Physical Sciences and Mathematics Commons^™

Seismic Characteristics Of The Eastern North American Crust And Upper Mantle: The Formation And Evolution Of Continental Lithosphere, Cong Li

Doctoral Dissertations

The impact of past tectonic events on formation and modification of continental lithosphere over the course of Earth’s history remains as an open question of fundamental importance. Physical properties of continental crust and mantle lithosphere, such as their age, thickness, composition, temperature, and velocity, contain crucial information for informing this question. Eastern North America provides at least two complete records of supercontinent assembly and breakup over the past 1.3 Ga, serving as a natural laboratory for our understanding of continental lithosphere evolution and for integrating geologic and geophysical observations. In this thesis, I have investigated the seismic properties of crust …

3-D Shear Wave Velocity Structures Of The Crust And Upper Mantle Beneath Cascadia And New Zealand From Full-Wave Ambient Noise Tomography, Sampath Rathnayaka Mudiyanselage

Doctoral Dissertations

The (de)hydration process and the amount of hydrated sediment carried by the downgoing oceanic plate play a key role in the subduction dynamics. The deformation and (de)hydration of the downgoing tectonic plates, as well as the seismic, tsunami, volcanic hazards, in Cascadia and the New Zealand regions are not fully understood, partly due to a lack of combined studies of onshore and offshore data. In order to address these questions, we developed a 3-D high-resolution shear wave velocity model beneath Cascadia, the North and the South Islands of New Zealand, extending from offshore to onshore, with the use of full-wave …

Nanoindentation Characterization Of Elastic Properties Of Shales And Swelling Clay Minerals, Shengmin Luo

Doctoral Dissertations

Oil and gas shales are a class of multiscale, multiphase, hybrid inorganic-organic sedimentary rocks that consist of a generally uniform, preferentially oriented clay matrix with randomly embedded silt and sand particles as solid inclusions. A thorough understanding of the mechanical properties of shales is crucial for the exploration and production of oil and gas in the unconventional shale reservoirs, but it can be a challenging task due to their nature of compositional heterogeneity and microstructural anisotropy. In efforts to better characterize the mechanical properties of shales across different length scales and to fundamentally understand the laws of upscaling from individual …

Insar Simulations For Swot And Dual Frequency Processing For Topographic Measurements, Gerard Masalias Huguet

Masters Theses

In Earth remote sensing precise characterization of the backscatter coefficient is important to extract valuable information about the observed target. A system that eliminates platform motion during near-nadir airborne observations is presented in this thesis, showing an improvement on the accuracy of measurements for a Ka- band scatterometer previously developed at Microwave Remote Sensing Laboratory (MIRSL). These very same results are used to simulate the reflectivity of such targets as seen from a spaceborne radar and estimate height errors based on mission-specific geometry. Finally, data collected from a dual-frequency airborne interferometer com- prised by the Ka-band system and an S-band …

Time Domain Sar Processing With Gpus For Airborne Platforms, Dustin Lagoy

Masters Theses

A time-domain backprojection processor for airborne synthetic aperture radar (SAR) has been developed at the University of Massachusetts’ Microwave Remote Sensing Lab (MIRSL). The aim of this work is to produce a SAR processor capable of addressing the motion compensation issues faced by frequency-domain processing algorithms, in order to create well focused SAR imagery suitable for interferometry. The time-domain backprojection algorithm inherently compensates for non-linear platform motion, dependent on the availability of accurate measurements of the motion. The implementation must manage the relatively high computational burden of the backprojection algorithm, which is done using modern graphics processing units (GPUs), programmed …

Validation Of Recent Shear Wave Velocity Models In The United States With Full-Wave Simulation, Haiying Gao, Yang Shen

Haiying Gao

Interpretations of dynamic processes and the thermal and chemical structure of the Earth depend on the accuracy of Earth models. With the growing number of velocity models constructed with different tomographic methods and seismic data sets, there is an increasing need for a systematic way to validate model accuracy and resolution. This study selects five shear wave velocity models in the U.S. and simulates full wave propagation within the 3-D structures. Surface-wave signals extracted from ambient seismic noise and regional earthquakes are compared with synthetic waveforms at multiple-frequency bands. Phase delays and cross-correlation coefficients between observed and synthetic waveforms allow …

From ~1.5 Ma To Today: Insights Into The Southern San Andreas Fault System From 3d Mechanical Models, Laura Fattaruso

Masters Theses

Three-dimensional mechanical simulations of the San Andreas fault (SAF) within the Coachella Valley in California produce deformation that match geologic observations and demonstrate the impact of fault geometry on uplift patterns. Most models that include the Coachella Valley segment of the SAF have assumed a vertical orientation, but recent studies suggest that this segment dips 60-70° northeast. We compare models with varied fault geometry and evaluate how well they reproduce observed uplift patterns. Our model with a dipping SAF matches geologic observations, while models containing a vertical fault do not. This suggests that the active Coachella Valley segment of the …

Scaling Relationships Of Source Parameters For Slow Slip Events, Haiying Gao, David A. Schmidt, Ray J. Weldon Ii

Haiying Gao

To better understand the physical mechanisms of slow slip events (SSEs) detected worldwide, we explore the scaling relationships of various source parameters and compare them with similar scaling laws for earthquakes. These scaling relationships highlight differences and similarities between slow slip events and earthquakes and hold implications for the degree of heterogeneity and fault-healing characteristics. That static drop remains constant for different-sized events as is observed for earthquakes. However, the static stress drop of slow slop events is within a range of 0.01-1.0 MPa, 1-2 orders of magnitiude lower than that found for earthquakes, which could be related to the …

Reading Landscape: Mid-Century Modernism And The Landscape Idea, Jeffrey David Blankenship

Open Access Dissertations

This dissertation traces the recovery of the landscape idea during the middle decades of the 20th century by a group of public intellectuals, scholars and designers responding to the everyday realities of the modern American built environment. That recovery served as a corrective to modernism's construction of landscape as either abstract utopian space or retrogressive historical tableau. The primary catalyst for this renewed interest in landscape as a representation of human cultures and their complex relationship with the natural world was the essayist and critic John Brinckerhoff Jackson (1909-1996) and his magazine Landscape. During the years of Jackson's editorship (1951-1968), …

Lacustrine Records Of Holocene Climate And Environmental Change From The Lofoten Islands, Norway, Nicholas L. Balascio

Open Access Dissertations

Lakes sediments from the Lofoten Islands, Norway, can be used to generate well resolved records of past climate and environmental change. This dissertation presents three lacustrine paleoenvironmental reconstructions that show evidence for Holocene climate changes associated with North Atlantic climate dynamics and relative sea-level variations driven by glacio-isostatic adjustment. This study also uses distal tephra deposits (cryptotephra) from Icelandic volcanic eruptions to improve the chronologies of these reconstructions and explores new approaches to crypto-tephrochronology. Past and present conditions at Vikjordvatnet, Fiskebølvatnet, and Heimerdalsvatnet were studied during four field seasons conducted from 2007-2010. Initially, each lake was characterized by measuring water …

Final Evaluation Report, Sagefox Consulting Group

IPY STEM Polar Connections

No abstract provided.

Melting Ice And Sea Level Changes, Morton Sternheim

IPY STEM Polar Connections

A simple experiment to demonstrate the effects of melting sea.

Thermohaline Circulation, Rob Snyder

IPY STEM Polar Connections

Surface currents, such as the Gulf Stream, are pushed by the wind. Deep ocean currents, called the “Thermohaline Circulation”, are the result of changes in the density of water. In this activity you can investigate how differences in the temperature and salinity of water can produce deep ocean currents

Globe Walk, Rob Snyder

IPY STEM Polar Connections

A “Globe Walk” can be used as a demonstration or classroom activity to guide students toward a better understanding of the affects that Earth’s axial tilt, rotation on Earth’s axis, and orbital motion have on the angles of incidence of sunlight, the lengths of daytimes, and solar insolation.

Polar Remote Sensing, Beth Caissie

IPY STEM Polar Connections

•Satellite sensors specialize in collecting data about specific wavelengths The Geostationary Operational Environment Satellites (GOES) operated by NASA, NOAA, and the U.S. Department of Commerce provide continuous monitoring of weather conditions. Orbiting the Earth’s equatorial plane at a speed exactly matching the planet’s rotation, satellites in the GOES network seem to hover over fixed spots. They monitor atmospheric conditions that lead to hurricanes, flash floods, tornadoes, and hail storms.

Detecting Atmospheric Carbon Dioxide With Btb, Stephan Schneider

IPY STEM Polar Connections

A study of the concentration of carbon dioxide gas in air samples requires an understanding of effective sampling techniques, the use of pH indicators, an understanding of chemical reactions that result on the formation of acidic compounds, and an understanding of the chemical processes that contribute to the composition and characteristics of Earth’s atmosphere.

Global Warming And Arctic Climate, Ray Bradley

IPY STEM Polar Connections

No abstract provided.

Build A Remote Sensing Satellite, Rob Snyder

IPY STEM Polar Connections

•Build a model of a remote sensing satellite. •Use your model of a satellite to transform reflected visible of different frequencies into electrical signals with different voltages. •Use different colors of paper to calibrate the model. •Create a model of a landscape using three different colors of paper. •Create a “false color” image of the model of a landscape (if time permits).

Seasonal Changes In Sea Ice, Rob Snyder

IPY STEM Polar Connections

No abstract provided.

Why The Arctic? An Overview, Julie Brigham-Grette

IPY STEM Polar Connections

No abstract provided.

Albedo Effects In Polar Regions, Morton Sternheim

IPY STEM Polar Connections

•Why are Polar Regions more affected by global warming than other parts of the globe? •One reason (there are others) is that as sea ice melts and more open water appears, more energy is absorbed, and warming accelerates. •This is a form of positive feedback and it makes the polar climate change faster than the climate in temperate areas. •Increasing vegetation on land also has a similar positive feedback effect.

A (Selective) History Of The International Polar Year, Ray Bradley

IPY STEM Polar Connections

No abstract provided.

Atmospheric Co2 And Temperature. What Is Normal?, Beth Caissie, Julie Brigham-Grette

IPY STEM Polar Connections

–How much of a change in CO2 concentration and other GHGs is natural? –What is the normal range of CO2 and temperature variability? How is normal defined in this context? –What is the relationship between CO2 and global temperatures?

Caribou, Whales, Andenvironmental Variability, Craig Nicolson

IPY STEM Polar Connections

How many caribou are there? Increasing or decreasing? Carrying capacity? How do we measure habitat quality?? Satellite imagery. Whale migration patterns. Activities on caribou and whales. Also, see http://www.nfb.ca/film/being_caribou/ a video entitled Being Caribou..

Melting Ice And Sea Level Change, Morton Sternheim

IPY STEM Polar Connections

Global warming can melt snow or ice on Greenland, Antarctica, and other land areas. It can also melt floating ice in the Arctic Ocean. How do the two cases compare in changing sea levels?

Brine Rejection Activity, Beth Caissie, Rob Snyder

IPY STEM Polar Connections

As salt water freezes, the salt is pushed out of solution through channels in the ice. This process is called brine rejection or brine exclusion. These channels are often used as microhabitats by ice algae, zooplankton, and even tiny fish. You can easily demonstrate what these channels look like.

Play Doh Coring Sampler Teacher Guide, Beth Caissie

IPY STEM Polar Connections

Sediment cores are one of the most valuable types of samples for researchers who would like to learn about past climate or ecological changes. Cores can be retrieved from lakes, marshes, swamps, fields, and the ocean. The layers often reveal striking changes in color (see photos) reflecting changing sediment composition (i.e. more clay deposition or more microfossil s). This easy activity illustrates the basic geologic principle that horizontal layers of sediment become older the deeper you go below the Earth’s surface (Law of Superposition). Each layer contains sediment, fossils and organic matter etc. that can inform us about past changes …

Sea Ice Food Webs—Hands On Sampler Teacher Guide, Beth Caissie

IPY STEM Polar Connections

This activity is a variation on a food web game that I’ve seen played many times before, but it is adapted to reflect a sea ice food web and show the many organisms that are intimately connected to polar bears.

Glacier Goo Activity, Beth Caissie

IPY STEM Polar Connections

We provided the students with background information about what a glacier is, where they are, how they move. Then split the students into four groups each tasked with a question to answer through experimentation

Group s 1 and 2: How does temperature change the way a glacier flows? (we provided frozen, and room temperature goo, and a microwave for heating the goo)

Groups 3 and 4: How does friction or obstacles change the way a glacier flows? (we provided different pvc tubes—tubes with nothing done to them, tubes with paintable sand applied to them, and tubes with rocks glued to …

Carbon Travels Game, Marie Silver

IPY STEM Polar Connections

Carbon cycle game.

Proportions for this activity are based LOOSELY on data from the Exploring the Environment website http://davem2.cotf.edu/ete/modules/carbon/effig11_full.html

They have a brief overview of the carbon cycle at http://davem2.cotf.edu/ete/modules/carbon/efcarbon.html