I read a book called Cascadia's Fault by Jerry Thompson (2011).  For the benefit of my family I need to do a book report.  The book was a fascinating detective story.  It chronicles the evolution of thought which changed scientists' thinking that the Pacific Northwest was aseismic (no earthquakes) to the belief that this is one of the most dangerous seismic areas in the world.

In 1912 geologist Alfred Wegener published his belief that the continents used to be all one land mass.  He noticed that the western coastline of Africa was the mirror image of the eastern coast of South America.  He theorized that the two land masses had once been attached.+  All the other geologists laughed at him.  Everyone knew that continents don't move.

It wasn't until the 1960s that the theory of tectonic plates began to evolve.  That theory states that huge areas of the earth are riding on the molten magma core of the earth, and that the plates are moving, and pushing into one another.  One plate tries to ride up over the adjoining plate which is diving deeper into the earth.

If the plates meet on the ocean floor, the boundary between the two is marked by a deep trench.  The Pacific Ocean is ringed by what is known as “the Ring of 'Fire.”  The Ring of Fire is so named because it is defined by a continuous line of volcanoes which circles the entire Pacific basin.

The Ring of Fire includes the dozens of volcanoes in the Cascade Range of Oregon and Washington.  It continues up through British Columbia, along the Aleutian Islands of Alaska, down Russia's Kamchatka Peninsula, through Japan and the South Seas, through New Zealand, back out under the south Pacific Ocean to South America, and up the Andes Mountains and Central America back to Mt. Shasta in northern California.

The volcanoes arise because this is where the tectonic plates meet.  The ring of volcanoes is accompanied by deep oceanic trenches.  The Marianas Trench off the Philippines is the deepest place on earth.  The Pacific Ocean is ringed with these trenches, showing where the tectonic plates meet.  They are everywhere along the Ring of Fire except in the Pacific Northwest.  The absence of an oceanic trench plus no earthquakes in recorded history led scientists to believe that the Pacific Northwest was aseismic.

In 1964, on Good Friday, March 26, a giant quake hit Anchorage, Alaska.  The seismometers of the day weren't able to accurately measure a quake of that magnitude, but the quake was eventually assigned a magnitude of 9.2.  Only the 9.5 quake in Chile in 1960 was larger.

The difference between a quake of magnitude 8.0 and one of 9.0 is a factor of 10.

The Alaska earthquake generated a tsunami that devastated areas all down the Pacific Coast.  Twelve people were killed by the tsunami in Crescent City, California.  Most of them were killed because they went to see the damage caused by the first wave.  The second wave was the biggest and most destructive of the six that the earthquake generated.  Wave number two arrived ninety-seven minutes after the first one.  Crescent City wasn't even in a direct line-of-sight from the epicenter of the quake.  To reach the city, the waves had to circle back from the south.

In 1960, the year of the 9.5 Chile quake, plate tectonics were unknown.  In 1964, the year of the 9.2 Alaska quake, the Cascadia Fault was still unknown.

Of the 115 people killed in Alaska by the quake, 106 died because of the tsunami.

The Alaska quake was horizontal, not vertical.  A 20-degree subduction angle probably exists in Alaska, and also along the Cascadia Fault.

There are 18 major volcanoes from California's Mount Shasta to the Canadian border.  One of them is Mount Mazama.  Mount Mazama erupted 7,700 years ago with a plume of ash 30 miles high.  It ejected 11 to 14 cubic miles of magma.  The eruption of Mount Mazama left a deep crater now occupied by 1,958-foot-deep Crater Lake, the deepest lake in the United States.  This eruption is significant because it left a deep layer of recognizable ash which enables the dating of subsequent events.  It is a stratigraphic marker, a key reference point.

Another geologic phenomenon that plays into this narrative is the story of Lake Missoula.  Lake Missoula was a huge inland lake in what is now western Montana, formed by a 2,500-foot-high glacier that blocked the outflow of water.  Perhaps as many as 80 times in the geologic past the ice dam broke creating massive floods that scoured eastern Washington, and sent huge amounts of silt down the Columbia River and out into the Pacific Ocean.

The Columbia River has an average flow of 265,000 cubic feet per second.  Unlike most large rivers it has no delta.  Five miles offshore the river water meets the tidal surge which creates the Columbia Bar.  The outgoing river and the incoming tide, amplified by howling winds, creates 30-foot waves.  The river begins dumping its cargo of debris creating sandbars and shoals that make the river's mouth one of the most hazardous places in the world for ships.  It's called the Graveyard of the Pacific because of the nearly 2,000 ships that have been wrecked there.

Oceanographers long thought that, unlike every other place on the Pacific rim, the Pacific Northwest had no oceanic trench.  The fact of the matter is that the trench does, indeed, exist, but is buried under more than two miles of silt, sand, and debris deposited there by the Columbia River and the Missoula floods.

The ocean floor looks just like land, with plains, mountains, river canyons, and tributaries.  Scientists at Oregon State University realized that if they were to take core samples from the mud in these canyons they could determine if the Pacific Northwest had ever had any big earthquakes.  The theory was that very large earthquakes would set off undersea landslides.  These landslides would send mud hundreds of miles down the undersea canyons.  They drilled offshore holes all up and down the coast of the Pacific Northwest and collected core samples.  At every site they were able to identify the Mazama ash layer.  At every site they also found 13 landslides above that layer that occurred 500-600 years apart.  Later studies narrowed the span between landslides to an average of every 300 years.  It was determined that the mudslides all occurred at the same times all up and down the Cascadia Trench.  That was indicative of major earthquakes.

Another study revealed Indian legends of a winter night when the sea rose up and obliterated coastal villages as the people slept.

Other studies found layers of grass and peat buried on the coast under layers of sand that had come up out of the bays.

Other studies focused on ghost trees standing knee deep in bays.  The trees had once been growing on dry ground, but the ground had sunk, drowning the trees.  It was theorized that by comparing the growth rings of the submerged trees with the growth rings of old, still living trees, a date could be established as to when the ground had sunk.  This study pointed to a date between 1690 and 1720 as the time of the subsidence.  A more accurate date was impossible to pinpoint because decay and the weather had destroyed the outer growth rings of the trees.

Another scientist realized that the roots of the submerged trees might not have been subjected to as much decay and erosion as the parts of the trees that were above water level.  Submerged stumps were excavated.  They showed growth rings for 1699. but not for 1700.  Radiocarbon dating had not been able to establish the date.  Neither had chemical dating, but the trees' growth rings did it.

It dawned upon a Japanese scientist that though the Pacific Northwest had no written records that went back that far in time, the Japanese did.  He combed through the Japanese records, and found reports of ghost waves, of unknown origin, that had struck the eastern coast of Japan, causing extensive damage.  It was a series of waves that swept down the Japanese coast after midnight on January 27 and into the early morning hours of January 28.  It was a strange event because there had been no earthquake, and it wasn't the season for typhoons.  There were seven waves.  They were 16 feet high, which eliminated the possibility that the tsunami had originated in Alaska, Kamchatka, or South America.  Japan had experienced tsunamis coming from those areas, but the main force of those tsunamis was directed straight ahead.  Japan was off to the side, so the side-angle waves that hit Japan were only a foot above the tide.  Those waves could only have come from the Pacific Northwest which was directly across the ocean from Japan.

Tsunamis travel at the speed of a jetliner, around 330 miles per hour.  Calculating the time it would take the waves to cross the Pacific, and judging from the size of the waves, it was calculated that a massive earthquake of magnitude 9.0 or above had occurred on the Cascadia Fault at 9:00 p.m. January 26, 1700.  That date and time are consistent with the Indian legends of a tsunami occurring during a winter night.

These various researches established the existence of the Cascadia Fault.  They also established the fact that the fault had ruptured numerous times in the past in megathrust quakes that had affected the entire length of the 800-mile-long fault.

The question became not whether there will be another mega quake, but when it would happen.

Studies were begun to determine if underground stresses were building.  Comparisons were made between current ground levels and the precise leveling surveys made of Washington roads in 1904.  Surveys made in 1974 showed that the coast had lifted, that areas east of the coast range had subsided, and that the mountains had slightly tilted to the east.

Using lasers that precisely measured distances, it was shown that mountains on either side of Puget Sound are moving closer to one another.  Puget Sound is being squeezed.

GPS technology makes daily measurements possible.  They show that the convergence rate of the Juan de Fuca plate's eastward movement, combined with the westward movement of the North American plate is about 13 feet per century.

The friction of these huge plates moving over one another is building stress.  The deformation of the land that is demonstrated by the rise or subsidence of broad areas shows that the plates are locked together, and that strain is accumulating.

This discovery derailed the planned construction of five nuclear power plants in Washington, two of them west of Olympia.  The power plants were planned during the time when it was thought that the area was aseismic.  Subsequent studies determined that the coming megaquake will relieve the strain that is building up, and will cause the whole area to make a 6-foot westward jump.  That would not be good if a nuclear power plant was present.

A magnitude 6 or 7 earthquake may produce shock waves that last forty-five seconds or a minute.  A magnitude 9 quake might produce shock waves lasting four or five minutes.

In a megaquake “a tall building might undulate 50 or a hundred times, flexing every beam, stressing every welded joint, every slab of concrete, every pane of glass to the limits of endurance.”

There has never been a magnitude 9 earthquake in a city full of skyscrapers.  Victoria, Vancouver, Seattle and Portland have over 900 of them.  They are engineered to withstand magnitude 7 quakes.  “Specifications don't exist for a magnitude 9 because there have been so few of these megathrust events—only four in the last century.”

The 7.1 magnitude quake that hit Ferndale, California on 25 April 1992 lasted 1-1/4 minutes.  A 14-mile stretch of coastline rose.  People at ground level 202 miles inland at Sacramento felt nothing, but people on the 16^th to 18^th floors of high rises fled down the stairs to evacuate.  The shaking was worse the higher they were.  High rise buildings vibrate in harmonic resonance with the quake.  Shock waves and harmonic amplification make high rise buildings sway.

A computer model was run for Seattle.  The ground shook for four minutes.  The deep sedimentary soils of Puget Sound amplified the waves and increased the duration of shaking.  It was determined that Seattle's high rise buildings “have a significant potential for collapse.”

Nor is the possible collapse of high rise buildings the only worry in a megaquake.  The 7.1 quake in San Francisco on 17 October 1989 collapsed bridges and a mile-long section of the Nimitz Freeway.  The lower levels of the freeway were crushed.

Cascadia's earthquake will cause damage as much as 125 miles inland.  A report that I read some years ago on the possibility of a Cascadia quake predicted that “everything west of I-5 will be toast.”

The Chinese actually predicted a large quake in February 1975.  They pinpointed the date that it would occur.  The prediction was based upon a rise in the release of radon gas in wells, upon fluctuating water levels in the wells, and upon the observation that snakes and frogs emerged from hibernation and froze to death in the cold.  But each quake is different.  Another large quake happened later nearby, and the Chinese were clueless about its imminence.

I, myself, once predicted an earthquake.  I was on a tractor down at my brother Tim's place.  All of his cattle started running.  I could see no cause.  I glanced over at Vic Semingson's Charolais cattle.  They were placidly lying in their field, but suddenly they jumped to their feet and started running, too.  I thought, “how odd,” and wondered what my own cattle were doing.  I drove a little way until I could look up on the slope where my place was located.  I couldn't see a single cow.  But all of a sudden they came running out of the woods.  The whole herd ran clear across my upper field and back again.

I wondered if there had been an earthquake.  The next morning I saw Richie Stephens.  He said, “Did you hear about the earthquake in Boise yesterday?”  It had been a mild one.  It occurred some hours after my observations of the cattle.  We live on a fault, and those cattle could feel that something was going on underground.

Cattle, horses, dogs, and chickens often get agitated before a quake, so pay attention to strange animal behaviors.

More people die in tsunamis that are the aftermath of big quakes than die as a result of the quake itself.  The 12 July 1993 quake in Japan generated a tsunami nearly 100 feet high in one place.  It happened at night, but most people knew to get to higher ground when the ground shook, so casualties were few.

The bottom line is that if you're near a beach and the ground starts shaking—and especially if that shaking lasts more than one minute—it's probably a subduction earthquake and there will probably be a tsunami.  Head for higher ground and don't wait for any official notification.

Places like Seaside, Oregon may have as little as 15 minutes before the wave makes landfall with as many as eight or 10 waves behind it.  A physically-fit runner started close to Seaside's beach and timed his run to high ground.  In the event of an earthquake gridlock will occur, and running will be the only way to escape.  The runner had to cross two bridges (that possibly wouldn't be standing after a big shake), and it took him 7-1/2 minutes to reach the safe zone after a hard run.  He additionally had the advantage that it wasn't night, it wasn't winter, and that there were no downed power lines or trees.

The 15 November 2006 Kuril Island earthquake in the North Pacific sent 10 waves to Crescent City, California.  The number 9 wave was the biggest.

The Christmas 2004 earthquake in Sumatra produced a tsunami that sent waves thousands of miles northwest to Sri Lanka where they crashed ashore with deadly force.  The back side of the island was shielded from the first wave, but the wave bounced off the Maldive Islands and hit the backside of Sri Lanka with much stronger waves.

These monstrous swells can turn corners around continents, and underwater mountains can change their direction.  Sumatra's tsunami went down around Africa's Cape of Good Hope, and caused a wave in Brazil over three feet high.

A satellite passing over the Indian Ocean at the time detected a 40-centimeter rise in the ocean's surface as the wave passed.  The ocean was several miles deep at that point, but the wave reached all the way to the bottom.  It was an enormous mountain of rolling water.

“When you feel a really long duration earthquake, you immediately grab your children, help grandma—and get yourself up to high ground.”

Here are the guidelines to follow:

1. If you're anywhere near the coast and feel the earth begin to shake, start moving to higher ground as soon as the shaking stops, or sooner if you can.
2. Know where the high, safe ground is and how to get there. Plan an evacuation route to safe ground from any place where you spend a considerable amount of time.
3. Don't wait for a warning siren. There probably won't be one.
4. If you stand there long enough to see the incoming tsunami, there is almost no chance you'll outrun it.
5. Develop a plan for reconnecting with loved ones. Plan a meeting place.  There will be no phones, and you won't be driving anywhere.

I want to underline the importance of having a designated meeting place in the event of any emergency, including that of a house fire.  This will save someone from going back into a burning building to save another person who has already evacuated.

And, finally, I will insert two heartwarming stories demonstrating the value of knowledge and preparation:

“On December 26, 2004, a powerful earthquake struck off the coast of Indonesia, creating a deadly tsunami that killed more than 200,000 people.  It was a terrible tragedy.  In one day, millions of lives were forever changed.

“But there was one group of people who, although their village was destroyed, did not suffer a single casualty.

“The reason?

“They knew a tsunami was coming.

“The Moken people live in villages on islands off the coast of Thailand and Burma (Myanmar).  A society of fishermen, their lives depend on the sea.  For hundreds and perhaps thousands of years, their ancestors have studied the ocean, and they have passed their knowledge down from father to son.

“One thing in particular they were careful to teach was what to do when the ocean receded.  According to their traditions, when that happened, the 'Laboon'—a wave that eats people—would arrive soon after.

“When the elders of the village saw the dreaded signs, they shouted to everyone to run to high ground.

“Not everyone listened.

“One elderly fisherman said, 'None of the kids believed me.'  In fact, his own daughter called him a liar.  But the old fisherman would not relent until all had left the village and climbed to higher ground.

“The Moken people were fortunate in that they had someone with conviction who warned them of what would follow.  The villagers were fortunate because they listened.  Had they not, they may have perished.”  (Joseph B. Wirthlin, in general conference of The Church of Jesus Christ of Latter-day Saints, October 2005).

This final story comes from page 315 of Cascadia's Fault, by Jerry Thompson:

“Tilly Smith, a ten-year-old British schoolgirl on Christmas holidays with her parents in Thailand, was strolling across the sands of Mai Khao Beach near Phuket when she noticed frothing bubbles on the surface of the sea as the tide started to recede quite suddenly.  Two weeks before Christmas break Tilly had learned about tsunamis in her geography class.  Old film footage of a wave that hit Hilo, Hawaii, back in 1946 had evidently left an indelible memory because she immediately recognized the same thing and ran to tell her parents.

“'I told my mom again and again,' she squealed later in a television interview, 'and I was hysterical at this moment, saying, you know, There's going to be a tsunami!  There's definitely going to be a tsunami!  You know?  Just believe me!'

“Her mum and dad did believe her, and they managed to clear everybody off the beach.  Got them into the hotel.  And they managed to vertically evacuate and get about a hundred people from that hotel into the upper floors.  And not a single person died in that particular hotel complex.  All because a ten-year-old girl had knowledge!  All because she recognized the natural warning signs.”