What the heck just happened to my house?

[ftg]

One thing that’s different about CA quakes is that they don’t propagate very far. All the mess of faults and all keeps things local. Elsewhere, modest quakes like this one can be felt over a far larger area.

This is one reason another big Madrid quake is such a scary thought. A lot of cities will be affected.

[naita]

@Duke_of_Rat

I was just about to roll out of bed and felt the bed moving like somebody was shoving on it, the alarm clock went off right after (I was already well awake aND had been for a few minutes). That’s the strange part, alarm is set to 7:05 and the clock is radio synced to the the standard time signal. So I figured the quake would be at about 7:04:45, but the USGS had it at 7:02:44 - two minutes off. No doubt that’s what it was, and I’m a ways outside the “shake zone” on the USGS website, just something off with the time.

Well seismic waves take time to propagate. Wikipedia has them at between 2 and 8 km/s in the crust:

The propagation velocity of the waves depends on density and elasticity of the medium. Velocity tends to increase with depth and ranges from approximately 2 to 8 km/s in the Earth’s crust, up to 13 km/s in the deep mantle.

Seismic wave

[Quimby]

FWIW when I wrote “Fracking” I was talking about the process of pumping fluid into the ground in order to forcibly extract Natural Gas, not oil, which I have understood is called "fracking"and is also the most likely cause for these new earthquakes in the OK area.

[Shagnasty]

@urban1a

There has been a large increase in earthquakes since fracking started in Oklahoma. It now appears that Oklahoma has shutdown a bunch of wells since the most recent one.

Back in the late 60s, there were a series of earthquakes in Denver. I remember one which caused my office chair to roll across the floor. The problem was that the Army was pumping toxic chemicals into deep wells at the Rocky Mountain Arsenal and this was lubricating the rocks and causing them to slip and slide.

Eventually, the Army drained the wells and did something with the chemicals and the earthquakes stopped.

While this is not the same thing as fracking, it amazes me that people forget things like that when it comes to making money.

Bob

It amazes me that people automatically assume that a large-scale earthquake felt over many states is the result of fracking. Do you honestly think that humans could trigger such an event even if it was intentional? Such events have always occurred because of plate tectonics and people have nothing to do with it.

Let me put it this way. If you told the best engineers in the world that you wanted to shake millions of square miles across many states at the same time, do you think they could do it without resorting to nuclear annihilation? If you still think they could, do you think the best strategy is to drill some rather shallow holes in the ground?

The Earth moves whole continents all the time and sometimes the pieces rub against one another (see the Appalachian mountains or Mount Everest). It has nothing to do with people except for the misconception that the ground beneath you has always been where it is now and will stay that way. It won’t. It is arrogant to think that people have the capability to cause earthquakes on a scale that large anymore than ants can bring down a skyscraper.

[Duke_of_Rat]

@Quimby

FWIW when I wrote “Fracking” I was talking about the process of pumping fluid into the ground in order to forcibly extract Natural Gas, not oil, which I have understood is called "fracking"and is also the most likely cause for these new earthquakes in the OK area.

OK, but that doesn’t explain why the immediate response was to shut down the wells used to dispose of salt water produced from oil wells (mentioned in a previous post), not to mention that waterflood (the process you describe) isn’t used on gas wells, and fracking is the process of fracturing the formation at the completion of the well to facilitate the flow of gas or oil from the rock formation - not injecting water back down wells to forcibly extract hydrocarbons - that is waterflood (also mentioned in a previous post).

For example, water injection is never used on natural gas wells.

Fracking Defined

Developed in the late 1940s, hydraulic fracturing, also known as a frac job, is the practice of injecting a well with large amounts of frac fluids under high pressure in order to break the rocks. Performed on both openhole and cased-well perforations, hydraulic fracturing quickly replaced explosive fracturing.

Used in a gel-like state, frac fluids consist of water and polymers, or long organic molecules that form a thick liquid. Both oil-based and foam-based frac fluids use nitrogen bubbles to achieve the fracture. Carbon dioxide can be used, as well, to minimize formation damage.

A frac job is performed in three steps. First, a large amount of frac fluids are pumped into the well. The high-pressure of the frac fluids and the continual pumping increases the pressure in the well, overcoming the strength of the reservoir rocks to break them apart. Fracing fluids are pumped into the well until the rocks are cracked to a desired length.

Then, frac fluid and propping agents are introduced into the well to extend the breaks and pack them with proppants, or small spheres composed of quartz sand grains, ceramic spheres or aluminum oxide pellets, that hold the fractures open after pumping has ceased. This is important, because then the hydrocarbons can flow through the open cracks in the reservoir rocks. Finally, the well is back flushed to remove the frac fluids.

I feel I fight a losing battle, and it’s a complicated subject (I don’t know if the salt water being disposed of is being used for waterflood, for example, or if it’s being disposed of in a separate formation), but what is being called “fracking” by you and the media isn’t actually fracking.

[Duke_of_Rat]

@naita

Well seismic waves take time to propagate. Wikipedia has them at between 2 and 8 km/s in the crust: Seismic wave - Wikipedia

Those figures work out pretty close. I’m about 250 miles away, so at a little over 3m/s, that’d put it here at right at 2 minutes later (if I did the math right).

[Northern_Piper]

It’s coming north!
Mild earthquake yesterday in south-central Saskatchewan.

Mild earthquake felt on Prairies | CBC News

[Quimby]

Well i did say fluid and not water specifically because I know it isn’t water (in fact thanks to the Bush administration they didn’t have to ever reveal what exactly was in the fluid, although I am not 100% sure if that is still true).

But anyway, let’s forget I mentioned the fracking The important point is it’s worrisome we are getting earthquakes in that area because the cities there can’t handle it the way the west coast and Japan can.

[Duke_of_Rat]

@Quimby

Well i did say fluid and not water specifically because I know it isn’t water

Well, let’s see what the Washington Post calls it:

The 37 **wastewater disposal wells **to be shut down in north-central Oklahoma, where a 5.6 magnitude earthquake struck this weekend, are just a fraction of the state’s total number.

(in fact thanks to the Bush administration they didn’t have to ever reveal what exactly was in the fluid, although I am not 100% sure if that is still true).

Hydraulic fracking of wells has been going on for decades before Bush (either one) became president.

But anyway, let’s forget I mentioned the fracking The important point is it’s worrisome we are getting earthquakes in that area because the cities there can’t handle it the way the west coast and Japan can.

No hurt in mentioning it, just that it has nothing to do with the conversation at hand.