And, here is the Times reporting on a 5.2 magnitude quake (5.5 on the Richter scale) on the night of February 13, 1981, a little ways northwest of Mt. St. Helens. It was just barely the largest earthquake in the NW since 1965: the series of quakes that led up to the St. Helens eruption on May 18, 1980 included many that were around a 5 magnitude.
Archive for the ‘Other Washington Quakes’ Category
This is the counterpart to the better known, and much better documented, Cascadia subduction zone quake of 1700. We have only geology and fairly hazy local Indian stories to confirm that the Seattle Fault released about a 7.3 magnitude quake in a year close to 900 A.D., with the results including a tsunami, land to the south of the fault being pushed up about 20 feet, and huge landslides that buried grown trees under the surface of Lake Washington.
It’s hard to visualize what such a quake could do today, although local agencies have produced a scenario for the havoc a somewhat smaller event on the Seattle Fault would produce. The Haiti earthquake was of similar size, and happened on a strike-slip fault, whereas the Seattle Fault is a reverse fault: land to the north of it drops in an earthquake, land to the south of it rises in an earthquake. The 6.9 magnitude Kobe earthquake in 1995 was also a strike-slip action, and the damage from it is probably the closest recent match for the sort of damage that would come from a circa 7 magnitude Seattle Fault quake.
Anyway, here is some information about those local Indian stories connected with the circa 900 quake. Back in 1893, the Seattle Post Intelligencer printed this explanation from Samuel Coombs, an early settler, of a long-ago earthquake and its associated ritual:
“During the past thirty-three years I have on many occasions endeavored to gather from the oldest and most intelligent Indians something for their earlier recollections; for instance, as to when the heaviest earthquake occurred. They said that one was said to have occurred a great many years before any white man had ever been seen here, when mam-ook tamah-na-wis was carried on by hundreds. This is the same performance they go through when they are making medicine men, and consists of shouting, singing, beating on drums and sticks and apparently trying to make as much noise as they can.”
Also, the Suquamish Tribe, located on the Kitsap Peninsula, had an oral tradition about the creation of Agate Passage, which separates the peninsula from Bainbridge Island:
“Long ago, when this land was new, the area we know as Agate Pass was much smaller than today. . . . There lived in this . . . body of water a . . . Giant Serpent. The Double Headed Eagle flew over the pass and the Giant Serpent came up very angry. The two began to fight, and the earth shook and the water boiled . . . the people began to scream and cry until it was as loud as thunder.
“Then, as if the earth was going to be swallowed by the waters, they began to boil and churn. Then, the Double Headed Eagle exploded out of the water and up into the sky with the body of the Giant Serpent in its claws. The Double Headed Eagle flew back into the mountain and behind him was left the wide pass . . . .”
The two above stories come from a 2005 research article, Serpent Spirit-power Stories along the Seattle Fault, which notes that “the description of the widened channel could reflect permanent ground-level change, and the sense of ground motion suggested by the story is accurate: Agate Passage is on the down-dropped northern side of the Seattle Fault.”
The article estimates that the circa 900 earthquake “caused 7 m of vertical uplift on the southern side [of Seattle Fault], sent massive block landslides tumbling into Lake Washington, and created a tsunami in Puget Sound that left sand deposits on Southern Whidbey Island.”
The article also links earthquakes and tsunamis to Indian stories about the a’yahos, a supernatural being thought of as either a huge serpent with fearsome eyes and horns [such as the one told of above] or as a composite monster with the head and toros of a deer and the tail of a snake. The a’yahos was “associated with shaking and rushes of turbid water and comes simultaneously from land and sea. At the spot where a’yahos came to a person the very earth was torn, land slides occurred and the trees became twisted and warped. Such spots were recognizable for years afterward.”
The article goes on to talk about a handful of a’yahos spirit boulders located near the Seattle Fault and thought to be markers for landslides and other damage wreaked by the huge circa 900 quake. It is one of the few documents that attest to not just the threat but the actual damage caused by ancient Northwest earthquakes that did not make it into the historical record. You can read a bit more about this in a University of Washington news release on Indian tribes and earthquake mythology in the Northwest.
In the wake of the massive subduction zone earthquake and tsunami emanating from off the east coast of Japan’s Honshu island, it’s important to remember the damage to the Northwest caused by the 1964 tsunami following the Good Friday earthquake on March 27, 1964. And, to keep in mind that much worse will happen if a coastal subduction zone quake happens here. After a 2005 tsunami scare in Crescent City, California, the San Francisco Chronicle reported from the town:
Over coffee at Glen’s, Bill Parker, Del Norte County’s former volunteer director of civil defense, recalled what he was doing the night of March 27, 1964, when a magnitude 9.2 quake off Alaska sent a series of terrible waves to Crescent City.
A mortician, Parker had been doing business in Brookings, Ore., when he got a call from the police. He hitchhiked back south with a driver who was stinking drunk. The next morning, he called the governor’s office and reported, “Crescent City is gone.”
About 150 buildings were destroyed or damaged. Boats were beached, and trailers were pulled into the sea.
“Cars were strewn everywhere,” recalled Sandy Nuss. “There were motels and houses in the middle of the street. The water rushed through the appliance store, and when it receded there were washers and dryers and refrigerators all over the place. It was a real mess.”
Nuss, a 67-year-old researcher at the Del Norte County Historical Society, said she had watched the tsunami from her home, inland and uphill from the coast.
“People saw the harbor go dry, and no one knew what it meant then,” she said. “Everyone knows what it means now.”
M.D. McGuire, 81, said he had responded to the first wave by driving to the harbor to see if his fishing boat was still there. He stopped by the Long Branch Tavern to buy cigarettes. Soon, the second wave came and his pickup was carried off by the flow.
When the water crashed through the tavern, McGuire and the bar owner’s son, Gary Clawson, moved several people to the roof. Then the two men swam to high ground, got McGuire’s rowboat and had a friend tow it back to town.
Clawson picked up five people from the tavern roof, including his mother, father and fiancée. But before they could make it to safety, the boat was pulled into a culvert, and only Clawson escaped.
When McGuire showed a reporter the culvert Wednesday, he had to pause to collect himself.
In November 2006, when an 8.1 earthquake off the Japan coast created a tsunami that did more damage to Crescent City, Glen Martin of the San Francisco Chronicle reported on the scene, and added some notes on the 1964 tsunami:
A tsunami generated by a powerful undersea earthquake near Japan struck the small Northern California fishing port of Crescent City on Wednesday, destroying docks, sinking a boat and fraying nerves.
Bill Steven, a commander with the Del Norte County Sheriff’s Department, said the tsunami was “more a series of big surges rather than waves,” but he said the damage to the town’s harbor was significant.
The surges were reported at 5 to 6 feet high.
“The water surged back and forth like a river, and our docks aren’t designed to handle swift water,” Steven said. “About 50 percent of the harbor was affected. There’s a lot of torn-up foam, wood and concrete. We know at least one boat was sunk, and we had to round up about 12 more that were torn from their moorings.”
Steven said no fatalities or injuries were reported.
Crescent City residents are particularly sensitive to tsunami threats. The town was struck by a 21-foot-high tsunami in 1964 that killed 11 people and destroyed most of the town center.
Steven said Del Norte County officials received a notification from the National Weather Service on Wednesday morning that a 3- to 5-foot surge resulting from an 8.1 magnitude quake near Japan would hit the Crescent City region about 11:40 a.m.
“We did have a very small surge at that time, and then everybody went back to business as usual,” Steven said.
Then around 2:30, Steven said, residents noticed an ominous sign — water started running out of the town’s harbor, a classic indication of an approaching tsunami.
“You don’t like to see that,” Steven said. “It looked like a very fast river.”
But instead of a large wave, Steven said, the tsunami was manifested as another large surge flowing back into the harbor.
“It went on like that until about 5 p.m., maybe later,” Steven said. “Just like a big river surging back and forth. It really hammered our docks. Pieces had to be tied off, whole sections disappeared.”
Harbormaster Richard Young, who described the event as a “river within the ocean,” estimated the damage to the docks and boats at around $700,000.
Steven said the surges came at a particularly inopportune time for the close-knit, isolated fishing community.
“Everybody was just getting warmed up for the Dungeness crab season,” he said. “Unfortunately, this could really slow things down.”
Steven, who was born the year after the killer waves hit the town in 1964, said his father often reminisced about the event.
“He was especially amazed by the tremendous field of debris it left,” he said. “It’s still a major topic of conversation in this town.”
In the immediate aftermath of the December 26, 2004 earthquake and tsunami off the Indonesia coast, Richard Eisner, coastal administrative chief for the California Office of Emergency Services, issued this warning in a San Francisco Chronicle article:
Eisner urged Californians to remember one of the ghastly lessons of the Crescent City tsunami of 1964, when 11 people died after the coastal town in Del Norte County was clobbered by a wave triggered by a mega-quake in distant Alaska. That lesson is this: The worst wave is not necessarily the first wave that hits the shore.
Tsunami waves tend to come in multiples — like multiple ripples on a pond after you toss a stone into it. Worse, the second wave often carries debris sucked to sea by the first wave.
“In Crescent City in 1964,” Eisner noted, “most of those who perished perished because they assumed the tsunami was over (after the first wave, and said), ‘Let’s go take a look.’ The second wave came in — these waves move 20 to 30 mph, you can’t outrun it — and the water doesn’t have to be very deep with those velocities to run you down, and you’re battered by debris and you’re battered into buildings.”
Finally, in a March 2005 review of The Raging Sea, a book by Dennis M. Powers that describes the tsunami, Robert Krier of the San Diego Union-Tribune quoted from the book:
The description of two men fishing in a river near the shore gives a good idea of the shock and horror one might feel upon seeing an approaching tsunami:
“Suddenly, a loud crash that sounded ‘like a cannon shot’ cracked through the air.
“Jerking their heads toward the sound, they froze at the sight of a twelve-foot wall of water bearing down on them in the moonlight. It then stood poised overhead, as if a film had stopped mid-show. The bulging wave’s white crest held captive huge logs and driftwood that protruded from it like a crown of thorns.
“The churning ocean crashed over the two men, as the wave pounded into them and up the river. The rampaging currents buffeted their bodies, twisting them savagely, head over heels. They reached instinctively for anything to grab onto, desperately trying to work their way back to the surface.”
The waves pushed the men two miles inland. One of the two survived the scramble, due largely to the heroic efforts of his friend, who was later swept out to sea and drowned when the waters retreated in an equally frightening pullback.
Powers quotes a father of four who was camping with his family on a beach nearby.
“We were awakened shortly after 11 o’clock by a small wave. … We grabbed the kids. But then came huge waves — battering waves. We were completely helpless. I had two of the kids by the hand, but I have no idea what happened. Nobody had a chance.”
All four of the man’s children were killed.
The book closely follows the story of a group in the Long Branch Tavern. The owner and friends and relatives had returned to the bar after the first two small waves hit. When they found no damage, they celebrated their good fortune, plus the birthday of one member of the group. Five of the group later died in a mad scramble after the third and fourth waves hit.
That group’s survivors lived to tell gripping and heroic stories, filled with gut-wrenching twists, escapes and life-or-death, split-second decisions. Don’t be surprised if their tale hits the multiplex within a few years, now that tsunamis are on our minds.
Powers gives first-hand accounts of houses floating for blocks in the waves, with people trapped inside. He tells of others scrambling onto rooftops, clapping when the structures held; and of frantic drivers and passengers trapped in vehicles bobbing in the churning water. He describes the subsequent fires that compounded the calamity and created a scene out of “Dante’s Inferno.”
In a 2005 review of Powers’ book, David Campiche of the Daily Astorian discussed the ongoing threat:
It is hard to swallow the medicine spooned out in Dennis Powers’ “The Raging Sea,” a detailed account of the four waves that wiped out between 10 to 20 square miles of Crescent City, Calif., on Good Friday, 41 years ago.
Powers shares all. This 288-page account carefully recreates the jagged depictions of hundreds of lives affected by those monstrous waves. Many survived, often by acts of heroism, or more often through the sheer human will to survive. Indeed, there is hope in that, and in the fact that so many did survive and rebuild. Of course, there were the others who didn’t. One reads on and on, each page more than a recollection, each of poignant significance to oceanside earth dwellers.
Each page fills in the jags still empty in our current and fertile imagination. What actually happened on the beaches in Indonesia? How big were those waves anyway, 30 feet or 80? Like so many of the victims of the catastrophe, people were led by their curiosity right to the water’s edge, so they could watch the debacle unfold. Unfold it did. Most, who pushed too close, died violently.
Truth be told, the majority of human beings avoid too much bad news. We are surrounded by constant reminders of aberrant human behavior and Mother Nature posturing with all her might. We know that every day, human beings are dying in Iraq. Do we really need to read the newspaper each morning with the intention of gleaning specific facts? Some do, and some don’t.
It is for this specific reason that Powers’ book is drawn into the ebb of human emotions. The book will remain uncomfortable in the minds of many of its readers, particularly those endangered by the reality that waves do come, and regularly, in geological time.
In all fairness, the book performs a service: It anoints us with truth. The tsunami that reaped devastation of Crescent City was not remotely as devastating as the cataclysms that recently struck the beaches of the South Pacific and not remotely as devastating as the projected quake and subsequent waves that sooner or later will reap havoc on the Oregon and Washington beaches.
Are we listening? Are developers listening? One wonders if they have built their homes at the ocean’s edge, or retired to some safe outpost like Oaxaca or some other inland property.
Powers’ book is an important read. One can’t bluff 30-foot waves, can’t imagine 80-footers. Ignore the truth and it will come, anyway.
When news broke of the seismic shaking that accompanied the 67-yard touchdown run by Marshawn Lynch of the Seattle Seahawks at Qwest Field on January 8, I thought back to the greater shaking that resulted from the Kingdome’s implosion. Two months after the implosion, Richard L. Hill of the Oregonian wrote a report on its seismic impact:
The implosion that recently crunched Seattle’s Kingdome is proving to be more than a 16.8-second spectator sport. The earth-shaking event also is part of a unique experiment giving scientists a clearer picture of the city’s earthquake risks.
Before the blast, researchers with the U.S. Geological Survey and the University of Washington placed more than 200 seismometers throughout Seattle. The detectors were spaced about every eight or nine blocks from Boeing Field to the south of the Kingdome to Green Lake in the north.
Treating the demolition as an earthquake, scientists are using the seismic waves detected by the instruments to study how the ground in parts of the city amplifies shaking and to develop a three-dimensional image of the geological structures near the Seattle Fault. Researchers are analyzing the data, with preliminary results expected by the end of the summer.
“The signal from the Kingdome implosion was much better than we had hoped for,” said William P. Steele, coordinator of UW’s seismology lab that monitors Northwest earthquakes.
Seismometers already in place to measure quakes detected the collapse from as far away as Olympia, about 60 miles south, and Mount Baker, about 85 miles north. It was the equivalent of about a magnitude 3.0 earthquake. Only people near the Kingdome felt the ground shake.
Rather than recording the explosion, the seismometers detected the shock waves produced by the collapse of the building — especially its 25,000-ton concrete roof.
It seems that the implosion was actually more like a 2.3 magnitude. The day after, the Seattle Post-Intelligencer wrote a report that in some ways sounds like a summary of damage from a minor quake:
The Kingdome took more than three years to build. Yesterday, it fell in 16.8 seconds.
And when the stadium – along with its 25,000-ton concrete roof – shuddered and crashed, the Earth literally moved.
Vibrations from the implosion, equal to a 2.3-magnitude earthquake, rippled through the Pioneer Square neighborhood. The sound of the blast traveled for miles, and some people said they felt concussions from far away.
Several windows of nearby buildings were blown out, which spelled opportunity for Brian Perkins, a fifth-generation glazier with Perkins Glass of Capitol Hill.
By noon, the company had replaced about 15 shattered windows in three buildings and was getting started on a fourth – the Salvation Army, east of the Dome on Fourth Avenue South.
A bigger nuisance was dust from the implosion. A giant cloud of fine white powder billowed north of the collapsed stadium and coated cars and streets in the International District. But shortly after the 8:32 a.m. implosion, crews spread into the streets to clean up the mess.
By the numbers
Duration, in seconds, of yesterday’s implosion : 16.8
Pounds of dynamite used: 4,461
Cubic feet of air, in millions, displaced by collapse: 68
Earthquake magnitude equivalent of implosion : 2.3
Seismometers hidden in back yards and buildings: more than 200
There’s a background note to the Kingdome seismic test: it was preceded by some forensic seismic work on the Oklahoma City federal building blast. The Seattle Times wrote:
“The benefit to us is that you never know ahead of time when an earthquake is going to happen,” said Thomas M. Brocher, a seismologist with the Geological Survey in Menlo Park, Calif. “So we treated the demolition like an earthquake to get a uniform sampling of how various neighborhoods are going to respond in a quake.”
The Kingdome blast wasn’t the first demolition that Brocher has examined. He was involved in studying the shock waves generated by the implosion of the shell of the nine-story Alfred P. Murrah Federal Building in Oklahoma City. A bomb a month earlier killed 169 people.
Brocher and his colleagues determined that only one blast, not two as some people initially thought, had destroyed the building. “The seismic waves generated by the criminal blast had been misinterpreted,” Brocher said. “The demolition helped us confirm that only one explosion had occurred.
“That experiment gave us confidence that we could get some useful signals out of the demolition of the Kingdome,” he said.
And, there’s a postscript: the World Trade Center attacks produced five different seismic events, which Columbia University recorded on this page. The two tower collapses registered 2.1 and 2.3 magnitudes. (By the way, earthquakes do happen in Manhattan: here’s one example only weeks after 9/11.)
This earthquake had an epicenter 27.6 kilometers WNW of Poulsbo, and the PNSN records it as having a 5.3 magnitude. It was felt at least from Victoria to Bellingham, but probably no farther south than Olympia or Centralia. There may be other Puget Sound earthquakes in the past 140 years or so that have been featured in newspapers, but this seems to be the most notable one that I hadn’t yet mentioned on the blog. Here’s the Seattle Times covering the quake:
EARTH TREMBLES VIOLENTLY
Hundreds of frightened persons in Seattle rushed from their homes last night about 8:20 o’clock when an earthquake of unusual violence and one that was felt distinctly throughout the Norhwest occurred. It threw a scare into everybody from Green Lake to South Seattle.
Little, if any, damage was done. As near as can be ascertained, the first of the two shocks occurred about 8:20 p.m. The second one followed closely upon the heels of the first, and although it was soon over, nevertheless nearly every front porch in Seattle was crowded with frightened humanity–persons who had rushed from their homes to see what the matter was.
The fact that there is an annular eclipse of the sun due today in Southern Asia has caused many persons to inquire if the eclipse had anything to do with Seattle’s surprise of last evening. Those who are authority say eclipses do not cause earthquakes.
Queen Anne Hill felt the shock the greatest of any part of the city. Many houses rocked like a bark at sea, while dogs howled in terror at the unexpected visitation.
On the first and second hills [First Hill and Capitol Hill, I suppose] the society people never received such a shock. When the earthquake went rumbling along Broadway, society folk rushed to their verandas and spilled golf club expressions all over the grass.
Down-town newspaper offices were busy until late into the night answering frightened inquiries over the telephone. There was no section of the city that did not feel the shock, and it is claimed by pioneers that it was the most pronounced ever experienced in this city.
Tacoma-The earthquake shock last night was the most severe pioneers can remember. the earth motion appeared to move from north to south and the shaking was so strong that people in buildings were apprehensive.
The oscillations lasted about fifteen seconds. No harm, so far as can be learned, was done by the earthquake.
Many people believe there has been some seismic disturbance in the vicinity of Mount Rainier, and connect the shock last night with it.
Ballard-The shock was felt more distinctly on Ballard Avenue and the water front than in the northern part of the city. The brick blocks swayed in some instance to such a degree that the people on the top floors ran out in fright, thinking that the buildings were about to collapse.
The Times relegated the news to the bottom of the front page: after all, the Russo-Japanese war was going on, and besides, a wandering tramp had found a bunch of gold in the snow and returned it to the man who lost it:
I recently compiled some of the stories and pictures on this blog into an article for the SunBreak warning about the Northwest’s ongoing history of earthquakes and what it means for the threat of another damaging quake. My sense was that I’d dug up stories about pretty much every significant quake on the record, but the article led me to look for any other ones I’d not yet noticed.
I found out about an earthquake swarm in Spokane in 2001 that lasted several months, from either late May or late June on into November, if not longer. In the wake of the Nisqually quake, it got some attention. I don’t know exactly what it means for Spokane’s earthquake threat, but it’s at least worth knowing about. On July 1, 2001, the Associated Press said seismologists thought the quakes might mean “the newly discovered Latah Creek fault could be rumbling to life again after a 1.5 million-year slumber.”
There were quite a few small quakes on June 25, causing damage to some brickwork, broken plates, and other fairly minor problems, and University of Washington geophysicist Bill Steele said, “We have to say it could be a precursor of a bigger thing to come. Due to modest historic seismic activity in the area, it’s a very low probability. But we can’t rule that out.”
In response, the Pacific Northwest Seismographic Network installed some digital seismographs in Spokane. Bob Derkey, a geologist with the state Department of Natural Resources in Spokane , said he’d only mapped the Latah Creek fault in winter 2000. It runs in a nearly straight line from Steptoe Butte southeast of Spokane to Tum Tum northwest of the city.
Steele said, “We just can’t predict, but if the faults there are of significant size, we couldn’t rule out magnitude 6 event or larger. It’s a low probability, but certainly possible.”
In August, the Spokane Spokesman Review reported on another seismograph being installed hours after a 1.5 quake registered as the 33rd earthquake in all; a 3.7 on June 25 may have started the swarm. A 4.0 happened in the morning on November 11, Veteran’s Day. In November, around Thanksgiving, the AP reported:
The temblors come day and night. Schools hold duck-and-cover drills. Workers in downtown high-rises study evacuation plans.
Since May 24, Spokane has been in the throes of what experts call an ” earthquake swarm.” More than 75 temblors have been recorded, and dozens more could not be measured because of a lack of seismographs.
There have been no injuries or major damage — other than bricks falling from chimneys and items off of shelves — but nerves are fraying.
“We’ve felt every single one of them,” said Cindy Burrows, who works on the 19th floor of the Bank of America Financial Center, downtown’s tallest building. “The building doesn’t sway. It jumps.”
One quake caused such a jolt she had to hang onto her desk, Burrows said. . . .
Spokane, a city of 190,000, has had no major quakes in its 120-year recorded history and wasn’t regarded as being in an earthquake zone. Because of that, there were no seismographs in the city when quakes started hitting in May. Now there are four.
Nearly all the quakes have been centered on the city’s north side, a few miles north of the Spokane River. The quakes have been shallow, sometimes only a mile or two deep, and noisy.
They are announced by loud cracks, sounding like explosions or the pounding of heavy equipment. In the tense atmosphere after the Sept. 11 terrorist attacks on the East Coast, such explosions have been particularly disconcerting.
Ground movement generally lasts only a few seconds.
Gonzaga Prep High School, directly over some of the temblors, is holding earthquake drills for its 970 students.
“Get away from the windows, get into the lowest position and stay there,” said dean of students Roger Cilley. “We don’t want them running out of the building.” . . .
The lack of recorded major earthquakes in the Spokane area is not a source of comfort, because the area’s recorded history is just a blink in geologic time, Tom Yelin of the USGS said.
While quakes have been going on for six months, the strongest occurred on Nov. 11, a magnitude 4 temblor that was followed by quakes measuring 3.1 and 3.3 over the next few hours.
“There’s no way to say if it is a harbinger” of a bigger quake, Steele said. “We can’t rule it out and can’t say if it is.”
Lack of information about location and length of the fault is a problem, Steele said.
“We don’t understand the fault’s parameters, so we don’t know what the maximum earthquake would be on that structure,” Steele said.
But the Spokane quakes are so shallow that even a magnitude 5 could cause plenty of damage, Steele said.
Spokane’s downtown includes a large number of historic buildings, built long before modern earthquake codes were developed.
If you want to learn more, the PNSN has a more extensive page giving an overview of the “2001 Spokane Earthquake Sequence,” as the page calls it.
It’s easy to forget, or simply never realize, that the big St. Helens eruption in 1980 was triggered by an earthquake. A USGS feature on St. Helens explains:
May 18, a Sunday, dawned bright and clear. At 7 a.m. Pacific Daylight Time (PDT), USGS volcanologist David A. Johnston, who had Saturday-night duty at an observation post about 6 miles north of the volcano, radioed in the results of some laser-beam measurements he had made moments earlier that morning. Even considering these measurements, the status of Mount St. Helens’ activity that day showed no change from the pattern of the preceding month. Volcano-monitoring data-seismic, rate of bulge movement, sulfur-dioxide gas emission, and ground temperature-revealed no unusual changes that could be taken as warning signals for the catastrophe that would strike about an hour and a half later.
About 20 seconds after 8:32 a.m. PDT, apparently in response to a magnitude-5.1 earthquake about 1 mile beneath the volcano, the bulged, unstable north flank of Mount St. Helens suddenly began to collapse, triggering a rapid and tragic train of events that resulted in widespread devastation and the loss of 57 people, including volcanologist Johnston.
Geologists Keith and Dorothy Stoffel, who were in a small plane over the volcano’s summit when the eruption started, wrote that they “noticed landsliding of rock and ice debris in-ward into the crater… the south-facing wall of the north side of the main crater was especially active. Within a matter of seconds, perhaps 15 seconds, the whole north side of the summit crater began to move instantaneously. … The nature of movement was eerie…. The entire mass began to ripple and churn up, without moving laterally. Then the entire north side of the summit began sliding to the north along a deep-seated slide plane. I (Keith Stoffel) was amazed and excited with the realization that we were watching this landslide of unbelievable proportions. … We took pictures of this slide sequence occurring, but before we could snap off more than a few pictures, a huge explosion blasted out of the detachment plane. We neither felt nor heard a thing, even though we were just east of the summit at this time.”
In the Seattle Post-Intelligencer of Tuesday, April 21, 1987, Debera Carlton wrote that Jim Zollweg of the U.S. Geological Survey at the UW and Chris Jonientz-Trisler of the UW seismology lab had developed a new understanding of the eruption. Carlton explained:
The two seismologists have been able to reconstruct the 1980 eruption and reinterpret what happened inside the mountain in the months before the big explosion. They’ve discovered that ”subedificial” quakes played a key role in what happened at Mount St. Helens. At the time of the eruption, scientists had recorded these small quakes but did not attach any significance to them.
Subedificial means ”beneath the edifice,” which in this case was the volcano.
”Right at the surface is where the volcano erupts, so scientists at the time were paying a lot of attention to that,” Zollweg said. ”That’s where the mountain was actually bulging, and that’s where the mountain failed. A magnitude 5.1 earthquake triggered the landslide that essentially opened up the crater and released the magma and gases.
”But if they’d recognized these other types of earthquakes , which we have dubbed subedificial quakes, they would have known that there was also stress being applied deeper within the system, not just at the top where the bulge was,” he said. ”There was magma moving down at depth, which is one thing they didn’t realize at all at the time.
”What we did was change the whole concept of what the volcanic system probably looks like.”
Zollweg and Jonientz-Trisler decided to reanalyze the 1980 data after noticing subedificial earthquakes during an explosive eruption of St . Helens in March 1982. The seismologists wanted to know if these quakes had occurred in 1980 but might have been overlooked.
”This was the first time something like this had been done for a North American volcano,” Zollweg said.
The two scientists analyzed an overwhelming volume of data from quake activity that occurred at Mount St. Helens from the time of the first steam eruption on March 27, 1980, to the explosion May 18.
More than 20,000 large earthquakes had been recorded in what the seismologists term the ”shallow system,” roughly occurring from one mile below sea level up into the cone, or the mountain itself. . . . The subedificial earthquakes lined up in a ribbonlike line directly below the bulge where the northern portion of Mount St. Helens eventually gave way.
A similar line of subedificial quakes was found on the west side of the mountain, indicating a second conduit system. This system, Zollweg said, begins deeper but does not extend as high within the volcano.
The seismologists not only located the conduit systems, but determined their approximate size.
”If you had X-ray vision and could look inside the mountain, you’d see a nearly vertical structure – a big pipe,” Zollweg said. ”It’s elongated like a ribbon, and runs off at a slant. The width has to be very small. It can’t be more than a few tens of yards across.
”The thinner the conduit, the less magma it can hold. The more magma that tries to pump through there, the greater the rate of rock breakage.
”We’ve described some very, very small pipes through which the magma travels, and the earthquakes are the result of this excess pressure, like when you try to push too much water through a pipe. If extra pressure is exerted, the pipe will really bulge. And since the pipe can’t really bulge in this case, the only thing it can do is break the rock around it.”
Eventually, the two seismologists came up with this play-by-play of what happened:
On March 27, 1980, the first steam eruption occurs at St. Helens. Subedificial earthquakes indicate magma moving through the conduit system.
Earthquake activity accelerates between April 5 and April 27-28, the time of ”maximum pre-eruptive stress” around the conduits.
Earthquake activity decreases between April 30 and May 18.
On May 18, a magnitude 5.1 earthquake causes a huge landslide that rips away the mountain’s bulge. This has the same effect as popping a cork off a champagne bottle. All the pent-up gases and magma explode out of the mountain.
”On May 18, the magma and gases were not ready to explode by themselves,” said Jonientz-Trisler. ”But after the landslide, the magma and gases were no longer contained and under pressure. They were then able to move up in the system.”
The number and size of subedificial earthquakes were greatest in the eight hours after the May 18 eruption.
”After the cap came off, the subedificial activity was the most intense,” Zollweg said. ”When you take the cork off, anything down there can start coming up, so the magma was actually moving faster through the conduits after the eruption than before.”
Finally, a Seattle Post-Intelligencer article by Mike Barber on Thursday, May 11, 2000, talked about Harry Truman, the old man of Spirit Lake. It said:
Just before St. Helens came to life in March 1980, Truman had been slowed by a series of mishaps and seemed to be deteriorating, said George Barker, who was the Skamania County Sheriff’s resident deputy at Spirit Lake.
“That winter I was more concerned about an elderly guy staying warm and having food; he was getting older and getting tired,” Barker said.
When the mountain started acting up, Truman seemed to come alive as well – especially when reporters started coming in on the helicopters that would land near his lodge.
“When they began coming around, he got another shot in life,” Barker said. “He enjoyed the attention.”
Rosen says Truman’s unwillingness to leave the mountain had more to do with protecting his property than making a statement. Others say the headlines contributed to his refusal to come off the mountain – he felt obliged to live up to his press.
“I think he kind of got himself talked into a Catch-22 situation to stay,” Barker said. “He wanted to come down. He was very much afraid of earthquakes.
“He felt, like everyone else, that he would be able to see lava start to ooze down and a news helicopter would come in and scoop him up at the last minute.”
Nature had other ideas. The searing blast came at 200 mph.
“One scientist told us Truman probably had time to maybe turn his head,” Rosen said.
A 5.1 earthquake in Grays Harbor County on the evening of July 2, 1999, forced the county to spend $7.2 million repairing and retrofitting its courthouse.
Here are a few quake stories about it from, first, Marshall Baldwin, who was watching TV in his Satsop home: “It was bang, bang, bang and just before it ended the ground swayed. I could see my car out in the driveway bouncing around. It was pretty exciting really.”
Beth Watkins, a waitress at The Oriole restaurant in Hoquiam: “We had a couple tables, and we were doing some work in the back room. Then the floor just started rolling, and we ran for the door.”
Heather Churchill, a waitress at the Tokeland Hotel: “Everything else in the hotel was shaking, and then the cook yelled that we needed to go outside. It felt like you were in the ocean, rocking. I looked down and my feet were shaking from the quake. It was scary.”
Stacy Charette in Satsop said: “As the rumbling started getting louder, I thought train, and then I looked around and right then it hit me, ‘Earthquake.’
“We felt it real good. Things tipped over. I could see the walls moving, and I could hear the house creaking. I just wanted to grab my kids and get in the doorway. There was a lot of creaking. A few things fell off shelves.”
Jim Rutto, a maintenance man at the Best Western Lighthouse in Ocean Shores: “I was just about to get into the elevator when things started shaking and the doors started moving. And I thought to myself ‘I’m not getting in that. I’ll take the stairs.’”
Rick Wilkins was at Pier 66 in Grays Harbor: “The whole pier shook. Then people were walking around nothing happened. They looked surprised, then were real nonchalant.”
John Brooks, of Elma, which was about five miles from the epicenter: “It sounded like it was right under the house. It was almost like dynamite going off right outside your window.”
Mary Harris, also in Elma, said: “At first, I didn’t know what it was. It was a really loud noise. Then it just got worse. The house just started swaying, and I looked up and my fans were swaying. My house felt like it was buckling. It was just very scary.
“I went in the kitchen, and I could hear my cups rattling in the cupboards. The oven was shaking. It felt like the house was just going to fall down.”
Mark Simon, at the Bee Hive restaurant in Montesano, said: “I was giving cash to a customer up front, and the floor started flexing under my feet. Right after that, it really rumbled. People all got down and some were screaming. Bottles were falling off the shelves. It seemed like it wasn’t going to stop.”
In Seattle, Steve Gershik, a Bay Area man in Westlake Center, added: “I saw the fixtures in the mall moving. It was so incongruent. You don’t expect to come from San Francisco and feel an earthquake.”
The Seattle Times reported:
The roof collapsed at Moore’s Furniture and Appliances in downtown Aberdeen, sending debris into the building and onto the sidewalk outside. Owner Jim Moore, 47, said he had just closed the store and was pulling away in his car when the quake hit.
“When I think about it,” he said, “if I had only been just a couple of minutes later getting out of there . . ..”
In Mason County, a 911 dispatcher said the only damage reported was cracked walls and merchandise knocked off a local Safeway store in the Shelton area.
The Aberdeen and Hoquiam areas had power outages, some broken water lines, and there was a small gas leak in the county seat of Montesano.
The county courthouse in Montesano suffered extensive damage to Superior Court chambers on the third floor, and the bell tower on the fourth floor had a supporting brick wall that was dislodged, said Rick Scott, undersheriff for the Grays Harbor County Sheriff’s Office.
“Right now nothing so severe that there’s a concern about evacuations,” he said last night.
The Red Cross began opening a temporary shelter for people in older homes in the area in the event that they want to go elsewhere for the night, Scott said.
The biggest concerns were around the structural integrity of dams and the cooling towers at the old nuclear power plant at Satsop, which is shut down. The dams and cooling towers seem to be structurally intact, Scott said.
Two inmates who tried to break out of the Aberdeen jail ripped a metal piece off a door and used it to smash several windows, police Sgt. Tom Siress said. But before they could climb out, a clerk noticed them on a surveillance monitor and alerted officers.
Some of the older buildings downtown appeared to have cracked walls or foundations and would have to be inspected to see if they are safe to enter, Siress said.
“From what I’ve seen, we have considerable major cracks to several older brick buildings,” he said.
In addition, he said, huge plate-glass windows shattered in some of the buildings.
Also, a 5.0 earthquake on January 29, 1995, was centered just off Maury Island, and didn’t cause either major damage or injuries. But it was the most prominent Puget Sound earthquake since the ’65 one. Scott Shabaz, who lived near Federal Way, said: “It started shaking the whole trailer. I have a rude friend that comes by once in a while and likes to do that with his truck. It lasted 30 or 40 seconds.”
Nancy Mendoza, spokeswoman for the Tacoma-Pierce County chapter of the American Red Cross, said: “I was in the kitchen talking on the telephone. The whole house started moving. Neighbors came running down banging on my door. People were right up on their porches almost instantly.”
And, in the aftermath of the Kobe earthquake, she warned: “Boy, if we’re going to get more of these, people should get themselves prepared. This is sure a wake-up call for people. We ought to seriously think about getting ready for an earthquake instead of worrying about it.”
A few days ago I responded to Knute’s Crosscut post about Puget Sound’s numerous natural hazards by letting him know about this project. He responded by sharing a couple quake tales of his and his father’s, starting with the Valentine’s Day 1946 earthquake:
My father had a great story about that. He was scrubbing for surgery at Virginia Mason; when the quake hit, the doctor next to him jumped up and sat in the sink! After the quake, my dad asked him why he took cover that way. The other doctor replied that he’d seen major quake devastation in Manila, and the building had collapsed, but their plumbing was still standing intact, with sinks, bathtubs and toilets hanging up in the air from the pipes. He said he promised himself that if he was ever in a major quake, he’d get into the nearest bathtub so he wouldn’t go down with the building.
And I well remember the ’65 quake. I was at before-school orchestra practice at John Muir elementary. Our teacher, Mr. Bloom (who looked just like Richard Nixon) continued to tune a violin throughout the quake telling us all to be calm. I put my French horn over my head for protection as cracks appeared in the ceiling of the school lunchroom overhead.
This earthquake didn’t get much attention even at the time it happened: a 5.2 or 5.5 (the authorities differ) quake centered in east Vancouver, it struck at 7:37 on a Monday evening. Overshadowed by the big Columbus Day storm of mid-October, not to mention the Cuban missile crisis and the next day’s elections, the Oregonian reported it inflicted “no reported injuries or serious damage.” At the time, seismologists placed the epicenter south of Portland. The paper said “it lasted only a few seconds, in contrast with other jolts with less intensity but of longer duration which have caused widespread damage in the area.”
The Oregonian: “Buildings shook violently, dishes were knocked off shelves, bricks in chimneys tumbled to the ground and some lights went out . . . The jolt was felt at Dexter, east of Eugene. . . Seattle reported only a slight tremor.
“In Camas and Stevenson, Wash., near where last year’s earthquake was believed centered, residents said it was the sharpest jolt they had ever felt.”
There was the normal surge of calls after the quake, and power was briefly lost in the Hillsdale neighborhood. The paper said otherwise, “damage in Portland was confined to cracked walls, toppling dishes and falling chimney bricks.” A San Francisco advertising guy named Charles Bigelow who was in the Portland Public Service Building said, “It is not a typical quake. It should be preceded by a rumble. Your quakes are unorthodox.”
In 2002, Richard L. Hill of the Oregonian revisited this quake. Lou Clark, a geologist with the Oregon Department of Geology and Mineral Industries, said: “People were just shellshocked by the Columbus Day Storm, so the earthquake quickly was forgotten. Oregon at the time was considered a seismic desert, and earthquakes weren’t seen as much of a risk in the Portland area.
“The earthquake didn’t change building codes or anything like that, but it was an important event in that it made both Oregonians and the scientific community understand that the risk is real.
“I was by myself in the kitchen when things started shaking. I had no clue as to what was happening. I was too scared to move and too scared to scream. It didn’t last long, a few seconds, but it felt like five minutes.
“That earthquake is one of the reasons I’m a geologist now. It made a huge impression on me.”
Thomas Yelin, a geophysicist with the U.S. Geological Survey at the University of Washington, worked with seismologist Howard Patton of Lawrence Livermore National Laboratory and calculated that the quake was a magnitude 5.2, centered about 10 miles beneath the surface and nine miles northeast of downtown Portland.
Two days after the quake, with Oregon having re-elected Mark O. Hatfield as governor and elected Wayne Morse as U.S. senator, the Oregonian said: “Monday night’s violent, though brief tremor was one of a series [of earthquakes], each recalling to mind the fact that the ‘young’ mountains of the Pacific slope . . . are on the move. Monday night’s quake found us already conditioned to the sound of falling chimneys and to the light of candles. For it came less than a month after we were brushed by Typhoon Frieda’s swirling skirt. . . . We must agree that the loss of life has been providentially low. The daily routine has scarcely missed a beat. But we don’t have to like it. The wonder is that some people still complain about the soft Oregon rain.”
Basically, if the quake had been centered 50 or 100 miles to the east, it probably would have merited a couple paragraphs in the Oregonian and been entirely forgotten within a week. But, it’s possibly the biggest quake to hit the Portland-Vancouver area in the last century, or at least was before the ’93 Spring Break Quake. Look at a shake map for the quake, and the Oregonian’s front page on Nov. 6, ’62: