Browsing Geophysics by Issue Date
Now showing items 1-14 of 14
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Upper-mantle structure of the Cascadia subduction zone from non-linear teleseismic travel-time inversion
(1991)The tectonic evolution of the Juan de Fuca plate system has undergone dramatic changes over the past several million years as evidenced by seafloor geomagnetic data. If there are large geodynamic forces active in the ... -
Theoretical calculations of magnetic hysteresis and critical sizes for transitions between single-domain and multi-domain properties in titanomagnetites
(1997)In this dissertation, I develop some theoretical tools to interpret measurements of magnetization in rocks, sediments and soils. I show that the magnetization curve for an ensemble of superparamagnetic particles depends ... -
The effect of vertical mixing on along channel transport in a layered flow
(1998)The Columbia River has a large, biologically productive estuary whose ecosystem depends on the balance of salt and fresh water. Outflow from the river also forms a vast buoyant plume which affects circulation for hundreds ... -
Imaging mid-mantle discontinuities: implications for mantle chemistry, dynamics, rheology, and deep earthquakes
(1998)Using teleseismic network data and new signal processing techniques, I investigated mantle structure in the vicinity of subduction zones. The 660-km seismic discontinuity in the Izu-Bonin region is depressed by up to 80 ... -
Interpretation of infrasound generated by erupting volcanoes and seismo-acoustic energy partitioning during strombolian explosions
(2000)Infrasonic signals provide a valuable tool for the study of volcanic eruptions because volcanoes generate the majority of their acoustic energy in the infrasonic bandwidth and infrasound is only slightly affected by ... -
Behavior of the atomic oxygen 5577 Ångström emission intensity at mid-latitudes: a climatological view
(2000)A global mid-latitude study of the atomic oxygen green line emission intensity at 5577 A has been undertaken with the goal of developing a climatological understanding of the emission behavior and its usefulness as a tracer ... -
Folding of stratigraphic layers in ice domes
(2001)This dissertation presents a two part model of the formation of recumbent folds in stratigraphic layers of ice sheets such as those in Greenland and Antarctica. The initial disturbances in the stratigraphy have their roots ... -
The indepth magnetotelluric experiment on the Tibetan Plateau and its implications
(2001)This dissertation focus on the application of the magnetotelluric method to tectonic studies on the Tibetan Plateau. The framework of this thesis composes three parts. The first part concentrates on magnetotelluric data ... -
Kinetic processes in the plasma sheet observed during auroral activity
(2002)In this dissertation we analyze plasma sheet magnetic field and plasma data observed during varying levels of auroral activity from very small, isolated events known as pseudobreakups to large, global events known as ... -
Fluid and particle simulations of the interaction of the solar wind with magnetic anomalies on the surface of the Moon and Mars
(2003)Simulations of the solar wind interacting with the Moon and Mars indicate that the presence of magnetic anomalies on the surface can lead to the formation of mini-magnetospheres around the anomalies. These mini-magnetospheres ... -
Effects of firn ventilation on geochemistry of polar snow
(2003)The effects of air motion in firn on geochemical species is examined. Stable isotope data from Taylor Mouth, Antarctica are compared with data from nearby Taylor Dome and are found to be significantly different. Three ... -
Juan de Fuca subducting plate geometry and intraslab seismicity
(2006)The geometry of the subducting Juan de Fuca plate beneath the Olympic Peninsula of Western Washington is modeled using wide-angle P mP reflections off the slab Moho. Active-source reflection data collected from the 1998 ... -
High pressure and low temperature equations of state for aqueous magnesium sulfate: applications to the search for life in extraterrestrial oceans, with particular reference to Europa
(2007)A prevalence of cold, high pressure (P > 100 MPa) environments in the Solar System, and beyond, is discussed in the context of contemporary efforts to understand the origin and abundance of life in the Universe. Constraints ... -
Self-consistent modeling of ice-sheet evolution and paleoclimate
(2012-08-10)A self-consistent approach has been developed to determine past climate histories while simultaneously determining the past ice-sheet evolution. We recognize that multiple physical processes are affected by the same climate ...