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Seismogenic Fault Characterization of the Quinton Sequence in East Oklahoma

Description: 

Over the last several years, we have recorded 1309 earthquakes ML 0.2-3.7 over the time period, near Quinton, OK. The seismic activity temporally coincides with the both the injection of wastewater from a single disposal well and adjacent hydraulic fracturing activity. The catalog locations suggest seismicity occurs around two parallel NE striking faults. However, due to the sparse regional seismic network in the area with poor azimuthal coverage, the seismicity hypocenters are poorly constrained for them to map onto the seismogenic faults or provide a conclusive spatiotemporal occurrence pattern. We re-analyze the seismicity by augmenting the regional broadband sensor network, operated by the Oklahoma Geological Survey, with two seismic arrays each composed of 15 3-component nodes recording for 35 days in July 2021 to assist in constraining the hypocenters. We relocate 1,300 earthquakes of magnitude ML0.2-3.7 using a double-difference scheme and a local 1D velocity model to unravel the seismicity patterns, delineate the seismogenic faults and perform source characterization. Preliminary analysis indicates clustering of earthquakes in three main fault segments, oriented in a NW direction, that linearly align to form an apparent NE striking fault zone. The spatiotemporal evaluation of seismicity indicate seismicity begins at the central fault segment that underlies the lateral positioning of the hydraulic fracturing wells and begins in a period when both hydraulic fracturing and waste fluid disposal activities occurred concurrently. Upon suspension of hydraulic fracturing activities, the seismicity then expands to the SW fault segment and later extends to the NE fault segment. Two earthquake swarm in the later period of the waste fluid disposal occur on the NE and SW fault segments respectively, reversing the spatial migration of seismicity with respect to the beginning of the sequence and coinciding with a period of reduced injection rates. We will present updated analysis that could highlight possible linear fault structures within the seismogenic fault zone.

Session: Understanding and Managing Induced Seismicity

Type: Oral

Date: 4/19/2023

Presentation Time: 10:30 AM (local time)

Presenting Author: Paul O. Ogwari

Student Presenter: No

Invited Presentation: 

Authors