And to put it another way, the expected horizontal ground acceleration is at least 1.2 times gravity. The horizontal seismic force is the mass of the structure times the acceleration of the structure (f=Ma~1.2Mg). That is modified for soil effects and then multiplied by 2/3. Then you divide it by a factor that can vary from 1.25 to 8 depending on the structure type and the level of ductility in the detailing of the structure. Ductility will release strains and desipate the energy put into the building due to inertial response. It is the ductile detailing that is the problem.

So buildings are designed for forces much less than they might need to resist. Bad detailing, bad construction and bad inspection of completed work will compound to a structural failure. Call me a sceptic, but I know what is going on and it will not be good.

On the other hand we are doing better than most countries and CA is doing a lot better than the rest of this country in this regard. Live in Charleston, SC, Boston, MA or Saint Luis, MO? Good luck to you all. There is a potential for very large seismic ground motions in those areas and not a whole lot has been done in construction of buildings in thes areas to resist them.

One of the biggest earthquakes ever, happened in NE Arkansas. We get real small quakes on a regular basis. I still prefer the tornados.

This map shows relative shaking hazards in the United States and Puerto Rico. During a 50-year time period, the probability of strong shaking increases from very low (white), to moderate (blue, green, and yellow), to high (orange, pink, and red). Map not to scale. Source: USGS

Click it for a fact sheet.

Thanks for your expertise Deep. Very valuable! Thanks for sharing.

Or is it South Carolina?

Top 25 in US

http://earthquakeadvisor.com/articles/00021.html

I believe the New Madrid, MO of 1812 is what caused a town in Illinois to be west of the Mississippi River.

Newer link

http://earthquake.usgs.gov/regional/states/10_largest_us.php

That is going to vary based upon several things.

Distance from the epicenter;
Ground acceleration;
Soil conditions at the building site;
Construction type;
DETAILING OF THE CRITICAL CONNECTIONS;
PROPER CONSTRUCTION;
ADEQUATE INSPECTION.

The powers that be want to cut out the last thing as much as possible saying that it is not cost effective. We need a big one to shake things up, politically. I cannot wait. We have the technology to prevent major damage, building collapse and loss of life.

More directly, single story wood frame structures without a lot of window openings will perform well. Old unreinforced masonry buildings will perform not so well. Many of these "ductile" connections in structural steel buildings built in a period from about 1980 to 2006(!) were proven to not be all that ductile in the Northridge EQ in 1994. Many were built AFTER that quake and many built before have not been repaired. A lot of these structures were near collapse after the Northridge EQ and that was only a richter magnitude 6.9. The big one will be at least 10 times stronger than that.

Hey if FLB gets to soapbox to everbody on here about the banking system, don't I get to about this said state of affairs?

Twenty-six urban areas in the United States are at risk of significant seismic
activity:

Albuquerque, N. Mex.
Anchorage, Alaska
Boise, Idaho
Boston, Mass.
Charleston, S.C.
Chattanooga-Knoxville, Tenn.
Eugene-Springfield, Oreg.
Evansville, Ind.
Fresno, Calif.
Las Vegas, Nev.
Los Angeles, Calif.
Memphis, Tenn.
New York, N.Y.
Portland, Oreg.
Provo-Orem, Utah
Reno, Nev.
Sacramento, Calif.
St. Louis, Mo.
Salinas, Calif.
Salt Lake City, Utah
San Diego, Calif.
San Francisco-Oakland, Calif.
San Juan, P.R.
Santa Barbara, Calif.
Seattle, Wash.
Stockton-Lodi, Calif.

Are you ready?

The latest news is showing that the quake was caused by the protest march started in South L.A. against this: Fast-Food Ban Proposed in South Los Angeles

Spoke to my son who's now in Huntington Beach; this was his first earthquake to go through. He said it wasn't bad, it wsa just kind of surreal when the bldg. started to shake.

Just to put things in perspective about the BIG ONE. The Northridge quake was 6.9, lasted about 30 seconds, maybe a tad longer. The Big One is anticipated to be 8.5-8.9 and last approximately 2-5 MINUTES! The San Andreas will rip approximately 300 miles from the Salton Sea (SE of Palm Springs) to Bakersfield. It's anticipated to be felt as far east as Texas! It's going to sound like the space shuttle is in your front room at takeoff speed!
The Aftershocks are going to be big and frequent!
And, it can happen at any moment!!!!

Sunday during our daily windstorm I took the video cam outside to shoot some footage. Afterward I stood on the dock, and looking at the mountains, I thought to myself "about due for an earthquake", and thought how the video of an earthquake would look shooting the land from the water...

It's not like it was a psychic prediction, the Japan earthquake was on my mind, but--we ARE about due for an earthquake. (where I live is listed TWICE on the list above--Salt lake and the Provo-Orem area)

We have been hearing that here for some time. This is a major fault zone. Small earthquakes with a moment magnitude greater than 1.3 commonly occur in New Mexico, but earthquakes with a magnitude of 5.0 or greater that can cause significant property damage are relatively rare events here.

We have been having these very bizarre short 'rolling' blackouts tonight. What makes these really unusual is that they are city wide. I was just talking to a lady friend across town on my cell, when she asks if my power just flickerd (which it had). She is at the foothills area next to the Sandia Mt. range, I am many miles away up on the West Mesa next to five extinct (we hope) volcanos. Checked with a couple of people near I-25 in the bar area, same thing there.

I have servers and desktops all over the house, several of the desktops rebooted (anything not sitting on a UPS, yet the lights flicker only slightly. Had about ten of them in the last hour. Pretty friggin' weird. Almost has to be a city feeder coming in from somewhere.....

Guess I need to make sure I am not being 'microwaved' tonight by the NSA......

Having grown up in L.A, I went some big earthquakes, I remember (in the 6.6 one in 1971) watching the water in my pool slop out at one end and then expose the lower step at the other end.

My perception in terms of buildings and damages:

There are "cracking" earthquakes that give you a sharp lateral jolt, and there are "rolling" earthquakes that seem to last longer, but do less damage, they seem to be in waves underground rather than the sharp lateral movement that does more damage.

I'd rather be in a 7.0 rolling one than a 6.5 cracking one.

It does get spooky when they last longer than 5 or 6 seconds. The 1971 one lasted almost 60 seconds, and seemed to build (that why I think of it as a rolling quake) in strength as it went on.

Both it and the Northridge quake put some cracks in the plaster ceiling and walls of my parents Whittier house; they are about 8 miles from the epicenter of the 1971 quake.

And I would take a quake over a tornado any day...but then again, I haven't been through the Big One, may change my mind if we get an 8.0 or better.

You all know that an 8.1 is twice as strong as an 8.0 quake, right? They run on an exponential scale. So an 8.0 is 11 times as strong as a 6.9



I think I'll go listen to "Atlantis" by Donovan now...

For those thinking that CAlifornia is the only place, I would rather take an occasional earthquake than annual tornados and hurricanes. That is just my opinion.

As for the big one. It is what it is and is not something I can control. I however can be prepared and intend to be in a position to take care of my family.

On a side note, " the big one" will likely create the type of social unrest that may be the catalyst to free this country from the current government since the government won't be capable of taking care of those that are used to being taken care of.

Back to the topic at hand, I slept through the Loma Prieta (sp) quake in 89. Only time will tell what will happen. The big one could happen tomorrow or not for 1000 years.

Sorry, I'll take my yearly kick in the shin than waiting for a random bullet to the chest.

The Northeast is close to a major fault line, but it is stable, as far as fault lines go. If we did get hit with anything with any magnitude it would be devastating. There are MANY old buildings around with more termites than nails or mortar left. Typical structures are rated for low seismic activity as well. Yep, a big one around here would be devastating, but very unlikely.