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Sorry to disagree, but Salt Lake is astride the Wasatch Fault, which is due for a California-like catastrophic quake in the future. When I lived there as a kid, we used to have "tremors" frequently. Of course they were testing nuclear warheads out in the desert at time.
when I lived in Minneapolis I purchased a tornado diverter that consisted of a bamboo pole with some pie tins with string passing through the middle of them and tied to the pole. Worked for many years with 100% effectiveness and I left it behind when I moved and have noticed that still no tornados ever hit this area of town so it still works after all this time.
when I lived in Minneapolis I purchased a tornado diverter that consisted of a bamboo pole with some pie tins with string passing through the middle of them and tied to the pole. Worked for many years with 100% effectiveness and I left it behind when I moved and have noticed that still no tornados ever hit this area of town so it still works after all this time.
There is a misunderstanding about Seattle. The great subduction quake, which is in the window of happening, would most greatly effect the coast. Seattle is not on the coast. Not to say there would no damage, but it has been greatly exaggerated by many media sources including the NY Times, which was retracted. The Volcano issue is also very "overblown", excuse the pun, but even if Mt. Rainier erupted, (very unlikely in our lifetimes), it would not come close to damaging Seattle.
If I'm reading this map correctly, after reading the linked explanations of the terms and the following Wikipedia article, this map show areas of Seattle subject to the earthquakes with GREATER force than the amounts indicated with a probability of 5 percent over 50 years (or 1/2 percent annually). The force is indicated as a percentage of gravity, or "g."
According to the Wikipedia article,
<<
Generally speaking,
0.001 g (0.01 m/s²) – perceptible by people
0.02 g (0.2 m/s²) – people lose their balance
0.50 g – very high; well-designed buildings can survive if the duration is short.>>
Note that most of the map is above 0.50 (or 50 percent) of g. Indeed, much of the map is above .70 g with many areas above 1 (100 percent) g. It seems to me that much of Seattle is at risk of severe damage with a 5 percent probability over 50 years.
Again, the map only shows the probability of exceeding these values of g over 50 years.
What would be most relevant is the probability of exceeding .5 (or 50 percent) g over 50 years, as perhaps less powerful earthquakes might still do considerable damage.
Admittedly, perhaps I don't understand the information provided as I'm not a geologist and the information provided by the Feds is relatively abstruse IMO, perhaps deliberately.
Obviously, what would be most useful to the public would be 50-year maps showing the probability of significant damage to various types of buildings. I'm certain the government could produce these maps, but they wouldn't be popular with developers, city promoters, etc.
Maybe it's because I'm from the Midwest, but neigher myself nor any other natives I've talked to have ever really been worried about tornados personally. They're an after thought to most people 99% of the time.
It's SO rare that one would ever impact you directly. I think an average point on earth in tornado alley gets hit by a tornado around once every 12,000 years.
Also even if one hits, at least it strikes a very specific area, and normally the other 95% of the city and all other surrounding towns are fully functional and can come to the rescue right away.
I would be way more worried about earthquakes or hurricanes. They strike points far more often than any tornadoes would, and devestate huge areas.
When people say "I would never live in the Midwest because I'm terrified about tornadoes" or "Is it safe to drive through Kansas in April, I'm worried about tornadoes" most people will just scrunch their face and go "..huh.....seriously?"
That's interesting. This seems like an example of how the mind adapts.
It's similar in California re; earthquakes. I live right near the San Andreas fault and never fret about a quake. Like the people in your area who shrug their shoulders at the prospect of a tornado, people in CA, speaking generally, have the same attitude.
I think about quakes now and then though. I have my "escape" plan just in case. "Trust God but tie up your camel."
I think Japan 2011 is a good indicator. While we can't re-create this exactly, we can see some comparisons. Most of the damage there was along the immediate coast. A similar quake would likely (but not positively) effect the coastal areas more than inland. I will again say that this is not to say the inland areas would not suffer damage. But you are correct, nobody can make an exact conclusion, we just go by stats and history.
<<In the Pacific Northwest, the area of impact will cover* some hundred and forty thousand square miles, including Seattle, Tacoma, Portland, Eugene, Salem (the capital city of Oregon), Olympia (the capital of Washington), and some seven million people....
In fact, the science is robust, and one of the chief scientists behind it is Chris Goldfinger. Thanks to work done by him and his colleagues, we now know that the odds of the big Cascadia earthquake happening in the next fifty years are roughly one in three. The odds of the very big one are roughly one in ten. Even those numbers do not fully reflect the danger—or, more to the point, how unprepared the Pacific Northwest is to face it. The truly worrisome figures in this story are these: Thirty years ago, no one knew that the Cascadia subduction zone had ever produced a major earthquake. Forty-five years ago, no one even knew it existed....
Thanks to that work, we now know that the Pacific Northwest has experienced forty-one subduction-zone earthquakes in the past ten thousand years. If you divide ten thousand by forty-one, you get two hundred and forty-three, which is Cascadia’s recurrence interval: the average amount of time that elapses between earthquakes. That timespan is dangerous both because it is too long—long enough for us to unwittingly build an entire civilization on top of our continent’s worst fault line—and because it is not long enough. Counting from the earthquake of 1700, we are now three hundred and fifteen years into a two-hundred-and-forty-three-year cycle....
The first sign that the Cascadia earthquake has begun will be a compressional wave, radiating outward from the fault line. Compressional waves are fast-moving, high-frequency waves, audible to dogs and certain other animals but experienced by humans only as a sudden jolt. They are not very harmful, but they are potentially very useful, since they travel fast enough to be detected by sensors thirty to ninety seconds ahead of other seismic waves. That is enough time for earthquake early-warning systems, such as those in use throughout Japan, to automatically perform a variety of lifesaving functions: shutting down railways and power plants, opening elevators and firehouse doors, alerting hospitals to halt surgeries, and triggering alarms so that the general public can take cover. The Pacific Northwest has no early-warning system. When the Cascadia earthquake begins, there will be, instead, a cacophony of barking dogs and a long, suspended, what-was-that moment before the surface waves arrive. Surface waves are slower, lower-frequency waves that move the ground both up and down and side to side: the shaking, starting in earnest....
Soon after that shaking begins, the electrical grid will fail, likely everywhere west of the Cascades and possibly well beyond. If it happens at night, the ensuing catastrophe will unfold in darkness. In theory, those who are at home when it hits should be safest; it is easy and relatively inexpensive to seismically safeguard a private dwelling. But, lulled into nonchalance by their seemingly benign environment, most people in the Pacific Northwest have not done so. That nonchalance will shatter instantly. So will everything made of glass. Anything indoors and unsecured will lurch across the floor or come crashing down: bookshelves, lamps, computers, cannisters of flour in the pantry. Refrigerators will walk out of kitchens, unplugging themselves and toppling over. Water heaters will fall and smash interior gas lines. Houses that are not bolted to their foundations will slide off—or, rather, they will stay put, obeying inertia, while the foundations, together with the rest of the Northwest, jolt westward. Unmoored on the undulating ground, the homes will begin to collapse.>>
As evidenced by the absence of a Japanese-like, early warning system in the Pacific Northwest, the region's citizens and leaders seemingly are ignorant and indifferent to the looming threat.
Has Seattle media produced a report similar to this candid report from Oregon? The report suggests that Portland, at least, will be devastated.
Mt. Ranier's west flank, facing Tacoma and Seattle, vulnerable to not only collapse, but a Mt. St. Helens-like explosion. A giant tsunami may impact coastal areas in the Puget Sound. Here is a pessimistic assessment.
<< And [the Mt. Ranier] volcano is much bigger than Mt. St. Helens and it erupts less frequently which means that it can be worse, not smaller than St. Helens, we don’t really know until it happens.>>
<<Around 5,000 years ago, a large chunk of the volcano slid away and that debris avalanche helped to produce the massive Osceola Mudflow, which went all the way to the site of present-day Tacoma and south Seattle.[36] This massive avalanche of rock and ice removed the top 1,600 ft (500 m) of Rainier, bringing its height down to around 14,100 ft (4,300 m). About 530 to 550 years ago, the Electron Mudflow occurred, although this was not as large-scale as the Osceola Mudflow....[37]
Mount Rainier: Danger at our door
Mount St. Helens is the Roman candle of the range, with a more highly explosive eruptive style and greater likelihood of blowing in the coming decades.
And while both can create flows of lava, Rainier's magma - the molten rock that wells up from deep in the earth - has less silica than St. Helens, which makes it less explosive.
But Rainier can get you with fire and ice, as lava and fast-moving pyroclastic flows of rock and gas can turn some of the two dozen glaciers into a powerful surge of ice, mud and water. There is as much water locked up in glaciers and unmelted snow on Rainier as on all other Cascade peaks combined....
Around 5,600 years ago, a huge mass of this material gave way on the mountain's east side, scalloping off the top 2,000 feet. Nearly a cubic mile of mud and water flowed like liquid concrete and filled the valleys of the White River some 300 feet deep.
The so-called Osceola mudflow, the largest ever on the mountain, moved north and west, covering what is now Sumner, Enumclaw and Auburn. Entire watersheds were shifted, with sediments flowing off for decades afterward to fill what used to be a lobe of Puget Sound, near what is now Federal Way.
Just 600 years ago, a slope on the west side of Rainier gave way and streamed at an average speed of 50 mph down the Puyallup River, snapping six-foot-thick trees. When the mudflow hit the Puget Sound lowland near the town of Electron, it was more than 30 yards thick. The town of Orting is about 20 feet higher because of that flow.
Tom Sisson, a USGS geologist in charge of a seven-year project to figure out Rainier's geologic history, said the Osceola mudflow removed nearly all the unstable, hydrothermally altered rock from the high east side of the mountain. But the west side remains a threat.
Moreover, the Electron flow appears to have begun without any volcanic activity. That means a similar flow could run into populated areas without the days and weeks of seismic activity that precedes an eruption - and tips off geologists and emergency crews.
Chances are that won't be the case, said Sisson.
"It looks like the greatest likelihood of mudflows or lahars would be during periods of volcanic activity," he said. "Which may not sound like good news, but it actually is."
"Tapping data from the National Oceanic and Atmospheric Administration, U.S. Forest Service and FEMA's National Flood Insurance Program, the real estate research firm Trulia compiled a list of the cities around the country with the lowest risk of being flooded, rocked by earthquakes, battered by hurricanes, struck with tornadoes or burned by wildfires."
1. Syracuse
2. Cleveland
3. Akron
4. Buffalo
5. Washington DC
6. Dayton
7. Allentown PA
8. Chicago
9. Denver
10. Detroit
The northern half of the Upper Midwest states. If you draw a line halfway through Michigan, Wisconsin, Minnesota and all of North Dakota you will be in an area that is often too far north to get a lot of tornado activity, very little earthquake risk, zero risk from tropical systems and a moderate risk for forest fires. The largest natural disasters in the history of this region are forest fires in the 1800s, however those were made much worse by over logging and left over deadfall burning quickly. This is still a wet part of America so forest fires in modern times have been controllable and rarely threaten towns and peoples lives in a large scale California kind of way. I can think of nowhere else that seems to be as safe as the far Upper Midwest, however if you consider extreme cold a natural disaster then it might not be for you. It does have a very brutal cold climate by US standards.
They get blizzards.
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Seattle volcano threats
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