De Ford Lecture Series: Pedro Di Nezio

UTIG Seminar Series: Athma Bhandari, UTIG

Speaker bio.

Host: Peter Flemings

UTIG Seminar Series: Anja Rutishauser, University of Alberta

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Title: Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic

Abstract: Two subglacial lakes have recently been identified from radio-echo sounding measurements underneath Devon Ice Cap in the Canadian Arctic. The presentation will begin with an introduction into how radar measurements can be used to identify subglacial water, and will then cover the discovery of the Devon subglacial lakes; including the challenges faced during data interpretation. Finally, why these lakes are compelling targets for further exploration and plans for future investigations of the Devon subglacial lakes will be discussed.
The subglacial lakes are located near the center of Devon Ice Cap, where basal ice temperatures are expected to be below -10.5 °C. This suggests that the lakes consist of brine-rich water with a significantly suppressed freezing point. The hypothesis of hypersaline water is supported by the surrounding geology demonstrating that a salt-bearing evaporite unit may outcrop underneath the ice and act as the salinity source for the brine.
The Devon subglacial lakes are not only the first lakes discovered in the Canadian Arctic, but also represent the first isolated hypersaline subglacial lakes on Earth. Their hypersaline nature makes these lakes particularly tantalizing analogs for brine pockets/bodies that are inferred to exist within Europa’s ice shell or beneath the Martian South Polar Layered Deposits.

Learn more about Anja Rutishauser.

Host: Don Blankenship

Alumni Reception during SEG in Anaheim

De Ford Lecture Series: Andrea Dutton

UTIG Seminar Series: Alice-Agnes Gabriel, LMU Munich

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Title: Dynamic viability of the 2016 Mw 7.8 Kaik?ura earthquake cascade on weak crustal faults

Abstract: The Mw 7.8 Kaik?ura earthquake struck New Zealand’s South Island on November 14, 2016. This event, considered the most complex rupture observed to date, caused surface rupture of at least 21 segments of the Marlborough fault system, some of them previously unknown. Puzzling features inferred from high-quality observations include a large gap separating surface rupture traces, the possibility of significant slip on the subduction interface, and slow apparent rupture speed. Here I present a dynamic rupture model to unravel the event’s riddles in a physics-based manner. The model reproduces key characteristics of the event and provides insights on the mechanical viability of competing hypotheses proposed to explain them. I show that the observed rupture cascade, involving strike and thrust faulting, is dynamically consistent with regional stress estimates and a crustal fault network geometry inferred from seismic and geodetic data. The rupture propagation requires a linking low-dipping shallow thrust fault, but not slip on an underlying megathrust. The complex fault system operates at low apparent friction thanks to the combined effects of over pressurized fluids, low dynamic friction and stress concentrations induced by deep fault creep. Our results associate the non-rupture of the Hope fault, one of the fundamental riddles of the event, with unfavourable dynamic stresses on the restraining step-over formed by the Conway-Charwell and Hope faults.

Learn more about Alice-Agnes Gabriel.

Host: Thorsten Becker

De Ford Lecture Series: Douglas Edmonds

UTIG Seminar Series: Michael Tetley, Lyon

Speaker bio.

Host: Thorsten Becker

Hot Science - Cool Talk "Fire Ants, Crazy Ants & Zombie Ants"

The red imported fire ant is an invasive species in Texas that can produce life-threatening allergic reactions in people, has major costs to agriculture, and causes severe impacts to native fauna. Dr. Rob Plowes shares insights into fire ant behavior and discusses a remarkable biological control opportunity. Dr. Plowes researches one of the fire ant's deadliest enemies - tiny phorid flies, which actually turn ants into zombie-like living incubators for their offspring! He also describes research approaches to other invasive species in Texas. We invite you to join us for a special Halloween celebration. Participate in our costume contest: come as your favorite creature or zombie!