Date of Award

Spring 1-1-2019

Document Type

Thesis

Degree Name

Master of Science (MS)

First Advisor

Abbie B. Liel

Second Advisor

Julian J. Bommer

Third Advisor

Ross B. Corotis

Abstract

Since 2009, the frequency of (moment) magnitude (M) 3.0 earthquakes and larger in the Central United States, and especially Oklahoma, has risen from an average of 2 per year, to 200-700 per year. This increase in seismicity is a result of the deep injection of large quantities of wastewater from oil and gas activities underground.

In this study, damage to built infrastructure from induced earthquakes is investigated through nonlinear dynamic analysis and probabilistic damage assessment for light-frame wood structures common in Oklahoma. Specifically, we focus here on investigating the smallest magnitude of injection-induced earthquake that may cause damage to the buildings of interest at various distances from the hypocenter (R). The simulations are based on two-story commercial, multifamily, and single-family buildings, which are designed with lateral strength and detailing consistent with modern code requirements in Pawnee, OK, and modeled nonlinearly in the Timber3D software simulations of the buildings. Ground shaking is defined by target spectra from the Novakovich et al. (2018) ground motion prediction equation (GMPE) based on the M and R of each earthquake scenario of interest. For each scenario, 25 records are selected to match the median and expected variance in the target spectra, providing the excitation for the nonlinear simulation models. Damage is identified as occurring if story drifts exceed a level associated with screws or nails popping out, minor cracking of wallboard, and warping or cracking of wallpaper in light-frame wood shear walls. This damage is minor, but is damage that many homeowners would choose to repair.

The results show that larger magnitude events result in higher damage probabilities and have the potential to impact the structures at further distances. For example, a M 3 event, is unlikely to damage the structures of interest, whereas a M 5.5 is likely (i.e., 50% probability) to cause damage up to 20 km away from the earthquakes source. The minimum magnitude that is associated with any damage to the structures is a M 4 with R < 7.5 km, but the probability of damage is 10% or lower. The minimum magnitude that has a damage probability of 50% is a M 5 event with R < 12 km. Magnitude and distance thresholds are used by government and regulatory agencies to define appropriate action thresholds, where injection volumes are reduced or stopped, for injection well operators. The goal of these thresholds is to mitigate the risk from induced seismicity.

Share

COinS