Category Archives: random thoughts

Debris Flow Experiments (Spring 2017)

This spring I taught an undergraduate Geomorphology class at Duke. For the last few weeks of class, I broke out my debris flow flume. I have written about this debris flow previously, and is described here on the Sediment Experimentalist Network site. Also posted is a slo-mo video of a typical debris flow.

Students planned and executed an experiment of their choosing — an example of a  ‘Course-based Undergraduate Research Experience’ (CURE). Though there has been some work done with ‘scaled down’ debris flows (e.g., de Haas et al. 2015) there seemed to be lots of room for the students to do something new.

Both groups ended up investigating various mitigation measures for slowing or stopping debris flows. This involved 3D printed several pieces as mitigation structures, from solid walls of various sizes and angles:

…to plates with various densities of upright rods/sticks to function as tree/vegetation mimics:

Each group ended up writing up their work as a paper (data and plots included), and I’m happy to share them here:

  • Paper 1 focused on solid walls
  • Paper 2 focused on the ‘green infrastructure’ mimics.

‘Sleeping Beauties’ of Geomorphology: a case from the American Journal of Science

Most papers in disciplinary geomorphology journals are cited at some point, but citations to papers do not always accrue immediately upon publication — ideas and papers might take time to be used by researchers and therefore cited. Extreme examples of delayed recognition (‘Sleeping Beauties‘) — where papers recieve no citations for long stretches of time only to recieve a large, late burst in citations — have been identified and investigated previously.

Do geomorphology ‘Sleeping Beauties’ exist? Using the methods of Ke et al. (2015) to find and score ‘Sleeping Beauties’, it turns out that 9 out of the 20 most delayed papers in GSA Bulletin are focused on quantitative geomorphology.

What other papers show this interesting signature of delayed recognition?

I have looked in other journals and found a few neat examples, which I hope to chronicle in a series of posts. Today, I will look at an example from the American Journal of Science (AJS):

The AJS has been published since 1818, and has long been a geology venue. In January 2017  I downloaded the 500 most cited AJS articles from the Web of Science. I used the algorithm presented in Ke et al. (2015) to find the papers with the highest ‘delayed recognition’ score — a ranking of each paper’s citation time series based on the largest, latest peak  (I urge you all to read Ke et al. (2015) which describes the method).

The most delayed paper is about brachiopods, but I want to focus on research related to geomorphology, so let’s look at the 2nd most delayed paper:

W.W.Rubey (1933): Settling velocities of gravel, sand, and silt particles. Am J Sci April 1, 1933 Series 5 Vol. 25:325-338; doi:10.2475/ajs.s5-25.148.325

(n.b., settling velocity has a special place in my heart)

Rubey’s paper has a score that is similar to the papers from GSA Bulletin. Here is the citation time series for the Rubey paper:Rubey CTS.jpg

So the natural quesiton is —  what happened that caused this 2014 burst of citations? As far as I can tell (from looking at the papers that cited Rubey), nothing in particular… Most papers that cite Rubey are focused on typical sediment transport questions. A close read of all the citing papers would be needed to figure out what is going on here, if there is some ‘signal’. Not a satisfying answer, and I apologize —leave a comment if you have an idea and I’ll update the post if I find anything out.

Arduino and Raspberry Pi in Geoscience research

Nature reported last week on the uptick in usage of Arduino and Raspberry Pi for research. The idea of building research tools with open source hardware has been covered before (see Pearce 2012 for an example), but this recent article had a nice plot of the # of papers/year that mention these boards (using PubMed and Scopus) .

After the article last week, I wondered how many Geoscience articles actually use an Arduino or Raspberry Pi….

Using the Web of Science, there are less than 10 articles under the ‘Geosciences Multidisciplinary’, ‘Geology’, and ‘Geography Physical’ topics that use the word ‘Raspberry Pi’ or ‘Arduino’ in the title, key words, or abstract. Not much uptake in the Earth sciences I guess.

Though the articles that use the Arduino are very neat, such as a system for geophone data acquisition, a microscope focus stacker, an earth flow monitoring tool, and temperature-sensing waders.

I have seen other Earth science research using these boards — by attending poster sessions at AGU that highlight low cost tech, and I have read about the Raspberry Shake, which could generate a host of papers in the future…

My interest here comes from dabbling with these two tools in the past. With the Arduino I have actually built a few things, including a primitive Optical Backscatter Sensor (OBS), a datalogger, and an ultrasonic distance sensor (see below; pic from 2014). I hope to get back to that dabbling some day..


US East Coast foredune grasses —quantifying the abundance of literature

Two grasses tend to cover much of the coastal foredunes of the US Atlantic coast. North of the North Carolina/ Virginia area, foredunes are often covered in Ammophila breviligulata (American Beachgrass). South of the NC/VA area, foredunes are often covered in Uniola paniculata (Sea Oats). After my look at how much is written about ‘Coastal Dunes’, I wanted to look at how much is written about these two species. I searched for both of these species — separately — using the Web of Science in early March 2017. Each search is done as a ‘topic’ search, so responses come from paper titles, abstracts and keywords.

Various other plants are present on the shifting sands of East coast foredunes, such as Panicum amarum (Bitter Panic Grass), Spartina patens (Saltmeadow Cordgrass), and Iva imbricata (Dune-marsh elder), to name a few. I included P. amarum in this analysis just for fun.

Shown below is the number of papers written about each species in 5 year bins.


A. breviligulata also grows along the shores of the US ‘Great Lakes’, and the US West coast — I would guess this is the cause of the dominance in  A. breviligulata studies.

  • The ratio of papers per 5 year period for A. breviligulata: U. paniculata: P. Amarum is roughly 5:3:1.
  • The ratio of articles sizes (measured in bytes) on Wikipedia for each of the species is currently 3:2:1.
  • I keep wondering if the ratio of papers about the species reflects the ratio of total shoreline covered the species… or perhaps the ratio of some other abundance metric…

I have a paper in review about some of the geomorphic consequences of these different foredune species.

Open Access charges for journals that publish geomorphology research

Here I compiled the Open Access charges for journals that publish geomorphology research (i.e., Gold Open Access; Author Pays). I’m sure some are missing — let me know which publications I should add to this list.

Keep in mind that some journals have page charges even if the articles are not Open Access, some journals provide open access after a given time period, and other journals ONLY publish Open Access. Your institution may also have an agreement with a publisher about paying the fee (i.e., they will pay for you)…

I hope to periodically update this list.. The data below was collected on March 26th 2017.

Journal Cost (various currencies)
Earth and Space Science (AGU + Wiley) $1800
Earth’s Future (AGU + Wiley) $1800
GRL (AGU + Wiley) $2500
Water Resources Research (AGU+ Wiley) $3500
JGR – Earth Surface (AGU+ Wiley) $3500
Reviews of Geophysics (AGU + Wiley) $3500
ESurf (EGU + Copernicus) €50-120/ journal page
GSA Journals $2500
Geomorphology (Elsevier) $3300
Earth Surface Processes and Landforms (BSG+ Wiley) $4200
Progress in Physical Geography (Sage) $3000
Marine Geology (Elsevier) $3300
PLoS ONE $1495
Scientific Reports (Nature) $1675
PNAS $1100- 1450
Nature Communications (Nature) $5200
Zeitschrift für Geomorphologie (Schweizerbart) €140 per article + €119 per published page

Our tiny debris flow flume

Last semester I taught an undergraduate level geomorphology class at UNC-Chapel Hill. It was a blast. In addition to reading lots of primary literature, and editing wikipedia, we conducted a class experiment. I built a small debris flow flume based on de Haas et al. (2015) and we did a few experiments. A description of the flume can be seen here on the Sediment Experimentalist Network site, and a slo-mo video of our debris flow can be seen here.

But what did we do with the flume? After watching the USGS debris flow videos and thinking about articles by John McPhee (one and two), the students decided to focus on how ‘baffles’ (obstructions in the outwash plain) can work as a debris flow mititgation strategy and modify debris flow runout (see an example of this type of research by Choi et al., 2014). The UNC students wrote up some preliminary results, and if you want more details (or the data), let me know… Eventually I will get it all up on figshare.

For now, here is a picture of our baby debris flow:



Twitter mentions of GRL papers

Last week I had a guest post on the AGU Blog ‘The Plainspoken Scientist’ regarding the percent of Geophysical Research Letters (GRL) papers that are mentioned somewhere on the web. Today I want to dig further into the data regarding Twitter mentions — Specifically, how many Twitter mentions does a typical article in GRL receive?

To recap, almost every recent GRL paper has atleast one Twitter mention. Here is the percentage of GRL papers published in a given year with atleast one mention:


In addition to more GRL articles being mentioned on Twitter, the total of all Twitter mentions to GRL articles published in a given year is increasing:

mentions per year.jpg

Parsing this data further, here are (yearly) histograms for the percent of articles from GRL with a given number of Twitter mentions:Histograms.jpg

Three observations:

  • ~ 40% of recent papers receive only a single twitter mention (perhaps from bots?).
  • The tail is long — a handful of papers are well of the chart, with several hundred twitter mentions.
  • The tail seems to grow fatter each year.

Crossing this data with the number of GRL papers published per year, here is the median number Twitter mentions per paper in a given year:

median mentions.jpg

(Keep in mind that this data comes from all time periods — for example, tweets referencing a paper from 2013 can come from any year.)