When an earthquake strikes, it can lead to loss of lives, properties, and resources. Geospatial tools like ArcGIS Pro can be used by map out both fault lines and seismic activity.
What to expect with this tutorial on earthquake mapping
This GIS tutorial teaches you how to use USGS data and ArcGIS Pro to map earthquakes and geological faults using the area around Dallas, Texas as an example. This tutorial uses Landsat 8 images and earthquake data from the USGS website. PCI Geomatica software is used to narrow the geographic area within the image and pull out features like geological fault lines.
This fault line GIS data, along with the earthquake data from the USGS, can then be imported into ArcGIS Pro software. Next, using ArcGIS Pro, the earthquake data will be interpolated using the “spline,” tool in order to visually represent earthquake magnitude as a raster layer. Finally, we will create a map that shows both the earthquake strength and the fault lines. Figure 1 shows the flow map of the tools and data you will use to make this map in ArcGIS Pro using Landsat 8 images and earthquake data.
Landsat 8 and preparing geological faults
Landsat 8 imagery can be accessed freely from the United States Geological Surveys (USGS)’s website after a free sign up. For this tutorial Landsat 8 (collection 2 level 1) imagery is used. For more information on how to access the imagery, watch this video. Geological faults is extracted from Landsat 8 imagery using the PCI Geomatica software. For information on how a free trial and how to used to download the PCI software, visit Catalyst Professional – CATALYST.Earth.
Extracting geological faults from PCI Geomatica
- Launch and create a new project.
- From the menu bar, click tools.
- Click clipping/subsetting from the set of options displayed.
- From the clipping/subsetting window, set input file to the location of Landsat 8 band 10.
- Set output file to name and location of your clipped dataset.
- Be sure to enable the input data, by checking the box of the raster (Landsat 8 band 10) under the Available layers section.
- Under the output raster size, click square to define the boundary of the clipped dataset.
- Click clip.
After clipping, geological faults are extracted from the clipped data by following the steps outlined below:
- From tools on the menu bar, select “algorithm librarian” from the drop-down menu.
- Select Analysis.
- Select Geological/geophysical analysis.
- Select Line/lineament extraction.
- Select Open.
- Set input file to the saved clipped file.
- Click Run.
- From the results, right-click on “Extracted lineaments” and select save as.
- From the output location section, set output name and location.
- Be sure to set file type to “ArcView shapefile.” Click Save.
Finding earthquake GIS data for a region of interest
For this tutorial, geological fault data helps to validate the earthquake data for a geographic area. Earthquake data can be retrieved from the USGS’s Earthquake Catalog using the steps outlined below:
- Set magnitude to 2.5+.
- Use the Draw rectangle to specify the geographic region.
- From the output options, set format to CSV.
- Set order by to Time-Oldest First.
- Click Search.
Creating an earthquake map showing geological faults in ArcGIS Pro
After retrieving the earthquake data from USGS and extracting the geological fault lines from Landsat 8 (band 10), use the following steps to create a map in ArcGIS Pro:
- Open and create a new project in ArcGIS Pro.
- Select Add data.
- Toggle to the location of the USGS earthquake data that you retrieved.
- Click Ok.
- Right-click on the query table.
- From the Display XY data, set X field to longitude. Set Y field to latitude.
- Click Ok.
- Type and search Spline from the search bar of geoprocessing toolbox.
- From the spline window, set input point features to downloaded earthquake data.
- Set Z value to “mag.”
- Click Run to create a raster.
Now add the geological fault data processed from Landsat 8 (band 10) as a overlay to your raster dataset of earthquake magnitude:
- Click the Add data tool from the Map tab of the menu bar.
- Toggle to the location of the fault data.
- Click Ok.