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!