Earth Sciences: The World is at Your Feet

To finish out their semester, I facilitated a presentation at Monticello Middle School’s Science Cafe in Monticello, IL in December 2019. Science Cafe is an excellent program that allows students to bring their lunch into one of the science classrooms to hear a presentation from a practicing scientist about what they do, why it matters to the students, and how the students can get involved in science as well.

I did a brief overview of the recent geology around Monticello, including the Cerro Gordo Moraine (“Fat Hill”), the Sangamon River, and several other glacial and pre-glacial features above bedrock. I also showed them some of the possibilities of life as an Earth-scientist, and then showed them some important seismic events captured by the IRIS Transportable Array when one of the system’s seismometers was only five miles from their school.

The a slideshare version of the slideshow is shown below and the full version can be downloaded at the link at the bottom of the page.

(To download presentation, open the link at the button above and save file in preferred format)

Citation: Balikian, R., 2019. The World is at Your Feet: A Career in the Earth Sciences. Oral Presentation at Monticello Middle School. Monticello, IL.

3D Imaging of Landslides

One of the areas of applied research we have been doing more of lately at the ISGS is delineation of landslides and creep failures. These occur on steep slopes where water works its way into the subsurface and reduces the friction that is holding the slope up.

Creep Failure, where land moves slowly over time. This causes damage to roadways and other infrastructure. It can occur steadily for decades if not stabilized. Creep failure, like other types of landslides, are often triggered by water in the subsurface reducing the friction between the materials that make up the slope. Image Credit: USGS

We have been working on using seismic and electrical geophysical methods to image the failure surfaces in landslides, to help engineers better understand the scale and type of remediation to undertake.

One recent example of the 3D modelling we have done with the data collected via electrical resistivity is shown below. The higher intensity red is higher conductivity, which at this site correlates to the failing material. The black is the approximate interface between the stable ground and the landslide material.

3D Tomography of the interface between the moving part of the hill (i.e., the landslide) and the stable part. Image Credit: ISGS
3D Tomography of electric resistivity distribution showing layers causing landslide in southern Illinois. Image Credit: ISGS

Aguacate: Water and Avocados in San Diego

I presented an overview of the work I did for my master’s thesis this past week as a part of the biweekly Illinois State Geological Survey seminar series. These are always interesting talks, and usually they have a lot more to do with geology than mine did!

My talk focuses on a survey with growers and interviews with stakeholders I performed surrounding farmland loss among avocado growers in San Diego County, California. There are some great charts, interesting trends, and provocative quotes and data throughout. Check it out below!

UPDATE Winter Hibernation (AKA Data Processing)

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3D Modelling of GPR data, attempting to visualize Cassava roots in-situ. The black-and-white areas are the individual plants that we have separated from the larger data set to do plant-by-plant analysis.

Winter at the ISGS means field work slows down, and especially since the last week or two have been frigid! For now, we have several things we are working on that will take plenty of time in-office to complete. I have been working the past week or so on developing an automation code (Visual basic language) to turn XYZ data from Ground-Penetrating Radar into a 3-D model we can use to estimate volume and mass of cassava roots in-situ. We started this process last year, and you can find information on that process here. We have tweaked the methodology this year to make our analysis quantitative and to improve the data recovery.

Students are working on digitization of geophysical data as old as the 1930s. This is a time-consuming process, but will hopefully produce great, public-facing resources similar to ILWater.