Events

UTIG Seminar Series: Emily Warren-Smith, GNS Science, New Zealand

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Speaker: Emily Warren-Smith, Seismologist, Geological Society of New Zealand

Host: Shuoshuo Han

Title: Stress and Fluid Processes During Northern Hikurangi SSEs: What Can We Learn From Microseismicity?

Abstract The occurrence of slow motion earthquakes, or slow slip events (SSEs), in subduction zones has been proposed to be linked to the presence of, and fluctuations in near-lithostatic fluid pressures (Pf) within the megathrust shear zone and subducting oceanic crust. In particular, the ‘fault-valve’ model is used to describe occasional, repeated breaching of a low-permeability interface shear zone barrier, which caps an overpressured hydrothermal fluid reservoir. In this model, a precursory increase in fluid pressure may therefore be anticipated to precede megathrust rupture. However, physical observations of such increases, and subsequent decreases, particularly within the subducting slab where hydrothermal fluids are sourced, remain elusive. Here we use earthquake focal mechanisms recorded on an ocean-bottom seismic network to identify changes in the stress tensor within subducting oceanic crust during four slow-slip events in New Zealand’s Northern Hikurangi subduction zone. We propose that these changes represent precursory accumulation and subsequent release of fluid pressure within overpressured subducting oceanic crust via a ‘valving’ model for megathrust slip behaviour. We also considermicroseismicity datasets alongside geophysical observations to identify spatially heterogeneous hydrological coupling between the two plates which we propose may be the source of fluids triggering shallow SSEs. We identify patches of co-located, differing seismic behavior, including: interface micro-seismicity, pre-SSE swarms, lower plate strike-slip earthquakes, long-term repeating earthquakes and elevated Vp/Vs zones. These patches correlate well with conductive interface regions constrained by magnetotelluric studies and thermal springs exhibiting mantle helium isotopic signatures. We propose these patches represent ‘vent’ sites where hydrological coupling between the plates is increased, facilitating episodic fluid valving which may be linked to SSE timing. These observations are important for future targeted efforts to monitor localised changes in fault zone properties during SSE cycles, in a bid to understand their physical behaviour and episodicity.

DeFord Lecture: Asmeret Asefaw Berhe

Looking deeper: role of sub-soils in Organic Matter Dynamics

About Dr. Asmeret Asefaw Berhe
Interests in soil science and global change science; understanding the effect of changing environmental conditions on vital soil processes, most importantly the cycling and fate of essential elements in the critical zone

DeFord Lecture Series
Since the 1940’s, the DeFord (Technical Sessions) lecture series, initially the official venue for disseminating EPS graduate student research, is a forum for lectures by distinguished visitors and members of our community. This is made possible through a series of endowments.

LEO Seminar Series: Scott Tinker and Varun Rai

Host: Geoscience Leadership Organization for Women (GLOW)

The purpose of LEO is to create a more inclusive and educated community within the JSG by sharing and listening to each other’s stories. Speakers will interview each other and talk about why they are involved in Diversity, Equity, and Inclusion efforts and the heart behind their work. By learning more about why individuals are involved in DEI, we will broaden our understanding of the impacts the JSG is making on students, faculty, staff, and greater society. Taking initiative to get to know each other, ask questions, and Listen to Each Other is a skill that will propel us further to be leaders in the geosciences.

UT Paleontology Seminar

DeFord Lecture: Kuheli Dutt

Advancing Diversity and Inclusion in the GeoSciences

About Dr. Kuheli Dutt
Chief diversity officer for Lamont-Doherty Earth Observatory of Columbia University; leads diversity, equity, and inclusion efforts at Lamont; interests in addressing implicit bias and STEM diversity.

DeFord Lecture Series
Since the 1940’s, the DeFord (Technical Sessions) lecture series, initially the official venue for disseminating EPS graduate student research, is a forum for lectures by distinguished visitors and members of our community. This is made possible through a series of endowments.

UTIG Seminar Series: Kennda Lynch, Lunar and Planetary Institute

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Speaker: Kennda Lynch, Lunar and Planetary Institute

Host: Duncan Young

Title: S^3 (Subsurface, Subaqueous, and Salty): Looking For Life in All the Right Places

WCE Seminar Series

Habitability Seminar: Prof. Ryan P. Russell, UT Austin

A seminar from the Center for Planetary Systems Habitability

Title: Spacecraft Dynamics for Outer Planet Moons Missions: Challenges of Searching for Life at Icy Worlds

Speaker: Prof. Ryan P. Russell, University of Texas at Austin

Abstract: Finding life beyond the Earth within our solar system is an age old quest. The icy moons of the outer planets are among the leading candidate search sites due to the abundance of water and internal heat sources driven by strong tides. In many observed cases, water transports to the surface and beyond via cracks in the dynamically shifting ice crust. Planetary scientists and other life hunters have long dreamed of sending in-situ robots to these exotic locations. While NASA has successfully executed and is currently planning flyby missions to icy world moons, orbiters and landing missions have not yet made it past the proposal stage. In this talk, we will discuss the challenges of designing such missions, primarily from a spacecraft dynamics perspective. Multiple phases of the mission will be discussed including the heliocentric planetary tour phase, the planetary capture and moon tour phases, the moon science orbit phase and optional landing excursions. The icy world moons lie deep in the gravity well of their gas giants parents. Exploration with current technology, therefore requires the extensive use of gravity assists in lieu of large propulsive maneuvers. The design space is extraordinarily large, as typical decade-long itineraries include hundreds of gravity assists and thousands of revolutions, while traversing every level of the sun-planet-moon solar system hierarchy. The open dynamical questions include which body to flyby and when, and where should the precious reserve of propellant be expelled. Intense radiation and perturbations due to third-body and non-spherical gravity make for a hostile environment near the planetary moons. Such constraints require hard limitations on radiation exposure and careful exploitation of the flow and equilibria of the natural dynamical system. Several recent and ongoing advances in the design of such missions will be discussed, including new algorithms to assess reachability, to solve the pathfinding combinatorial optimization problem, to locally optimize promising solutions in high fidelity, to find long-life science orbits, to solve and archive databases of periodic orbits, to identify feasible landing options, and to automate the whole process.

https://habitability.utexas.edu/events/

Softrock Seminar Series

UTIG Discussion Hour: Lindsey Yazbek, UT Green Labs

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Speaker: Lindsey Yazbek, Green Labs Coordinator, UT Green Labs

DeFord Lecture: Jérôme Gaillardet

What the geochemistry of rivers tells us about critical zone processes and representation

About Dr. Jérôme Gaillardet
Chemical potamology; the global role of chemical weathering in the Earth’s chemical engine; focus on the « drainage basin » approach both at large scale and small scale; geochemistry of sediments transported by rivers and produced by chemical weathering in soils.

DeFord Lecture Series
Since the 1940’s, the DeFord (Technical Sessions) lecture series, initially the official venue for disseminating EPS graduate student research, is a forum for lectures by distinguished visitors and members of our community. This is made possible through a series of endowments.

LDE Seminar Series

UTIG Seminar Series: Jeanine Ash, Rice University

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Speaker: Jeanine Ash, Rice University

Host: Chris Lowery

Title: Making and Breaking Molecules

Abstract: Methane is fundamentally significant to Earth’s habitability and the evolution of life. Its concentration in the atmosphere is the result of constant interplay between biological and geological process. My work focuses on the enzyme-level chemical reactions that make and break methane molecules, and how recent advances in isotope ratio mass spectrometry can provide new tools for tracing these reactions at the global level. In this talk I’ll introduce the concept of multiply-substituted isotopologues (commonly called “clumped” isotopes), and share experimental and case studies that show how these tools can be used to illuminate methane creation and destruction processes in the deep.

UTIG Discussion Hour: JSG Alumni Talks - Novi Labs

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Speaker: JSG Alumni Talks – Novi Labs: Kris Darnell, Kiran Sathaye, and Ted Cross

LEO Seminar Series: Leah Turner and Dev Niyogi

Host: American Association of Petroleum Geologists (AAPG)

The purpose of LEO is to create a more inclusive and educated community within the JSG by sharing and listening to each other’s stories. Speakers will interview each other and talk about why they are involved in Diversity, Equity, and Inclusion efforts and the heart behind their work. By learning more about why individuals are involved in DEI, we will broaden our understanding of the impacts the JSG is making on students, faculty, staff, and greater society. Taking initiative to get to know each other, ask questions, and Listen to Each Other is a skill that will propel us further to be leaders in the geosciences.

UT Paleontology Seminar: Travis Stone (JSG)

Exploring Reef Dynamics in the Late Triassic and Early Jurassic.  

DeFord Lecture: Gaby Katul

Evapotranspiration: From kinetic theory to the limits of plant life

About Dr. Gaby Katul
Micro-meteorology and near-surface hydrology with emphasis on heat, momentum, carbon dioxide, water vapor, ozone, particulate matter, water transport in the soil-plant-atmosphere system and implications to hydrological, ecological, atmospheric and climate change-related problems; new modeling tools to diagnose forest vulnerability to drought in order to better predict the future of the water and carbon cycles.

DeFord Lecture Series
Since the 1940’s, the DeFord (Technical Sessions) lecture series, initially the official venue for disseminating EPS graduate student research, is a forum for lectures by distinguished visitors and members of our community. This is made possible through a series of endowments.

UTIG Seminar Series: Michele Koppes, University of British Columbia

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Speaker: Michele Koppes, University of British Columbia, Canada

Host: Demian Saffer

Title: Reading the story of climate change in the landscape

Abstract: Climate change is causing more than warmer oceans and erratic weather. It can also change the shape of the planet. Glaciers are a fundamental link between climate and the tectonic and surface processes that create topography. Mountain ranges worldwide have undergone extensive reshaping due to the erosive action of ice, and yet, the mechanisms that control the timing of this reshaping and the rate by which ice erodes remain poorly understood. We find a wide range of erosion rates from individual ice masses over varying timescales, suggesting that modern erosion rates exceed long-term averages by two to three orders of magnitude. We also see that glaciers in temperate climates erode 103 times faster than they do in the polar regions today. These rapid erosion rates are most likely due to the dynamic acceleration of ice masses as both air and ocean temperatures have warmed, and the ice has thinned and retreated over the past few decades. The repercussions of the increasing pace of erosion add to the already complex effects of climate change in polar and high mountain regions. Shrinking and accelerating glaciers destabilize valley slopes, increasing the risk of landslides and tsunamis, and deliver more sediment and nutrients to downstream basins, disrupting aquatic habitat and access to clean freshwater for mountain and coastal communities. The dramatic increase in recent erosion rates in the Arctic and the Antarctic Peninsula, two of the most rapidly warming regions in the world, suggest that polar ice masses are on the brink of a major geomorphic shift as mean temperatures warm above 0ºC.

UTIG Discussion Hour: Erik Fredrickson, University of Washington

UTIG Seminar Series: Brian Boston, Lamont-Doherty Earth Observatory

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Speaker: Brian Boston, Lamont-Doherty Earth Observatory, Columbia University

Host: Harm van Avendonk

Title: From Construction to Collapse of the Hawaiian-Emperor Seamount Chain

Abstract: The Hawaiian-Emperor seamount chain is one of the most well-known geological features on Earth, covering ~6,000 km from the Island of Hawaii to the Meiji seamount near the Aleutian Trench. Consisting of a mixture of volcanic islands, atolls, seamounts and guyots, this feature was first explained by the motion of the Pacific plate moving over a focused spot of melting that has produced the age-progressive volcanic chain. Here, I will present recently acquired deep penetration, active-source seismic data collected with R/V Marcus G. Langseth as part of the Hawaiian-Emperor Seismic Experiment. During this two-cruise experiment in 2018 and 2019, R/V Langseth acquired multichannel seismic reflection data and wide-angle seismic data across the Hawaiian Island Chain, the youngest part of the chain, and along and across the Emperor Seamount Chain, the oldest part of the chain. This wide separation in space and time of formation enables us to investigate how magmatic addition has varied with time and study the time-dependent response of the oceanic lithosphere to the resulting volcanic load. Furthermore, gravitational collapse soon after the formation of the Islands produced some of the largest landslides on Earth, which were also targeted for the experiment. For acquisition of the seismic reflection data, we used a 6,600 in3 tuned air gun array and a 15-km-long hydrophone streamer cable, and for wide-angle seismic data, we used the same source with ocean-bottom seismometers spaced at ~15 km, with ocean-bottom seismometers provided by Scripps Institution of Oceanography, Woods Hole Oceanographic Institution, and GEOMAR Helmholz Centre for Ocean Research. Integrated analyses of data from both cruises allows us to capture the effects of wide variations in the time elapsed since loading, the age of the lithosphere at the time of loading, and timing and volume flux of magma emplacement. In addition, I will discuss potential volcanic spreading features from the Hana Slump caused by the collapse of the Haleakala Volcano on East Maui to the giant landslide of the Waianae Volcano on the western half of the Island of Oahu, highlighting the dynamic evolution of the Hawaiian-Emperor seamount chain.