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Landslides, Rainfall and YOU!


The term “won in a landslide” is particularly troubling to me because when a landslide happens, the kind that I study at least, there are seldom “winners”. My research looks at how rainfall interacts with the environment to cause natural disasters like flooding and landslides. Knowing where, when and how much rain or snow is falling is key to understanding where we may have extreme events that can impact people.

If you consider where we get a lot of rainfall, like some of our tropical regions…

...and combine that with areas that have the right factors to cause a landslide, such as steep topography, fractured rocks, areas where trees and other vegetation have been removed as a result of fires or deforestation, and locations where humans have influenced the surface from building, mining etc., you can start to get an understanding about where in the world we are most likely to experience landslides. The key in accurately predicting these landslide events and evaluating how they impact our population is having good data.

First we need to have reliable data on where landslides may occur have happened in the past. I have developed a global landslide catalog (http://ojo-streamer.herokuapp.com) that provides information for over 6,000 landslides around the world. From this information, we can figure out the hotspot regions for landslide activity:

Maps show rainfall-triggered landslides in the Global Landslide catalog from 2007-2013: a) landslides with reported fatalities, b) reported landslides without fatalities. Kirschbaum et al. 2015, http://www.sciencedirect.com/science/article/pii/S0169555X15001579

 

Next, we need information on the slope, elevation, vegetation, soil type, soil moisture and other variables that suggest where landslides are more likely. Many of these products can be obtained from satellites, like the Shuttle Radar Topography Mission (SRTM; http://www2.jpl.nasa.gov/srtm/), among others.

Global elevation from the SRTM data. Credit: SRTM, Thomas Stanley (NASA/USRA)

 

Finally, we need to know that need information on where and when it is raining (and how much!) in order to try and predict where we may experience landslides in the future. We can do this with rain gauges. But if you take all the rain gauges in the world and put them together, they only fit into 2 basketball courts!

                         

Therefore, we need the vantage point of space to observe how much rain is falling around the globe. The Global Precipitation Measurement (GPM) mission provides near real-time rain and falling snow information to better understand how much rain is falling that could cause landslides.

Global rain and snow from the GPM multi-satellite product IMERG:

                         

What I find so amazing is that we can use our “eyes in the skies” (satellites) as well as valuable measurements taken on the ground by scientists, weather enthusiasts and students to shed new light on how extreme rainfall can cause landslides that can occur both in our back yard and around the world. Using satellite and ground-based data, my ultimate research goal is to be able to provide a warning system where people all over the world can understand where and when landslides are likely to happen in their area and be able to respond to protect their communities.

For more information on how we can use GPM and other satellite products to measure extreme events, check out: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11091 and www.gpm.nasa.gov/applications.

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