Some Very Strange Maps

Once in a while I stumble upon, not StumbleUpon, just stumble upon a blog that makes me press the subscription button at once.

Strange Maps is one of these sites. A wonderful collection of weird, creative and humorous ways of depicting the world in "maps".

Having spent long late afternoons in Appalachia sipping sweet tea after a day's fieldwork this one I could relate to all too well; the north to south distribution of McDonald's selling unsweet and sweet tea in Virginia.



Source: Eightoverfive.com via Strange Maps

I am not sure how many geo-bloggers have this site on their blogroll. It's a refreshingly different spot. You can't really categorize it as a geoscience blog although there are posts on geology related topics. But it's just the spatial depiction of information that caught my interest. Maps always give you a different perspective, makes you ponder over previously unrecognized connections. You can create your own story of places visited, geology observed, people you have met. Definitely worth a regular visit.

Hat Tip: Geology News

Are Most Papers in Nature Likely To Be Wrong?

A friend emailed me this article from The Economist:

In Economic theory the winner’s curse refers to the idea that someone who places the winning bid in an auction may have paid too much. Consider, for example, bids to develop an oil field. Most of the offers are likely to cluster around the true value of the resource, so the highest bidder probably paid too much.

The same thing may be happening in scientific publishing, according to a new analysis. With so many scientific papers chasing so few pages in the most prestigious journals, the winners could be the ones most likely to oversell themselves—to trumpet dramatic or important results that later turn out to be false. This would produce a distorted picture of scientific knowledge, with less dramatic (but more accurate) results either relegated to obscure journals or left unpublished.

Marginal Revolution has a more detailed debate in the comments section.

I don't read much geosciences in Nature or Science. But should I now pay more attention to papers in Carbonates and Evaporites instead of Journal of Sedimentary Research?!

Apologies to the Editors.

More importantly, is some of my unpublished PhD work really the real deal!?

Was September 08 Earthquake Month?

The September earthquake story has developed nicely with just the right amount of coincidences to cause excitement in the astrology community. Triumphant comments have been left on my earlier posts on earthquakes claiming "prediction" success. I noticed throughout the month of September quite a bit of traffic coming to my blog from search queries of the like " September astrology earthquake prediction" and so I gather there is a lot of curiosity about whether astrologers can really predict earthquakes.

Just a quick recap for those who have not been following this thread. Some astrologers claim that they can predict big earthquakes based on the alignment of the moon with the sun and other planets in the solar system. Mr. Amit Dave who lives in Mumbai is one such astrologer. He claims that certain alignments of the moon and sun (and other planets) exert tidal stresses on earth. No one doubts this. Nothing new here. The relevant question is whether these tidal stresses acting alone i.e. without input from internally generated tectonic stresses are enough to cause big earthquakes. The answer is clearly no.

In two earlier posts I exposed Mr. Dave's lack of understanding about geology and earthquakes and explained just why tidal stresses acting on their own are incapable of causing big earthquakes on earth. He never gave me a single substantive reply to my questions but kept making foolish claims about his "predictions" in the comments sections of my posts. So in this post I will try to explain what is a scientific earthquake prediction and whether Mr. Dave's "predictions" measure up to this standard.

The main confusion among people is between making the rather mundane claim that earthquakes will occur on any particular day against the more meaningful exercise of predicting a earthquake. Astrologers are unable to grasp this distinction or more cynically ignore it since the laypersons they are trying to reach certainly don't make this distinction.

When geologists make a prediction about a earthquake it is in this format:

An earthquake of magnitude ...6.5-7 magnitude (range).. will strike (with a probability) ...time range..(usually in the range of the next few years) at location... Longitude X and Latitude Y due to ... hypothesis of how and why an earthquake is due /imminent in the declared region.

Astrologers ignore the third requirement of the location and are puzzled by the fourth. Why give a hypothesis of how and why an earthquake is imminent.

Here's why. Geologists studying earthquakes and working in a particular area have a hypothesis on how geological stresses may cause an earthquake. This hypothesis describes for example the rates at which strain is accumulating along a particular fault based on say the motion of the earth's plates. Or take tidal forces. Ultimately they can only act or trigger earthquakes by imposing stresses on the crust. So even a theory of earthquakes like Mr. Dave's which relies solely on tidal forces needs to explain in terms of the imposed stress and accumulating strain how , why and where these tidal forces are likely to cause a rupture. If an earthquake does occur in that region, this hypothesis can then be validated against what actually happened. It gives geologists a chance to test how good their understanding of earthquake mechanisms is.

Here is a great example of this process from the September issue of Geology in a paper that studies the big Kashmir earthquake of 2005:

.... We thus conclude that the 2005 event did not occur on the plate boundary megathrusts, but on intraplate active faults within the Sub-Himalaya. Consequently, the accumulated elastic strain around the complex northwestern margin of the Indo-Asian collision zone has not been significantly released by the 2005 earthquake.

What this means is that the earlier hypothesis that a big earthquake in Kashmir will likely take place along a major boundary fault zone was wrong. The earthquake instead took place on a subsidiary fault system. This however warned geologists that strain is still accumulating along the major fault and another big earthquake in that region is likely.

Science is a self correcting process. If we are to improve our understanding of earthquakes, a prediction must include a declaration of a hypothesis which can then be validated against what actually took place.

Alright, on to Mr. Dave's "predictions". Here it is

1) 7th September 2008 -- 2020GMT ---- 7.2 On Richter scale at 12 Degrees East or/168 Degrees west ( Precise location both longitude and latitude is not possible as of to day)2) 10th September 2008 --1950 GMT ---7.3 on Richter scale-at 66 Degrees east or 114 degrees West3) 15 th September 2008 --0910 GMT----More than 7.5 on Richter scale -at 147 Degrees East or 33 Degrees west4) 16 th September 2008 ---2015 GMT---- 7.5 on Richter scale -at 87 Degrees East or 93 Degrees West

The original prediction he gave me did not have even the incomplete location information. It is only when the USGS insisted that a location is necessary (he forwarded me a mail from the USGS) that he put in just the longitude.

But that's not it. These dates are way too specific and Mr. Dave then provides a hedge.

As per my theory the dates of September 2008 are already published in my blog. However one more thing required to be noted is that , the dates shown are the peak force dates ,and have maximum potential of triggering the quakes. However , the quakes follow a sinusoidal pattern. As the dates mentioned approaches nearer the quake intensity and frequency keep on increasing. After the dates have passed the tidal force slowly fades away.

And then not satisfied that his sinusoidal wave will cover enough ground, a few more dates:

Thus , there are fair chances of quakes of 6.5 to 6.8 Richter scale on following dates also. places not known.27 th August 2008----0415 Hrs IST31 th August 2008-----0115 Hrs ISTAlso 22 nd and 23 rd September 2008----up to 7.0 on Richter scale
So, he has covered so much time with his spread of dates that he has ensured himself a high degree of "prediction" success.

Why is that? Because of the high frequency of moderate to big earthquakes, something most people are unaware of. 7-8 magnitude earthquakes occur at a frequency of 1-2 per month, 6-7 magnitude earthquakes occur 10-12 per month, 5-6 magnitude earthquakes occur 2-4 per day, and 4-5 magnitude earthquakes occur 20-25 per day.

As expected Mr. Dave claimed earthquakes of varying magnitudes on dates before, between, on and after his peak potent period. Not a single 7+ earthquake occurred on any of these days, but Mr. Dave blatantly misstated the magnitudes of these earthquakes. It is a comical list of claims, but one that speaks to his disingenuity. He seems incapable of reporting accurately even the most basic of facts.

You can check for yourself all this earthquake information by going on the USGS earthquake search.

But my main quibble is not with these reporting inaccuracies. I put that down to over-excitement. My objections are over procedures.

What is the justification for claiming that tidal forces caused the earthquake that was claimed and not one of the dozen others that took place on that day? All Mr. Dave is doing is choosing post facto from a list of earthquakes that occurred on the day, the earthquakes that is closest to the magnitude he gave or one he deems significant in some way.

I like to call this retrospective coronation.

Again, how does he know that tidal forces caused the bigger earthquake he has claimed and not a smaller earthquake that took place some where else? He doesn't know, but you see without a prior declaration of a location and a hypothesis it is impossible for anyone to verify his claim. And that suits the astrology community just fine.

That is why astrologers never give a location.

Mr. Dave will deny that he chooses earthquakes after they occur, but here is an example which gives his game away. He had "predicted" that an earthquake of magnitude 7.5 or so will occur on September 16th. Unfortunately for him there was no earthquake larger than 6 on that day. So what did he do? He claimed a 5.0 magnitude earthquake (he gives the mag. as 4.9) that occurred in the Satara district of Maharashtra as proof of his "predictions"!

It is stupid claims like this one that lays bare the intellectual bankruptcy of these bogus earthquake prediction schemes astrologers concoct from time to time.

Remember earthquake frequencies? There were 26 earthquakes on September 16 of magnitudes 4-6. There were 4 earthquakes of magnitude greater than the one he choose. How does he know that tidal stresses caused the Satara earthquake and not any one of the other 25? He doesn't. The only reason he choose to claim this particular earthquake is because thousands of people in the Mumbai-Pune area felt it. Humans react to and remember events that occur close to the place they live and Mr. Dave knew he could fool people into believing that he actually predicted that earthquake.

So astrologers are not really predicting a earthquake. They are simply just highlighting after the fact one out of the many that occur on any given day.

Location and a hypothesis, Location and a hypothesis, Location and a hypothesis. Without these any claim to a prediction is meaningless.

Did I mention even the incomplete location information given by him was wrong for all the earthquakes he has claimed?

I find this non-disclosure of location information most revealing! Mr Dave and other astrologers argue that they too are trying to save lives by coming up with a prediction system. That is as strange an argument as I have even come across. How on earth can you save lives if you don't specify where an earthquake is going to strike?

One last requirement of a scientific prediction is the complete disclosure of negative results. Mr. Dave has never admitted that his location information is missing or wrong in all the cases. Another type of negative result is earthquakes that occur on days other than those given. Ambuj pointed this out sometime back. Mr Dave claims that big earthquakes occur solely due to tidal stresses and there are potent days when they will occur. Since his September prediction which appeared on my blog on July 13 to the date of this post, leaving aside the entire month of September, there were 25 earthquakes of magnitudes 6 and above. How does he explain these earthquakes which all fell on days when the heavenly bodies were not engaged in a destructive tango?

In fact how does he explain not just these biggish earthquakes but the hundreds of smaller earthquakes that occur every day?

Here is my suggestion for what Mr. Dave's next prediction should look like:

Magnitude X (range) , Time range , location in Longitude and Latitude and a hypothesis of how and why tidal stresses will cause strain to build up and rupture rocks in the region he has indicated. This is to be followed by a full disclosure of negative results.

If he does this I am sure the seismology community will follow his claims with interest. But just rolling the dice and jumping up in excitement whenever an earthquake happens to coincide with a full moon, new moon or quarter moon day is not acceptable.

I predict Mr. Dave will not accept this qualifying criteria.

I am sure because:

Gustav ,Hanna and Ike three major storms in first week of September08Vanuattu quake of 6.5 on 8th September 2008 ,at 0305 Gmtkeep counting pleaseDave
Astrologer / Engineer

Yes hurricanes too. With this mindset Mr. Dave will continue to fool himself and other ignoramuses who are already convinced that their destiny has been decided by the alignment of distant planets.

Killer Limestones And The American Civil War

Okay, I guess the post title is a bit sensational, but an interesting study by Robert Whisonant and Judy Ehlen of Radford University in Virginia has explored the relationship of geological terrains and casualty rates at Antietam, one of the bloodiest battles of the American Civil war.

From Earth magazine summary:

Then, on Sept. 17, in the shadow of the Blue Ridge Mountains, the Battle of Antietam began. The armies blasted each other with gunfire from dawn until nearly dusk. That day proved to be the single bloodiest day of the American Civil War, with more than 23,000 men lying dead or wounded in the valley’s fields by nightfall.

But in addition to the bullets and cannonballs, soldiers in both armies had another common enemy that day: carbonate rock.

This was from an era where soldiers just used to line up on opposite sides and let go with their muskets and then charge at each other. The battle of Antietam in 1862 took place in the area surrounding the town of Sharpsburg, Maryland.

The fields are underlain by limestones and associated sedimentary rocks of Cambrian to lower Ordovician in age. Way back around 500 million years ago that area was part of a complex of Cambro-Ordovician marine sedimentary basins that stretched along the length of the now eastern U.S. Thousands of feet of carbonate sediments accumulated in these basins over time.

As with any depositional system the composition of the sediments varied over space and time. So there were depositional sub-centers where relatively pure carbonate sediments were being produced, other sub-centers which could be just a few 100 meters away accumulated a mix of carbonate and terrigenous clastic mud and sands. At places the original calcite sediments were replaced by the mineral dolomite.

Now these compositionally different sedimentary rocks respond differently to chemical weathering. Sediments composed of calcite (limestones) are most susceptible and over millions of years such areas will get worn down to relatively flat terrains. Areas with a mix of shale, limestone and dolomite respond differently. Limestone gets weathered faster than shale and dolomite and the results is a more uneven, undulating topography.

When the geologists mapped the casualty rates at Antietam to the underlying geology they found a correlation. The highest casualty rates were in those portions of the battlefield which were underlain by pure limestone and which had weathered down to a relatively flat terrain. On a plain, the opponent is in plain sight and there is nowhere to hide. The image below is a tilted view of an area known as Cornfield just north of Sharpsburg, where the casualty rate was especially high.


Here are a couple more images. The one below is a shaded relief map of the battlefield.


Source: Military geology of Antietam battlefield

The red circle in the upper part of the image is the Cornfield area. You can see the terrain is less dissected by streams and appears flat. The outlined area to the bottom of the image is more dissected by streams and shows a marked relief. This is the Burnside Bridge area which is a couple of miles from Cornfield and where soldiers could find cover in the deeply dissected gulley's and streams. Here casualty rates were three times lower than Cornfield.

The image below is a terrain profile of Cornfield and Burnside Bridge.


Source: Military geology of Antietam battlefield

Given time even granite terrains can wear down to a flat featureless plain. So the important factor here was not the composition of the rock by itself, but the difference in facies heterogeneity. Both sides during the Civil war used the terrain to their advantage. But studies which specifically try to draw out a connection of geology to a particular battle are rare and I enjoyed reading this one.

Flightless Birds Don't Form a Natural Group

Last week I wrote about how paleontology provided an insight into evolution that genetic methods so far have not anticipated. I am not biased towards paleontology or any other field. It is futile to debate whether "my field is better than yours". Clearly evolutionary science benefits from a variety of inputs. More complimentary data the better.

Even so here I am writing about another finding where this time genetic methods produced results that fossils and morphological comparisons alone did not anticipate. Large flightless birds of the southern continents like the emu, ostrich, rheas and the kiwi were believed to be more closely related to each other than to other flighted birds. A genetic analysis has apparently redrawn the family tree of these birds.

It was thought that flightlessness evolved just once. I have depicted this scenario in the figure below.


Here flightlessness evolves in a stem or ancestral species. This happens when the southern continents are still part of the super continent Gondwanaland. The stem species gives rise to several descendant species. The flightlessness in each of these descendant species is a plesiomorphy or an ancestral trait inherited from the stem species. As Gondwanaland breaks up different flightless descendant species end up on different continents and diverge in response to the unique conditions.

But the recent genetic analysis indicates a different scenario. There may have been flightless bird species on Gondwanaland but none of them were the common ancestor of all modern southern continent flightless birds. Rather:


Loss of flight evolved several times on different continents independently in different lineages of flying birds. The flightless trait of the modern flightless birds is said to be an apomorphy or a derived trait in each of these lineages.

Why am I not that surprised? Here is what Edward Braun, one of the researchers had to say:

Scientists assumed that a single flightless common ancestor of the ratites lived on the supercontinent of Gondwana, which slowly broke up into Africa, South America, Australia and New Zealand; once divided, the ancestor species evolved slightly in each new location to produce the differences among the present-day ratites

So, the hypothesis that flightless birds formed a monophyletic group with respect to flying birds was never tested using morphological criteria? It seems that a convenient paleo-geographic story was available and so the assumption was made that flightless birds are monophyletic. Does this speak to the limitation of morphological comparisons for understanding evolutionary relationships or is there something else going on? Why was convergence i.e. the independent evolution of similar features never considered a possibility?

Off course the most heretical suggestion is that we still carry an unconscious bias for typological thinking, a tradition of grouping organisms that goes back well before evolutionary thinking. Flightless birds form a group or a type different from flying birds not because we know they are evolutionarily more closely related to each other but simply because they share the distinct trait of losing flight. No evolutionary scientist thinks this way any more.