Archive | September 2014

What you can blame fracking for

GG has complained about the conflation of “fracking” with oil and gas development as a whole.  So while problems with water quality and local air pollution frequently caused by oil and gas development are blamed on fracking, it isn’t fracking itself that causes those problems but other aspects of oil and gas development such as poorly cased wells and leaking well heads.

But there are a few things.  In areas where clean water is at a premium, fracking does compete for water when waste water is not reused. And the disposal of that waste water in deep injection wells has led to earthquakes as large as M5s (Oklahoma seems to be dedicated to seeing if they can make something bigger).

GG had missed the impact on sand mining.  While fracking originated as injection of water or a fluid mixture, it was recognized that adding something to hold fractures open would help production.  So now most of the mixture of stuff pumped down a well being hydrofracked is water and sand, and there is a strong preference for nice clean quartz-rich fine grained sand (there are artificial sands, too).  An LA Times story (largely based on a report from the Boston Action Research group) notes that 95 billion pounds of sand will be used in fracking this year.  Or, put another way, that is 47 million tons of sand; the USGS estimated 32.5 million tons was used in fracking and well packing in 2013, so the numbers in the BAR report seem a bit high for fracking alone. This is dominantly from the well-worked lower Paleozoic sands of the mid-continent since a high silica content and well rounded grains are preferred; the St. Peter Sandstone being one of the present main resources. The BAR report notes that air and water quality issues exist with such mining, with silicosis being an obvious potential issue and heavy metal poisoning being a bit of a surprising possible side effect.

For perspective, how big a deal is 30-50 million tons of sand?  Since this is largely coming from a small area of Wisconsin and Minnesota (so far), the local impact is large. But there is a huge amount of material mined for construction use of sand and gravel in many construction uses, over 861 million tons per year in the U.S. in 2013.  So the frac sand industry is only something like 5% of the overall aggregate production, and many of the issues with frac sand production mentioned in the report also exist when mining aggregate for other uses.  (For additional comparison, the magnitude of frac sand mining is comparable to salt mining in the U.S. and half the production of cement).

So, whatever the impacts of frac sand mining, that is one thing you can lay squarely on the expanded use of hydrofracking.

I do not believe the scientists because it is their profession, not their hobby.

So Jon Stewart summarizes the view expressed by Rep. Larry Bucshon in this The Daily Show clip exposing some of the inanities of the House Committee on Science, Space and Technology (starts 3:00 into the clip). Although undoubtably cut for optimal humor, it is hard to imagine a context that would make any of the questions asked by committee members seem intelligent. Of course, the confrontation is not unexpected when the committee titles its page on the hearing “Full Committee Hearing – The Administration’s Climate Plan: Failure by Design“. Some more complete clips are at ThinkProgress (GG couldn’t get the Committee’s archived webcast to work to see the whole thing). This sort of thing is not new; a blog hosted by Scientific American recounts some earlier adventures with this group.

Sierran Escarpment: Uplift Driver or Sideshow?

Perhaps the most impressive aspect of the Sierra Nevada is its eastern front.  A bold wall of rock challenges any who would cross the range; the southern part in particular is so daunting that Americans weren’t inclined to try to cross it until well after the Gold Rush was underway. No road crosses the range crest between Devil’s Postpile and Nine Mile Canyon Road to Kennedy Meadows (on the South Fork of the Kern).  That eastern front is controlled by a system of normal faults, and as such they define the eastern edge of the Sierra.

For many years in talking about the uplift of the Sierra Nevada, GG has been asked from time to time about whether the Sierran uplift is a response to normal faulting on the east side.  And the answer has been essentially no; this adds some height near the fault but isn’t the main player.  Now a couple of papers have shown up in the last few years on this, and they proceed from some occasionally complex assumptions to investigate this.  Frankly this was more work than was warranted; you can show pretty directly with little work that there is a firm upper bound on how much that faulting could create.  What is more, what little is predicted also carries a prediction about the gravity field, one that is very much at odds with observation.

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Fracking makes you ill…or not

Reading about fracking certainly will make you ill…or grumpy…

So here’s an update on the ongoing attempts to understand what oil and gas development is doing.

First, a new study in PNAS (thanks to Ars Technica for pointing this out) takes a rather clever approach using noble gases to determine just where the stuff showing up in water wells near some gas wells is coming from.  Doing this reveals that all the failures are in the well area and have nothing to do with fracking (basically, there is no evidence that fracking deep below shallow aquifers permits gas to leak up from those deep source areas).  This is no surprise to anybody who really has been paying attention, but it again underscores the mistaken impression made both by detractors and defenders of unconventional gas and oil recovery.  Fracking is NOT the issue.  What is the issue is the commonplace ineptitude in sealing wells properly (remember the Deepwater Horizon?) and the vastly increased density of wells associated with unconventional development.  This kind of leakage has gone on for a long time but is probably a lot worse with the rapid increase in drilling (hard to imagine that there aren’t more than a few fly-by-night operations trying to seal wells with little or no experience), so it is easy to imagine that the shear number of troublesome wells has increased greatly.

On a separate front, another recent study in Environmental Health Perspectives that made news in several corners surveyed folks living near gas wells and using water wells in areas with recent gas development. Read More…

Citation Abuse

On the heels of GG’s tirade about really lousy citation of literature, we find a recent paper by Ole Bjørn Rekdal  pointed out by Retraction Watch that has this to say about citations:

Due to the digital revolution, it has never been easier to look up and verify, learn from, and check the relevance of sources being referred to. Instead of grabbing this opportunity to increase the quality of academic publications, a wave of scholars is doing exactly the opposite. Academia is being flooded by irrelevant, useless, and outright misleading references, and we are at risk of losing respect for one of the most important tools we have for academic communication and the joint project of building knowledge.

(In following the suggestions in that text, we note this is from page 582 of the preprint). GG couldn’t agree more. Anyways, this is a far more thoughtful screed on the whole issue of citation abuse and (aside from the annoying preprint text layered across it) is very readable.

For those with little patience, the main points are that (1) citations increasingly are becoming too vague to locate the source of the material being cited (this is not as critical in most earth science, where citations to books are relatively rare), (2) citations to primary sources are not being made (this was GG’s gripe), (3) citation of secondary sources (or simply reproducing citations to primary sources without checking them) leads to a game of telephone and subsequent misrepresentations of the literature, (4) citations are mistakenly being used for self promotion (mainly by journals–GG has not seen this in practice in geoscience–and individuals–GG has seen this), and (5) an overload of citations as window dressing to feign knowledge is also a bit of a trend. Again, a worthwhile read for anybody in the science biz.

When Exfoliation Becomes a Hazard (Updated)

There is a really cool video of an exfoliation event at Twain Harte Lake in the Sierra near the Sonora Pass road that went on (or might still be ongoing) in August 2014. (Copied to Ars Technica and Gary Hayes Geotripper blog; a shorter wider view is on YouTube).  Exfoliation is the creation of joints nearly paralleling the earth’s surface.  While these have been the subject of discussion in the Sierra for a long time, actually seeing one form (let alone videoing it) is one surprise, and that there seems to be a whole swarm of exfoliation events going on. Steve Martel at the University of Hawaii has taken a major interest in the creation of exfoliation (or sheeting) joints; his 2011 paper in GRL suggests that you get these by the application of lateral compressive stresses (note these are not deviatoric but total stresses) to certain topographic geometries (basically ridge lines and saddles).  He makes a good case that it is not simply unloading of the rock that creates these fractures, which is the explanation typically put forward.

MartelExfoliation

The cartoon from his paper illustrates the idea: if the net sum of the compressive stresses exceeds the weight of the rock and the tensile stress of the rock, then the rock will fail in tension at the base.  This actually seems like a reasonable explanation for what is seen at Twain Harte Lake, where the dam abutment where the problem arose is a small dome; the lake being in a broad topographic depression means that there is plenty of regional topographic stress near the surface.  It would be interesting to know if the failures tended to be at the hottest parts of the day (we might expect expansion of the rock to add a bit more to the compressive stresses).

It still seems we are missing some pieces.  For instance, profound exfoliation joints are seen on the upper parts of Half Dome in Yosemite.  Just where the compressive stresses are coming from on Half Dome is a mystery to GG; about the only source would seem to be gravity at this location.  (It is interesting that Martel cites an unpublished 1970 thesis as having measured surprisingly high horizontal stresses at Tuolumne Meadows; the orientation is consistent with the N60W direction of many extensional markers to the east, suggesting some connection to the regional stresses at depth).

Update 9/29/14: Kerry Leith at Munich has pointed out his own blog post about similar events in Finland this year and provides links to a somewhat different take on how these kinds of events work mechanically. In the Finnish case, the rock being deformed was still glacially striated, making this the first such event there is about 10,000 years.

College Polling, or Believing is Seeing…

More continues to stream forth on what college should be. We already discussed whether the sole purpose of college is vocational training; today let’s just pretend that is really important.  Thomas Friedman latched onto some Gallup/Purdue polling from last February (way to be on top of breaking news, Thomas!) about college to opine that colleges should be making sure students are mentored and offered internships .  Basically Gallup found that if you either had a mentor in college or professors who cared about you or had a professor who excited you about learning, you were about twice as likely to be engaged at work.  Interestingly, having had all three doesn’t really bump the number up much.  Similarly, having had an internship bumps up engagement at work, as does having an extracurricular activity or having completed a long term project; again, these don’t really multiply (so having all three doesn’t make you 8 times more engaged, just 2.4 times). 

Of course, the results tell us that college is failing students, right? Sorry, while colleges might be failing students, this isn’t the dataset that shows it.  Let’s ponder a moment. (Quick test: if you know where this is headed, maybe you had a good college education…)

First, these factors don’t multiply or even add.  In a way, that is odd.  Why would that be?  A MOOC professor might excite you about learning but would probably be unable to pick you out in a lineup. A caring professor might not even be your teacher in a class but might be a dorm RA (yes, that happens). Same thing with extracurricular activities and internships: if these are the factors producing more engaged workers, why don’t they build on one another?

Here’s the reason: these are the characteristics of engaged students; is it a shock they become engaged workers? They don’t become more engaged the more things they engage in; this is why these factors don’t pile up. And because this is the profile of a more proactive individual, they probably sought out more job opportunities before committing to one, meaning they sought out their work instead of settling for what came up.

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