Tag Archive | earth science

A different view of science

Today is Earth Day, and many folks will be out marching for science. There are lots of reasons one might do this–provides the grist for technological advance, allows for finding ways of living longer and better, etc–but GG would like to explore a different tack.

GG was recently in Ireland, and at geologic sites like Giant’s Causeway and the Cliffs of Moher he looked for books on geology in the visitor center stores.  There was one rather generic book on deep time at Giant’s Causeway (with a cover shot of the Grand Canyon) and nothing at the Cliffs of Moher.  There were, on the other hand, fistfuls of books on Irish history, most of which dealt with events nowhere near the places where the books were being sold.  This is hardly unique to these places, but it is sobering.  Here are landscapes–geological landscapes–that people have travelled some distance to see, and there isn’t enough interest for there to be even one book specific to the place?

The point? People seem to gravitate to history books but avoid science books.  Science books, it would seem, are too heavy for casual reading. Many of the marchers today may feel science is important, but you wonder if they would pick up a science book while on vacation. Now perhaps this reflects a certain inability of those writing science to author accessible books (but there are some really excellent science writers out there), but it might also mean that folks feel that science is best left to scientists.  Just give me my smartphone, thanks, and make sure the plane gives me a smooth ride home and all is good.

Science can be more though than just the mechanism by which we find our way to new and better gadgets. It can also provide the same kind of insights into the human experience that we seek in art and literature. But by limiting science to an academic pursuit, the public misses out on this facet of the scientific enterprise.

This is why GG wrote The Mountains that Remade America. The book fuses human history with geological history, so in some ways it is a bit deceptive–here is some nice tasty history, and oh by the ways, there is some geology here too–try it, just a smidgen, and you’ll get a bit more yummy history. Who we are, why we do things some ways, how we live in others is rooted in the geology of a region, but this aspect of history is buried in most of those history books cluttering visitor center shelves.  Hundreds of books address the California Gold Rush.  Few if any consider how the gold got to be there–or that the presence of different kinds of gold deposits dictated how the rush would affect later history. Or consider how John Muir’s idolization of empty landscapes might have been different had he been tramping in the Rockies with Indian settlements all around instead of the High Sierra where occupation was purely seasonal.

So today, as many trumpet how important science is as a practical matter, don’t forget that science is a human endeavor, and there is real gratification in learning the origin stories that make us what we are.

The silver bullet that ricocheted

[W]e note that if [elastically accommodated grain-boundary sliding] were as ubiquitous as theory implies, then the interpretation of seismological observations of any hot, solid regions of Earth based on single crystal elasticity would require a significant revision.-Karato et al., 2015

This concluding sentence from a recent paper suggests that a lot of seismological interpretations out there are wrong.  Fully understanding what is going on is worthwhile but takes a bit of background. Unfortunately their press release is so tied up in knots that it hides what could be a really significant contribution.

One of the key elements in plate tectonics is, not surprisingly, plates.  While the bulk of the mantle convects as a viscous fluid, some of it near the surface cools enough to essentially remain undeformed.  This mantle tends to stay attached to the crust above it; it deforms more simply as an elastic material than a viscous one.  Together, that uppermost part of the mantle and the crust form the lithosphere.  And the lithosphere is basically where the plates are [let us set aside tectosphere arguments for today]. This paper in essence explores the failure of a promising approach to figuring out the thickness of the lithosphere and in so doing might undercut a fair amount of current understanding of the physical state of the shallow mantle.

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Confusion over causation

One of the trickiest concepts in earth science has got to be causation.  We like to write things like “earthquakes caused by fracking” or “volcanoes are caused by subduction” or things like that. But it can get a lot more confusing; this is true in spades when we start talking about situations where “causation” is equivalent to “liable for.”

Take “arc volcanoes are caused by subduction” as a starting point.  What does it mean to cause something?  Well, one aspect is that if we remove that feature, then we don’t get the result: if we don’t have subduction, we don’t get an arc volcano.  Another is that if this is the sole cause, wherever that process is taking place, there should be that result: if subduction is the sole cause of arc volcanoes, then we should always find arc volcanoes where there is subduction. In this case, plate boundaries lacking subduction usually don’t have arc volcanoes (how you define an arc volcano is why the answer is a bit of a weaselly one).  But we know of subduction zones lacking arc volcanoes.  So there is something else that is a cause. In this case, it would appear to be the presence of asthenosphere above the subducting slab.

We can get into some more unclear situations rather easily.

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Eyeblink Erosion

Just how significant are extreme events in the geologic record? Well, we now have a really exceptional measure thanks to some work due to be published in Geology by some of GG’s colleagues here at CU Boulder.  Back in 2013 we had a really intense rainstorm, arguably something like a once in a thousand year rainfall in Boulder. Associated with this were numerous debris flows and landslides.  It just so happened that part of the area so pounded was being studied as one of NSF’s Critical Zone Observatories, and as part of that project they had flown Lidar to get a high-resolution topographic map of the watershed.  This was done in 2010.  The authors then managed to use a new Lidar image obtained by FEMA to determine just how much material had moved during the flood.

The results are stunning.  Over the few days in September 2013, hundreds of years of geomorphic work was accomplished in the basins with slope failures; in these basins, some 15 mm of average lowering occurred.  As these basins only represent 7% of the overall drainage area of Boulder Creek, for the Boulder Creek watershed as a whole this represents removal of some 30 years of weathering as measured by geologic rates using cosmogenic isotopes–maybe less impressive but still it means that if you were out of town for a week, you missed 30 years of erosion. Interestingly, such failures were found equally on areas burned in recent fires and areas that were unburned.

These results are even more striking when considering that Boulder Creek’s drainage actually was less impacted relative to the drainages to the north.  Really massive storm damage was found in the St. Vrain River drainage and parts of the Big and Little Thompson Rivers.  It seems likely that the entirety of these drainages saw far more geomorphic work done in this flood. This underscores how the geomorphic evolution of some areas can occur over dramatically short times.

PS.  It appears that most of the erosion was in removing soil and regolith that were the product of erosion acting on bedrock; mobilization of bedrock was rarely observed.  With the removal of that material, any new large rainstorm presumably would not produce much lowering of these basins, but that also means that the water would come roaring down Boulder Creek carrying very little material, which means it would be capable of a lot of erosion.

The Geoscientists’ Blind Spot

One advantage of looking back at the history of earth science is to recognize patterns that suggest certain biases.

Consider, for instance, continental drift.  Now this is often portrayed as Wegener right, others stupid dunderheads, but obviously that is too simple. First off, Wegener had a mix of good and bad observations.  Aside from fitting continents (a somewhat old parlor game by then), he noted common terrestrial species, ice deposits far from the pole, and the fundamental division between continental crust and oceanic crust.  But he also put a lot of weight on his own grossly inaccurate geodetic surveys and so concluded that Pleistocene deposits on either side of the Atlantic predated the separation of the continents.  But the big objection to continental drift was simply: how would it occur?

Here’s the funny thing: this is common to any number of ideas based off of observation in earth science.  If you want to bet, bet in favor of observation-based occurrences having occurred and against objections based on an incomplete explanation of how it works.

How common is this?  A few examples follow:

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A Map, A Map, My Kingdom for a Map (and NOT those things showing up in papers)

What is wrong with this figure?

No, its not the color scale or using t’ for elevation (though, um, why t’ anyways?).  It is that this is not a map*.  This is what GG has always called a “computer-stupid” map projection.  Why? Look at the axes.  Since when is one degree of latitude equal to one degree of longitude at 40°N? Look, twenty or thirty years ago you might have had an excuse.  Today? No. None. Nada.  Not in the age of Generic Mapping Tools or the geographic toolbox in Matlab. You could at least make a computer-stupid Mercator (that is where you simply squish the horizontal axes to approximate the latitude:longitude ratio at some point in the map; a true Mercator has a varying latitude scale). Look, maps are useful when done right.  In this case, you probably want to preserve area, so you look for an equal-area projection (there are lots).  In some cases (e.g., SKS split maps), you probably want to preserve angles, so you might opt for the Mercator. This map (and its many cousins in this paper) preserves nothing.  Distance scales depend on what direction you are measuring, angles do not correspond to angles on the earth, area is not preserved–in short, there is absolutely nothing good to say about this. Now this is far from the only paper GG has seen with this failing, but this has got to stop (just like the insane inability to properly cite the literature). All geoscientists should be able to make a map. This is, to the Grumpy Geophysicist, a demonstration of profound inability to get the simple things right, and if you don’t get the simple things right, why believe anything else in the paper?

A partial apology: In choosing this map to act as a stand-in for GG’s rant (which, on a broad scale, he stands behind), it appears (see comments below) GG chose an example where this projection was consciously chosen–why, GG cannot figure, but as there was a deliberate reason, the innuendo in the text above is misguided.  So apologies to Thorsten Becker: that last sentence should not be construed as condemning that particular paper.  But GG still hates this projection.

*OK, GG is wrong.  It is a map and a named projection, as Thorsten kindly pointed out below.

Can you falsify an earth science hypothesis?

Answer: No.  Read on for why.

Science, they tell us in grade school and middle school and high school and often into college, has four simple steps: Observe, formulate a hypothesis, test that hypothesis, reject or accept that hypotheses (usually testing against a null). In this model, hypotheses should be falsifiable.  Is this done in earth science?

Consider the big mountain building hypothesis of the late 19th and early 20th century: geosynclinal theory. The idea was that parts of the earth’s crust would warp down, accumulate a lot of sediment, heat up and get injected with magma and deformed by thrust faults and rise up to be mountains.  One side was continental (the miogeosyncline) and the other we’d now consider to be oceanic (the eugeosyncline). Lots of embarrassing problems emerged: among them, fossils from one part of the geosyncline were totally different from those elsewhere in the geosyncline, so magical barriers had to be made (various flavors of eugeanticlines). Arguably many of these demonstrated that the theory was wrong, but instead scientists proposed ways that the theory could still be right.  It isn’t until plate tectonics overcame the objections to its predecessor of continental drift that geosynclinal theory was abandoned. It took a theory to kill a theory.

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Are There Good Geo Movies?

Having already discussed bad earth science movies (no shortage of those), one may ask, are there any good earth science movies?

Now somewhere out there is some imaginative filmmaker who can come up with a watchable movie about the extremely zen art of field mapping.  Field geology is kind of like a slow-motion CSI episode.  How do these two faults link up? Does that bed pinch out? Why are these fossils only found here? How will I ever get a strike and dip in this crud? Slowly reading the history of long-gone events is a different kind of experience. As a personal experience, GG recommends a stretch of field mapping as being good for the soul.  But so far, no takers on that movie….

While a bad geology movie says and does things so central to the plot that are simply impossible or stupid, to be good we need more than just avoiding those potholes.  We’d like to see something of the logic, the give and take, the hypothesis and refutation of science to share with a broader audience.

So far in GG’s experience, no movie pulls it off in entirety.

The closest in GG’s experience is probably Dante’s Peak.  The errors in the movie are ones of exuberance and exaggeration, not outright misrepresentation or fantasy (the acid lake wouldn’t eat away the boat–though burning human flesh is plausible, the earthquake experienced is larger and longer than the ones you usually find in volcanic areas, the swift lava flows and pyroclastic eruptions are not going to occur at the same time and place),  though driving across a fresh lava flow kind of jumps the shark (that would be hard to pull off, but maybe someone should pitch that to Mythbusters).  The USGS page on the movie is helpful in considering the science of the movie. A lot of the objections you find out there to the science in this movie are based on typical behavior, not possible behavior (and some are themselves representative of misunderstandings arguably greater than the moviemakers’: for instance, one post says that major element composition determines whether a flow is aa or pahoehoe; in fact you will find both in the same flow: it appears viscosity is the key player, possibly affected by the water content of the flow).

What makes this an interesting movie is that, rather unusually in these films, science is actually conducted (if you are wondering, science’s usual role is as a reference library).  The protagonist, Dr. Harry Dalton, is sent to check out a volcano, he sees signs he views as disturbing and wants to put the town on alert.  His superior (Dr. Paul Dreyfus) shows up and stops that from happening.  In a more typical film, Dreyfus would be a simple heavy, keeping the hero from doing anything until a crisis erupted, ignoring evidence.  But here, Dreyfus is basically saying that they need more data before moving forward: in essence, Dalton’s hypothesis that the volcano is now active makes some predictions, one of which would be seismic activity, another would be evidence of some primary magmatic gases. So they set out to test this hypothesis, deploying seismometers (and their seismometer deployment is indeed a very nice one), sampling gases (well, they wouldn’t be sending a robot down a crater wall, but its a cute idea and something like it has been tried). A lot of this part of their story was reflective of the USGS’s misadventures in Mammoth Lakes in the early 1980s when a survey decision to issue a volcano alert was scooped by the LA Times, blindsiding local officials and producing a major backlash against the agency. (And grandma’s attempt to stay at home is referring to Harry R. Truman and his 16 cats defying evacuation orders at Mt. St. Helens in 1980, one suspects). After monitoring awhile with no quakes, Dreyfus decides enough is enough as they haven’t seen anything and its time to pack up and monitor from home, which is a perfectly reasonable response.  It just feels like a likely set of actions and reactions (the desire to dope slap characters is relatively absent).  Of course, at this point everything goes nuts and we enter pure disaster action movie mode (Sparks fly! Buildings fall! Dog saved! Lava! Lahars! Death! Life!).

Another movie worth mentioning here is Jurassic Park. Why? Because unlike so many movies, there are different kinds of scientists with different backgrounds and modes of operating.  In many movies a “scientist” is as likely to know the details of the Drosophila genome as the magnetohydrodynamics of the earth’s core (think of all the stuff Spock seems to be expert in in Star Trek if you want the extreme example).  Here we have a couple of paleontologists and a mathematician with different backgrounds and different experiences, which was a nice change. And, you know, the little episode in the helicopter where Dr. Grant has to tie his seat belt together is in many ways the mark of a field scientist–if you can’t get things done by the book, you need them done well enough to get through and so necessity is the mother of invention.

Other movies? The Core? The Day After Tomorrow? Armageddon? Deep Impact? Volcano? Pompeii? Ice Age movies? One Million Years BC? Walt Disney’s Dinosaur? Journey to the Center of the Earth (either version)? Star Wars? Earthquake? Krakatoa East of Java? A View to a Kill? Tremors? The Day the Earth Stood Still? 10.5? Superman (the first one)? The Lone Ranger (the Johnny Depp one)? Avatar? Well, though some have a glimmer of redemption, none are good geoscience movies….

If you want, there are plenty of more in-depth discussions of geology in movies out there (though they are mostly poking fun at the gaps in movies); GG isn’t intending to get into regular movie reviews…:

Bad Movies, Earth Science Edition

With the release of Godzilla, we are in the summer movie season.  And we already have some of the fun chuckles for GG like monsters that can suck the radiation out of things and hearing that they used to get the radiation coming from the core. [And why did they set a railroad scene in Lone Pine, when there hasn’t been a rail line there for a really long time, where lots of filmmakers have actually been, but of course this time they didn’t film in Lone Pine, so it doesn’t look anything like the place? They could have said Mojave or Tehachapi, or if they really wanted some interesting scenery never on the screen before they could have chosen Caliente, NV, and its classic rail station.  But GG digresses….]. So this brings to mind the occasionally fabulously bad geoscience that shows up in the movies.

For how little earth science shows up in standard K-12 curricula or, for that matter, most college requirements, it is surprising how many times you see it appear in movies. Maybe the earth isn’t worth study, but it makes a decent movie star. Anyways, with any of these movies there is an accompanying outcry from scientists that “it just isn’t that way.” [Kind of like lawyers complaining about law movies and doctors about medical shows]. We won’t try to list all the offenders here (others have done that); instead, what makes a bad geology movie bad? 

It is funny how movie makers go to huge lengths to reproduce some things while utterly disregarding others. You will hear a costume designer brag about studying vintage photographs to reproduce exactly the right look, or a production designer getting the precisely correct telephone in a room. The whole idea is to make the viewer buy in to what is being seen. If a character tried to use a 1920s telephone as a telegraph, banging the ear piece against the microphone, everybody might laugh as we’d know that was wrong, but show a character using, say, a Betsy seismic source with a GPR imaging setup (Jurassic Park is where you find that) and the audience, save for a few geophysicists, raptly watches as this impossible setup yields an impossible image. Does this alone make a movie a bad geology movie? Well, it depends.

We can throw out a few obvious chestnuts as irrelevant. Movies are notorious for hopping all over the real world and pretending that this is a simple linear journey; geologists are probably more familiar with landscapes than most and so can be distracted (or amused) at, for instance, the real world path that Maverick takes in the movie of the same name from the early 1990s. Or be puzzled (along with history buffs) that the Transcontinental Railroad was realigned through a relocated Monument Valley, now moved to Texas (wouldn’t do to have the Lone Ranger not be a Texas Ranger) and adjacent to (nonexistent) mines in 2013’s The Lone Ranger. Or that Afghanistan looks precisely like the Alabama Hills and the Sierra Nevada in Iron Man. You get the idea. So this isn’t enough to make a bad geology movie.

Turning professional lingo into bafflegab? You know, like doing the Kessel run in less than 12 parsecs? Lazy and unnecessarily annoying, but usually innocent.

Can a fantasy movie be bad geology? Hmm. Superman is clearly fantasy but is placed otherwise in our real world (as much as a real world exists in escapist movies), so complaining about him flying or defying bullets and all that is pointless, but if he misunderstand the San Andreas Fault, say, then maybe it becomes bad geology. But a wholly fantastic world? Are we going to knock Lord of the Rings for an improbably located active volcano? No.

How about science fiction? This depends on how hard the science fiction wants to be; nearly every movie with science in it is some form of science fiction. So you could say that things like Volcano, Dante’s Peak, Jurassic Park, The Day After Tomorrow, etc., are all trying to be set in the “real world” and so if the geology is bad, it is a bad geology movie. How far do you go? Do you knock Revenge of the Sith for a volcanic planet that has no hope of having a breathable atmosphere? Can you challenge Pandora as geologically implausible in Avatar?

Making a terrifically dull movie about geology? No, that is making a bad movie, not a bad geology movie. We need to separate the dramatic success from the intellectual failings.

How about showing something that violates geology as we understand it? So, for instance, at the time Jurassic Park was filmed, the largest Velociraptor was the size of a medium dog and some felt that making them bigger was cheating. Of course, shortly after that Utahraptor was found and we were all good as far as big raptor-ish dinosaurs were concerned. Or the big explosive eruption in Dante’s Peak coinciding with eruption of nice fluid (basaltic) lava flows? Well, this is one of those gimmes to drama; they just couldn’t resist having characters chased by lava. (Does anybody recognize that lava is molten rock and not just hot red water? When Gollum falls into the lava in Mt. Doom in Return of the King, he shouldn’t have sunk in—he is less dense; more likely he would writhe in pain from burns before he burst into flames on top of the lava).

No, the thing that transforms a movie with some earth science into a truly bad earth science movie is when the premise relies on science and screws it up, sometimes so horribly that people walk away from the movie knowing less than when they walked in. The scariest example of this might well be The Day After Tomorrow, which left European audiences believing less in climate change than before they saw the movie because, well, they knew enough to know that what they were seeing made no sense. (Americans were on the opposite side, as they believed in climate change more after seeing the movie, but Americans probably also feared sharks more after Sharknado).

For laughably bad, though, it is hard to exceed The Core, which screws up so many things so intensely and in such an essential manner that no earth scientist can really get involved in the movie. The list is so long—gaps in the magnetic field allowing the Sun to kill things instantly and demolish structures on the ground? Really? Wow, those space probes and astronauts must be made of something really incredible. Flow in the core just stops? You can restart it with explosions? Varying fields cause birds to collide with things? Hello, they have eyes for a reason. Stopping pacemakers? Really? In a tiny area? Giant geodes at nice cold temperatures in the mantle? Mega diamonds? Erupting from the core to a volcano in Italy—no wait, that was another movie journeying to the center of the earth. The problem with The Core isn’t that it promises an impossible trek to the core—that silliness is simply the addition of a miracle machine—it is that it so destroys any resemblance to reality that anything goes. 

So when a movie depends on earth science and just absolutely mangles it so that a geologically literate viewer cannot suspend disbelief, it is a really bad geology movie.  When a movie shows science being done wrong or gratuitously mangles some science that could be correct without damaging the story arc, that makes GG get more grumpy, but the magnitude of ‘badness’ depends on how much of this goes on. 

However, even bad geology movies are kind of cool in that it means somebody is noticing some science being done.  Obvious ones like Dante’s Peak and Volcano and Earthquake come from earth science disasters, though they gain dramatic tension from the possibility that scientists can provide meaningful warnings, while Armageddon and Deep Impact owe their origins directly to research on the extinction at the end of the Cretaceous.  The Day After Tomorrow is kind of a misreading of a 1989 hypothesis by Wally Broecker and others on how the Younger Dryas episode (when Northern Hemisphere temperatures briefly returned to Ice Age cold) was spawned.  Maybe Hollywood should be funding some science; they had nearly a billion dollars on receipts from Armageddon and Deep Impact, but the original research that turned up this meteorite-wiping-out-the-dinosaurs cost under $24,000. Or, maybe, the next time the NSF Director testifies on the reason why NSF should get more money, he should ask to move to a movie theater and just show some movies that were inspired by research NSF funded…