A STUDY OF EARTHQUAKES DUE TO HYDROFRACKING IN OKLAHOMA

Over twenty-five earthquakes due to Oklahoma hydrofracking were recorded on simple inexpensive seismographs (AS1 and AQ1) at SUNY Potsdam, NY. A study of these was undertaken to determine source parameters and other characteristics of the earthquakes induced by wastewater disposal. The earthquake epicenters were located at a distance of 19 degrees, and an azimuth of 242 degrees from SUNY Potsdam, NY. Nuttli travel time data and crustal model for central United States were used to interpret the seismograms of the earthquakes. An objective of the study was to identify parameters typical of hydrofracking and wastewater disposal induced earthquakes from normal tectonic events.

An analysis of the seismograms and Nuttli’s crustal model enabled us to identify the Pn and the Sg phases of the earthquakes. The S_g-P_ntimes and Nuttli’s travel time data were used to determine the distance to the events. A Fourier transform was calculated to determine corner frequency for each event and a nomogram was used to determine the source parameters, including source radius, stress drop, and moment of the event. Formulas were used to calculate intensity, felt area, length of faults, and energy released by the earthquakes.

Waveforms of fracking earthquakes were compared with those of normal earthquakes of tectonic origin. An attempt was made to identify the earthquakes induced by wastewater disposal from tectonic events. Using various methods for determining the parameters of the seismic events, discrepancies between methods emerged which may present a way of identifying hydrofracking induced earthquakes from those of normal tectonic origin.