Hazard Implications of the 2016 Mw 5.0 Cushing, OK Earthquake from a Joint Analysis of Damage and InSAR Data

Bridger Baird,Abbie Liel,Kristy Tiampo,Magali Barba-Sevilla

doi:10.3390/rs10111715

Abstract

The Cushing Hub in Oklahoma, one of the largest oil storage facilities in the world, is federally designated as critical national infrastructure. In 2014, the formerly aseismic city of Cushing experienced a Mw 4.0 and 4.3 induced earthquake sequence due to wastewater injection. Since then, an M4+ earthquake sequence has occurred annually (October 2014, September 2015, November 2016). Thus far, damage to critical infrastructure has been minimal; however, a larger earthquake could pose significant risk to the Cushing Hub. In addition to inducing earthquakes, wastewater injection also threatens the Cushing Hub through gradual surface uplift. To characterize the impact of wastewater injection on critical infrastructure, we use Differential Interferometric Synthetic Aperture Radar (DInSAR), a satellite radar technique, to observe ground surface displacement in Cushing before and during the induced Mw 5.0 event. Here, we process interferograms of Single Look Complex (SLC) radar data from the European Space Agency (ESA) Sentinel-1A satellite. The preearthquake interferograms are used to create a time series of cumulative surface displacement, while the coseismic interferograms are used to invert for earthquake source characteristics. The time series of surface displacement reveals 4–5.5 cm of uplift across Cushing over 17 months. The coseismic interferogram inversion suggests that the 2016 Mw 5.0 earthquake is shallower than estimated from seismic inversions alone. This shallower source depth should be taken into account in future hazard assessments for regional infrastructure. In addition, monitoring of surface deformation near wastewater injection wells can be used to characterize the subsurface dynamics and implement measures to mitigate damage to critical installations.

Highlights

Cushing, Oklahoma, the “pipeline crossroads of the world,” is home to the largest crude oil storage facility in the United States and the Keystone pipeline
We compare the displacement data to monthly injection rates of of class II Underground Injection Control (UIC) wells from the Oklahoma Corporation Commission (OCC) [27]
Wells that have injected or are currently injecting into the Arbuckle have an additional column of information, injection period, where the table lists the time period that the well was injecting into the Arbuckle before the well was plugged and recompleted into a shallower formation, typically the Wilcox formation

Summary

Introduction

Oklahoma, the “pipeline crossroads of the world,” is home to the largest crude oil storage facility in the United States and the Keystone pipeline. Wastewater injection threatens this critical national energy infrastructure through both large, instantaneous ground acceleration from induced seismicity and through smaller, incremental, longer term movement from ground surface deformation [1]. Since seismicity initiated in Cushing in 2014, three earthquake sequences have ruptured two fault zones (Figure 1). The aftershock alignment revealed the reactivation of the unmapped Cushing fault, a 5 km long, N80W striking, left-lateral, strike-slip conjugate fault within the Wilzetta–Whitetail fault zone [3]

Methods

Results

Discussion

Conclusion