Isabel Villaneda-van Vloten

Years participated in RESESS: 2012

An Overview

Major: Geology

Academic Affiliation: Wichita State University

Biography

Isabel was born in Guanajuato, Mexico and lived there for nine years before moving to Alexandria, Virginia with her only English being the phrase, “Wait a minute.” She attended T.C. Williams High School, where her interest in science began with many visits to the museums at the Smithsonian Mall. Her decision to go into Geology was inspired by an Environmental Resources Class passionately taught by Dr. Gries at Wichita State University. When she is not studying, Isabel likes to go on trips with the Geology Club, seek out delicious food, sample artisan coffees, travel, experience the Midwest, shoot guns (at targets), share her culture with friends, and watch the Discovery Channel. Isabel is passionate about reducing the negative anthropogenic effects on the environment and sharing her passion for science with the next generation.

Abstract

Fluid injection and induced seismicity: Two Ohio case studies

This study analyzed the link between the injection of fluid wastes and earthquakes at two sites in Ohio. Four criteria were used to determine if seismicity was induced by injection activity: (1) low background seismicity prior to the start of injection, (2) a strong spatial correlation between earthquake epicenter and injection well, (3) a strong temporal correlation between the start of injection and timing of the earthquake sequences, and (4) high pore pressure in the vicinity of the hypocenters at the time of the earthquake. The first event chosen was a M3.0 earthquake that occurred near Deerfield, Ohio in August of 2000. The second site of interest is Newport, Ohio where earthquakes of M3.0 and M3.1 occurred in August of 2011. Both the Newport and Deerfield sites were seismically inactive intraplate sites prior to the start of injection. The large volumes of fluid wastes were injected into zones co-located in space (0.25 km and 3.78 km, respectively) and depth with the earthquake hypocenters. The Newport site exhibited a strong temporal correlation, as the earthquake sequence occurred less than 2 years after the injection started. The Deerfield site did not exhibit a strong temporal correlation, as earthquakes occurred more than two decades after the start of injection. Pore pressure increases due to injection were calculated using the injection data and assumed hydraulic properties of the rock formations. Pressure increases of 1.9 MPa at the Newport site and 0.6 MPa at the Deerfield site were calculated at the earthquake hypocenters at the time of the earthquake. These values have been shown to be sufficient to induce seismicity assuming there are preexisting weaknesses. Evaluating the results against the four criteria suggests that the Newport site is most likely a case of induced seismicity. While less definitive, the evaluated criteria for the Deerfield site also support a likely case of induced seismicity.