Oklahoma earthquakes-a bad thing?

http://earthquakes.ok.gov/

So Oklahoma has had over 500 small earthquakes this year, is this a bad thing? My novice geologic mind thinks that a lot of small earthquakes is better than one large one.

If fracking does relieve some pressure underground in small events, what’s the harm?

It’s a bad thing if the fracking is creating earthquakes in places they wouldn’t otherwise occur or increasing their magnitude if they would.

It’s incredibly unlikely that they would have combined into a single massive earthquake. There is no possible way to spin this as a good thing.

But you have a future in politics if you think so.

At some point the oil fracking fluid creating the earthquakes may seep into the groundwater supply. And if Oklahoma doesn’t have adequate earthquake construction requirements, quite a few building owners will be uninsured for any damage to their buildings.

It would take a huge number of small earthquakes to release the energy of one large one. The Richter scale is exponential - a difference of 1.0 represents a factor of 31.6 in terms of energy. This means it would take about 31,554 quakes of magnitude 3.0 to release the energy of one 6.0 quake. So the 500 small quakes that Oklahoma has had will do very little to prevent a really big one.

If fracking is associated with an increase in earthquakes, it doesn’t mean that the fracking is merely relieving stress. That is, it’s possible that fracking could increase the likelihood of a large quake, rather than decrease it. I don’t know whether there’s enough data to say what effect fracking has on different-sized quakes.

The USGS does NOT agree.

Guys, there were major earthquakes in the central US long before fracking. For example, the New Madrid earthquake.

Here’s a history specific to Oklahoma earthquakes.

Somewhat of a minor qitpick, but the thought is not that fracking may cause earthquakes; it is that saltwater disposal wells may be the cause.

Guys, there were major earthquakes in the central US long before fracking.

Known and accounted for by the USGS in their report (link above and here).

USGS statistically analyzed the recent earthquake rate changes and found that they do not seem to be due to typical, random fluctuations in natural seismicity rates. Significant changes in both the background rate of events and earthquake triggers needed to have occurred in order to explain the increases in seismicity, which is not typically observed when modeling natural earthquakes.

The analysis suggests that a likely contributing factor to the increase in earthquakes is triggering by wastewater injected into deep geologic formations. This phenomenon is known as injection-induced seismicity, which has been documented for nearly half a century, with new cases identified recently in Arkansas, Ohio, Texas and Colorado. A recent publication by the USGS suggests that a magnitude 5.0 foreshock to the 2011 Prague, Okla., earthquake was human-induced by fluid injection; that earthquake may have then triggered the mainshock and its aftershocks. OGS studies also indicate that some of the earthquakes in Oklahoma are due to fluid injection. The OGS and USGS continue to study the Prague earthquake sequence in relation to nearby injection activities.

The first earthquake I ever felt was in the middle of Illinois. However the worry is that the rate of Oklahoma earthquakes has increased dramatically since fracking, to the point where there are more earthquakes in Oklahoma than California. No one is claiming that there were never any.