Research Projects
Seismo-tectonics of Haiti and the 2010 and 2021 Haiti Earthquakes
PhD student Yi-Chieh Lee is studying the seismotectonics of Hispaniola using InSAR and GNSS. She is investigating new methods for how to combine the two datasets together to obtain high-resolution strain rates where GNSS observations are sparse. Results from the study will be used with information on fault geometry to estimate fault slip rates and seismic hazard from earthquakes, and look at vertical deformation rates. We also published on the 2021 Haiti earthquake.
Seismo-tectonics of the Caribbean - Cocos - North America Triple junction in Guatemala
We have several projects that are just starting or being proposed for the triple junction in Guatemala. Working with colleagues Jonathan Obrist-Farner and Andi Eckert at Missouri S&T and Omar Flores at University of San Carlos in Guatemala, we are currently looking at strain rates and faulting along the entire triple junction and more detailed in the Guatemala City graben. I also have proposals submitted for both on-shore and off-shore geophysical work on the Polochi-Motagua Fault System, the Swan Fault, and am a collaborator on an ICDP project led by Dr. Obrist-Farner to drill multiple shallow boreholes for seismic and strain gauge instrumentation in the vicinity of Lake Izabal.
Near-surface geophysical investigation of levees
PhD student Kola Arowoogun is studying the shallow geologic stucture of levees and how near-surface geophysical methods, including a towed time-domain EM system (TTEM), can be used to image the shallow subsurface and correlates to geologic materials. We are currently studying Kaskasia levee on the Mississippi River in Illinois.
Improving InSAR Tropospheric Corrections
Microwave signals from SAR satellites traveling through the atmosphere are delayed by the troposphere and the ionosphere. Spatial and temporal variations in pressure, temperature, and relative humidity, mainly in the lower part of the troposphere, result in a spatially varying tropospheric delay, which can be 15 cm of apparent deformation. We are working on new methods to estimate and remove the troposphere noise to improve InSAR estimates of ground deformation. We are working on developing a new tropospheric correction package for Python called RAiDER.
Past Projects
Are induced earthquakes limited in size by the injected volume?
Two outstanding questions for induced seismicity is whether the volume of injected fluid limits rupture size, and what we can learn about the earth from induced earthquakes. We are working to compare earthquake simulations and fault models to real induced seismicity observations to both learn what likely controls earthquake size and what properties of the crust and faults can be determined by looking at earthquakes. See our recently-published paper for more details.
Slow-slip events and earthquake hazard in Mexico
We are using InSAR and GNSS to constrain slip during the 2017/18 slow-slip event and associated earthquakes. Our results indicate that the event likely released only a fraction of the accumulated moment deficit on the fault, and that it transferred stress to nearby locked asperities.
Declustering Induced Earthquakes Increases Risk in Oklahoma
Induced seismicity has been a growing problem around the world, including the Central and Eastern US (CEUS). Many studies have considered seismic hazard from ITS in the CEUS and elsewhere. Few scientific studies, though, have directly considered the financial risk implications of damage caused by ITS. We model one-year seismic hazard and risk for the CEUS based on the USGS one-year model and the RiskLink software package developed by Risk Management Solutions, Inc., to model risk in Oklahoma See the paper for more details! from induced seismicity.
Moment Deficit and earthquake potential in southern California
We all know that Southern California is seismically active, but how many large earthquakes are possible in the upcoming decades, and where will they occur? The answer to these questions is obviously critical for preparing for future earthquakes, but to get the answers, we need to know the moment deficit rate (a measure of future earthquake potential). We are developing methods to measure moment deficit rate that account for uncertainties in the data and models we use, to build an accurate picture of seismic hazard in the region. See Maurer et al. 2017 and 2018 for more details.