In 1872, before Washington was ever admitted as a state into the Union, when it was simply known as the Washington Territory, there occurred the largest earthquake (1)(2)(3)(4) ever experienced by white man in this region...so far. From the information available, it appears that no one really knows the true magnitude of this 1872 quake, but the general belief is that it was around an M6.5 to M7.5. It also appears that the scientists are not totally sure about the location for the epicenter of this quake, nor sure of the exact geologic feature which caused this large quake.
A 2011 article linked here is titled The Earthquake That Wouldn't Stay Put. A 2014 article linked here is titled Scientists may be cracking mystery of big 1872 earthquake. Both articles speak of one group's plans, back in the 1970s, for two nuclear plants in the Skagit River area, on the west side of the Cascade Mountains, and another group's plans, during the same time period, for three other nuclear plants which were to be built at Hanford, near Richland WA, to the east of the Cascades. According to what is seen in the linked articles, neither group wanted evidence which showed the 1872 quake as being too close to their intended project. So, what happened?
The articles linked above appear to indicate that geologic information can readily be "fudged" by various geologists and organizations to suit the desires of their particular client, especially when it comes to the nuclear industry. The 2014 article declares that there was "a series of reports that lobbed the epicenter [for the 1872 quake] back and forth across the Cascades like a tennis ball. One Seattle politico dubbed it 'the earthquake that wouldn't stay put.'" And, the 2014 article clearly states: "No one was able to find the fault." Why weren't they able to find it? Well, possibly the geologists were not considering all the available information.
For those who care about our future wellbeing in the Pacific Northwest, it possibly is time to start doing our own thinking, rather than leaving it up to others. It possibly is time to look at what appears to really be happening, geologically, in the Hanford region and the Pacific Northwest. It is time to logically consider all the evidence, and what it potentially points to as the actual cause of that large 1872 earthquake. Let us begin by first considering some important facts about the Hanford region and its associated faults, because there is something very important which needs to be established.
A 2011 page linked here is titled Washington's Hanford Reservation and nuclear plant may lie on faults. The page speaks about "an interconnected [fault] system underlying the Cascades, from Puget Sound to Umtanum Ridge and Rattlesnake Mountain, which loom above Hanford Nuclear Reservation and the Northwest's only commercial nuclear plant, the Columbia Generating Station." The magnetic alignments noted on both sides of the Cascade Mountains, plus other available information, indicate that there are deep, northwest-southeast trending faults (1)(2)(3)(4)(5) which pass beneath the Cascade Mountains, and which faults "formed long before the range's volcanoes did."
The information above is presented in order to establish that there are deep fault lines which appear to pass in a northwest to southeast direction beneath the Cascade Mountains. The information in the paragraph above mainly considers fault lines in the area of the Hanford Nuclear Reservation. But, it does not appear that these are the fault lines which produced the large earthquake of 1872. The deep fault or rift system which produced the 1872 quake appears to be located further north. From the writer's research, it does appear that the fault or rift system which produced the 1872 quake also passes deeply beneath the Cascade Mountains. And now, let us begin to consider some facts relating to the 1872 quake.
A page linked here is titled 1872 North Cascades Earthquake Aftershocks by Date and Local Time. According to the page, it appears there may have been a foreshock associated with this quake event, which occurred "two hours BEFORE the mainshock." A page linked here also makes a note of this potential foreshock. This claimed foreshock was felt in Idaho. Keep this potential foreshock in mind, for it may be very important later in this discussion.
About one-third of the way down, a page linked here provides statements from Peter Wapato, who, at the time of the 1872 quake "lived at what is now Winesap." In regards to events prior to the large 1872 quake, Peter declared: "There had been many shakes that winter. When they came they'd be in intervals of half an hour, or an hour, or sometimes longer" So, it appears there had been many smaller quakes in this area in the latter part of 1872, prior to the large event which occurred on the night of December 14, 1872. It appears there may have been a number of foreshocks, before the main event.
According to an article linked here, the 1872 Washington earthquake "rattled seven states and provinces..." In this quake, "trees toppled in Puyallup and fissures split the ground south of Seattle..." In 1872, the small town of Seattle had "a population of about 1,500" people (link). It was not the spread out metropolis that it is today. From what is indicated in the page linked in the first sentence, this 1872 quake "was felt from Montana and British Columbia down into Oregon and Northern California," according to USGS researcher Brian Sherrod. From the available information, it appears that it was something rather big which caused this large quake.
It is time to start "assembling the puzzle pieces," and see what "the picture" looks like. Not only did "fissures split the ground south of Seattle," on the west side of the Cascade Mountains during this 1872 quake, as noted in the paragraph above, but a page linked here speaks about things which happened on the east side of the Cascades. It speaks of "two cracks in the earth 'up the hogback east of the Columbia,'" which formed as a result of this quake.
Pages linked here and here give more details about the cracks which formed on the hogback. These two cracks were located "near the summit of the first hog-back across the canyon from where the tram was formerly located." A satellite photo, linked here, notes the location of the former tram and also locates the apparent hogback on which the cracks formed. And, according to information in the first two links above, it appears that for a period of time, at about five minute intervals, petroleum had been forced out of the cracks on the hogback. More is spoken about this petroleum in a section of a page linked here. From the available information, it does appear that these cracks went rather deep into the earth.
A 477 page document linked here is titled Proceedings of Seminar on New Developments in Earthquake Ground Motion Estimation and Implications for Engineering Design Practice. This seminar, in 1994, was by the Applied Technology Council and was funded by the U.S. Geological Survey. The linked document goes by the identifier of ATC 35-1.
At the bottom of PDF page 68 of 477, the document linked above declares: " The 1872 North Cascades earthquake is generally considered the largest earthquake known in the Pacific Northwest, (Milne, 1956), with an estimated felt area magnitude of 7.4 (Malone and Bor, 1979). It was felt over an area of over 1,010,000 square km, including Washington, northern and central Oregon, northern Idaho, western Montana, and southern British Columbia. The earthquake was followed by an extensive aftershock sequence (Milne, 1956)."
Let us look further at this "extensive aftershock sequence." About one-third of the way down, a news article linked here declares: "Throughout Washington and Oregon, strong aftershocks kept the populace on edge for more than a year." A little more than half the way down, a page linked here declares: "In 1873 from about mid-February through out most of the rest of the year the whole mountain range between Lake Wenatchee and Lake Chelan was shaken by continuing tremors that scarcely missed a day."
As far as the event on the night of December 14, 1872, further down, the page linked above states: " It was reported that there was a total of over 80 shocks in one night." A page linked here indicates that there were "64 aftershocks in the first 7 hours after the 1872 quake, 8 of which were strong." Regarding the aftershock sequence, about two-thirds of the way down, a page linked here states that in the Colville, Washington area, "the earthquake which began at that place on the 14th, continued at brief intervals for ten days, and that it was very severe, both at Colville and points to the north of that place."
At the bottom of a page linked here is a eye-witness report of the 1872 quake event from a Mr. Covington, "who has a trading post on the Columbia river, at White Stone." A page linked here notes Mr. Covington's 1872 earthquake experience and speaks of "the Whitestone area, on the Columbia just downstream from the mouth of the Spokane River." This means that the White Stone or Whitestone area was on the Columbia River, less than 40 miles upstream from where Grand Coulee Dam is now located. The linked pages note that Mr. Covington spent the winter of 1872 in the White Stone area and experienced events occurring even after the main quake.
The two pages linked above, which present the 1873 account from Mr. Covington, note that "he counted ONE HUNDRED AND FORTY-TWO DISTINCT SHOCKS, continuing at irregular intervals for forty-two days. At one place he saw a crack in the surface of the earth which is now open for about one hundred and fifty yards in length, and is from two to three feet wide at the top, and is from two to six feet deep. At another place he saw where the bank of the Columbia river had CAVED OFF AND SETTLED DOWN for two or three hundred yards. The mountains and cliffs were so shaken up and appear to be so greatly agitated and disturbed that large masses of rock are still constantly falling, tumbling and sliding down."
At this point, there is something important to note. It appears that things were shaken strongly in the White Stone area, "on the Columbia River just downstream from the mouth of the Spokane River," during the earthquake of 1872. But there is now more to consider in this story. That which is presented in the paragraph above, took place in the region where Grand Coulee Dam is now located. If Grand Coulee Dam and its huge reservoir had existed in 1872, at the time of the huge quake, what would have been the final outcome for the dam and its reservoir, plus for things located downstream?
So, let us once again collect some important "puzzle pieces" of solid evidence. During the 1872 quake, there were cracks which formed in the ground on both sides of the Cascade Mountains. This would tend to indicate that the quake was associated with a deep geologic feature...one which possibly passed under the Cascade Mountains. It appears that, because of the "cracking" evidence to the east and west of the Cascade Mountains, possibly we should be looking for something like a large, deep seated east-west trending fault or rift. Possibly we should be looking for something similar to what is happening in the region of the Hanford Nuclear Reservation, where faults pass under the Cascade Mountains.
At this point, let us take a close look at a map of the area most affected by the 1872 quake, which map is linked here. On the map, there is that large, main area that was affected, which area includes the epicenter. But then, there is that isolated, affected area in Montana, to the east-southeast of the suspected epicenter. And then, in between these two locations was Fort Lapwai (link), which was located in Idaho. Fort Lapwai is the place where the foreshock is said to have been noted two hours before the main quake (link).
Let us now do something a bit different. Let us place an imaginary line from the suspected epicenter to the center of that isolated area to the east-southeast in Montana. Near the center of this imaginary line would be Fort Lapwai in Idaho, where a foreshock was said to have been felt about two hours before the main quake of 1872. Now, extend that imaginary line the other direction from the epicenter, toward the west-northwest. What does that imaginary line then pass through, to the west of the epicenter?
To the west of the epicenter, shown on the map linked above, the imaginary line would pass very close to the Strait of Juan de Fuca, which is located to the south of Victoria, British Columbia. At this point, there are some important things to note. An article linked here notes that, because of the way geologic things were happening in the area, early observers assumed "the quake was centered under Puget Sound." And, during the 1872 quake, "windows also shattered as far away as Victoria, B.C." This damage would be along that imaginary line which passes through the Strait of Juan de Fuca.
There are now some things to think about. The 1872 quake map, linked here and above, shows the epicenter for the quake as being quite a distance to the east of Seattle. Yet, a page linked here, from historylink.org, plainly declares: "There are four shocks over an eight-minute period. In Seattle 'frame buildings swayed to and fro like a small craft at sea.' A Seattle newspaper reported that the earthquake came in 'an undulating motion, from South to North, like waves of the ocean, unaccompanied by any violent jar, or irregular upheaval.'"
So, let us think about something. If the epicenter for the quake was quite a distance to the east from Seattle, then why was the ground at Seattle moving in waves, from the south to the north? If the epicenter was located far to the east of Seattle, shouldn't the earthquake waves have been moving from the east to the west?
Let us consider this matter further, about where the quake was coming from. Page 62 in a book titled List of Recorded Earthquakes is linked here. The bottom half of page 62 has an entry for the 1872 Washington Territory earthquake, as reported from Olympia. At the bottom of that entry are the following words: "The direction of the shock (December 14) at Olympia, was south to north at first, then southeast to northwest."
Once again, if the epicenter was located as indicated on the earthquake map linked here, far to the east of Seattle, then how could the shock be coming from the south and moving toward the north, at both Seattle and Olympia? It appears there is a lot more to consider in this situation.
It is time to do a bit of sleuthing. Once again, consider that 1872 earthquake map linked here and above, which now has our imaginary line running from the Strait of Juan de Fuca, through the claimed epicenter, and onward in a southeasterly direction, to the isolated area in Montana which was affected by the quake. Now, is there any known geologic feature which generally follows the path of our imaginary line? Let us consider one possibility.
In a December 1981 article linked here, scroll down to the map which indicates a rift or huge crack in the continental landmass, which spans diagonally across the United States, from Georgia to Washington State. Look how that line on the map aligns with the Strait of Juan de Fuca.
Other information about the cross-country rift is found on page 15 of the December 16, 1981 issue of The Nevada Daily Mail, which comes from Nevada, Missouri, and is linked here. The article is titled Scientists find continental 'rift' across face of U.S. Another article about this rift is found on page 14 of the December 17, 1981 issue of Lawrence Journal-World, which comes from Lawrence, Kansas, and is linked here. The Lawrence article is titled Scientists discover big rift, 1700 miles long, across U.S.
A 1981 article from the New York Times, which it titled Inactive Rift, Twice as Long as San Andreas Fault, is Found, is linked here. In the article, Dr. Raymond F. Arvidson of Washington University in St. Louis, speaks of this subterranean feature as potentially being a "shear zone." An image indicating the general location of this potential shear zone, which calls it the "Crack Across America," is found at the following links: (1)(2)(3). Note that the Yellowstone supervolcano is located along this cross-continent rift. Images which call the rift the "Missouri Gravity Low" are found at the following links: (1)(2)(3).
Are there any other geologic features, especially in the Pacific Northwest, which generally line up with this giant "Crack Across America?" Extending things out a bit, there is a page from the Montana Department of Transportation, linked here, which is titled A Lost World. In the lower-left portion of that page, it speaks about "the Lewis and Clark Fault Zone, a series of faults that stretch between northwest Washington State and the Helena area" in Montana.
For this series of faults to stretch from northwest Washington to the Helena area, this series of faults would have to pass under the Cascade Mountains. This would be similar to what is happening with faults associated with the Hanford Nuclear Reservation (link). Now, is there any documented evidence that clearly indicates that the Lewis and Clark Fault Zone is associated with or connected to that cross-continent rift or shear zone?
Moving onward with an investigation of this cross-continent rift, a page linked here is from the NASA Technical Reports Server. The page is titled Structure of the midcontinent basement. Topography, gravity, seismic, and remote sensing. The Abstract states: "A linear gravity low that is approximately 120 to 150 km wide extends from southeastern Nebraska, at a break in the midcontinent gravity high, through the Ozark Plateau, and across the Mississippi embayment. The low is also aligned with the Lewis and Clark lineament (Montana to Washington), forming a linear feature of approximately 2800 km in length." For those wanting to know more, the full NASA report from November 1, 1981 is linked here.
In the full NASA report, linked above, on PDF page 3 of 29, it states: "In southeastern Missouri the gravity low has...a value that is too high to be explained by simply valley fill by sedimentary rocks. Rather, the feature must be a basement structure. In fact, folds, faults, fold axes, dikes and basement topography in Missouri trend in directions that are approximately parallel to the gravity low." The page states: "The origin of the linear gravity feature is problematical - it may be a rift, a transcurrent fault, or some combination." On PDF page 12 of 29, the report plainly states: The Missouri gravity low is clearly a basement feature."
On PDF page 14 of 29, the NASA report states that "the gravity low lies along the southeastern projection of the Lewis and Clark Lineament, forming a combined gravity-topography signature that may extend for about 2800 km in length." The report continues: "Perhaps the most plausible explanation is that the gravity low may be as part of an extensive transcurrent fault system or a failed continental rift. Most likely, parts of the system were reactivated during various periods..."
Considering that last sentence presented in the paragraph above, could the 1872 Washington Territory earthquake have been simply movement on that western part of the cross-continent rift or shear zone which momentarily reactivated? At this point, there is one more thing to think about.
Prior to the main quake in 1872, there was that slight foreshock noted by some at Fort Lapwai in Idaho (link), about two hours before the main quake. Since Fort Lapwai is generally located near the deeply buried cross-continent rift or shear zone, could something have first shifted beneath Idaho, which then transferred geologic stress to then trigger the main quake in the area noted on the map (link) as the epicenter?
Looking once again at that page from the Montana Department of Transportation, linked here, in the lower left of that page it speaks about the Lewis and Clark Fault Zone which extends from northwest Washington State into the Helena area of Montana. And, from the NASA document linked further above, it is understood that the cross country rift or fault system in the basement of the continent is associated with the Lewis and Clark Lineament. Let us now look at the apparent path of the Lewis and Clark Lineament or fault zone in Washington State.
A map linked here shows the Lewis and Clark Fault Zone (LCZ) in the upper-right portion of the page. As the LCZ extends westward, its inferred path has it following that generally east-west path of the Columbia River, passing right through the area where Grand Coulee Dam is located. (Yes, Grand Coulee Dam is built in a large, ancient fault zone, as noted in the right-side column of a page, at the level linked here. More information will also be presented about this issue, further down on this page.) Continuing westward, the LCZ points toward the Strait of Juan de Fuca and its submarine canyon. It is very likely that there is a portion of the deeply buried LCZ which passes under the Cascade Mountains.
A page linked here is titled The Day the Earth Shook. The page notes that in the early 1970s, a geologic study of the 1872 earthquake was led by the respected geologist Howard A. Coombs. The four volume Coombs Report, which resulted from this study, set the magnitude of the 1872 quake at 7.0 to 7.3. From the evidence which was found, the Coombs Report placed the depth of the quake at "40 miles below the earth's surface." But there is more to consider, when it comes to the Coombs Report.
When the Coombs Report was produced, the cross-continent rift or shear zone in the basement of the continent was not yet known about. That basement geologic feature was not widely known about until the early 1980s. Had Coombs known about the deep, cross-continent rift or shear zone, his report may have been much different. Now, that "40 miles below the earth's surface" for the earthquake focus, which Coombs declared, may possibly be at the level of at least a portion of that deeply buried, cross-continent rift or shear zone.
It is now time for some questions. Was the Washington Territory earthquake of 1872 actually initiated by movement in the deeply buried, cross-continent rift or shear zone? Did movement in the rift or shear zone, in turn, affect or trigger various faults closer to the surface? Is this why cracking in the ground was observed to both the east and west sides of the Cascade Mountains? And, what effect could future movement on the deeply buried rift or shear zone have on those faults in the region of the Hanford Nuclear Reservation, or on those around Grand Coulee Dam or other dams in the region? There is a good reason for asking about multiple faults being triggered.
Is there a chance that when the deeply buried rift or shear zone moved, it affected at least a portion of the Olympic-Wallowa Lineament and various other surrounding fault systems which are located closer to the surface? Is that why the earthquake at Seattle "came in 'an undulating motion, from South to North, like waves of the ocean?"(link) Is that why, further to the south at Olympia, "The direction of the shock (December 14) at Olympia, was south to north at first, then southeast to northwest,"(link) even though the claimed epicenter for the 1872 quake is located far to the east or northeast?(map)
There is yet more to consider, as the "big picture" is looked at. A page linked here states that "chimneys cracked in Olympia, trees toppled in Puyallup and fissures split the ground south of Seattle..." These things "led early observers to assume the quake was centered under Puget Sound." The page also states that windows were shattered "as far away as Victoria, B.C., and people were knocked off their feet at Snoqualmie Pass."
The page linked in the paragraph above states that "The first analysis of newspaper reports from the time put the epicenter not far from Vancouver, B.C." This quake affected a large area. The page linked above declares: "It was felt from Montana and British Columbia down into Oregon and Northern California." Now, it does not appear that a shallow, more "surface" quake in northern Washington would have been felt way south in Northern California. So, the focus (link) beneath the epicenter of this quake must have been rather deep in the ground. But there is more to this story.
From what they observed, various scientists have placed the epicenter for the 1872 quake at different locations. A page linked here declares that "a Canadian seismologist named W. G. Milne, had the epicenter of the 1872 quake about a hundred miles east of Vancouver, near Hope, on the west side of the mountains..." In 1979, University of Washington seismologists, Malone and Bor, placed the epicenter in northern Washington State, "near Ross Lake." According to Wikipedia (link), one study had "a proposed location [for the epicenter] on the east side of the Cascade Range near Lake Chelan." And now, they are saying the epicenter was near Entiat WA, in Spencer Canyon.
Why have they been having so much trouble trying to figure out the epicenter for the 1872 Washington earthquake, plus what geologic feature actually caused this quake? Well, they are trying to claim that it was a shallow quake. They are trying to "pin" it to a single surface fault. To the writer, the evidence does not point to a shallow quake. The evidence points to deep movement, which then affected more than one fault closer to the surface. Potentially, faults quite a distance apart could have been affected. That is why they are having such a hard time identifying the epicenter for this quake. The shaking experienced by the populace appears to have been coming from various surface faults that were affected.
Before it is forgotten, further above, it was stated that more information would be presented about Grand Coulee Dam being built directly in a large, ancient fault zone. A page titled Deepest Hole at Base of Grand Coulee Dam, from the Washington State University Libraries site, is linked here (at least as of 10/9/2018: check it out quick, before the evidence disappears). The picture is now missing from the page, but the description declares the following:
"This is a view of the deepest hole in bedrock on the east side [of the dam site]... These deep fissures in the bedrock were filled with a dense, sticky clay deposit... Following debridement these faulted zones were heavily pressure grouted... While excavating an ancient fault line in the eastern portion of the Columbia River several slides occurred that threatened to bury the excavated fault line."
Satellite photos of the dam are found at the following links --- (1)(2) --- so the reader can more easily understand how Grand Coulee Dam is situated, in relation to the Columbia River and its direction of flow in this particular area. In the area of the dam, the Columbia River is flowing toward the top of the photos, or toward the north. The eastern portion of the Columbia River would be toward the right side of the photos.
A picture linked here looks down into the excavated faulting on the east side of the dam project. But, there is more to the story about serious faults under Grand Coulee Dam than just those under the eastern side --- that side where the Third Power Plant was later built. A 1978 document linked here is from the National Academy of Sciences. The document is titled John Lucian Savage: 1879-1967, and is A Biographical Memoir by Abel Wolman and W.H. Lyles. PDF page 7 of 16 in the document speaks about "the treatment of extensive shear zones at Grand Coulee Dam by unprecedented grouting, and the extensive and unprecedented treatment of fault zones by concrete-filled trenches and deep cutoff shafts at Shasta Dam."
From what is stated above and elsewhere in this page, there are extensive shear zones under Grand Coulee dam. These shear zones under Grand Coulee Dam appear to be associated with that ancient fault or rift zone which spans the United States, from Washington State to Georgia. But, there is a bit more to the story about what has been done with dams. From what is stated in the last paragraph of the section above, it appears there are also some serious fault zones under Shasta Dam in California. In a major quake in that region, could Shasta Dam also be compromised or fail?
Looking again at the construction project for Grand Coulee Dam, a page linked here is from the Washington State University Libaries site, Digital Collections. There is no picture available, but the text in the news clipping speaks about a fault that needed to be sealed with concrete, which was located in the "bedrock in the middle of the west side excavation area..." Part of a news clipping linked here states: "Almost 12,000 sacks of cement have been forced into the fissures in the close-grained granite under the west shore end of the dam." The title of a news clipping linked here is, Much Cement Used to Close Fissures in Coulee Bedrock.
So not only does Grand Coulee Dam have faults or fissures under the eastern section, but there is faulting under the western section. It is as John Savage declared further above on this page, that there are "extensive shear zones at Grand Coulee Dam" which they dealt with "by unprecedented grouting." All this may appear to be good and fine under normal operating conditions, but what could things be like if there was a major earthquake in the region...something like a repeat of the quake of 1872?
Looking at the situation at Grand Coulee Dam on a world scale, the dam is rather tiny in comparison to the earth (1)(2)(3). Should the earth move in a massive earthquake in this region, such as in a repeat of the 1872 quake, Grand Coulee Dam and all its grouting may be like a tiny glass thread trying to hold back a D9 bulldozer (link). Something will give, and it will not be the bulldozer. And now, there is some further, important information to consider.
A page linked here provides a testimony given to the Nuclear Regulatory Commission Petition Review Board. On PDF page 2 of 3, the testimony declares: "According to the NRC's own studies, a complete dam breach at Grand Coulee, whether through earthquake or terrorist act, would send a wall of water blasting out the seven dams below it on the Columbia River and reach the edges of the ultimate heat sink of the Columbia Generating Station. It would destroy all primary power and water intake to the site, threatening a station blackout." And now, there is one more thing to look at --- an interesting pattern of quakes which is still ongoing.
Further up on this page (link), it was noted that during the 1872 Washington earthquake, cracks opened in the ground on a hogback across the Columbia River from Entiat, Washington. Out of those cracks flowed petroleum. But there is something to now look at. A page linked here is from the Pacific Northwest Seismic Network. The page declares: "A persistent producer of small earthquakes is located near the town of Entiat, WA just south of Chelan. This area has been known to be active since 1975 when the first set of seismic stations were installed near this area." Take a look at that pattern of small earthquakes shown on the map. Something is definitely happening down below in this area.
More than half way down in a page linked here is a section titled Seismic Aberration. Regarding the strange, persistent quakes in the Entiat area, the page notes the findings of one scientist: "Other faults in Washington are moving at the same rate or faster than the Entiat fault, but they don't have anywhere near Entiat's seismic activity." The scientist states further: "It's hard to think that these earthquakes are being caused by ongoing tectonic deformation because we're just not seeing that elsewhere."
So, what is actually happening beneath the surface in the Entiat region? Let us begin by considering some important clues. As noted above, during the 1872 earthquake, cracks opened in the ground on the hogback across the Columbia River from Entiat. Out of these cracks, for a period of time, about every five minutes there was the sound like a discharging cannon and out of the cracks would come heated petroleum (link). This heated petroleum coming out of the earth is important to keep in mind, as the rest of the story is considered.
Further north from Entiat, near the outlet of Lake Chelan, some very strange things resulted from the 1872 quake. About half way down, a page linked here states: "Other accounts from 'near the lake' tell of the earth subsiding up to five feet in one place, and of cracks opening up in the ground. Some of the cracks spurted water two or three feet into the air and reeked with sulfurous fumes." Now, sulfur is commonly associated with petroleum (link), and there was that petroleum coming out of the cracks in the ground near Entiat, south of Lake Chelan.
The page linked above also declares: "At Chelan Station a great hole opened in the earth and a veritable geyser was thrown into the air to a height of 20 or 30 feet. For weeks the Indians from all parts of the country came to see the strange phenomenon ... The geyser continued all winter but got weaker and as time went on it subsided. Springs in this location still remain to show the place where there occurred this remarkable water spout."
A little more than half way down, a page linked here speaks further about the geyser and other occurrences near the outlet of Lake Chelan. It declares: "The earthquake of December 14, 1872, that threw Ribbon Cliff into the Columbia, stopping its flow, also ruined most of the stored winter food supply of the Chelan Indians when stinking sulfur water spewed out all over it from the yawning cracks opened and then closed by the quake. This quake also evidently opened a large crack in the substructure of Lake Chelan, for a tremendous geyser ('Tsillane'--'Chelan') shot up for a long time at Chelan Falls during this period, but gradually stopped itself up leaving only the large springs there."
So, what does it appear is being dealt with, geologically, in the Entiat-Chelan region? During the great earthquake of 1872, there was heated petroleum coming out of cracks on the hogback, which was across the Columbia River from Entiat. In the Lake Chelan area, cracks formed in the ground and out came sulfurous water. And then there was that short-lived geyser. And in the Entiat area, there are those persistent earthquakes. What is going on here? What is nature trying to tell us?
Look again at that map of the persistent Entiat earthquakes, which is linked here. Since petroleum came out of cracks in the ground near Entiat during the 1872 quake and sulfurous waters came out of cracks in the ground near Lake Chelan, there possibly is something important happening in this region, even today. There possibly is something happening which we need to pay close attention to. Possibly we need some further information about the geologic structure beneath this area.
A page linked here is titled Peeking below Columbia River flood basalts with high-resolution aeromagnetic data: implications for central Washington earthquake hazards. The page states: "Numerous smaller earthquakes (>1000 earthquakes since 1971 with 1.0 ≤ MW ≤ 4.3) continue to occur 20 km south of Lake Chelan near the town of Entiat, yet little is known about active structures responsible for this ongoing deformation." The page then notes that in 2011, an aeromagnetic survey was performed. And, what did this survey find?
The page linked above states: "Entiat earthquakes are occurring where NW-striking basement structures are offset by a NE-striking basement lineament. Entiat earthquakes are loosely aligned along the lineament, and most first-motion solutions are consistent with a NE-striking fault plane. The lineament is sub parallel to a NW-side-up topographic scarp 5 km SSW of Entiat observed in the field and in new LiDAR data."
The linked page then states: "Although the lineament is evident in basement magnetic anomalies, it also appears in anomalies filtered to emphasize shallow sources, suggesting that the source of the lineament penetrates CRBG. These associations suggest an active NE-striking fault that deforms topography, penetrates Miocene CRBG, and roots into pre-Tertiary basement."
So, the aeromagnetic survey suggests that there is an active NE-striking fault or basement lineament which is rooted into the basement rock beneath the Columbia River lava flows, which then deforms the topography above it and penetrates upwards into the Columbia River Basalt Group. From the findings of this aeromagnetic survey, it appears that this fault which shows up in the Columbia River lava flows closer to the surface of the earth, continues downward into the basement rock beneath the basalt flows and potentially very deep into the earth beneath.
It appears that the crossing geologic features in the basement rock beneath the Columbia River basalt flows possibly provide a form of conduit for the movement of fluidic materials from deeper in the earth in the Entiat area. There is also a question to consider. Does the NE-striking fault or basement lineament, as it continues in a northeast direction, join into the Lewis and Clark Fault Zone, which is also deeply buried beneath the Columbia River basalt flows?
Now, look closely at that Entiat earthquake map (link). Look at that high-density area for quakes in the area around Entiat. When considering the petroleum and sulfurous water coming out of cracks in the ground during the 1872 quake, is there a chance that the dense area of quakes around Entiat is signalling the upward penetration of something from deep in the earth? Would any material moving upward be following a "conduit" provided at a point of weakness provided by crossing geologic features beneath the basalt flows? And, could it be the upward penetration of this "something" forced up from much deeper in the earth which helped to crack the basalt layers above and trigger the large earthquake of 1872?
There is now something else to look at. During the 1872 earthquake, heated petroleum was being forced out of cracks in the ground in the hogback across the Columbia River from Entiat WA. Is there a chance that we may need to drill into some petroleum deposits around whatever may be penetrating upward in the Entiat region, in order to relieve at least some of the pressure underground? Could taking this action now, help to prevent something devastating --- something like a repeat of the 1872 quake? Could this action help to prevent future damage to infrastructure like Grand Coulee Dam, or even Hanford Nuclear Reservation? Could taking this action, ultimately work toward saving lives and property in the future?
People have drilled wells looking for oil and gas in other areas of this general region. In the early 1900s, prior to the Hanford Nuclear Reservation, there was the Rattlesnake Mountain natural gas field, as noted in a section linked here, from a large page on Hanford. There were some wells drilled about 20 miles south of Entiat, around the Wenatchee area (1)(2). A couple of these wells showed signs of gas and oil. But it appears that no one has drilled where nature virtually "handed us the petroleum on a silver platter," during the earthquake of 1872. You might say that nature "rubbed petroleum right in our face," and we, instead, looked the other way.
At this point, there are some things to once again consider. What could all this geologic evidence mean in regards to the Hanford Nuclear Reservation, plus to Grand Coulee Dam and the other dams on the Columbia River, in the days ahead? If movement were to once again occur on the western end of the deeply buried, cross-continental rift or shear zone, or on one of its interconnected offshoots as the result of fluidic materials penetrating from deep in the earth, could the dams and the Hanford Nuclear Reservation be greatly damaged? At this point, there is even more to think about.
As far as Hanford goes, could a massive earthquake in its general region translate to a large release of radionuclides into the surrounding environment; which would include the air, the Columbia River, and the surrounding farm lands? Could it translate into a large release of radionuclides into that very important regional aquifer system, from which comes irrigation and drinking water? And, if there was such an earthquake in the region, because of the population centers involved, what could be the final death toll and extent of property destruction?
There could be some who feel that the reservoirs behind the dams on the Columbia River should be drained and the dams removed, in order to eliminate one major source of disaster, in the event of a repeat of that 1872 quake. But, there is just one thing to say. That just won't happen. The powers that be will not allow all the reservoirs to be drained and all the dams to be eliminated from the Columbia River. So, those downstream of these dams will have to come up with a plan of action, to be implemented in the event of a major quake or series of quakes in this region.
When it comes to Hanford Nuclear Reservation, there is not much that can be done there, in order to prepare for a repeat of the 1872 quake event. A true cleanup of radioactive materials at the Hanford site will never happen. It appears that it would be virtually impossible to ever truly clean up Hanford. That is the "eternal" mess that Hanford presents. They may cover things at Hanford and make it "look pretty" on the surface, but beneath the surface, it is a whole different story. In the event of a repeat of the 1872 quake, or possibly even in the event of a full-potential Cascadia mega-quake (link), just plan on ionizing radiation to be spread into the surrounding environment from the Hanford site.
What can really be done in this whole situation? All the writer can say is, always be aware of your surroundings. Be aware of any unusual things which are happening around you. Understand that the potential does exist for Grand Coulee Dam or other dams to fail, sending a wall of water blasting downstream. Understand that Hanford Nuclear Reservation could have a major discharge of harmful or deadly ionizing radiation, which could spread throughout the surrounding environment. Once a person becomes informed about what could happen in their region, the next step is to make their "survival" plan.
Don't wait until a disaster happens to start thinking about what you should do. Don't be taken by surprise and become a statistic. Think about how you would deal with things or your escape route now. Where would you have to go from where you are now, in order to quickly escape the flood waters from a failed Grand Coulee Dam or from some other dam. And, what would be the best ways for personally dealing with any radiation from Hanford, should it be spread throughout the environment to a greater degree than it already is. The information which can help make informed decisions is available. Start checking it out.