and Current Survey; G. Rogers,Seismology and Geothermal Studies; R. Brazee, National Geophysical andSolar-Terrestrial Data Center; and J. Derr and R. Kangas, NationalEarthquake Information Service.
:1iII
:1II
I,·1
!IIi
.''11
.,
.1;'1.,"
j
:1
23
References
Braddock, R.D. 1975. An analysis of the conventional tide well.
Applied MathematicsPreprint No. 86, University of
Queensland.
Cox, D.C. and George Pararas-Carayannis, with revisions by J.P.
Cal.ebaugh , 1976. Catalog of tsunamis in Alaska•. \lorld
Data Center. A for Solid Earth Geophysics, Boulder.
Henry, R.F. and T.S. Nurty. 1972. Resonance periods of multi
branched inlets with tsunami amplification. Marine
Sciences Directorate Ottawa. Manuscript Report Series
No. 28.
Iida, K. 1961. Nagnitude, energy, and generation mechanism of
tsunamis, and catalogue of earthquakes associated with
tsunamis. Tenth Pacific Science Congress.
Iida,_ K•., Doak C. Cox, and George Par-aras-Carayannf.s ," 1967. Pre
.Limfriaz'y catalog of tsUnamis occurring in the PacifiC.
Ocean. Hawaii Institute of Geophysics, University of
Hawaii.
Neyers., H.; R.J. Brazee, J.L. Coffman, and S.R. Lessig. 1976. An
analysis of earthquake intensities and recurrence rates
in and near Alaska. National Geophysical and Solar
Terrestrial Data Center, Boulder. NOAA Technical
Memorandmn EDS NGSDC-3.
Nurty, T.S. and L. Boilard. 1970. The tsunami in the Alberni
Inlet caused by the Alaska earthquake of March 1964.
Proceedings of the international symposium on tsunamis
and tsunami research. Ed. W.N. Adams. East-West Center
Press. Honolulu. p. 165-187.
1964. Tsunami of March 27-29; 19'64,.
Department of Mines and Technical
24
Nurty, T. S. and R. F. Henry. 1972. Some tsunami studies for the
west coast of Canada. Marine Sciences Directorate,
Ottawa. Manuscript Report Series No. 28.
Murty" T~S., S.O. Wigen, and R. Chawla. 1975. Some featur.es of
tsunamis on the Pacific coast of South and North America.
Narine Sciences Directorate, Ottawa. Manuscript Report
Series No. 36.
National Ocean Survey. 1971. Tsunami travel time charts. Na
tional Ocean Survey, NOAA. Rockville,'Md.
Pararas-Carayannis, G. 1969., Catalog of tsunamis ,in the Hawaiian
Islands. World Data'Center,-A Tsunami. U.S. 'Coast &
Geodetic 'Survey.
Silgado ~. Enrique. 1974. Historia de los grarides tsunamis'pro
ducidos en- la'costa occidental de America del Sur. Centro
Regional de Sismologia para America del Sur. Lima.
(in Spanish).
Soloviev,'S.'and Ch, N. Go. 1969. Catalog of tsunamis in the
Pacific Ocean. Sakhalin Complex Scientific Research
Institute. (in Russian)
Wigen, S.O. ,1960. Tsunami of May 22, 1960, west coast of Canada.
Technical report, Marine- Sciences Branch.
Wigen, S.O. and W.R.H. l~ite.
west coast of Canada.
Surveys. Victoria.
.;'"
,:",;~.' .. " ',')"1::',."
''''.";1''.''.,,',"
Appendix A
Tabulation. of earthquake epicenters, by area,
and tsunami waves registered 'at Tofino
".'.':
.\
TRAVEL TIMES OF MAJOR TSUNAMIS
AREA OF ORIGIN: Chile ... Peru GkdGl~ SITE ~,ECORPEn:, Tofinoi • ; ,. : J . '
HOUR HRS FRON EST.AR. INIT.WAVE MAX. WAVEYEAR 1'10. DAY. (D. T.) LAT. LONG. }fAG. DEPTH GAUGE (U. T. ) ARR. HT. ARR. HT. PERIOD' COMMENTS
1868 Aug 13' 1645 l8S 7lW
1877 May 10 0059 21.55 ' 71W
1906 Aug 17 0040 338 72W 8.4 16 '1/2
1922 Nov 11 0433 28.58 70W 8.3 16 2033 2030 3R 12/0333 27F1928 Dec 1 0406 358· 72W 8.0 16 '1/2 2036 No tsunami1943 Apr 6 1607 31.58 71.4W 7.9 10 16 7/0807 No tsunami1959 Feb 7 0937 48 81.5W 7.5 0 12 1/2 No record1960 May 21 1003 37.58 73.5W 7.5 17 22/0303 No tsunami'
1960 May 22 1911 39.58 74.5W 8.. 5 17 23/1211 1221 22R 1730 126F
1966 Oct ,17 2142 10.7S 78.7ii1, 7.5 , 24 ,'13 1/2 ,No record
1966 Dec 28 0818 , 25.58 70. 7iii 7.6 32 ,16 ' No record
1967 Dec 21 0225 21.7S 70.0W 7.5 15 1/2r " , No tsunami- .~ ,
1970 Nay 31 2023 9.28 7S.aW ' 7.8 43 13' 1/2 No tsunami,
1971 July 9 0303 32.58 71.2W 7.5 58 16 1/2 No record,
1974 Oct 3 1421 11.58 nv. 7.7 13 13 1/2 No tsunami
1975 May 10 1428 38.13 73, •• 2W' 7.8 6 16 1/2 No tsunami
'.,
TRAVEL TIMES OF MAJOR. TSUNAMIS
AREA OF ORIGIN: Ecuador - Mexico• ' :' 'j , .' ~. I
GAUGE SITE ~EPO~TJED;' _T_of_i_n_o _
ERS FROM ES~.ARt INIT.WAVE MAX.WAVELONG. MAG~ DEPTH GAUGE .(U.T.) ARR. UT. ARR. HT.
HOURYEAR HO. DAY (~)
1906 Jan· 31 1536
1928 June 17 0319
1932 June 3 1037
1932 June 18 1012
1934 July 18 0136
1941 Dec 5 2047
1950 Oct 5. 1610
1953 Dec 12 1731
1957 July 28 0840
1958 Jan 19 1407
1973 Jan 30 2101
LAT.-IN.16.2N
18.5N
IB.5N
8N
8.5N
10.4N
3.5S
16.5N
1.5N
18.5N
81.5W 8.6
98W 7~8
:.104.2W 8.1
103.5\>1 .7.8.
82.5W. "7.7
83W 7.5
85.7W 7.7I
81\>1 7.8
99.0W 7.9
79.5W 7.4103W . 7.5 .
95
60. 43 .
12 1/2.
'9
7 1/2
7 1/2
12'
12
11 1/2
12
8. 1/.2
12 1/2.
a.,',
PERIOD COMMENTS
No tsunami
No tsunami
No tsunami
No tsunanii
No record
No record
No record
No tsunami
No tsunami
No tsunami
"
---_._._----.._...._... _... _.. .. ····- ...~·:."':?c-:::·.:= .._.;;:t:·"·.'i',,,·::~i!
I:';"",.", '"'""·"";'''''A"7' I., , • _
AREA OF ORIGIN:Baja California Alaska Panhandle
. ~;"" '""~'."., ,.".,,~,
TRAVEL TIMES OF MAJOR TSUNAMIS
pAUG~ ST.tE R¥~d~~p;' ~To~f~i~n~o ~ ___I
fIRS VROH EST.AR. INIT.WAVE ' MAX.WAVELONG. }-rAG. DEPTH GAUGE (U. T.) ARR. HT. ARR. HT. PERIOD'
HOURYEAR MO. DAY (U.T.) LAT.
1906 Apr 18 1312 38N
1928 Feb 9 0304 49N '
1946 June 23 1713 49.8N
1949 Aug 22 0401 ,53.7N
1958 July 10 0615 , 58.6N
1976 Dec 20 2033 49.0N
123W 8.25
125W ',5.8'
124.9W 7.3, '
133~2W, 8.1
137.1W 7.9
i28~8W '6.7
3
1 1/2
3
1
COMMENTS
No tsunami
No record
No tsunami
AREA OF ORIGIN: 'Gulf of Alaska - Aleuttans
TRAVEL TIMES OF MAJOR TSUNAMIS
.: .' I I. 1.,:,( • .GAUGE SItE RECq~p~D: T.;..;."o....,:f:..:;·i:..:;n:..:;o _
HOURYEAR MO. DAY (U.T.)-,---1$97 Sept 10 2140
1899 Sept 4 0022
1929. Mar 7 0134
1938 Nov 10 2018
1946 Apr. 1 1229
1957 Mar 9 1422
1964 Mar 28 0336
1965 Feb 4' 0501
19'65 Mar· 30 0227
1975 Feb 2 0843
','
LAT.
60N
60N
51N
55.5N
53.5N
51.3N
61.1N
51.3N
SO.6N
53.5N
In~S FROM ~sT,AR. INrr.WAVE l-fAX.WAVELONG. MAG~ DEPt!! GAUGE /1], T.) ARR. HT. ARR. HT. PERIOD'
140W 8.6 .
·142.3W 8.
l70W· 8.1 5 ... · 0634 06394F ,0800,llF
158W 8.3 4 11/0030 001112R '0125 27F
l63.0W 7.4 4 u: 1700 ·1650 21R '.20,52 58F
17S.8W 8.3 6 2022 1907·14R1Q/013749R
147~7W 8.4 33 4· 0736 . 0700 ~9R' 0850 240F,178.6E 8.2. :40 6
177.9E 7.3 51 6 1/2
173E 7.4. 10 '7'
"
, .
COMMENTS
- No record
No record
No tsunami
, ,
TRAVEL TIMES OF MAJOR TSUNAMIS
AREA OF ORIGIN: . Kamch~tka .... Kuri1 Is~ GAUGE SITE RECO{¢kq: Tofino,,'." ~=::;.::---------
HOURHRS FROM ~sr.AR, rNIT.WAVE MAX.WAVEYEAR 1'10. DAY CU. T•) LAT. LONG. HAG. DEPTH GAUGE (U. T•) ARR. HT. ARR. HT. PERIOD COMMENTS
SIN 157E
43.2N 145.8E
8/0216 014~ 9R. 0306 14F
2400 2354 6R 4/0350 ZiF'
2331 14/0027 9R 0806 15F
5/0100 . 0042 21R 0347 58R
7/0830, 0807 9R 1655 10F
1918 Sept 7 1716
1923 Feb 3 1602
1923 Apr 13 1531
1952 Nov 4 1658
1958 Nov 6 2258
1959 May 4 0716
1963 Oct 13 0518
1969 Aug 11 2127
1971 Dec 15 0830
1973 Feb 28 0638
1973 June 17 0355
45.5N
54N
56N
52.7N
44.5N
52.5N
44.8N
43.5N
56.0N
151. 5E.
161E'
162.5E
160.3E.
148.5E
159.5E·
149.~E.147.4E
163.3E
8.2
8.3
7.2
8.2 33
8.7 75
8.0 60
8.2' 60
7.8 28
7.8 33
7.6 27
8.0' 48
·9'
8
8'
8
9 i/2
9 1418
9 1/2 12/0700
8 1430
9 1/2' '1325
"':' 3
0630 2
1857 16F
6
No record
No record
No tsunami
No tsunami
TRAVEL TIMES OF MAJOR TSUNAMIS ..- -MEA OF ORIGIN:
r • . ' I:. ~ I, .' ,; ( I_l1ariana __ Japan T~ench__~ GApGE S:l::~E Rf'CO~IDED I .Tofino
HOUR HRS FROM EST,A~~ I~IT.WAVE MAX. WAVEYEAR HO. DAY (U.T.) LAT. LONG. }tAG~ DEPTH. GAUGE (U.!.) ARR. HI. ARR. HT. PERIOD CONMENTS
1896..
June 15 1033 39.6N" 144.2E 7.6
1931 Mar 9 0349 4l.2N 142.5E7.6 . 10 1400 No tsunami
1933 }far 2 1731 39.1N l lf4.7E 8.3 9. 1/2 3/0300 . 0312 .10R 0457 23F
1936 Nov 2 2046 38.2N 142.2E 7.7 80 10 3/0700 No tsunami
1938 .. Nov 5 0843 36.7N ·141. 7E 7.1 33 10·i/2 1900 No tsunami
1938 Nov 5 . 1050 38.2N 141.7E 7.6 100 10 1/2 2130 No tsunami
1938 Nov 6 0854 36.9N 142~ 6E 7.5 - '10 1/2 1930 No tsunami,1952 Mar 4 0123 42.2N . 143. 8E 8.1 45 10 1123 1150 3R 2112 12F
1953 Nov 25 1748 34N . 14l.5E 8.0. 50 10 '1/2 26/0430 . . No records
1960 Mar 20 1707 39.8N ·143.5E 7.5 .60 .10 . 21/0300 No tsunami
1964 . June 16 0402 38.3N 139.2E 7.5 . 57 - . Sea of Japan
1968 May 16 . 0049 40.9N 143.5E 8.2 7 9 1/2 1000 .. 1017 .5R 1625 12F
, 1968 May 16 1039 . 41. 6N 142.9E 7.5 33 9 1/2 2000 Not identifiable overprevious tsunami.
TRAVEL TIMES OF MAJOR TSUNAMIS~ .
AREA OF ORIGIN: Ryukyu - Philippine Trench" GAUGE SITE RECORDED: Tofino" ,
HOUR HRS FROM EST.ARi INIT.WAVE MAX. WAVEMAG. DEPTH
' I
YEAR NO. DAY (U.T.) LAT. LONG. GAUGE (U. T.) ARR. HT. ARR. HT." PERIOD COMMENTS
1911 June ,15 1426 29N 129E 8.7 12 1/2 16/0300
1921 Nov 11 1836 8N- 127E 7.5 14 12/0900 No tsunami
1923 'Sept 1 0259 35.2N 139.5E 8.2 11 1/2 1430 No tsunami
1923 Sept 2 0247 35N 137.5E 7.7 11 1/2 1415 No tsunami
1924 Apr 14 1620 6.5N 126.5E 8.3 15 15/0720 No tsunami
1944 Dec 7 0435 33.7N 136E 8.0 ' 11 1/2 1600 No record
1946 Dec 20 1919 33.0N 135!6E 8.1 11 1/2 21/0700 No tsunami0
1952 Mar 19 1057 9.5N 126.7E 7.7 14 20/0100 No tsunami
1966 Mar 12 1631 24.2N 122.6E' '7.5 48 14 13/0631 No record
1968, Apr 1 0042 32.6N 132.2E 7~7 33 12 1242 No record
1968 Aug 1 2019 16.5N 122.2E 7.7 37 15 2/1100 No tsunami
1972 Jan 25 ' 0206 22.5N 122E 7.7 33 14 1600 No tsunami
1972 Dec 2 0020 6.5N 126.6E 7.7 33 15 1/2 1600, No tsunami
",
~---- ~--~ .• _. "__ w. __ ••• _
TRAVEL TIMES OF MAJOR TSUNAMIS
AREA OF ORIGIN: S, China - Sulu - Celebe~ Seas' GAUGE SITE RECC)RPED: .__T",-,Q"-"f...,.i,,",,,n=o~_~_~ _
HOUR IlRS Fiimx EST .AR. IN1T. WAVE . MAX. WAVEYEAR HO. DAY (U.T•) LAT. tONG. MAG. DEPTH GAUGE (U. T.) ARR. HT. ARR. HT. PERIOD COMMENTS-1897 Sept 20 1906 6N 122E .8.6 17
1918 Aug 15 . 1218 5.5N 123E 8.2 . 16 1/2 16/0500 " No tsunami
1934 Feb 14 0400, 1.7.5N . 119E 7.6 .15 1900 No tsunami
1937 Aug 20 1159 14,5N ' 121.5E 7~5. 15 1/2 21/0300 No tsunami
1948 Jan 24 1747 10.5N 122£- 8,2 15 '1/2 25/0900 No record
1976 Aug 16 1610 7.2N 123,7E 7.8 33 15 1/2 17/0800 No record
."",",.=o_=,!=,,~..•..•••.•..,·1'
h:
!i~
TRAVEL T:hms' OF MAJOR TS1JNAMIS
AREA OF ORIGIN: Java Trench - Banda Sea GAUGE SITE R~CO~)EO; Totino
HOUR ERS FRO~ ~S+~~~. !NIT.WAVE MAX. WAVEYEAR MO. DAY (U.T.) LAT. LONG. MAG. DEPTH GAUGE Jd.T,;) ARlt. HT. MR. HT. PERIOD. COMHENTS
1883 Aug 27 0259 16.7S ·105.4E i7.1/2 Krakatoa Explosion
1938 May 19 1708 IS 120E 7.6. 16 20/0900 No tsunami
1939. Dec 21 '2100 ON 123E 8.0 100'. 16 22/1300 No tsunami
1965 Jan 24 0011 2.4S. 126.0E 7.6 . 6 15 1500 No record
1968 Aug 10 0207 1.4N 126.2E 7.8 33 15 1700 No tsunami
TRAVEL TIMES OF MAJOR TSUNAMIS
AREA OF ORIGIN: N. New Guinea-Bismark ArchipeiagodAUGE SITE: RlI:CO~Dl~D: _T...:;o...:;f;.;;:i;.;;:n,..:..o ------
HOUR HRS FROM EST.AR, INIT,WAVE MAX. WAVEYEAR MO. DAY (U.T.) LAT. LONG. MAG. DEPTH GAUGE (U ~ T.) ARR. HT, ARR. HT. PERIOD
1914 May . 26 1423 28 137E 7.9 15 1/2
1935 Sept 20 0147 3.5S 141.8E 7~9 33 . 15 1700
. ,
""
COJ:.fMENTS
No tsunami
J";1~:c;rio\~~._---------_._--- __. . ~._._.~.. ._ ..._, w._..·_.__ ._._·__··_··_ ..__·_..
TRAVEL TIMES OF MAJOR TSDNA}fIS
AAEA OF ORIGINi Solomon Sea - New Hebrides ' GAUGB S11'~ RECORDED! Tofino
HOUR HRS }~OM Est.AR~ INrT.WAVE MAX.WAVE, YEAR MO. DAY (D.T.) LAT. LONG. MAG. DEPTH GAUGE l.U.T.) ARR. HT. ARR. HT. PERIOD' COMMENTS- e d
1919 May 6 1941 :is 154E 8.1 1l~ 1/2 7/0600 ' No record
1920 Feb 2 1122 6.58 150E ,,' 7.8 15 1/2 3/0300 ,No tsunami
1931 Oct' 3 1913 10.5S 16L8E 7.9 14 1/2 4/1000 0952 ,2R 1313' 6F
1934, July 18 1940 138 '166.5E 8.2 13 1/2 19/0900 No tsunami
1939 Jan 30 0218 6.5S 155.5E 7.8 33 14 1/2 1700 -- No tsunami
1939 Apr 30 0256 9.05 159.5E. 8~0 rso. 14 1/2 '1700 No tsunami
1949 Oct 19 2100 6.58 154E 7.5 ' 60 14 1/2 20/1100 No tsunami.1953 Apr 23 1624 45 154E 7.5 14,1/2 24/0700 No record
1966 Jun~ 15 0132 10.38 160. SE, 7.6 ' 23, 14 1/2 1600, No record
1966 pee 31 1823 11.88 16?5E '7.7 56 14 1/0800 No record
, 19i1 July 14 0611 5.58 153.9E 7.9 4i ' 1,5 2106 No record
1971 July 26 0123 4,98 ,153.2E 8.4 48 15 1600 No record, ,
14 1/2 21/05001975 July 20 1437 6.5S 154.9E 7.7 49 'No tsunami
, I
'\.
• ••.._._-, •.-._._-_...__"'lfI"" ..,,~.,.---.
AREA OF ORIGIN: ~T~a~s~m~a~n~S~e~a~ ~
COMMENTS
No tsunami
No tsunami
19 .2100
16 1/2 17/1500 .
.: TRAVEL TIMES OF MAJOR TSUNAMIS
~AUG~ si~:~ ~~c6¥Pf~; -=-T:.::;o..:::.f=in=,o~ _
HRS FRO}! ~S1'.M, INIT,WAVE MAX.WAVELONG. HAG. im:p±H GAUGE. CO. T.) . ARR. liT. ARR. liT. PERIOD
157E 7.8 .
172.2E 7.6
HOURYEAR MO. DAY CU. T ~ ) LAT.
1924 June 26 0138 568
1929 June 16 2248 41. 8S
--------_._.....-._._-_._-_.....__._- --'-'---'---.-._..
,. <-.~ ,....~'~.,.:::;: ..~:::::-.::.;~_.~'.6,,;;I,'!""'~ ...i:-~,'1
AREA OF ORIGIN: Kermadec - Tonga Trench
'.
TRAVEL TIMES OF MAJOR TSUNAMIS
GAUGE SITE RECORbp:p: _.T....:;.o....:;.f.::,in:.:.o::..-- _
AREA OF ORIGIN: --=H.:::.aw~a::.:i==i=-- _
I
PERIODHOUR
YEAR MO. DAY (U.T.) LAT.
TRAVEL TIMES OF MAJOR TSUNAMIS
GAUGE SIT~ RECORDED: Tofino-=-===;;:.;:....--------nRS FROM Est.AR, INIT.WAvE MAX.WAVE
LONG. MAG. DEPTH GAUGE CU. T. ) AllR. HT. ARR. HT. COMMENTS
1975 Nov 29 1448 19. 4N 155.1W. 7.2 .. 5 1/2 2018. ·2056 3R' 22029F
"..
'M' __·_"_,'._.__• ~_"""_'" " __'~._"'.'''.' ,_, •