GEOLOGICAL SURVEY OF CANADA PAPER 88-14
CANADIAN EARTHQUAKES - 1985-86
R.J. Wetmiller J. A. Drysdale R.B. Homer M. Lamontagne
Energy, Mines and Energie, Mines et ••• Resources Canada Ressources Canada Canada THE ENERGY OF OUR RESOURCES THE POWER OF OUR IDEAS NOTE
The format of the annual catalogue of Canadian earthquakes produced by the Geophysics Division and the Cordilleran and Pacific Geoscience Division of the Geological Survey of Canada has been chan ged with this edition. This catalogue covers two years of activity, only lists events with magnitude 4.0 or greater and is also available in a French version. Subsequent editions will be published every other year. More detailed information about Canadian earthquakes is available in the form of quarterly reports prepared by the Geological Survey. Enquiries about Canadian earthquakes, earthquake hazards or seis mological research in Canada should be directed to the Geophysics Division, 1 Observatory Crescent, Ottawa, Ontario, KIA OY3 (613-995-5548) or the Pacific Geoscience Centre, 9860 West Saanich Road, Sidney , B.C., V8L 4B2 (604-356-6500).
GEOLOGICAL SURVEY OF CANADA PAPER 88-14
Seismological Series Number 97
CANADIAN EARTHQUAKES - 1985-86
R.J. Wetmiller J. A. Drysdale R.B. Homer M. Lamontagne
1989 © Minister of Supply and Services Canada 1989
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Cat. No. M44-88/14 ISBN 0-660-55553-0
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Cover photo Aerial view of the English Chief rock avalanche which was triggered by the magnitude 6.6 N ahanni earthquake of 5 October 1985. The avalanche, which is the fourth largest known in Canada in this century, incorporated almost 7 million cubic metres of rock and spread out over a distance of 1.5 km from its start. It occurred on the northeast face of the English Chief anticline located about 15 km north of the epicentre of the earthquake in the District of Mackenzie, Northwest Territories. CONTENTS
1 Abstract Introduction Analysis procedures Seismograph networks 2 Significant Canadian earthquakes 4 Plate boundary features 4 Summary of seismic activity for 1985-86 4 Larger earthquakes 5 Felt earthquakes 10 Eastern Canada 10 Ontario 11 Quebec 11 New Brunswick 12 Newfoundland and Labrador 12 Offshores areas 12 Central Canada 13 Saskatchewan 13 Western Canada 13 Alberta 14 British Columbia 14 Vancouver Island 14 Queen Charlotte Islands 15 B.C. interior 15 Offshore areas 15 Northern Canada 16 Yukon Territory 22 Northwest Territories 22 Mackenzie Valley 22 Arctic Islands and Greenland 22 Beaufort Sea, Arctic Ocean and Baffin Bay 23 Earthquakes hazards in Canada 24 Acknowledgments 24 References 25 Appendix
Figures 2 1. Seismograph stations 5 2. Plate boundary features 10 3. Earthquakes magnitude 4.0 or greater 11 4. Earthquakes in eastern Canada
Ill 12 5. Felt reports in southern Ontario for the Painesville, Ohio earthquake of 31 January 1986 13 6. Earthquakes in central Canada 14 7. Earthquakes in western Canada 15-16 8. Felt reports for the Nahanni earthquakes of a) 5 October and b) 23 December 1985 17 9. Earthquakes on Vancouver Island and B.C . lower mainland 18 10. Felt reports for the 16 June 1986 earthquake off Estevan Point, B.C. 19 11. Earthquakes on the Queen Charlotte Islands 20 12. Felt reports for the 21 March 1986 Prince George, B.C., earthquake 21 13. Earthquakes in northern Canada 22 14. Earthquakes in Yukon Territory 23 15 . Seismic hazard zoning map from the 1985 National Building Code of Canada
Tables 6 I . Canadian earthquakes magnitude 4.0 or greater 8 2. Earthquakes felt in Canada
iv CANADIAN EARTHQUAKES - 1985-86
Abstract During the two year period 1985-86, 169 earthquakes of magnitude 4. 0 and greater occurred in or near Canada. The location and magnitude for these events are listed chronologically in a table following the text and are shown on maps for all regions of the country. Events smaller than magnitude 4. 0 are also shown on the maps but are not listed in the tables. The larger events included two magnitude 6 events in the Nahanni region of the Northwest Territories and six magnitude 5 events, three in British Columbia, one in the Yukon Territory, one in the Northwest Territories and one in the Lake Erie region of northern Ohio which affected most of southern Ontario. Information on 69 earthquakes reported felt in Canada during this period is given in a second table. The distribution of felt reports for five widely felt earthquakes are shown on regional maps. The report also gives information on 32 important earthquakes that have occurred in Canada in this century. The locations of these events are shown on the regional seismicity maps and a summary of the events is given in the Appendix. Also shown are the distribution of seismograph stations in Canada, the distribution of the active plate boundary features around Canada and the relative distribution of long term seismic hazard in Canada.
INTRODUCTION Magnitudes are based on the Richter magnitude scale, although they are calculated in several different ways. The Canadian earthquakes are studied by seismologists in the magnitude scale is a logarithmic scale, so a 1-unit increase Geophysics Division (GD) and the Cordilleran and Pacific in magnitude is equivalent to a 10-fold increase of earthquake Geoscience Division of the Geological Survey of Canada "size". Magnitude 3 earthquakes are generally big enough (GSC). The research centres for the two groups are located to be felt (if they are located close to populated areas) and in Ottawa, Ontario and in Sidney, B.C. magnitude 5 are generally big enough to cause minor prop erty damage. Analysis procedures The GSC surveys the area affected in Canada for any The earthquake parameters listed in this report are determined earthquake reported felt, either by telephone or by mail for by the GSC with information collected from all seismograph widely felt events, and analyzes the reports in terms of the stations operating in Canada during this period. The analysis 12-point Modified Mercalli intensity scale. Intensities I-III procedures are similar to those described by Wetmiller et represent mild shaking, IV-VI represent moderate to strong al . (1983) and Drysdale et al. (1985) with the exception that shaking and intensities VII-XII describe various levels of only earthquakes with magnitude 4.0 or greater are property damage. The felt reports collected in 1985-86 are documented here, although smaller magnitude activity is summarized for every felt event in a separate table and, if plotted on the maps. Information about any events shown sufficient data are available, plotted on an isoseismal map. in this report including those smaller than magnitude 4.0 is In addition to these catalogues on Canadian Earthquakes, available on request. GSC prepares various quarterly reports on current seismic In the present report earthquake times and dates are activity in Canada, which are available free of charge to always given in Greenwich Mean Time (GMT) not local time; interested agencies. All earthquake data are maintained in thus , there will be some variance with the times given in local a digital database which can be searched for specific infor press reports of the events listed here. Note that the origin mation on a modest cost-recovery basis. Please contact the times given here are generally not in error by more than a Geophysics Division for information about these services. few seconds. Geographic co-ordinates are given for the epicentre of each event. The epicentral determinations are Seismograph networks generally not accurate to more than a few kilometres and may be in error by as much as 20 km or more in some cases. Figure 1 shows the distribution of permanent seismograph Focal depth is the most difficult earthquake parameter to deter stations in Canada operated by the GSC in 1985-86 for the mine and depths given here should be regarded as approxi purpose of studying Canadian Earthquakes and which have mate only. been used to locate the earthquakes summarized in this report. Detailed notes regarding the stations' instrumentation, calibra Significant Canadian earthquakes tions and any changes to the stations in 1985-86 can be found in the reports "Canadian Seismograph Operations" for 1985 Although Canada is not well known for earthquake activity, and 1986 (Munro et al., 1987, 1988). a number of important earthquakes have occurred in its his tory: 27 deaths in an earthquake-generated tsunami on the The magnification levels of these seismograph stations southern Newfoundland coast in 1929; millions of dollars during 1985 and 1986 allowed the location of most seismic of earthquake damage in Cornwall, Ontario in 1944 and again events of magnitude 3.5 or greater anywhere in Canada or on southern Vancouver Island in 1946. The Appendix lists its offshore areas . Detection of earthquake was poorest in 32 important earthquakes that have occurred in or near Canada the Northwest Territories because of the wide spacing of sta in this century. It does not list just the larger earthquakes , tions in the north. However, in the Vancouver Island-B.C. but those which , by virtue of their size and location, have lower mainland area, the Queen Charlotte Islands and parts been significant to the understanding of earthquake activity of the St. Lawrence Valley and Ottawa Valley of Quebec in Canada. The locations of these important events are shown and Ontario, the closer spacing of the stations permitted the with the activity for 1985-86 on the seismicity maps through location of most events above magnitude 2. 0. Within the dense out the text for comparison. arrays of the southern Vancouver Island-B.C. lower main land area and the Charlevoix, Quebec area, many events smaller than magnitude 1.0 have been located.
160° 140° 120° 100° Standard • Standard Regional 6 Regionale Regional 0 Regionale (3- component) (3-composantes)
/ 60° / // INK • / / /:::,.DWY / / / 7. 6HYT i_);QWHC i ·. fb. I "":-:-.. L'l.FST f!ij_ I L'l.DLB ·., _. y~ 6BLC Jl \ 7 .. ~- v RUB / ...._ ...._ ..._ ----.OC"r=::i::-.6WB /:::,. / /------r---- 5 0° oFB FSB / I i W~B Err / I 66°"MNB / . FFC / WKB ·\ : / ...... ' PNT ·.I .I ~./ ·.._, '· 4 0 km 800 120° 110 ° 100° Figure 1 a. Standard and regional seismograph stations operated by the Geological Survey of Canada. Standard stations have 3-component long- and short-period sensors; all others have a single component short-period sensor except where noted. 2 10-0\~ D ECTN * RTEC Regional !::::.. Regionale HUDSON ) BAY Standard • Standard 0 km 400 ~-----_J BAIE D HUDSON SCH• LABRADOR 5501 LRX } l j~8 ~ QUEBEC STJ ~' JAQ 50° I KAO I !::::.. \ GBN ONTARIO ATLANTIC OCEAN 0 t.,O OCEAN ATLANTIOUE E.-u A. 70° 60° I I Figure 1 b. The Eastern Canada Telemetred Network. ECTN stations are digital telemetry stations linked to computers at the Geophysics Division , Ottawa. The other stations record on paper records at their sites. 3 Plate boundary features Significant earthquake activity also occurs within the crustal plates away from the plate boundaries. Such earth In order to understand the distribution of earthquake activity quakes are called intraplate earthquakes and are not as well throughout Canada, it is necessary to be aware of the loca understood as the interplate earthquakes. It is thought that tion of large plates which are setting the stage for earthquake the stresses and strains generated by the plate movements activity by slowly moving relative to one another. Figure 2 can spread over a wide area inside the plates and trigger earth shows the distribution of those plates that affect Canada. Most quakes on old existing faults of other zones of weakness. earthquakes in the world occur on the active faults that form Thus even though eastern Canada is well away from the the boundaries of such plates. Earthquakes of this type are nearest plate boundary, a spreading ridge located in the mid termed interplate earthquakes. Atlantic, significant earthquake activity does occur in eastern Three general types of plate boundaries are recognized: Canada which seems to have characteristics related to the rift zones or speading ridges where new (oceanic) crust is compressive stresses that may be being generated in the North created, subduction zones where old crust is destroyed, and American plate by that rift boundary. strike-slip zones where crustal plates simply move past each other and material is neither created nor destroyed. Exam SUMMARY OF SEISMIC ples of these three types of zones occur along the west coast of British Columbia where they represent the interactions ACTIVITY FOR 1985-86 of the Pacific and North American plates and some smaller Larger earthquakes plates in this region. The active faults are located primarily in the offshore areas, but do affect onshore areas directly There were 169 earthquakes of magnitude 4.0 or greater in on Vancouver Island (subduction), the Queen Charlotte Canada or its environs in 1985-86 (Table 1, Fig. 3). The Islands (strike-slip) and the southern Yukon (strike-slip and largest were magnitude 6.6 and 6.9 earthquakes which took subduction). These areas are thus subject to more frequent place along the North Nahanni River in the Mackenzie earthquake activity and to a higher risk of large damaging Mountains of the Northwest Territories on 5 October and earthquakes than other parts of Canada. 23 December 1985 respectively. These earthquakes have been \ BRITI SH COLUMBIA \ \ COLOMBIE- 50°- BRITANNIOUE \ PAC1FIC OCEAN OCEAN WASH INGTON PACIFIOUE 48° WCTN * RTOC Regional 6 Reg1onale Standard • Standard 0 km 100 '------~ 12 6° ~24 ° 122° Figure 1c. The Western Canada Telemetred Network. WCTN stations are digital telemetry stations linked to computers at the Pacific Geoscience Centre, Sidney, B.C. The other stations record on paper records at their sites. 4 called the Nahanni earthquakes and are the most important 1986 in the Beaufort Sea. Each of these events was located earthquakes to occur in Canada in several years (see Wet in a remote area and they were reported felt only mildly or, miller et al. , ( 1988) for a summary of the studies of these in the latter case, not at all. events). Eight magnitude 5 earthquakes occurred as part of the strong aftershock activity that followed the Nahanni earth quakes. Other important events in 1985-86 included a mag Felt earthquakes nitude 5.0 event near Cleveland, Ohio, on 31January1986 There were 69 earthquake tremors reported felt in Canada (Cajka and Stevens, 1986 ; Stover, 1986), a magnitude 5.4 in 1985-86 (Table 2). These included the five strong ones earthquake near Prince George, B.C. on 23 March 1986 noted above, which were widely felt , and many others, with (Rogers et al., 1988) and a magnitude 5. 2 earthquake on the magnitudes less than 4.0, which were felt only over a small west coast of Vancouver Island on 16 June 1986. These five area. By region , 18 tremors were reported felt in both B. C. events were all widely felt in the areas surrounding them, and Quebec, 12 in the N.W.T., eight each in Alberta and but they did not cause any significant property damage New Brunswick, four in Ontario, three in Newfoundland and because they were all located away from areas of dense popu Labrador and two in Saskatchewan. The strongest shaking lation. Three other magnitude 5 earthquakes occurred: mag (intensities V-VI) occurred in the Mackenzie Mountains, nitude 5.7 on 9 January 1985 in the southern Yukon Territory, N. W. T. accompanying the Nahanni earthquakes on 5 October magnitude 5.4 on 15 September 1985 in the northwestern and 23 December 1985 and in eastern B. C. on 21 March corner of British Columbia and magnitude 5.0 on 22 April 1986 with the Prince George earthquake. Milder tremors (intensities III-IV) affected most of southern Ontario with the Ohio earthquake on 31 January 1986 and central Van couver Island with the earthquake on 16 June 1986. Eurasian Plate I I /r / / / Pacific Pl ate \:'African / \ ,( \ I I Plate , \ I \ I \ / I ~ y I '0 Figure 2. Present configuration of crustal plates and their boundary zones. Subduction zones are zones of plate convergence where underthrusting occurs and old crust is consumed, rift zones are zones of divergence where rifting occurs and new crustal material is produced and strike-slip zones are zones of strike-slip faulting. 5 0\ Table 1. Canadian earthquakes magnitude ~ 4.0, January 1985 to December 1986. 0 :\o. Oi!.t.e Timt' Lnt • ~ I.on~•\\ li.lag Oeptb LOCATION AND cori.t ri.IENTS '\o Date Time Lal ~ Long' \\' Mag Depth LOCATION AND COMMENTS 001 1985/01/09 19:27 G0.2!Jl 110.ili 5.7 1r1 YU "O N-AL ASKA BORDER O:l6 1986/01 / 1019:.59 45.SOO ii :120 3.3 Is. EASTERN ONTARIO. FELT IN PEMBROKE {IV), NE:An f\IT . ST. ELIAS. LOCl\SLEY AND PETAWAWA. MOST PEOPLE FELT ALONG T HE ALASKA IJIG ll WAY THOUGHT IT WAS A SNOWPLOUGH FRO~ID EAVER CREEi\ T O W HITEHORSE. 017 1986/01 / 110.1:0·1 -Ii 2i0 i0.100 2.S 10. FE LT IN CHARLEVOIX REGION. QUE. ALSO FELT AT YAK UTAT( I V) AND CAPE YA l\ATAGA(ll), ALASKA . o:Js 1986/ 0I/l In29 Ii i!O i0.120 4.0 !>. FE LT IN CHARLEVOIX REGION, QUE. 002 198.5/01/11!3,Qi li.!110 122.SiO :J.l 20. OLY~lPIC PENINSULA, WASH INGTON . o:l9 l986/ 0I/3l !(;:l!i 41 iOO SI 1.so 5.0 .). PAINESV ILLE, 0 1110 NEAR CLEVEL AND. FELT (IV) AT QU ILCENE AND (111) FIF'TEEN PEOPLE TRE ATED FOR M INOR AT PQllLSOO. BRINNON AND PORT INJURIES. SOi'.I E DAMAGE IN EPICENTRAL GAl\IBL E. ALSO FE LT AT PORT AREA . FELT FROM WISCONSIN TO TOWNSEND, WASHI NGTON ANO IN T ll E MARYLAND . IN CANADA PERCEPTIBLE TO GORDON ll EAD ,\JlEA OF VICTORIA , B.C ABOUT 420 KM , MAXIMUM INTENSITY V. FELT WIDE LY TllROUGllOUT SOUTHWESTERN oo:J 1985/ 0l/1 7(fr2:l 1' .S20 .\G.sSO :J.O POSSIBLE ROCl\BURST AT OUC ll ANS , NFLD. ONTARIO (Ill -IV) A ND NORTH TO FELT FO !l 5--10 SEC, t\IA NY PEOPLE AWAKENED. MUSKOl\ A, EAST TO BELLEVIL LE. NO Oi'\E UNDERGROUND IN T HE MINE . SEE FIGURE 5. .~). 00·1 198.5/0l/2 1ll1:2.'1 Ii 110 65.SGO 2.6 !\llRA~llClllREGION, N.B FELT AT NEWCASTLE 010 1986/ 02/0005: 1:J li.:l20 i0 ..590 2.8 I.l. CHARLEVOIX REGION, QUE. FELT JN oor, 1985/02 / 1121·.)7 11.CiOO (j!l.!l·IO 2.7 12. FELT IN T IJE CllARLEVOIX REGION , QUE. ST--lllLARION , BAIE-ST-PAUL ANO ST--PLACIDE OOfi 1985/02/ lilJD 1-, Ii 110 i0 .190 2.7 l·I CHA RL EVOIX REG ION, QUE. Oil !9S6/02/ 10I2:0S !1fi.ll!l 120.iSO 3.1 !l. NORTHEASTERN BRIT ISH CO LUJ\IOIA. FELT AT ST--ll lLARION ANO LA MALB AIE, QUE. FELT AT FO RT ST. JOHN. B.C. 007 1985/03/03121·1 li .190 iO. ISO 3.1 11 Cll AB.LEVOIX REGION, QUE. 012 l 9S6/02/1 32U::lfi 62.IO:l I 2·1.212 5.4 10. l\IACl\ENZ IE MOUNTAINS, N.W .T . AFTERSllOC J<. FELT IN ST--lll LARION. CLERMONT , II,£. FELT AT WRIGLEY . FORT SIMPSON , AUX--COUDES AND OAm--ST--PAUL, QUE. NA ll ANNI BUTTE AND FORT LIARD , N.W.T . 160 l\~1W FROM FORT SIMP SON. N W.T. OOS 1985/03/1 112:99 .52.1!)0 I J.5.2i0 3.9 SOUTHW ESTERN ALBERTA FELT OVER A SMALL AREA ABOUT 20 KM 013 1986/02/1002:16 66.520 1:J.5..t20 4.8 l~. NORTHERN YU h'.ON TE RRIT ORY. SOUTll WEST OF ROCKY MOUNTA IN HOUSE. FE:LT AT FORT MCPHERSON, Al\LAV IK , A ND INUVll\ , N.\V T . NOT FELT AT DAWSON . 009 1985/03/221.UG IS.S20 .56.S.50 2.6 FELT IN BUCllANS, NFLD . NOT AS STRONG AS JANUARY EVENT 01 l I986/02 / 20Io:2l 62.136 12-122·1 H IO. l\IAC l\ ENZIE MOUNTAINS, N \VT . FELT AT WRIGLEY AND FORT SIM PSON . 010 1985/0·1/06!9: t:1 !i2.210 106.SSO 2.9 INDUCED EARTHQUAKE. FELT{IV) AT TllE CORY POTASH ~llNE.WEST OP SASKATOON, SASK 01.5 I986/03/ 06ls::l3 Ii.000 6G.GOO 3.4 5. l\llRAMI CIII REGION, N.B. FELT IN BATHURST 011 1985/0·l/ l CIJS:.51 li ..520 69.960 3. 1 12. Cll ARLEVOIX REGION, QUE. Olli 1986/03/20 11 19 60.iIO I:l7.4.50 2 ..5 5. SOUTHW ESTERN YUl\ON TERR ITORY PELT ST lllLARI ON, QUE. FELT AT HAI NES J llNCT ION 012 1985/05/0 !ll!O.s G2.213 111 2si ·1.3 2. YUh'.ON TERR ITORY . FELT (I V) AT BEAVER Oli 1986/ 03/2122· 1! 5t.2i0 132.>90 3.2 IO. QUEEN CHARLOTTE ISLANDS CREEi\ , WHITE RIVER LODGE AND KOIOERN FELT AT LANGARA ISLAND , 13.C. ALSO FELT AT STEWART RIVER. O·IS I9S6/03/ 2 12:l:.1.5 .51.2·10 121.000 .5.4 IO. EASTERN BRITISH CO LUMBIA . 011 1985/05/140(>:21 IS.b70 123.2:10 2.5 21 ll ARO STll1\IT , WASlllNGTON . FELT STRONGLY IN THE PRINCE GWRGE FELT (111) ON MOST OF SAANICll AREA . MAX IJ\IUJ\1 INTENSIT Y (V I) AT PEN INSULA INCLUDI NG SIDNEY AND WILLOW RI VER, G ISCO~IE,UPPER FRASER THE GORDON HEAD AND OAK BAY AREAS AND SINCLA IR MILLS . SEE FIGURE 12 OF VICTORIA , ll.C 0·19 1986/04/2(\J~59 5i.3SI .5!1.. 50!1 ·1.8 IS. LABRADOR SEA . FELT DY SEVERAL PEOPLE ALSO FELT ON SO~IE OF THE GULF ISLANDS WHO WERE AWAKENED JN NA IN, LABRADOR. 011 1985/07/3017:01 ·IS.100 12:l.:J20 :J.O l!i OFF VICTOlllA WATERFRONT . NOT FELT 90 l\M S OF' NAIN. FELT ON SA ANICII PENINSULA AND NOT FELT IN ll OPEDALE . SOUTHERN VANCOUVER ISLAND FRO~I IJ!>O 1986/05/0l~:l:O.;li2. 1'12 i 2·1. l 9:J 4.9 IO MACl\ENZIE MOUNTA INS, N.W T SOOl\ E TO SIDNEY. MAX IMU.\I INTENSITY FELT AT FORT SIMPSON (I \') IN VICTORIA . 0.51 1986/05/ 000!!:01 ·l(i.51'1 66.12·1 3.3 IS. EAST ERN NE\\ ' BRUNSWICK FELT JN 01.5 I985/08/06 I:Vi:J 1•1.2.so I 16.>ilO 4.0 IS SOUTHERN BRITISll CO LU~IBIA. DOAKTOWN FELT AT TRAI L AND CRESTON, B.C. FELT (IV) AT CUSIC!\ , WASHI NGTON AND 0~121986/06/16 1001 I'J I:ll 127.0li .s.2 n OFF WEST COAST OF VANCOUVER ISLAND. NORDl\IAN , IDAllO FELT (Ill ) AT ION~:. FELT INTENSITY (IV) ON NORTllERN NEWPORT, l\I ETALINE AND USK , WASH INGTON VAN COUVER ISLAND ALSO FELT IN THE ALSO F'ELT AT PRIEST RIVER AND VANCOUVER AREA AND IN NORTllW ESTERN POR'l lllL L, IDAllO WASH INGTON . SEE FIGURE 10. 016 l985/08/20 1ii:27 .5:J.S20 l:J2.i20 :J.2 18. NO RTH ERN QUEEN CHARLOTTE ISLA NDS , 13.C. 0.5:l I 986/06/2 0J!i:02 .10.410 (i-1 .. l 10 3..I IS. FELT IN LOW ER ST. LAWRE NCE VALLEY, QUE FELT AT LA NGA RA ISLAND INTENSITY I V ~llNGAN,L ONGUE POINTE RIVIERE-ST~JEAN,MAGP IE, PORT-l\IENIE!l 01 i I985/08/ H J6:03 tl.680 ifdi'10 3.1 IS. EASTERN ONTAR IO FELT IN RENFREW RIVIERE-AU-TONNERRE . Sll ELDRAKE . Ols 1985/ 08/2411 :J FELT l\ll LDLY ABOUT 25 I\~! 0.5·1 1986/07 / 0 108:5·1 62.I.;; 12.UIS 4.8 IO. ~IAC KENZIEM OUNTAI NS, N.W T . SOUTHWEST OF ROCl\Y MOUNTA IN HOUSE FELT AT WRIGLEY , FORT SIMPSON AND NA HA NNI BUTTE , N.W .T. Tableau 1. {cont .) 020 1985/08/25 22:39 .52.1 iO 11.1.:no 2.5 .'). SOUTHWESTERN ALBERTA. AFTERSHOCK . FELT t\llL DLY ABOUT 25 KM SOUTHWEST 055 1986/07/08 05:1.5 48.269 122.563 3.4 6·1. WASHINGTON . or ROC h'.Y MOUNTAIN HOUSE. FELT (V) AT LYMAN; (I V) AT COUPEVILL E, FREELAND, HAM ILTON, MUKILTEO, OAK 021 198.5/08/29 09:26 18.·160 12·1.050 2.-1 II. SOUTHERN VANCOUVER ISLAND. HARBOR AND SILVANA; (111) AT FELT i\llLDLY NEAR SOOKE OUllLINGTON, LA CONNER, MOUNT VERNON 022 1985/09/01 120, 52.220 l J:).2SO 3.8 .'j_ SOUTHWESTERN ALBERTA AND SHAW ISLAND; (II ) AT LAKE STEVENS. FE LT OVER A SMALL AREA 25 10~1SOUTHWEST ALSO FELT AT ALGER, ARLINGTON, OF ROCKY t\IOUNTA IN HOUSE. CONCRETE, GREENBANK, LEDGEWOOD BEACH AND i\lARYSVI LtE, WASH INGTON, AND 023 1985/09/03 09:26 ·l.5.·102 72.(iS.1 2.4 SOUTHERN QUEBEC. FELT 9. NEAR GRANBY VICTORIA , B.C. 02·1 1985/09/15 01:28 .\9.13.J J:l6 ..\.j.J 5.4 2. SOUTHEASTERN ALASKA. 056 1986/07 /10 16:00 .t!J ..597 3.5 .). NEAR PITT LAKE, B.C . FELT ( \') AT ll AINES AND GUSTAVUS, (IV) 122.462 FELT AT BURNABY, PORT COQUITLAM, AT SKAGWAY, PELICAN AND JUNEAU , (111) NORTH VANCOUVER AND VANCOUVER . AT AllKE BAY. ELFIN COVE. KAKE, llOONAll AND YAl\UTAT , ALASKA. ALSO FELT AT Q.57 1986/07 /12 20:31 ·16.111 GS.2:.W 3.4 9. NEW BRUNSWICK-MA I NE BORDER. llAINES JUNCTION. WlllTEllORSE AND FELT AT HOULTON, MA I NE. CA llCROSS, Y T ALSO FELT AT NEW LI MERICK , LUDLOW AND DREW LAKE, ME. AND HARTLAND, N. B. 02.5 1985/10/05 05::]1 17.000 66.600 3.9 ;j_ ~llRMdlCHI REGION.NB . FELT JN BATHURST o.\8 1986/07/28 1.5:26 1.1.160 71..)IO 2.6 IX. WESTERN QUEBEC. FELT IN RIGAUD 02G 1985/10/05 J.5:2·1 61.:Ws 121.~l7 6.6 r.. MACKENZIE MOUNTAINS, N.W .T . FELT STRONGLY WITH SLIGHT DAMAGE 059 1986/07 /29 00:40 4i..570 70.230 2.6 14. CHARLEVOIX REGION. QUE. AT WRIGLEY , FORT SIMPSON AND FELT IN ST-lll LAR ION FORT LIARO. FELT I N PARTS OF 1986/07 /29 00:.51 2.2 CHARLEVOIX REG ION, QUE. THE YUKON TERR ITORY, BRIT ISH 060 4i..570 70.2l0 12. FELT IN ST-H I LA RION COLU~IBIAAND ALBERTA. ALSO FELT AT JUNEAU AND SITKA, ALASKA . 061 1986/08/06 11:18 16.370 7.5.220 3.5 IS WESTERN QUEBEC. FELT I N MONT- LAURI ER LANDSLIDES OBSERVED IN T H E EPICENTRAL AND MANIWAKI , QUE REGI ON NEAR THE NORTH 3.3 SOUTHWESTERN QUEBEC. FELT (IV) IN NAllANNI RIVER . SEE FIGURE 8. 062 1986/08/13 04:5.5 4.5.101 7·1.2.55 7. HUNT INGDON, COTEAU STATION , QUE., AND 027 1985/10/06 01:!.5 62.0.58 I 2·L292 5.0 10. MAC I\ENZIE ~lOUNTA INS.N.W .T. CORNWALL , ONT . FELT I NTENS ITY (HI) I N LARGEST AFTERSllOCK. VALLEYFIELD, QUE . FELT IN MALONE , ~IASSENA FELT AT FORT SJJ\1PSON, FORT LI ARD , OGDENSBURG AND MORIA OF NORT HERN N.Y. WRIGLEY AND NAllANNI DUT'TE, N.w:r . RESIDENTS AWAKENED IN ll UNTINGDON , QUE. (JV). LOUD NOISE LAST I NG FEW SECONDS 02S 1985/10/13 20:.\G 62.170 12·1.WO 3.6 10. MACKENZIE ~tOUNTA INS,N .W.T. IN COTEAU STATION. QUE. (111). IIOUSES FELT AND HEARD BY FI ELD PARTI ES WERE Sll AKEN. o:rn 1985/10/16 10:22 51.(;.10 12,.6:lO 2.8 10. COAST ~IOUNTAINS,B.C. WEAK SHAKING JN VALLEYF I ELD, QUE.(111) FELT AT TERRACE W HERE A NOISE AT END OF TRE~IOR. FEW PEOPLE WERE AWAKENED. I N CORNWALL, ONT . (JV), TREMOR LASTED 10-20 SECONDS. o:w 1985/11/01 2:J::l2 1.5.286 7:1.·lS.j 3.4 12. SOUTHEAST OF MONTREAL , WEST OF ST-JEAN REPORT OF HOUSE CREAKING, AND Of F'ELT LOCALLY OBJECTS RATTLING o:i1 1985/11/02 11:41 16.000 7.""i.760 2.5 l:S. WESTERN QUEBEC, NOllTll OF OTTAWA 063 1986/09/19 J.):Cil 17.300 4.2 CHAR LEVOIX REG ION, QUE. FELT DY HUNTERS IN T ll E AREA 70.:l20 22. FELT AT L A POCATIERE, LA MALDAIE, O:J'l 1985/12/23 O\:J.\ G2. IS7 12.1.21:1 6.9 10. ~IACl\ENZIE~I OUNTAINS,N.W.T . BAIE-ST-PAUL, ILE-AUX-COUDRES, FELT (V) AT WRIGLEY, FORT SI J\IPSON ST-JOSEP!l-DE-LA-R I VE, ST-HI LARION, AND NAllANN I BUTTE , N.W .T . FELT AND ST-IRENEE (Ill- I \ ') OVER LARGE PARTS OF THE WIDELY FELT IN THE QUEBEC CITY AllEA (IV) YUl~ON,BRIT ISl l COLU~IBIA AND ALDERTA . NEAR QUEDEC C ITY , I N C ll ARLESBOURG , ALSO FELT IN T HE STATES OF BOISCllATEL , STE-JJRIG ITTE DE L AVA L NORTH DAKOTA, MONTANA , WASHINGTON AND ST-RO~IUALD,QUE., PEOPLE AND ALASKA NUJ\IEROUS SMALL LANDSLIDES REPORTED VIBRAT ING WINDOWS, WERE OBSERVED IN THE EPICENTRAL 061 1986/09/24 11 :0 I IG.700 (i.'j . .SSO 2.3 18. J\l lRAMIClll REG I ON , N.B. FEl~T BY TWO REGION. SEE FIGURE 8. PEOPLE NEAR BL ACKV I L LE OT! 1985/12/23 l!L:!7 62.Q(;.~,12·1.2!ll 5.6 10. J\IAC J-.:ENZIE MOUNTAINS, N.W.T. AFTERS HOCK OG.5 1986/10/17 11:17 17.000 GG.GOO 4.1 ,). J\llRA~llCHI REG ION, N.B. FELT I N BATHURST FELT AT WRIGLEY , FORT SIMPSON, NA ll ANNI BUTTE AND FORT LIARD, N.W.T 066 1986/10/28 16"17 17.000 66.600 3.4 .~). J\llRA~llC!llREG ION, N.B. FELT I N BATHURST IHI Ci2.0J~l~ I I 1985/12/25 15:12 I. Js:J 5.3 10. ~IACKENZE ~IOUNTA NS.N W .T. AFTERSHOC K. OG7 1986/11/07 10::]5 l<>.120 123.317 2.9 :J,, NEAR PORT ANGE LES, WAS IHNGTON. FE:LT IN F'ELT AT WR IGLEY , FORT Sli\IPSON, NAllANNI THE JAi\IES BAY AREA OF VICTORIA , B.C. BUTTE AND FORT LIARD, N WT. 06S 1986/ 11/09 19:57 ·19.2:3.5 67.10'1 4.2 JS. LOWER ST. LAWRENCE VA LLEY , QUE. ALSO FELT IN TllE SOUT118RN YUKON, FELT ON T HE NORTH SHORE OF T HE NORTHERN ALDEllTA, NORT HERN BRITISH ST.LAWRENCE AT RAGUENAU , BAI E--COMEAU , COLU~ll31AAND AT YAKUTAT , ALASl\A . GODBOUT. BAIE:-TRINITE, SEPT-ILES. QUE. 0'.1.'J 1985/ 12/25 IS:l'l Gl.!J70 12·1 ~S2 .5,3 10. ~IACl\ENZIE i\I OUNTA INS, N.W .T. AFTERSHOCK ON T HE SOUTH SHORE FROM FELT AT WR IGLRY, FORT SI J\I PSON, NA HANNI J\IATANE TO CAP -CHAT , QUE. BU "lvfE AND FORT LIARD , N.W .T. OG -.J 00 Table 2. Earthquakes felt in Canada, January 1985 to December 1986. l'im1· La1° !\ Long 0 t-.tag [)ppth LOCAT ION AND COl\lt-.IENTS No. Date I imc Lat 0 :-\ Lon~/\\' Ma g D<'pth LOCAT ION AND COMMENTS \'o. Date \\ l\IACl MAC l\E:NZI E t-.IOUNTA I NS, N.W.T. 005 1985/03/30 OS:ll 7'.l2'i0 71.270 4.7 i' BAFFIN BAY 091 1986/01/07 122'> G2.021 1212:11 4.-1 Ill. LABRADOR SE:A OOG 1985/04/04 06::lG 'il.OiO l'J:l.110 4.2 JS QUEEN CHARLOTTE ISLANDS 092 1986/01/08 02:00 :;7 2'10 .\o.lfill 4.3 1:-. GRE ENLAND SEA 007 1985/04/26 O·l.·IO \l.0!10 l:lJ ..\uO 4.0 JO WEST OF VANCOUVE R ISLAND 093 1986/01/10 J J:U7 oS.li'JO 7.GOU 4.6 IS. CllAllLEVO I X REG ION. QUE. FELT OOo 1985 / 05/09 01:0:; 62.21.l 141.2>'7 4.3 °2. YUKON -A LASKA BORDE R. FELT O'll 1986/0l/l l \:1:2 PA IN ES , 111 C L L . .~l. VI LLE 0 0 NEAil EVE AND 011 1985/06/24 17:16 ·17.51i0 128.SSO 4.0 Ill WEST OF VANCOUVER ISLA ND 097 1986/01/31 IG,Jcj \l 700 SI ISO 5.0 FELT WIDELY 012 1985/07 / 25 17·11 s:1.9.;o 2.700 4.9 Ill. GREEN LAND SEA O l 27 1986/U6/U6 11 17 "10.i '0 i:!0.211 ·1.5 10 WEST or \'ANCOUVER ISLAND 012 1985/10/12 21 15 62 i'lU "21.2ill "-6 10 ~IACh'.ENZIE~IOUNTA INS,NWT 12' 1986/06/14 l"l·' l!l.O:!I 12S.7:l2 ·1.2 10 WEST OF \"ANCOl'\'ER ISLAND 011 1985/J0/13 0.1-22 lil.!l7S i2·1.2fil 4.3 Ill. i'.IACKENZIE i'.IOUNTAINS, N.W T. MACKENZIE r>.IOtJNTAl\'S, N \\' T l'.l!I 1986/06/ 15 0:1:02 fi:l.2J.~}12-12!19 4.0 IO Oil 1985/10/13 17·1fi f.2.:120 121.211 4.2 10. ~IACl\E!'\ZIE~IOllNTAINS, NWT 130 1986/06/16 lfi:.\I -!!). t:l! 127.017 5.2 ;J.5. OFF WEST COAST OF VANCOUVER ISLAND ~IACKENZIE MOUNTAINS.NWT 015 1985/10/14 2:U'I 62.09:1 12121\.! 4.2 IO. FELT WIDELY Olh 1985/10/16 12:5:1 \11.~!ill1:!11.2'10 4.2 10. WEST OF VANCOU\'Ell ISLAND 111 1986/ 07 /01 11':"»1 {i2.l'i7 121.21' 4.8 10. MACl\ENZ IE MOUNTAINS, NWT. FELT 017 1985/10/16 ls:ll h210s 12-UI 4.5 Jn i\.IACKENZIE MOUNTAINS, N.W.T IJ2 1986/07/27 0S:l6 li0.2·t:I 12!1.'.lS:I 4.3 I~. SOUTHEAST YUKON 0-Hi 1985/10/19 IO:Oh 11.110 7:!.'1211 4.1 J...... CENTRAL U.S.A I :n 1986/08/07 Ofi 11 ·l'L:l i:l 129. l!i:J ·I.I I 0. WEST OF VANCOUVER ISLAND Oi'l 1985/10/21 12: 11 !i2.W>I 1:1.1.:121 4.8 ((I ~IAC'KENZIEMOUNTAINS , NWT. 111 1986/08/12 i:>:l'l li2.011 124.:Jl:I I.I 10. MACl\ENZIE f\IOUNTAINS. N.W T 0" 0 1985/10/24 2:1 1-1 'i:!S20 1.ll .iOll 4.1 ls. QUEEN CllARLOITE ISLANDS 1 J\IACl\ENZIE i\.IOUNTAINS, 13.'.i 1986/08/16 O!l:.Jl ti2.2~h1'2-1:i:,~1 4.0 10. NWT Q.51 1985/10/27 OJ :Jq 19.:.!SO 12/. 1110 1.7 10. \\'EST OF VANCOUVEll ISLAND I.Hi 1986/08/20 IS:5:J Iii 770 12·1 :121 4.3 10. MACKENZIE MOUNTAINS, NWT. O'J2 1985/10/28 I I.OJ GO 1'1"1 111 17r; 4.1 ~IACl\ENZIE~IOUNTAINS, NWT. 1:n 19S6/08/20 2J:.11 ti0:2 or1:1 1985/11/09 0.1 lh 1;2 217 12.1.2u:J 4.6 !0. ~IACl\ENZIE~IOUNTA INS.l\".W.T. 138 1986/08/27 11.11 .\S.992 112 ..%(; •1.5 :IQ. GULF OF ALASKA O'JI 1985/11/12 O.':\'l 71.110 i:lh.700 4.3 IS. BEAUFORT SEA 1:19 1986/08/28 I 16 !i2.'222 12-1.211 4.2 JO. ~tACl\ENZIEMOUNTA INS, N \VT O!i!) 1985/11/12 14:-1!) G2.l!!7 l'.!1 ·112 4.0 IU. i\.I AC l\ENZIE MOUNTAINS, N.W T. llO 1986/09/07 00:21 liO.l:ll IHl71 4.2 !'\. YUKON-ALA Sl\A BORDER 0:16 1985/11/16 07·10 .')S.q'jQ l:Hi.7.')Q -1.6 IS. SOUTHEASTERN ALASKA 111 1986/09/ 12 17:10 {i0.7'1 .>72:!7 4.2 i ''. LABRADOR SEA Q.17 1985/1 1/24 J!l:"l!I G2.0i'O l'.!l.2\S -t.0 10. MACl\ENZIE MOUNTAINS, NWT. 112 1986/09/15 1117 Iii !i!S IH.S!i2 4.7 .)2. SOUTHERN ALASKA Q.'")S1985/12/05 01:'.W GU.htiU fi0.1-\0 4.2 JS LABRADOR SEA 1-l:J 1986/09/19 1.):.\:1 17 :100 70.320 4.2 '22. CHARLEVOIX REGION , QUE. FELT 0.'">91985/12/07 I.'i:2q ti2.:!12 12-t.:!s!l 4.0 JO MACKENZIE MOUNTAINS, N.W.T. lH 1986/09/2·1 {l(i:Ol '117-1 .\1.!l'IS 4.5 JS. LABRADOR SEA 060 1985/12/15 12--12 c,o.!1xu 1:11.u:w •1.7 10. WEST OF VANCOUVER ISLAND 1-1.\ 1986/09/26 210·1 ·1'.S:l2 129.121 4.3 IO. WEST or VANCOUVER ISLAND 061 1985/12/23 O.i:l.5 ti2 1'7 121.2H 6.9 10. ~IACKENZIEr>.l OUNTAINS, N.W T FELT WIDELY 116 1986/09/29 t:l:OI S:l.170 22.,!iO 4.1 \s. GREENLAND SEA Ofi:! 1985/12/23 0.5:2h (i:!.l!IO 12·\.2-IO 4.3 l{J. r>.I AC l\ENZIE MOUNTAINS, N.W.T. JH Hl86/I0/11 :l:!::!."> ts.is:! 1:2t1.i:is 4.5 10. WEST OF VANCOUVER ISLAND Ofi:l 1985/12/23 OS:2!i 62.190 12·1.2·10 4.1 10. r>.tACKENZIE MOUNTAll\S, N.W.T. I IS 1986/10/11 22:.\:) ·IS.S21 12s.:IOI 4.2 llJ. WEST OF VANCOUVER ISLAND 06·1 1985/12/23 o.i:ls 62.llO 12.i:1so 5.2 10 ~tACKENZIE MOUNTAINS.NWT. 119 1986/10/13 0:2:'2.) fi'2.(ifi.') 1·11.%-1 t.3 Js. MACKENZIE MOUNTA!i'\S, N.W.T. or;c, 1985/12/23 06:02 62.oor; 121..122 4.1 10 ~IACl\ENZIE MOUNTA INS, N.W.T. !.\Q 1986/10/17 1117 17.000 6u.GUll 4.1 .). f\ll RAJ\llCl!I REG ION, N.B. FELT 06fi 1985/12/23 Ofi:O'J 61.911 121.o.\2 4.1 10. MACKENZIE ~IOUNTAINS,N.W T 1.11 1986/10/25 l \·.'}.'j /~l.:}.j:l!li ..'"").S() 4.5 Ji''i. ARCTIC OCEAN 067 1985/12/23 06:11 62.119 121.S16 •1.0 10. MACKENZIE ~!OUNTAINS,N \VT lf12 1986/11/09 02 l!i CU.1">7 110.'li:l •1.3 ,.. Yl:l\ON-ALASKA BORDER OIJS l 985/12/23 OS:O!l G2. J Sfi 12-1.:l:lS ·1.2 10. .\IACKENZJE MOUNTA INS, N.W T. l.')3 1986/11/09 !!l:.17 JCJ.:2'.3.5 ()7..10!1 "I•) \S. LOWEil ST. LAWRENCE RIVER , QUE. 06!l 1985/12/23 O!l:'.li f.l.%fi 1:21.171 1.8 10. .\lACl\ENZIE MOUNTAINS, N.\\' T FELT I l i\.IACl\ENZ IE MOUNTAINS, N W.T. 070 1985/ 12/2.J 11 :2fi !i2.2 I:! I :11.:l•J! Ll JU. ~ AC \ENZIEMOUNTAINS, N.W T 1-'i·I 1986/11/10 1.1::12 {i2.0S9 12t.:17b ·1.3 10. 071 1985/ 12/23 11 :J!I 7!1. 7...,0 q.1 :!'IO 4 ..) [S. AXEL llEIDERG ISLAND, N W .T. 155 1986/ 11/11 t:1:12 17.\Xfi 12'1.2!12 4.3 10. WEST OF VANCOUVER ISLA ND 072 1985/12/23 lfi:Yl fi'.?.:.!11 l:!Lll!i 1.0 10 r>.!ACl\ENZ IE ~IOUNTAINS,N.W.T l!ifi 1986/11/11 1:l:1:J Tl.7:17 X!i.. \17 4.4 IS EASTERN PART OF BRODEUR POINT, BAFFIN ISLAND, N.W.T. 07:J 1985/12/23 Pl::l7 62.0h.'""> l:!·I :!!II 5.6 10 J\li\Cl\ENZ IE r>.IOUNTAINS, N.\V.T FELT 107 1986/12/01 16:1!i fil.1:19 1.10.:1211 .1.2 Ill YUJ\ON-ALASKA BORDER 071 1985/12/23 22:11 h2.02:' 12·1 2'<1 4.3 Ill f\IACl\ENZIE r>.!OUNTAINS, NWT. 1r,s 1986/12;01 1s:oo hl.1"»1 110 ..1n 4.2 10 YUl\ON-ALASl\A BORDER 07.'1 1985/12/23 2:1:22 {i2.000 121 IO'I 4.1 10 .\IACl\ENZIE MOUNTAINS, N.W T 1 1;,!1 1986/12/ 03 ().'""1::JI l!Ui.57 11q.ss1 1.5 0 WEST OF VANCOUVER ISLAND 07u 1985/12/24 07: 10 Gl.'17b 12·1 :ll{i t.6 IO ~IACl\ENZIEMOUNTAINS, N.W T. 1()0 1986/12/03 0:1:.J.') ·l!l.70ri l:!!l.Sfi:! -1.7 10. WEST OF VANCOUVER ISLAND 077 198.5/12/2-t 20:01 6:!.fl:!fl l:!I '2S7 ·1.1 10 f\I ACl J(iJ 1986/12/03 :!l :!(i l~J.lil:!l:.!!l.7i!I -1.8 IU WEST OF' VANCOUVER ISLAND OSO 1985/12/25 IG:Oti (il.02s l:!I ;r,G 4.0 Ill i\.IACKENZIE MOUNTA INS, N.W T. !Iii 1986/12/03 21 1'1 l'l.fil2 12'1.SOI 4.0 {) WEST OF \'ANCOUVER ISLAND OSI 1985/12/25 l()::!U !iJ.q/s l:!-1.:!hi 4.0 10. MACKENZIE MOUNTAINS, N.W T !fi.\ 1986/12/06 llC>::12 .;O.Ofi9 1:10.IC12 4.6 10 WEST OF VANCOUVER ISLAND OS:! 1985/12/25 !S:-IH fil.9/U l:!·l.:!S:l 5.3 10. ~IACl\ENZIE ~IOUNTAINS,N.W T FELT IG6 1986/ 12/06 21:01 .\1111 1:10.",s2 4.5 WEST Of VAl\COUVER ISLAND OS:! 1985/12/26 00:02 !i2.U'l!I 121.17(i 4.0 IU ~IACKENZIEMOUNTAINS, N.W T. ' lh7 1986/12/07 16:17 Ci~.llH1~1.:117 4.0 Ill. MACKENZI E i\IOUNTAINS, N W.T. OSI 1985/12/26 :!:!:~,~fi:!.U.'"",Q l:!-1.:!I:! l. lfi~1986/12/17 o•J:lii 7s.•111 20.G:ls 5.0 IS. GREENLAND 0$.) 1985/12/29 l'l:l'i (i2.12(i 121.:101 4.0 10. MACKENZIE f\IOUNTA INS, N.W.T l(i!.I 1986/12/2 1 II\.) 60.0!19 1-10.~l/(i4.2 II YUKON-ALASl\A BORDER OSG 1985/! 2/30 I S:.i.5 ti2.o:n 121.127 <1.8 Ill J\IACl\Et\Z IE f\IOUNTAINS, N.W T '° Table 2 does not list some earthquakes which were are plotted on the eastern region map (Fig. 4). Prince Edward located and felt in areas adjacent to Canada but were not Island had no earthquake activity located in it during these reported felt in Canada. Table 2 also does not list some two years; Nova Scotia had onl y two small events. mining-induced tremors in eastern Canada that were felt in communities surrounding the mines. Ontario A more detailed description of the seismic activity for each region of Canada is given in the following sections. More In 1985-86. the earthquake acti vit y was largely confined to than three thousand earthquakes were located in Canada the Ottawa Valley area of eastern Ontario, with isolated events during this two-year period. However, this report only lists in the Lake Eri e-Lake Ontario Basin and northern Ontario. the larger events; the smaller events with magnitudes less The northwestern part of Ontario is shown on the Central than 4 .0 are not tabulated here but are shown on the maps. Region map. The largest earthquake affecting eastern Can ada was the magnitude 5.0 event on 31 January I 986 located on the south shore of Lake Eri e. This tremor was felt through EASTERN CANADA out southern Ontario (Fig. 5) and caused isolated minor prop Eastern Canada is generally a stabl e continental region and erty damage and some minor injuries in Ohio (Stover, 1986; as a consequence has a low rate of earthquake activity. How Cajka and Stevens, 1986). It was also widely fe lt in north ever, large earthquakes have occurred here in the past, nota central U.S.A. bly in the Charlevoix Region of Quebec in 1925 , off the Many of the small events shown in northern Ontario in Atlantic coast south of Newfoundland in 1929, in the Lake the Sudbury, Kirkland Lake, Elliot Lake and Red Lake areas Temiscaming region along the Ontario-Quebec border in 1935 are mining-related rockbursts. and near Cornwall , Ontario in 1944 . For 1985-86, 644 events U.SA. km 1000 Figure 3. Earthquake activity (magnitude 4 or greater) in Canada and its environs in 1985-86. See Figure 4 for legend. IO Quebec No earthquakes in the west Quebec zone had magnitude 4 .0 or greater in 1985-86, although a number of smaller events The earthquake acti vity in Quebec occurred in three di stinct were reported felt by local residents (Tabl e 2). seismic zones: west Quebec (WQU) , Charl evoix (CHY) and lower St. Lawrence (LSL). Only scattered and isolated acti v ity occurred outside these three acti ve zones, except fo r the New Brunswick cluster of small magnitude events visibl e to the east of James Bay (BJ) . These events were likely induced seismi city at the Scattered small magnitude earthquake acti vit y was recorded Baie James Hydroelectric Project. throughout New Brunswick during this peri od, with a con tinuing seri es of earthquakes in the Miramichi region (MIR) The largest events were two magnitude 4 earthquakes of central New Brunswick at the site of a large magnitude that occurred in the Charl evoix zone on 11 January and 19 5. 7 event that occurred there in 1982 . The largest earthquake September 1986 and one magnitude 4 event that occurred in the province in 1985-86, magnitude 4 . 1, occurred at the in the Lower St. Lawrence zone on 9 November 1986. All Mi ramic hi zone on 17 October 1986 and was felt mildly three tremors were strongly felt in the areas surrounding the throughout the province. More than 75 small aftershocks were epicentres, but caused no property damage (Tabl e 2). recorded by the cl osest seismograph stati on (about 25 km di stance) in the three days fo ll owing the tremor. However, by the end of October this activity had subsided . 60° • SEISMICITY MAGNITUDE "<3 35 .. <4 45 • <5 55 * <6 65@ I' YEAR OF LARGE 1929 EARTHQUAKE 1949 )( NOTE IN TEXT AA ATLANTIC OCEAN Figure 4. Earthquakes in eastern Canada for 1985-86. BJ is the Baie James Hydroelectric Project, WQU is the west Quebec seismic zone, CHV is the Charlevoix seismic zone, LSL is the lower St. Lawrence seismic zone and MIR is the Miramichi seismic zone. Location and year of significant earthquakes in this century in the region are indicated. 11 Newfoundland and Labrador CENTRAL CANADA Three small earthquakes were recorded in central Newfound This region is characterized by an extremely low rate of earth land at the town of Buchans in January and March 1985. quake activit y ; it is probably one of the most stable areas Two of the tremors were felt by residents in Buchans ( 17 in the world. In the past most earthquakes in this region have Janua ry and 22 March 1985). It is believed that these events occurred in southern Saskatchewan and adjacent areas of were rockbursts in the Buchans mine, but this could not be Montana and North Dakota. The largest earthquake known confirmed because the mine had been closed and flooded dur in this region occurred in 1909 with a magnitude of 5.5. For ing the previous year and could not be inspected. 1985-86, 14 events are plotted on Figure 6. Manitoba had no earthquake activity located in it during this two-year Offshore areas period. There was one magnitude 3 event detected in north ern Ontario near the Manitoba border (Fig. 6) where no earth Four magnitude 4 earthquakes were detected in the Labrador quake activity had been known previously. Sea, and a few small er events were detected there and in the Grand Banks area south of Newfoundland. One of these events was felt onshore, at Nain , Labrador on 20 April 1985. 0 0 0 N co co r-... 0 0 0 ONT. 0 44° 3 4 4 44 3 3 4 4 4~ 4 4 4 4 44 4 4 INTENSITY NOT FELT 0 INTENSITY 4 ZONAL INTENSITY IV ZONAL INTENSITY v km 100 EPICENTER * Figure 5. Felt reports and isoseismal distribution in southern Ontario for the 31 January 1986 earth quake near Painesville, Ohio. 12 Saskatchewan Charl otte Islands. It had a magnitude of 8. I and was fe lt th roughout British Columbia and as fa r away as western Only four events were detected in the province. The largest, Albe11a. Other strong earthquakes have occurred fa rther north magnitude 3 and located near the Manitoba-Saskatchewan along th e southeastern Alaska coast in 1958 and 1972 and border, was probably related to potash mining near Esterhazy . near the B.C.-Alberta border in 19 18. For 1985-86 2 11 2 Two other smaller events, which were also probabl y mining events are plotted on Figure 7. related , were detected, one near Esterh azy and one near Saskatoon. Alberta WESTERN CANADA Earthquake acti vity in Alberta was confined to the western Most of the earthquake activity in this region is related to part of the province. No events with magnitude 4.0 or greater the North American-Pacific pl ate interactions whi ch are most occurred in the province during this two-year period . Three obvious in the offshore areas. However, a hi gh rate of earth magnitude 3 events and a number of smaller events were quake acti vity is also experi enced on Vancouver Island and located in close proximity to gas-producing plants west of the B.C. lower mainl and . Large earthquakes occurred on cen Rocky Mountai n House and were felt locall y. They were tral Vancouver Island in 19 18 and 1946, in southern Puget probably related to the gas-recovery processes. Sound (Washington State) in 1949 and 1965, and south of Residents of northern and west-central Alberta, includ the Queen Charl otte Islands in 1929 and 1970. In 1949 ing Edmonton , felt th ree earthquakes located some distance Canada' s largest earthquake, and one of the world 's great outside the provi nce in 1985-86. The first two were the earthquakes, occurred along the western coast of the Queen N.W.T. SASK. MAN. ONT. SKT lC EST lC • lC 1909 u.s .A. 0 km 200 (f ( Figure 6. Earthquakes in central Canada in 1985-86. SKT is Saskatoon and EST is Esterhazy. Location of the largest earthquake in the region in 1909 is shown . See Figure 4 for legend. 13 Nahanni, N. W .T. earthquakes of 5 October and 23 Decem The strongest earthquake, magnitude 5.2, occurred on ber 1985 which were strongly felt in northern and north 23 March 1986 just off the west coast of north-central Van central Alberta (Fig. 8) ; the third tremor was the Prince couver Island. This tremor was widely felt (Fig. 10) , but George, B.C. earthquake of 21 March 1986, which was caused no property damage. It was the strongest of many mildly felt in extreme west-central Alberta. earthquakes which took place on the active fault zone run ning from Nootka Island on the northern Vancouver Island coastline to the active tectonic features farther offshore. The British Columbia Nootka zone represents the boundary between the Juan de Vancouver Island Fuca and Explorer crustal plates in this area. The earthquake activity on southern Vancouver Island (Fig . 9) is the result of underthrusting of the Pacific Ocean crust Queen Charlotte Islands from the west (Juan de Fuca plate) under the continental crust Most of the earthquake activity , including several events of (North American plate) to the east. This affects southern Van magnitude 4, occurred off the west coast of the islands on couver Island, Georgia Strait, the Gulf Islands and the B.C. the active Queen Charlotte Islands Fault, which was the loca lower mainland in Canada and the Olympic Peninsula, Puget tion of the magnitude 8. 1 earthquake in 1949. Clusters of Sound, the San Juan Islands and northwestern Washington small magnitude activity occurred at several spots along the in the U.S. with a high rate of small magnitude earthquake western coasts of the islands and off the eastern coast of Gra activity and the potential for large damaging earthquakes. ham Island in Hecate Strait (Fig . 11) . However, in this two-year period only events with magni tude less than 4.0 occurred onshore in this region and none was widely felt. 60° • )( )( •)( )()( ALTA . B.C. )( )( )( EDM so• )( ... )( • PACIFIC OCEAN )( • 0 U.S.A. 0 :::o 0 km 200 0 Figure 7. Earthquakes of western Canada in 1985-86. PRG indicates the Prince George earthquake, RMH is the Rocky Mountain House seismic zone, EDM shows the location of the city of Edmonton and NAH is the Nahanni seismic zone. Location and year of the significant earthquakes in this cen tury in the region are indicated. See Figure 4 for legend. 14 Earthquake activ ity on the islands was minor during Offshore a reas 1985-86 with one event of magnitude 4. 0 being located inland The earthquake activ ity of the western offshore areas between of the Queen Charlotte Fault. On northern Graham Island Vancouver Island and the Queen Charl otte Islands was intense two magnitude 3 earthquakes were felt. They were located and dominated by the long linear zone of seismic acti vity in a zone of frequent earthquake activity which has been whi ch fo ll ows a sequence of active pl ate boundary features detected by improved monitoring in this area in recent years. in this region (Fig. 7) . These active features (Sovanco Frac ture Zone, Expl orer Ridge, Dell wood Kn oll s) mark the pres B.C. interior ent boundary of the Pacific and North Ameri can crustal pl ates The largest earthquake in 1985-86, magnitude 5 .4, occurred in this region. Twenty-seven events with magnitude 4.0 and in the area near Prince George on 2 1 March 1986. This earth greater occurred in th is general region in 1985-86. None were quake was widely felt in cent ral British Columbia (Fig. 12) fe lt. and caused minor property damage close to the epicentre (Rogers et al. , 1988). Otherwise, onl y scattered earthquake NORTHERN CANADA acti vity was seen in British Columbi a interi or, particul arly in the southern Rocky Mountains, with one other magnitude Northern Canada has acti ve fa ul ts along the Fairweather 4 event which was located near the U.S. border in the south Yakutat zone in the south western part of the Yukon Terri eastern part of the region on 8 August 1985 (Fig. 7) and was tory with a correspondingly high rate of earthquake acti vity. fe lt locall y. Four great earthquakes, magni tude 8.0 or greater, occurred in this area in a space of 13 months in 1899- 1900. Other 0 KM 200 N.W.T. ~ASK. 0 PACIFIC OCEAN 0 0 (") Figure Sa. Felt reports and isoseismal distribution for the 5 October N·ahanni earthquake. See Figure 5 for legend. 15 strong earthquakes have occurred in the southern Yukon in seismograph stations even though they do not affect the Cana 1944 and in the northern Yukon in 1940 and 1955 . The North dian landmass directly. In all , 1370 events are plotted (Fig. west Territories, by contrast, are part of a large generall y 13) , but most of these are in the Yukon. Because of the wider stable region of the North American plate without active plate spacing of the seismograph stations in the Northwest Terri boundary features and have a correspondingly low rate of tories, earthquakes with magnitudes less than 3.0 can not earthquake activity. Nevertheless, pockets of significant earth be routinely detected there. quake activity do occur in several parts of the Northwest Ter ritories and the largest earthquake known above the Arctic Circle, magnitude 7. 3, occurred in Baffin Bay in 1933. Strong Yukon Territory earthquakes also occurred in the Baffin region in 1945 , 1957 The earthquake activity of the southwestern Yukon is fre and 1963 and in the Beaufort Sea in 1920. quent and there is a history of large magnitude events. This The active plate boundary between the North American area marks a transition from the active strike-slip faults along and Asian plates is located at the Arctic Mid-Ocean Ridge the coast of southeastern Alaska to the south to the active northeast of Greenland and a higher rate of earthquake activity thrust fau lts of the Aleutian Trench farther to the west. A occurs there. Some of the larger earthquakes on this feature total of 11 3 1 events are plotted on Figure 14 . However, and the adjacent areas of northern Greenland are noted in several hundreds were aftershocks to the Nahanni earthquakes this section because they record well on northern Canadian located in the western Northwest Territories, which are described in the next section. Vu~~ 0 ~1;;,\ 0 KM 200 ~ _J N.W.T. B.C.4 IV 4 4 3 4 OSASK. 0 PACIFIC OCEAN 0 0 (") Figure Sb. Felt reports and isoseismal distribution for the 23 December 1985 Nahanni earthquake. See Figure 5 for legend. 16 x x IC x x ~~~~ x./.7 x ~- ~< i • )( x )( B.C. x l x Ax x ·rc:~ " n VA Nr!'f:JTJVTi!R T~))lJ\'-cS J x \~ x x xx x x x ~ xx · - x I .. ~S{-N ~ I .. \.. X . \ (If/ x " )( x A x • x , )VV x )( x i ~ l/(''.:X id)_.._.. )~ A-o _,.-,I, ,._ I xx 1"U 1 >-< "---. ~ n "" ~ M A lC x xx "'-0 LMx x x r-x.x x x x x -- x .490 )( x x '* )( x~ x x x x x lf< x A . . I *. x x lC x I x x I x x xx • PACIFIC OCEAN OP ~,l°~ \ )' G I A x i \ I x )( 1949 0 km 100 kl I \~I ~,A 1 65 .470 x Figure 9. Earthquake activity on Vancouver Island and the B.C. lower mainland. NKI is Nootka Island , GI are the Gulf Islands, SJI are the San Juan Islands, LM is the B.C. lower mainland, OP is the Olympic Peninsula and PG is Puget Sound. Location and year of the more significant earthquakes in this century in the region are indicated. See Figure 4 for legend. -.J 0 km 100 B.C. 51° * 49° -----T~~~--~~~~--+~~I ~--i IPACIFIC OCEAN ~ I Figure 10. Felt reports for the 16 June 1986 earthquake off Estevan Point, B.C. See Figure 5 for legend. 18 )( )( )( )( )( 1970 )( )(~ PACIFIC OCEAN )( )( >ex)( I( *x )( 1929 .A )( )( )( * )( )(. )( )( ~ ti Figure 11. Earthquake activity on the Queen Charlotte Islands in 1985-86. GI is Graham Island, Ml is Moresby Island and HS is Hecate Strait. Location and year of the larger earthquakes this century in the region are shown. See Figure 4 for legend. 19 0 km 100 3 B.C. 4 0 5 5 4 5 44 2 2 55° 4 4 o4 ALTA. KELOJfNA Figure 12. Felt reports and isoseismal intensity for the 21 March 1986 Prince George earthquake. See Figure 5 for legend. 20 0 km 500 • /11 ARCTIC OCEAN I Figure 13. Earthquakes in northern Canada in 1985-86. FWY is the Fairweather fault zone, RIC is the Richardson Mountains seismic zone, NAH is the Nahanni seismic zone, BAB is the Baffin Bay seismic zone and AMOR is the Arctic Mid-Ocean Ridge system. The location and year of the larger earthquakes this century are shown. See Figure 4 for legend. 21 The seismi c activity in the Yukon is arranged generally )( )( 0 in fo ur zones parallel to the west coast. The first zone fol )( km )( lows the Fairweather-Yakutat faults (FWY) along the coast and the St. Eli as Mountains. This zone has produced some large earthquakes. The most recent was the 1979 magnitude 7. 5 St. Eli as earthquake ; frequent a ft ershock activity is still occurring at the site of this earthquake on the extreme south western corner of the Yukon. Inland of the FWY zone is a di stinct linear zone of earthquake activity along the active Denali fa ult system (DFS). Northeast of the Denali fault in the interi or of the Yukon is a diffuse zone of of earthquake activity associated generally with the Tintina Trench and the Olgivie Mountain s (T-0 ). Finall y in northeastern Yukon along the border with the N. W . T. is a zone of frequent activity associated with the Ri chardson Mountains (RI C) . )( The largest events in this area during 1985-86 were a magnitude 5.7 event in the Fairweather zone on 9 January 1985 and a magnitude 5 .4 event on 15 September 1985 at the southeastern end of the Denali zone on the border of British Columbia and Al aska. Both events were fe lt locall y; neither )( caused any property damage. Y.T. Northwest Territories Mackenzie Valley • Canada's largest earthquakes in 1985-86, and largest in the Northwest Territories since 1963 , were in this area on 5 October and 23 December 1985 . These two events, magni tude 6.6 and 6 .9 respecti vely, occurred near the North Nahanni Ri ver (N AH) in the Mackenzie Mountains of the western Northwest Territories . Both were widely felt (Fig. )( 8) including many parts of British Columbia and Alberta to the south of the epicentres. A number of interesting studies Figure 14. Earthquakes in the Yukon Territory in 1985-86. of these earthquakes have been carried out , including those FWY is the Fairweather fault zone, DFS is the Denali fault by Wetmiller et aJ. ( 1987, 1988), Weichert et al. ( 1986a,b), zone, T-0 is the Tintina-Ogilvie seismic zone, RIC is the Evans et al. ( 1986) and Boatwright and Choy ( 1988). Per Richardson Mountains seismic zone and NAH is the Nahanni haps the most noteworthy of the effects of the earthquakes seismic zone. See Figure 4 for legend. documented in these studies are the occurrence with the October event of the fourth largest landslide known in Can ada this century and , fo r the December event , the strongest Arctic Islands and Greenland near-fi eld seismic accelerati ons ( > 2g) ever recorded fo r an A number of earthquakes with magnitudes less than 5 .0 earthquake. occurred on or near Baffin, Melville, Prince Patrick, Ellef The aftershoc k sequences which foll owed these two large Ringnes, Devon , Bathurst and Axel Heiberg Islands in events were intense, and included at least 78 aftershocks mag 1985-86. None were reported felt. nitude 4 .0 and greater and 8 magnitude 5.0 and greater. The A magnitude 5 .0 earthquake was detected on the east largest aftershock was magnitude 5.7 , on 25 December 1985. coast of Greenland on 17 December 1986. Many of the larger aftershocks were felt in the closest com munities such as Wrigley and Fort Simpson, but caused no damage. Beaufort Sea, Arctic Ocean and Baffin Bay Ea rthquakes with magnitude less than 5 .0 occurred else Earthquake activity occurred in all these offshore areas in where in the western Northwest Territori es in 1985-86 . A 1985-86. The largest events were a magnitude 5.0 earthquake magnitude 4 .8 event , located in the Ri chardson Mountains in the Beaufort Sea on 22 April 1986 and a magnitude 5.0 (RIC) of the northern Yukon on 16 February 1986 , was event on 29 January 1985 in the Greenland Sea part of the reported felt in communities in the Mackenzie delta area such Arcti c Ocean off northern Greenl and , where it was part of as Fort McPherson and Inuvik. Strong earthquakes occurred the trend of seismic activity related to the Arctic Mid-Ocean in the RI C zone in 1940 and 1955 . Ridge (AMOR), the active plate boundary feature between North America and Asia. Ten events magnitude 4.0 or greater were detected in this region during 1985-86. 22 Peak Horizontal velocity (m/s) Probability of Exceedance 10%/50 years Vitesse horizontale de pointe (mis) Pobabilite de depassement de 10%/50 ans 60° m/s V Zv o -- 0 0 .04 ·05 1 .08 ·10 2 .11 ·15 3 .16 ·20 4 .23 / ·30 5 I r / I> I \ : \./ 9I "·~. i / ~ . ·~ .../~. Figure 15. Seismic hazard zoning map from the 1985 National Building Code of Canada. Zv is the seis mic zone number. EARTHQUAKE HAZARDS IN CANADA (Fig. 15) is the current zoning map from the 1985 NBCC. It divides the country into zones of equal earthquake hazard : The descriptions of seismic activity given above show that seven zones from 0 to 6 . The higher zones, which include earthquake activity affects almost all parts of Canada and parts of the British Columbia coast, the southwestern Yukon, that large, potentially destructive earthquakes have occurred part of the lower St. Lawrence valley in Quebec and two several times in Canadian territory this century. The fact that areas off the east coast of Canada, are the areas where stronger none of these large earthquakes has resulted in a social dis earthquake effects are likely to occur. People who live in aster with extensive property damage and many casualties or near these areas should be prepared to deal with the effects has been more due to good luck than to any special proper of strong earthquakes. The lower zones have correspond ties of the earthquakes or to Canada's position in the world ingly less risk of earthquakes, but they still may experience of plate tectonics. Large earthquakes will occur again in Can strong earthquakes only less frequently than the higher zones. ada and one of them, if it occurs in a densely populated region, could potentially be the largest single natural disaster this Seismologists cannot predict when the next strong earth country will ever face. quake will occur in Canada. It is most likely to occur in one of the zone 6 regions , but not necessarily . The two strongest The relative level of long-term hazard due to earthquakes earthquakes in 1985-86, the magnitude 6.6 and 6.9 Nahanni across Canada is quantified for the National Building Code earthquakes in October and December 1985 , occurred in an of Canada (NBCC) in terms of seismic ground motion values area of the Northwest Territories which is in seismic zone which have a small probability of being exceeded in a given 1 of the NBCC map. time period ; for the NBCC parameters of 10 % in .50 years are used to define the seismic zones. The map shown here 23 ACKNOWLEDGMENTS Evans, S.G., Aitkin, J.D., Wetmiller, R.J., and Horner, R.B. 1986: A rock avalanche triggered by the October, 1985 North Nahanni Arrival times, amplitudes and/or epicentres were provided earthquake, District of Mackenzie, N.W.T.; Canadian Journal of to us for events in the following areas to augment data from Earth Sciences, v. 24, p. 176-184. the Canadian Seismograph Networks: Yukon-C. D. Munro, P.S., Shannon, W.E., Halliday, R.J., and Schieman, D.R.J. Stephens, USGS, Menlo Park, California and staff of the 1985: Canadian Seismograph Operations - 1984 ; Earth Physics Branch , Seismological Series no. 94, 118 p. Palmer Observatory, Alaska; southwestern British Columbia-Linda Noson, University of Washington; east Munro, P.S., Shannon, W.E., Halliday, R.J., and Schieman, D.R.J. 1986: Canadian Seismograph Operations - 1985 ; Geological Survey of ern British Columbia-B. Chandra, B. Chandra and Associ Canada, Paper 88-10, Seismological Series, no. 96. ates; Saskatchewan-D.J. Gendzwill , University of Rogers, G.C., Cassidy, J., and Ellis, R.M. Saskatchewan ; southwestern Ontario-R.F. Mereu, Univer 1988 : The Prince George earthquake of March 21 1986. (in Prep.) sity of Western Ontario; eastern Canada and the northeastern Stover, C.W. U .S.-Kim Lock, Lamont-Doherty Geological Observatory 1986: Preliminary isoseismal map for the northeastern Ohio earthquake of Colombia University, and J.E. Ebel, Weston Observa of January 31 1986; U.S. Geological Survey, Open-file Report , tory of Boston College; eastern Arctic Canada and 86-356, 7p. Greenland-E. Hjortenberg and S. Gregersen of the Danish Weichert, D.H., Wetmiller, R.J., and Munro, P.S. Geodetic Institute, Copenhagen; all of Canada-staff of the l 986a: Vertical earthquake accelerations exceeding 2g? The case of the USGS National Earthquake Information Service, Boulder, missing peak ; Seismological Society of America, Bulletin, v. 76 , Colorado. p. 1473-1478. Weichert, D.H., Wetmiller, R.J., Horner, R.B., Munro, P.S., and Our colleagues, F.M. Anglin, J.E. Adams, M.G. Cajka, Mork, P.N. R. Kolinsky, G.C. Rogers and A.E. Stevens, participated l 986b: Strong-motion records of the 23 December 1986, Ms 6.9 Nahanni , in reading seismograms for this catalogue. D. Schieman, D. N. W. T., and some associated earthquakes; Geological Survey of Higgs, W.E. Shannon and M.J. Gregory assisted with record Canada, Open File 13-30, 9 p. and data management. Wetmiller, R.J., Horner, R.B., Stevens, A.E., and Rogers, G.C. 1983: Canadian Earthquakes 1980 ; Earth Physics Branch, Seismological Series, no . 87, 60 p. REFERENCES Wetmiller, R.J., Basham, P.W., Weichert, D.H., and Evans, S.G. 1987: The 1985 Nahanni earthquakes: problems for seismic hazards esti Choy, G.L. and Boatwright, J. mates in the northeast Canadian Cordillera; Fifth Canadian Con 1988: Teleseismic and near field analysis of the Nahanni earthquakes in ference on Earthquake Engineering, Proceedings, A.A. Balkema, the Northwest Territories, Canada ; Seismological Society of Amer Rotterdam, p. 695-703. ica, Bulletin, v. 78 , p. 1627-1652 . Wetmiller, R.J., Horner, R.B., Hasegawa, H.S., North, R.G., Cajka, M.G. and Stevens, A.E. Lamontagne, M., Weichert, D.H., and Evans, S.G. 1986: Intensity survey of southern Ontario, Canada, following the Perry , 1988: An analysis of the Nahanni earthquakes; Seismologocal Society of Ohio, Earthquake of31January1986; Earthquakes Notes , v. 57 , America, Bulletin, v. 78, p. 590-6 16. p. 109 (Abstract). Drysdale, J.A., Horner, R.B., Wetmiller, R.J., Stevens, A.E., Rogers, G.C., and Basham, P.W. 1985: Canadian Earthquakes 1982 ; Earth Physics Branch, Seismological Series, no. 92, 61 p. 24 APPENDIX Significant Canadian earthquakes in this century 1899-1900: Four great earthquakes (M about 8) occurred 1945: A strong earthquake (M6.5) occurred in Baffin Bay along the southeast Alaska coast in the 13-month period from on 1 January. September 1899 to October 1900. Major topographic changes were made to the Alaska coast by these earthquakes and strong 1946: A major earthquake (M7 .3) occurred on central Van effects were experienced in many parts of northern British couver Island on 23 June. Serious property damage occurred Columbia and southern Yukon. along the east coast of Vancouver Island and one person was drowned. 1909: A moderate earthquake (MS. S) shook the central plains of southern Saskatchewan on 16 May. Isolated minor prop 1949: A major earthquake (M7. l) occurred in the southern erty damage from the event was reported in several localities. Puget Sound area of Washington State on 13 April. The earth quake caused heavy property damage over a wide area of 1918: A strong earthquake (M6) occurred on 4 February in Washington and was strongly felt in Victoria and Vancouver. the southern Rocky Mountains of eastern British Columbia 1949: Canada's largest earthquake (MS. I) and one of the 1918: A major earthquake (M7) occurred on 6 December world's great earthquakes occurred along the west coast of on west-central Vancouver Island near Estevan Point. the Queen Charlotte Islands on 22 August. The tremor was felt over a wide area of western North America. 1920: A strong earthquake (M6.S) occurred on 16 Novem ber in the Beaufort Sea. 1955: A strong earthquake (M6.6) occurred in the northern Yukon Territory on 1 March. 1925: A strong earthquake (M6.S-7.0)occurred in the Charlevoix area of Quebec on 1 March. The earthquake 1957: A strong earthquake (M6.3) occurred in Baffin Bay damaged most of the houses in the epicentral area and caused on 2 May. considerable damage in Quebec City. 1958: A great earthquake (M7 . 9) occurred along the south 1929: A major earthquake (M7) occurred in the Pacific Ocean east Alaska coast on 9 July. Several people were killed in just south of the Queen Charlotte Islands on 26 May. Alaska by the tremor, and strong sea-wave and landslide activ ity was reported. Parts of northwestern British Columbia and 1929: A major earthquake (M7) occurred in the Atlantic the southern Yukon were strongly shaken by the tremor. Ocean south of Newfoundland on 18 November. The earth quake generated a tsunami on the south coast of Newfound 1963: A strong earthquake (M6.4) occurred on Baffin Island land which blled 27 people and caused a large underwater on 4 September. landslide which broke 12 trans-Atlantic telegraph cables. The tremor was felt over a wide area of eastern North America. 1965: A strong earthquake (M6.5) occurred in the southern Puget Sound area of Washington State on 29 April. The 1933: The largest earthquake known north of the Arctic Cir tremor caused considerable property damage in Washington cle (M7 .3) occurred in Baffin Bay on 20 November. and was strongly felt in Vancouver and Victoria. 1935: A strong earthquake (M6.3) occurred on 1 November 1970: A major earthquake (M7 .0) occurred in the Pacific in the Lake Terniscaming area along the Ontario-Quebec Ocean south of the Queen Charlotte Islands on 24 June. border. Chimneys were knocked down in Mattawa and North Bay. The tremor was felt over much of eastern Canada. 1972: A major earthquake (M7 .6) occurred along the south east Alaska coast on 30 July. The tremor caused some prop 1940: Two strong earthquakes (M6.2 and 6.S) occurred in erty damage in Alaska and was strongly felt over wide areas the Richardson Mountains of the northern Yukon on 29 May of northern British Columbia and the southern Yukon. and 5 June. 1979: A major earthquake (M7 .S) occurred in the St. Elias 1944: A strong earthquake (M6.5) occurred in the Denali Mountains along the Yukon-Alaska border on 28 February. Fault Zone west of Whitehorse, Yukon on 3 February. The tremor caused some minor property damage in the Yukon and was widely felt. 1944: A moderate earthquake (MS. 7) occurred near Corn wall, Ontario on 5 September. Many homes in Cornwall were 1982: A moderate earthquake (MS. 7) occurred in the damaged by the tremor and property damage from the event Miramichi Highlands of central New Brunswick on 9 Janu totaled two million dollars in Cornwall and the surrounding ary. The tremor caused isolated minor property damage in communities. several New Brunswick communities. 1985: Two strong earthquakes (M6.6 and 6.9) occurred in the Nahanni region of the Northwest Territories on 5 October and 23 December. 25