Quick topic, Earthquakes are happening ALL over the globe! Haiti, Chile, and one more... I forgot! I am starting to think we might be next. San Andreas, New Madrid? Which fault? If so, what should we do to prepare? In the event of an earthquake, your hause will most likely be destroyed and you will or wont get out alive. What to do....

Baloney.

Go to the library and get a basic book on geology and earthquakes. There are plenty. Earthquakes result from the movement of the earth's crustal plates. Stresses build up and then release - we have a quake. Somewhere between a million and half a million occur annually. Most can barely be felt. Earthquakes are a normal phenomenon, as natural as storms, fires, and tornadoes, which, given where you live, is a much more likely possibility.

Your house, at least here in the US, most likely will not be destroyed. Look at the disparity between Haiti and Chile. The Chilean quake was roughly 500 times more powerful - there the death toll is around 700 (my guess is it will eventually be about 1000). Compare that to poor Haiti - 200,000 dead. Why the difference? Most of the answer is in the different infrastructure and building standards of the two areas.

Most of the US is susceptible to earthquakes, some regions more than others. I recently read that only four states have not experienced quakes - North Dakota, Iowa, Wisconsin, and....Florida! That's right, Minnesota has had an earthquake - I had to look it up. So has Illinois.

I live in Earthquake Central (Southern California). We do some things a bit differently here. Building codes are shaped for earthquake resistance. Water heaters are fastened down. Heavy objects are not on the wall above the bed (nor are mirrors). Prudent folks have emergency gear, food, and water stashed. I have a flashlight, multitool, and shoes (broken glass) right by the bedside. With a few exceptions, earthquake preps are not all that different from those for most other emergencies.

The one factor that is exceptional for quakes is that there is no way of predicting with any degree of accuracy and precision, when they will occur - vastly different from the situation with weather related incidents today. You need to be on your toes here in Earthquake Central.

So evaluate your local situation and realistically prepare for what you are likely to experience. Meanwhile, over the next year, the Pacific Plate will carry me about 5 cm. closer to San Francisco (or at least part of SF). When are they going to reduce the air fare?

"Not I" said the frog...

Minnesota quakes are the result of the bedrock shifting back up after sitting under a ice sheet until just 10,000 or so years ago.
which is a strange thought in itself.

Mysteries remain in geological science. It seems to be accepted truth that earthquakes on a particular fault line are far more likely to trigger future quakes elsewhere on that isolated fault system than on a distant, unconnected fault line.

But both the massive Sumatra quake (9.1) of 2004 and the Chile quake (8.8) last week were said to "ring the Earth like a bell" and there is evidence that the 2004 Sumatra "great" quake increased stresses on the San Andreas fault.

The Chile quake released 500 times more energy than the Haiti quake (7.0) which preceded it. Unfortunately, Haiti was exponentially less prepared to deal with any sizable earthquake.

http://news.nationalgeographic.com/news/2009/10/091002-earthquakes-tsunami-connected-indonesia.html

Were Last Week's Pacific Earthquakes Connected?

Richard A. Lovett
for National Geographic News
Updated October 5, 2009

In four days last week there've been at least five substantial earthquakes—and a tsunami—in the same general region, the tectonically rambunctious Ring of Fire in the Pacific Ocean.

Coincidence? Maybe yes, but probably not, scientists say.

...earthquake vibrations may affect faults at surprisingly great distances.

In particular, the researchers found that vibrations from the 2004 Indonesian earthquake may have increased the frequency of small earthquakes in California's San Andreas Fault by causing fluids to move into the fault lines. Such an inflow would have lubricated the fault, making it more likely that the two sides would slip and slide.

Still, the study team is cautious about suggesting the same thing happened with last week's two large quakes.


http://www.mcclatchydc.com/2010/03/01/89568/after-haiti-and-chile-are-earthquakes.html

An earthquake as powerful as the one that devastated Haiti takes place somewhere on earth about once a month, said Tim Dixon, geophysics professor at the Rosenstiel School of Marine and Atmospheric Science in Miami.


http://articles.latimes.com/2009/jan/24/local/me-fault-quakes24

Study finds troubling pattern of Southern California quakes
The southern stretch of the San Andreas fault has had a major temblor about every 137 years, according to new research. The latest looks to be overdue.

http://www.ussartf.org/earthquakes.htm

in many places, the assumption of random occurrence with time may not be true, because when strain is released along one part of the fault system, it may actually increase on another part. Four magnitude 6.8 or larger earthquakes and many magnitude 6 - 6.5 shocks occurred in the San Francisco Bay region during the 75 years between 1836 and 1911. For the next 68 years (until 1979), no earthquakes of magnitude 6 or larger occurred in the region. Beginning with a magnitude 6.0 shock in 1979, the earthquake activity in the region increased dramatically; between 1979 and 1989, there were four magnitude 6 or greater earthquakes, including the magnitude 7.1 Loma Prieta earthquake. This clustering of earthquakes leads scientists to estimate that the probability of a magnitude 6.8 or larger earthquake occurring during the next 30 years in the San Francisco Bay region is about 67 percent (twice as likely as not).



Largest Earthquakes in the World Since 1900.

Interesting world map showing a gaping quiet stretch along the Pacific ring of fire -- from Alaska to South America.

The Juan de Fuca tectonic plate along the Cascadia subduction zone is one to be concerned about. The Pacific Northwest coast would have maybe 30 minutes before a massive quake generated tsunami came ashore.

The last major earthquake in the Cascadia subduction zone occurred in 1700 and was estimated to measure about 9.0 -- give or take .2 Japanese tsunami records indicate the quake hit during the evening of January 26, 1700.

But on any given day, there is a far greater risk to your health from traffic on the roads to the coast.

http://earthquake.usgs.gov/earthquakes/world/10_largest_world.php


Interesting CalTech re-cap of the fault movements in the Sumatra quake:

http://www.tectonics.caltech.edu/outreach/highlights/sumatra/what.html

The giant 2004 Sumatra earthquake ruptured the greatest fault length of any recorded earthquake, spanning a distance of 1500 km (900 miles), or longer than the state of California. Rather than tearing the land apart all at once, the rupture started beneath the epicenter marked in the figure below and progressed northward along the fault at about 2 km/sec (1.2 miles/second). The whole rupture lasted about 10 minutes. Compare this with California's 1994 Northridge earthquake, which ruptured about 20 km (12 miles) and lasted 15 seconds.

This giant quake of 2004 was followed just four months later by the magnitude 8.7 quake of March 28, 2005. This one was west of Sumatra, under the islands of Nias and Simeulue. Although the 2005 quake was one tenth as powerful as the 2004 quake, it is still the fourth largest quake of the last 100 years, and many lives were lost. A third major quake followed two and a half years later. The magnitude 8.4 event of September 13, 2007 rocked the Mentawai islands.

There was a magnitude 3.8 earthquake in northern Illinois just a few weeks ago.

Quite minor - no damage that I'm aware of. I didn't feel it as I was sound asleep.

There are a few minor fault lines in northern Illinois:

http://www-esh.fnal.gov/Regional/Fig_9(R).GIF

There is a fairly substantial New Madrid fault just south of Illinois.

The USGS has a nice earthquake web site as mentioned in a previous post:

http://earthquake.usgs.gov/earthquakes/

Here is a link to an AP story from yesterday, regarding the risks to the PNW for a big one.

http://www.google.com/hostednews/ap/article/ALeqM5iFz_6L3X5KzE8JrgPc2gn343if5AD9E6OFF83

A quick reminder for new-comers on this topic: standard home-owners insurance does not cover earthquakes. Your agent may not think to offer it; I had to ask. The extra cost here in central PA is miniscule.

If you aren't certain that you have the coverage, you probably aren't covered.

A somewhat off topic note, standard auto insurance does not cover vehicle to aircraft collisions. I found out when I was stopped from driving to a warehouse at an airport to upgrade network equipment, had to move everything to one of their vehicles.

I was reading a history of the Great Lakes area. It said that at one point during the process (~7K years ago) the weight of the retreating ice sheet depressed the land so far that what is now Lake Michigan drained northward (like pressing down on one edge of a bowl full of water), leaving thousands of square miles of what is now lakebed exposed.

Mind-boggling.

I forget the exact description of the factoid, but something like a dozen magnitude 8+ earthquakes occur every year somewhere in the world. But the public really only notices them when they affect heavily populated areas directly through shaking, or indirectly, like the Indonesia tsunami. So that's the main reason why these giant earthquakes are on our minds lately.

AFAIK, the frequency of these massive earthquakes hasn't really increased. So the chance of a massive earthquake in your neck of the woods is probably just the same as it was 10 years ago, more or less.

There is the argument that a large earthquake can trigger other large quakes in other areas, but it's probably just as true that large quakes can also reduce the chance of quakes elsewhere by relieving tectonic stresses.

You can be sure that quakes will either reduce the chances of additional quakes somewhere, increase them, or leave them unaffected.

Well, sorta. Most of us math dummies (including me) are not used to working with log scales, but they are necessary because the range of energy released by earthquakes is so wide ranging. I recall from somewhere that the maximum likely tremor would top out at somewhere around 10.5. But that is theory.

"Whole lot of shakin' goin' on"

I have to tell you that this made me laugh. Certainly, its very thorough!

The day after the Chilean earthquake, I read this. I agree with the author's basic ideas. To suggest that the earth is more or less active than it has been will probably be considered "unsubstantiated" at best. If you look at the history... earthquakes are regular occurences and sometimes earthquakes WILL hit populated areas.

As far as your question, "Are we next?" the short answer is that we are no more "next" than we were last year, or the year before.

Your questions about what to do to prepare are worthwhile, a really big one is to keep the larder stocked and make sure you have some water on hand while you ride out the aftermath. Red cross classes would be high on my list too.

Assuming you get out alive. I don't pretend to be an expert in "what to do" if you don't get out alive, which was your other scenario.

Lots of little blue squares yesterday- much higher than you normally see.

http://earthquake.usgs.gov/earthquakes/recenteqsus/Maps/special/California_Nevada.php

Are there any unusual cloud formations, strange fogs or mists and any missing animals or strange animal behaviors in this part of the world?

With sincere regrets for the people who died - Chile was almost ideally suited to this quake.
It's developed enough to have building codes, and the equipment and infrastructure to cope but not so developed that it has 10 million people living in skyscrapers in the city center.

There is a sort of GDP-damage event curve and you don't want to live at either end, Tokyo or Haiti.

If and when an earthquake is going to happen is a crapshoot. Any time, any place, any strength.

Chile had the world's worst recorded earthquake, 9.5, on May 22, 1960. The recent one was 'only' 8.8.

Alaska had a 9.2 quake in 1964, with surface land displacements of as much as 38 feet. Think of that when people talk about earthquake-proof buildings. (Sneering? ME????)

The only thing you can do is be prepared for disasters in general. Be ready to leave, or ready to stay and camp in your backyard.

Sue

Indeed, and Haiti has no code. It's not merely unenforced: there is no code, and no inspectors.

What I wonder about are things like the 1958 Lituya Bay earthquake & tsunami. Are there populated areas that where the same thing could happen? I'm not sure how one prepares for a 1/3 mile tall tsunami wave.

There are some things that are basically impossible to prepare for, or at least not cost effective to prepare for. One consequence of a potential large asteroid impact, something like the one that snuffed out the dinosaurs, would be a 200 foot tsunami wave on an open coast. Imagine how that would build in a narrow fjord. Of course, the tsunami would just be one of the problems you might face.

One unusual ocurrence that is happening in Chile.

The aftershocks are getting stronger, not weakening as the norm post-earthquake behavior.