Partial Auto-Correlation of Low Magnitude Earthquakes From the 2016 Iris Array in Grant County, Oklahoma
The Anadarko Basin in is a seismically active basin that spans central and western Oklahoma into Kansas. In June and July of 2016, the IRIS Community Wavefield Experiment array was deployed for approximately a month, recording over 300 earthquakes. Using 4 of these earthquakes and an east – west array of 129 Fairfield Nodal Z-land 3C nodes, I present a novel application of correlation. These four earthquakes with a ML of 2.8-3.0 represent a varied azimuthal distribution and are between 9 and 40km from the array and have a frequency peak at approximately 10 Hz. As a proof of concept, the presented method of partial auto-correlation uses the first arrival from the entire array to correlate the array traces rather that a single trace (cross correlation) or the trace itself (autocorrelation). The results show a reduction in seismic noise as expected from a correlation, as well as strengthened horizons and feature clarifications such as fractures. Isopach maps and a nearby well log were used to define a stratigraphic column for geologic interpretation. The core theory of this method is built on taking advantage of multiples and the results show improvements of multiples after the first. The results presented show promise for further application of this method that can lead to a process of generating pseudo 3D models using new midpoints after virtually transferring the source to a multiple’s reflection point on the surface. To do this, the virtual source midpoint will need to identified and the method will need to be designed to handle non-linear arrivals.
Eddy, Alex Christopher, "Partial Auto-Correlation of Low Magnitude Earthquakes From the 2016 Iris Array in Grant County, Oklahoma" (2023). ETD Collection for University of Texas, El Paso. AAI30635088.