Hydraulic Fracturing and Earthquakes

A comparison of known gas and oil wells in TX, OK, and NM to recent earthquake data

Introduction

Earthquakes are natural disasters caused primarily by an increase in activity around tectonic plate boundaries. However, in recent years earthquakes have been occurring more frequently in areas where no plate boundaries are located and would typically only experience low levels of seismic activity.

As seismic activity has increased in states like Texas, Oklahoma, and New Mexico, so too has a process called hydraulic fracturing. In this process, pressurized liquid is injected into underlying bedrock through wells in order to extract oil and gas. According to scientists, such actions can result in the kind of increases in seismic activity these areas have been experiencing.

The goal of my project is to illustrate the relationship between areas experiencing seismic activity in Texas, Oklahoma, and New Mexico and gas and oil well locations (places where hydraulic fracturing is taking place).


Data and Sources

I obtained my earthquake data from the United States Geologic Survey website. The data I chose included earthquake data from Texas, Oklahoma, and New Mexico for the past year (May 2022-May 2023).

FracTracker Alliance provided the buffer layers I used, which represented the combined area of gas and oil well locations with a buffer of 1 mile.


Methods

I used ArcGIS Online to analyze my data. First, I uploaded USGS earthquake data for the past year. This resulted in 930 individual locations spread throughout Oklahoma, Texas, and New Mexico. I then added each FracTracker buffer layer and merged them together to more easily manipulate the single layer. From there, I ran multiple analyses on the data, including Kernel density, Hotspot Analysis, and Aggregate Points to isolate the earthquake data within the buffer area.


Earthquake Locations

The map below shows every location that an earthquake occurred in these three states in the last year.

Earthquake_Locations


Oil and Gas Well Locations

The map below shows the combined 1 mile buffer for oil and gas well locations in the aforementioned three states.

Gas_and_Oil_Well_Locations_Buffer


Results and Findings

Using three different methods I analyzed the earthquake data within the oil and gas well buffer.

The first method I used was Kernel Density to calculate the density of seismic activity within the buffer region. The darkest areas represent those of high density seismic activity, while the lighter areas represent those with less dense seismic activity.

Kernal_Density_Earthquake_Buffer

The second method I used was the Hot Spot analysis tool to calculate significant clusters ("hotspots") of earthquake locations within the buffer area. The results show those hotspots of high seismic activity in increasingly darker shades of red.

Hotspot_Buffer_Earthquakes_Fracking

The last method I used to analyze the data was aggregating points within the buffer region. The aggregate tool allows you to show the sum of how many points lie within a certain region. Using it, I was able to determine how many earthquakes occurred within the buffer area. By clicking on each state's buffer region, you can see how many earthquakes occurred within the buffer regions.

Aggregated_Buffer_Earthquakes_Fracking

Conclusion

Using data from USGS and FracTracker, I compared earthquake locations to known oil and gas wells (hydraulic fracturing locations). The various methods used show a clear relationship between seismic activity and locations where hydraulic fracturing are taking place. All maps show an especially high concentration of earthquake incidents within the buffer region of Texas, indicating that perhaps those locations pose a greater risk of causing seismic activity.

Moving forward with this information, it would be interesting to analyze the Texas region over an extended period of time. Using earthquake and fracking data from past decades and comparing it to modern data could point to potential causes behind the high levels of seismic activity in Texas.

Credits

United States Geological Survey | FracTracker

ArcGIS Online