Individual Event Report
| Event #95 - Summary, and parameter estimates with source IDs |
This event has, in the past, been referred to as the 1872 "North Cascades" earthquake. It
is the largest crustal earthquake known to have occurred
in Washington or Oregon in historic times.
Magnitude and location given here are from Bakun et al. [2002),
which concluded that it probably originated near Entiat (near 119.9 W longitude, 47.75 N latitude), and had a magnitude of around 6.8.
Dozens of communities reported severe shaking, but no surface faulting was found.
The 1872 earthquake was originally thought to have originated in the North Cascades, a rugged area inaccessible for most of the year. Reports of shaking came from more populous areas some distance away, making the location and size of the earthquake very hard to determine. Magnitude estimates have ranged as high as 7.4, and location estimates have spanned a wide area of the North Cascades.
The preferred magnitude and location were determined from reports of shaking intensities from communities throughout the northwest and an improved model of how shaking intensities fall off with distance. Hundreds of trial magnitude/location combinations were modeled and compared to the observed shaking intensities. The best fit was a magnitude 6.8 crustal earthquake near the southern end of Lake Chelan.
Several other observations offer some support:
Following the 1872 earthquake, additional felt events - likely aftershocks - were reported in the "Winesap" area, near Entiat. Felt events continue to occur in the vicinity,
including magnitude 5.0 quakes on Dec. 30, 1926 and August 6, 1959. Since 1975, more than 20 earthquakes larger than M 3.0 have been
felt in the Entiat area. These are part of a persistant cluster of seismicity that has been continuously active in the Entiat area as
long as the PNSN has recorded data there.
Placing the 1872 earthquake in the Entiat area helps to focus the search for
candidate faults. The area lies on the margin between the Cascades and the Columbia River Plateau, and geologically young structures
within the Plateau may include thrust faults large enough to have produced the M 6.8 1872 North Cascades quake.
PDF Version
of the Article - "The December 1872 Washington state earthquake", by William H. Bakun, Ralph A. Haugerud, Margaret G. Hopper, and
Ruth S. Ludwin, Bulletin of the Seismological Society of America, Vol. 92, No. 8, pp. 3239-3258 (2002).
The maximum intensity
is Milne's projection of the likely intensity in the epicentral area. Intensity values of VIII and IX (MM) were reported in the
Chelan/Entiat area by some later investigators. No primary faulting has been definitively connected with this earthquake. Prior
Estimates of the location of this earthquake vary from southern British Columbia, to the Entiat, Washington area. Much of the extensive
information available on this earthquake is in "grey literature", technical reports that are not included in most library catalogs.
The best information regarding the timing of the mainshock and its felt aftershocks at Olympia was provided by Capt. James S. Lawson of Olympia, whose observations were published in the Oregonian of 12/20/1872, and also elsewhere. The Oregonian says:
"... It was timed with a chronometer watch, absolutely correct, ... A shock occurred precisely at 9:40½ PM. It commenced with a light movement, gradually increasing for eighteen or twenty seconds. Then came the heavy shock, lasting four or five seconds; then it gradually decreased. In six minutes after the first shock there was another, followed by two others one minute apart. At 10:12 2/3 there was another shock, lasting four or five seconds; then it gradually decreased. In six minutes after the first shock there was another, followed by two others. During the night other shocks were reported, (I did not feel them) at 3 and 5 o'clock. On Sunday evening, at 6:37½, a light shock. December 16th at 9:17½ AM another light shock."
Some catalogs and newspapers give the date as 12/15 or 12/17, but it is my opinion (RSL) that these dates are misstatements, as it seems clear that the main event was on Saturday, December 14 at 9:40½ PM.
An extensive collection of articles and information on the North Cascades earthquake was made by Weston Geophysical Research, Inc. (1976; 'The 1872 earthquake; significant data and conclusions, prepared for United Engineers and Constructors, Inc.', unpaginated - /HIST_CAT/1872/Weston), and much or all of the same material is also included (in a rather different arrangement) in the "Report of the review panel on the December 14, 1872 earthquake" (1976) by Howard Coombs, W.G. Milne, Otto W. Nuttli,and David B Slemmons. This report has extensive appendices titled: a) landslide discussion, b) reports related to the 1872 earthquake, c) earthquake catalogs and isoseismals, and d) selected supporting information. Volume 2A of the Preliminary Safety Analysis Report for
WPPSS Nuclear Project No. 1, includes the Coombs et at. report (with a listing of sources for appendices b and d, rather than the entire articles), and a 1977 addendum to it. The volume also contains a "Review of North Cascade Earthquake of 14 December 1872" by Woodward-Clyde Consultants, with an iso/meizo-seismal map indicating several suggested locations. Other grey-literature resources are :
Bechtel, Inc. (1975) Investigation of the December 14, 1872 earthquake in the Pacific Northwest, Puget Sound Power and Light Company Skagit Nuclear Power Project, Preliminary Safety Analysis Report, Appendix 2J, 128 p.
Scott, N.H. (1976) Evaluation of the epicenter and Intensity of the Pacific Northwest earthquake of December 1872, Prepared for Bechtel, Inc., September, 1976, 24 p.
See /CATDAT/northcascades.html for extensive information on this event.
|
| TIME |
LOCATION |
MAGNITUDE |
MAX. INTENSITY |
FELT AREA |
| YR |
MO |
DAY |
HR |
MIN |
AM/PM |
Time
Type |
LAT(N) |
LON(W) |
DEP
(km) |
MAG |
Mag
Type |
Felt
Plc. |
Felt
St. |
Inten-
sity |
Int.
Type |
Felt
Area |
Felt
Area
Int. |
Felt
Area
Units |
| 1872 |
12 |
15 |
5 |
40 |
|
G |
47.75 |
119.90 |
|
6.80 |
MI |
Pacific Coast Region |
B.C. |
IX |
MM |
150000.00 |
|
mi2 |
| N-Ore - 1199 |
BSSA - 7125 |
- |
BSSA - 7125 |
MILNE - 1399 |
USEQS - 917 |
Underlying Source Material
| Source ID |
Publication |
Pub Date |
Pub Details |
| 1984 |
Oregonian |
1872 |
December 17, 1872; pg 3, col 1 |
Transcription: 1872, December 17. The Dalles, Walla Walla.
Not Felt
Although the shock was felt uncomfortably plain at the Dalles last Saturday evening, the residents of the Cascades, it appears, were in blissful ignorance of the fact until the Oregonian reached there yesterday morning, which contained an account of the shock in this city, and also dispatches from east of the mountains. If the earthquake visited that place at all it must have been so slight that its pressure was not detected. |
| |
| Source ID |
Publication |
Pub Date |
Pub Details |
| 1399 |
Milne, W.G., 1956, Seismic Activity in Canada, west of the 113th meridian 1841-1951: Canada Dominion Obs. Pub., V. 18, No. 7, pp. 119-146 |
1957 |
|
Transcription: 1872 DECEMBER 14. 9:40-5 p.m. This was one of the major earthquakes of the Pacific coast region of British Columbia. It has been reported as being felt quite strongly as far north as Quesnel and Soda Creek in the Cariboo and as far south as Eugene, Oregon. If Neumann's curves of intensity versus distance are used, the intensity at the origin of this earthquake must have been VIII or IX on the Modified Mercalli Scale. A corresponding magnitude reading would be 7 1/2, although some of the reports outlined below indicate an even higher value. There were few towns in British Columbia at this time, and fewer newspapers to print accounts of the event, so data are very scarce. Any information available is presented below.
Yale: Doors were rattled, bells rang, and floors of buildings were made to wave "like the decks of a vessel in a light sea".
Chilliwack: The houses oscillated and there were waves on the ground. A report in a 1915 newspaper states that a big slice of Mount Cheam (near Chilliwack) dropped 1000 feet during the earthquake. This was likely a landslide, but it indicates that Chilliwack was quite close to the epicentre.
Vernon: A report in 1936 from this city states that 60 years ago (probably in 1872) the Indians reported a very bad earthquake. It was strong enough to knock people from their feet, and buildings and tepees came down with the vibrations.
Clinton: The earthquake awakened many people, and staggered others off their feet, causing general excitement and alarm.
Victoria: The motion seemed to be from the east to the west. Bells were rung and crockery was knocked from the shelves. People ran out on to the streets. There are reports of the earthquake being felt very strongly at Matsqui, all along the Fraser River, and at Race Rocks. In the United States there are accounts from Olympia, from Seattle where dishes were broken, from Portland and Delles, from Wallulu and Walla Walla and all along the lower Columbia River. The felt area of this tremor seems to have covered about 500,000 square miles, part of which was at sea.
To fix an epicentre for such a tremor, using only scanty macroseismic reports and no instrumental records, is a great problem. Taking the area where waves were seen on the ground as an indication of the epicentral region, then Yale and Chilliwack seem to be very near the origin. On the map the origin has been shown as being within a circle whose radius is 30 miles, andwhose centre is at 49 degrees 10' N.lat. and 121 degrees 00' W.long. No estimate can be made of the accuracy of this epicentre, and it is presented merely as an attempt to fix approximately the origin of the tremor. Certainly it was east of Vancouver, north of Seattle, and probably south of Clinton. The absence of reports from further east than Vernon indicates that the centre was west of that city, and probably west of Okanagan Lake.
Following the earthquake, many tremors were reported from various places in British Columbia and northwestern Washington, which were prob- ably aftershocks of the main disturbance. These are listed here to make the record as complete as possible, but there is the likelihood that some listed as aftershocks may well be unrelated events. |
| |
| Source ID |
Publication |
Pub Date |
Pub Details |
| 1942 |
The Weekly Mountaineer |
1872 |
Saturday, Dec. 21, 1872, vol. XIII, no. 12, p. 2, c.. 2. |
Transcription: The Earthquake," ,
On Saturday evening last, at about half past 9 o'clock, this section of country was visited by a shock of earthquake, which, as far as we are able to learn, did little or no damage. The vibrations lasted probably thirty seconds, and seemed to be from the east to west. The sensation we felt was a very peculiar one and had a tendency in a moment to destroy the illusion and faith we have always had in the stability of the surface of the earth. Animals, especially cows, dogs, and swine, seemed to experience the disturbance, if we judge from the commotion they made at that time. This we believe is the second one that has ever been felt at The Dalles, the former being some six years ago and was quite light. It has been supposed by many that a calm, an oppressive heat and misty horizon are always the fore runners of this phenomenon; but, we are happy to says that in this instance these signs all failed, for we did not observe any thing peculiar, either in the air, or other wise, about that time. The cause of earthquakes is supposed to come directly from volcanic force. For instance, when a volcano is in active operation, or as we might term it, "letting off steam," there is no danger of an earthquake; but should it quiet down for a length of time and be followed by a large fall of rain, terrible explosions and quaking of the earth may be expected. The wave of an earthquake is said to travel at the rate of several miles in a second, until it expends its force. |
| |
| Source ID |
Publication |
Pub Date |
Pub Details |
| 1944 |
Gilbert, Frank T. "Earthquake of 1872," Historical Sketches of Walla Walla, Whitman, Columbia, and Garfield Counties, Washington Territory, and Umatilla County, Oregon, Portland, Oregon: A. G. Walling Publishers, 1882, p. 310. |
1882 |
quote is from page 310 |
| Transcription: Saturday night, December 14, 1872, at 3 minutes past 10 o'clock, Walla Walla experienced a severe earthquake lasting about half a minute. Buildings rocked dangerously from SW to NE, though no damage was done except in the breaking of a few articles of crockery and glassware ... This was a very extensive earthquake, being severely felt in British Columbia, Washington, Oregon, Idaho, Montana ..." |
| |
| Source ID |
Publication |
Pub Date |
Pub Details |
| 1946 |
Oregonian |
1872 |
December 16, 1872 |
| | |