DeFord Lecture: Ran Feng

DeFord Lecture: Geeta Persad

Alumni Reception in Houston in conjunction with winter NAPE

UTIG Seminar Series: Sarah Brownlee, Wayne State University

Speaker: Sarah Brownlee, Wayne State University

Host: Rob Porritt

Title: Seismic anisotropy in the middle and lower continental crust: using rocks to improve seismic interpretations

Abstract: Seismic anisotropy, the directional dependence of seismic velocity, has been an invaluable tool for understanding strain and flow in the upper mantle. The utility of seismic anisotropy in the upper mantle can be attributed in part to a wealth of studies characterizing the properties of mantle rocks and minerals. In contrast, the continental crust is not nearly as well-characterized due in large part to its very small volume in relation to global seismic raypaths. The continental crust also poses numerous complexities in mineralogy and structure making it significantly more difficult to characterize. Recently, a number of studies have been focused on characterizing the full anisotropic elasticity of rocks from the continental crust. These studies have motivated efforts to predict how these rocks will appear in seismic observations, and thus to recalibrate the assumptions used in seismic inversions in order to improve our ability to distinguish various rock types and deformation in the continental crust. I will begin by discussing the basics of seismic anisotropy and how it is observed. Then we will delve into the catalogue of crustal rock properties, reviewing some of the trends in elastic symmetry with deformation and rock type in the continental crust. I will present a simple scaling scheme to allow for more realistic non-elliptical hexagonal elastic tensors in seismic inversions, and discuss how real crustal rocks might appear in seismic data. The take home message is that while the continental crust is complicated, it cannot be ignored, because even when the focus of study is the mantle, most of our observations are made through the window of the continental crust. Further characterization of the elastic properties of crustal rocks, and how these rocks are expressed in seismic data will improve our ability to use seismic methods to understand deformation in and beyond the continental crust.

Hot Science - Cool Talk "Investigating Our Cosmic Origins"

The cosmos is too vast for us to comprehend - from the backyard of our solar system, which spans hundreds of millions of miles, to the Milky Way galaxy, and beyond to the cavernous voids of deep space. Dr. Casey will share some of the remarkable recent strides in studying distant realms of the Universe, what implications this has for our cosmic origins, and what challenges lie ahead in solving its most elusive mysteries as well as the quest for life in the cosmos.

DeFord Lecture: Cristian Proistosescu

DeFord Lecture: Yi Ming

UTIG Seminar Series: Baole Wen, UT ICES

Click to watch the seminar online.

Speaker: Baole Wen, Bureau of Economic Geology, Jackson School of Geosciences & Center for Petroleum & Geosystems Engineering, Institute for Computational Engineering and Sciences, The University of Texas at Austin

Host: Kehua You

Title: Modeling of convective CO2 dissolution in a closed porous media system: from low-pressure ideal-gas to high-pressure real-gas conditions

Abstract: Motivated by geological carbon dioxide (CO2) storage, many recent studies have investigated the fluid dynamics of solutal convection in porous media. Here we study the convective dissolution of CO2 in a closed porous media system, where the pressure in the gas declines as convection proceeds. This introduces a negative feedback that reduces the convective dissolution rate even before the brine becomes saturated. We analyze the case of an ideal gas with a solubility given by Henry’s law, in the limits of very low and very high Rayleigh numbers. The equilibrium state in this system is determined by the dimensionless dissolution capacity, ?, which gives the fraction of the gas that can be dissolved into the underlying brine. Analytical approximations of the pure diffusion problem with ? > 0 show that the diffusive base state is no longer self-similar and that diffusive mass transfer declines rapidly with time. Direct numerical simulations at high Rayleigh numbers show that no constant flux regime exists for ? > 0; nevertheless, the quantity F/Cs2 remains constant, where F is the dissolution flux and Cs is the dissolved concentration at the top of the domain. Simple mathematical models are developed to predict the evolution of Cs and F for high-Rayleigh-number convection in closed systems. Finally, the modeling is extended to high-pressure & real-gas conditions and verified using laboratory experiments.