This is the price of fracking.

The frequency of earthquakes in Oklahoma has gone from negligible in 2008 to 6000+ in 2015.

Guess why.

EM, is it due to an increase in the number and sensitivity of gadgets designed to measure earth tremors?

Very few earth tremors had ever been noticed or recorded until the USA started "listening" all over the world for the Soviets detonating atomic weapons. I don't know how many atom bomb tests they pinpointed, but they established the pattern of the earth's tectonic plates in the late 50s to early 60s. The idea of Continental Drift had first been proposed in 1912.

Martin A is correct, the recent Oklahoma earthquakes are attributed to he injection of water previously used in fracking down specifically designed water disposal wells. Subsurface water disposal is NOT proposed in the UK for water returned to the surface from fracking operations.

More little ones make fewer big ones.
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Kim. So sorry but wrong. At low rates of water injection (ie your "little ones" = wells being fracked)) the bottom hole pressures (high enough to initiate fault movement) do not extend away from the well sufficiently far enough to cause problems. In contrast, sufficient water volumes are injected down water disposal wells (= your big ones) that high downhole pressures extend further away from the well, potentially to intersect faults inducing them to move.

The small Lancashire earthquakes must have been caused by the unfortunate circumstance that the fracking well passed through a fault plane. This meant that when the well was fracked, the fault plane was activated by the increased bottom hole water pressures.

ACK, I think what kim was suggesting (but happy to be corrected) is that loads of minor tremors are preferrable to a build up of stress/pressure etc, that is not relieved or vented until a "big one".

Man does not cause movement of tectonic plates, and can not prevent them with araldite superglue either. IF man has triggered minor tremors, and therefore avoided more major tremors, surely this warrants further research as a deliberate method of reducing the severity of earthquakes.

In the Alps etc, they have learned how to trigger avalanches by firing small artillery shells, before snow builds up to critical levels. Having managed to plot out the tectonic plate pattern of the entire planet for free, courtesy of the Cold War, there was hope that earthquake prediction would become a more precise science. It has improved, but recent events in Italy have confirmed there is a long way to go.

If earthquake research had received 1% of the budget of climate science, lives might have been saved. All the more reason to get fracking ASAP, and fund genuine research into earth tremors, rather than pay for more scaremongering.

Martin A. Whatever your source it appears to be mixing up different things. We should distinguish between
1. Fracked wells - water and other materials injected under pressures sufficient to fracture designated subsurface strata to improve hydrocarbon production. Once fractures formed, backflowing water returns to surface and must be treated or disposed of.
2. Waste water disposal wells - most hydrocarbon production wells also produce waste water. Commonly this is returned to the producing stratum through marginal wells (commonly former production wells that have "watered out" in order to maintain subsurface fluid pressures that are being depleted by continued hydrocarbon production. This pressure maintenance increases final oil productivity from the hydrocarbon field and is called "secondary production". Clearly such practices maintain bottom hole pressures and do not increase them.
3. Fracking waste disposal wells get rid of unwanted and commonly contaminated waters returned to the surface after fracking operations. Pressures in disposal wells may be high enough to induce fault movement.
4. Waste disposal wells. Used to dispose of toxic and otherwise dangerous chemicals by injecting them into the subsurface. They have a long history of causing earthquakes. These wells usually are sited away from potential hydrocarbon production because waste would contaminate subsurface steralizing it for possible production.

Ravishing Rattie. Re Italian earthquakes. No one really knows why the earthquakes are occurring this year. However we have a reasonably good idea why they are occurring. Essentially that part of Italy lies near some splinters of the African tectonic plate that is inexorably continuing to plough into the Eurasian plate. Friction resists this movement and the boundary faults between them stick for a time until the strain reaches a critical point and the fault plane unzips. Usually this is insufficient to release all the strain or alternatively extra strain is transferred to other faults demarkating other nearby splinters. These then unzip causing further earthquakes nearby (constituting an earthquake swarm). It is theorized that humans could theoretically induce fault movement by use of explosives or adding lubricant water to the fault planes (a source of some thrillers like Crighton's State of Fear, or films like one James Bond escapade in California). But this didn't happen in the case of the Italian earthquakes.

It has been proposed that the strain along the San Andreas Fault should be relieved by inducing smaller quakes, but no one would dare. We don't know if any deliberate action by us would not cause the "Big One".

One of the factoids I recall from when I worked in San Francisco was that if the "Big One" occurred during rush hours (= almost any time of the night or day) the resultant casualties minus deaths would fill all available hospital beds across the entire USA. Puts into perspective human's impotence in the face of what nature could throw at us. Helps explain why I am a sceptic.

ACK 10:53 the African tectonic plate smacking into Southern Europe is also I believe the cause of earthquakes and tremors down the West Coast of Greece. There was a "big one" in 1953, and not many historic buildings survive from before then. There was a fairly scary one in 2003, but not too much damage as reconstruction, and new builds were reinforced concrete. I was there in 2006 when a series of tremors occurred over 4-5 days, that prompted a lot of "agitation" amongst the local population, but no damage. After a week with nothing further happening, the local population were pleased that the next "big one" had probably been postponed, and the gloom and doom was replaced with relief.

It made me appreciate that "we" can't stop the earth from moving. We can't predict it, but we can make slightly better educated guesses.

RC. My life is a ruin. I shall burn my geology diplomas and retreat into anonymity. How could I have been hoodwinked it was all due to plate tectonics when it was the LHC in France and Switzerland? How could I have been so wrong? Other theories I missed include "its potential to pull an asteroid into the planet, and even that it is run by illuminati scientists, hell bent on opening a portal to bring the devil back to Earth." I take a little comfort from the statement that "None of the above, however, are scientifically proven", but not much.
Leave me to my misery.

Radical Rodent, as ACK has confirmed, Africa has been bashing into Southern Europe for a few years now, causing big ripples like the Alps.

The Global Warming argument could be that the weight of human numbers fleeing the Northern shores of Africa due to human conflict not caused by GlowBull Warming, and setting foot in Southern Italy, has caused some form of imbalance.

I believe this is a more balanced and considered idea, than most of the false attributions coming out of Team Greeny Grauniad SKwiffySkience at the moment.

Ravishing Rattie. Almost all of italy is susceptible to major earthquakes although it may have been a considerable time (in human terms) since one occurred in some parts. How many people would consider the southernmost Iberian peninsula, the Rhine Valley or the Oslo region earthquake prone? - but they are, just wait awhile.

I really should stop writing such rubbish when CERN is responsible for every geological disaster.

ACK, never fear, the Ancient Ley Line that runs from Stonehenge, down the spine of Italy, to the Giza Pyramids has always been in disruptive flux since the Celtic Driuds failed to assemble their FlatPack Home Delivery Pyramid correctly, having failed to decipher the hieroglyphics, and set out the main stones in a large circle, rather than a more compact square, and never managed to get the roof to fit snuggly, without gaps.

Historians and archaelogists have been trying to work out for hundreds of years what it was supposed to be, unfortunately the builders didn't have a clue either.

golfCharlie. Should we be asking Ayla or her chief Druid (the one with a bucket and stick simulacrum of Joshua's trumpets) to put it right, solve the Supreme Court Brexit impasse and stick it to those mad French/Swiss CERN scientists? Perhaps Stonehenge (which should have been a geological tribute to Toblerone) could be restored to its intended mediocrity.

Ravishing Rattie. "This is no laughing matter, you know, even if it can’t be taken seriously." Indeed it isn't. There was a really serious concern when the LHC was first switched on that it might create a mini black hole that, before it evaporated away, would sink through the crust and mantle and begin to consume the Earth's core. As a possibility it could not be eliminated.

Sometimes you come across such stupidities (like the CERN and illuminati story) that humour is the only remedy. Anyway Gwen started it with "his" leylandii lines. Blame her.

Radical Rodent, Leylandii Lines are a major threat to modern buildings when planted too close, especially as formation hedges. Many journalists write about how they "attack the foundations". John Wyndham wrote "The Day of the Triffids" about alien mobile plants with vicious stingers, but he never mentioned the possibility of lines of Leylandii tooled up with jack hammers.

CERN is a doughnut, NOT a polo. That is why it has super heated jammy stuff flying around. Why we need it nobody knows, but the Green Blob are terrified it might prove more cost effective and useful than they are, even when doing nothing at all. The Green Blob now have to come up with a more stupid non scientific rumour about CO2 causing volcanic eruptions, to justify their existence. They have had over 20 years of making stuff up, and no one believes them any more.

Oh dear yet more Micky Mouse science from science teacher extraordinaire... Entropic moron

Ravishing Rattie. The sloping shoulders are part of my cherished Neanderthal heritage. Do you think Neanderthals may have sat around a fire swopping mammoth jokes, and discussing vacations to Gibraltar?

Gwen's crown is ever safe, although I have recently missed the zany jewels that have been too often absent recently.