I think I felt an earthquake. (Prescott: hotel, home, crawl space)

[DellNec]

Moderator cut: snip I remember some talk about how the pumping of ground water from the Big Chino Aquifer could possibly cause earthquakes to occur more often due to voids developing from the water being pumped out.

Does anyone have any studies if this is possible?

Moderator cut: snip

[DellNec]

Arizona is designated by the FEMA National Earthquake Hazards Reduction Program as a "High Risk" state for earthquakes.

With that being said, who in the Chino Valley and Prescott area has earthquake insurance?

6.0 or greater quakes in the Prescott area since 1900:

January 25, 1906 = 6.2
September 24, 1910 = 6.0
August 18, 1912 = 6.2


** Yavapai County should strengthen the project permit and review process to ensure that proper actions are taken to mitigate the impact of seismic hazards, to encourage structural and nonstructural seismic design and construction practices that minimize earthquake damage in critical facilities, and to prevent the total collapse of any structure designed for human occupancy."

**Yavapai County should provide review and enforce seismic design provisions and to identify and prevent structural and nonstructural design flaws in projects involving dependent, essential, high-risk, high-occupancy, or major commercial projects requiring approval. This provision should include training programs for plan checkers and building inspectors, or the retention of a State-certified structural engineer.

[DellNec]

Through my research I found some interesting facts. There are areas in Paulden, Chino Valley and Williamson Valley that boast that the ground water table is only 50 feet below the surface. While that is a great selling point to drilling wells, it poses a serious risk in earthquakes:

"Liquefaction occurs primarily in saturated, loose, fine to medium-grained soils in areas where the ground water table is 50 feet or less below the ground surface. When these sediments are shaken, such as during an earthquake, a sudden increase in pore water pressure causes the soils to lose strength and behave as a liquid. The resulting features are called sand boils, sand blows or "sand volcanoes". Liquefaction-related effects include loss of bearing strength, ground oscillations, lateral spreading, and flow failures or slumping (Yerkes, 1985). Ground failure caused by liquefaction is a major cause of earthquake damage. For example, most of the extensive damage caused by the 1964 Alaska and the 1989 Loma Prieta earthquake was a consequence of liquefaction."

http://www4.nau.edu/geology/aeic/reports/yavapai.html

"For example, during the ML 6.2 1906 earthquake the Prescott newspaper, The Arizona Weekly Miner on 1/31/1906 reported that, "One peculiar freak of the temblor was that it affected only the eastern part of town, the shock being quite marked in that section east of Cortez street". The later comment may reflect the earthquake effects to structures underlain by young sediments and shallow ground water associated with Granite Creek. Plates 1 through 5 (In-Pocket) illustrate the areal extent of the basic geologic ground shaking types transferred from regional published geologic maps."

[keninaz]

Just some history regarding damages in AZ from earthquakes.
I think I would take my chances regarding insurance and such as not much has really happened so far. http://www.azgs.az.gov/Hazards_ocr/e...%20in%20AZ.pdf
I know growing up in CA in very likely earthquake country that damages there over the years were light just miles from some major quakes.
Having examined earthquake policies there when they started offering them many had high deductibles and in my opinion were not worth the money.
If your house is destroyed completely or you cannot afford to rebuild and you owe money as many do bankruptcy is available.
And I can find nothing that says there are records of lots of injuries or deaths from any quake in AZ, anywhere.
My wife's family was in Cochise County during that quake shown in 1887 and although the link I showed refers to major damages in that area they saw none at the time to speak of. That quake was estimated to be a 7.2.
Roll those dice!

[Kimballette]

Originally Posted by keninaz

Just some history regarding damages in AZ from earthquakes.
I think I would take my chances regarding insurance and such as not much has really happened so far. http://www.azgs.az.gov/Hazards_ocr/e...%20in%20AZ.pdf
I know growing up in CA in very likely earthquake country that damages there over the years were light just miles from some major quakes.
Having examined earthquake policies there when they started offering them many had high deductibles and in my opinion were not worth the money.
If your house is destroyed completely or you cannot afford to rebuild and you owe money as many do bankruptcy is available.
And I can find nothing that says there are records of lots of injuries or deaths from any quake in AZ, anywhere.
My wife's family was in Cochise County during that quake shown in 1887 and although the link I showed refers to major damages in that area they saw none at the time to speak of. That quake was estimated to be a 7.2.
Roll those dice!

Agreed. Only people who never lived in earthquake country in California would get so worked up over all of this in Arizona.

[wretched wrench]

How worked up a person gets is an individual decision. But knowledge is always useful.

Liquifaction is indeed a big deal in CA, and is even underrated there. I was glad to know that my house there was not in a liquifaction prone area.

I would have to be a geologist to have an opinion here, as there is much more to liquifaction than water level in wells.

[keninaz]

I was 30 miles from the last 7.2 in CA in 1989.
Our new two story built in 1987 suffered not even a crack in the paint that we could find.
The house was built on pilings of some sort down to rock we were told. Good job anyway.
It shook us really good though, we did get out of the house just in case.
It was hard to stand in the front yard and I had a 4' CB antenna on a 1 ton truck we used for towing a trailer in the driveway that was doing 180° on a med weight spring.
I would still rather go through that once in a great while than the threat of twisters of hurricanes every year like many do.

[DellNec]

Case-in-point; Yavapai County is trying to reject the 2012 IBC. They don't like the new code. Even though it makes for safer homes and better energy efficient homes.

New building code 'unrealistic,' say Yavapai County officials - The Prescott Daily Courier - Prescott, Arizona

[DellNec]

Originally Posted by keninaz

I was 30 miles from the last 7.2 in CA in 1989.
Our new two story built in 1987 suffered not even a crack in the paint that we could find.
The house was built on pilings of some sort down to rock we were told. Good job anyway.
It shook us really good though, we did get out of the house just in case.
It was hard to stand in the front yard and I had a 4' CB antenna on a 1 ton truck we used for towing a trailer in the driveway that was doing 180° on a med weight spring.
I would still rather go through that once in a great while than the threat of twisters of hurricanes every year like many do.

30 miles away from the epicenter makes that 7.2 quake turn into a 5.0 quake. Location is key to damage in an earthquake.

That is why if the BC Fault moved and caused a 7.0 quake, northern Prescott would experience 6.0 damage and southern areas of Prescott would be more like 5.0. While Chino Valley & Paulden would experience the full 7.0 damage.

[keninaz]

Tell us about all the earthquakes that you have experienced in your life!
I live with them in one of the worst areas of the country for almost 42 years of my life and know them well.
And the area I lived in had far more than this area has even thought of.
Does that mean we can't see a big one, no.
Does that mean that paranoids should run out and buy insurance and rebuild their homes to suit what may come?
If there is a chance of having a disease of "what if paranoia" and dying from it you have to be high on the list guy.