Earth Sciences Commons^™

2012 Haida Gwaii Quake: Insight Into Cascadia's Subduction Extent, Walter Szeliga

Geological Sciences Faculty Scholarship

The limits of Cascadia were first defined to contain nearly the entire margin of the Pacific Northwest, from Cape Mendocino through the Alaska Panhandle [Schuchert, 1910; Schuchert and Barrell, 1914]. Since that time, the boundary of Cascadia has shrunk to become essentially synonymous with the region where the Juan de Fuca plate subducts beneath the North American plate. As a consequence, seismic hazard assessments in the Pacific Northwest have conventionally focused on the potential for large megathrust earthquakes along the interface of the Juan de Fuca and North American plates.

Nucleation And Seismic Tremor Associated With The Glacial Earthquakes Of Whillans Ice Stream, Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Douglas A. Wiens, Richard B. Alley

All Faculty Scholarship for the College of the Sciences

The ability to monitor transient motion along faults is critical to improving our ability to understand many natural phenomena such as landslides and earthquakes. Here, we usedata from a GPS and seismometer network that were deployed to monitor the regularly repeating glacial earthquakes of Whillans Ice Stream, West Antarctica to show that a unique pattern of precursory slip precedes complete rupture along the bed of the ice stream. Additionally, we show that rupture can be independently tracked by increased levels of microseismic activity, including harmonic tremor, that are coincident with the onset of slip at any location, thus providing a …

Modeling The Metamorphic History Of Ultrahigh Pressure Rocks: Western China, Jesse Walters

Undergraduate Honors Theses

In order to better understand metamorphism during continent-continent collision, the pressure-temperature history of a garnet-k:yanite paragniess from the Dulan region of the N. Qaidam high-pressure (HP)/ ultrahigh-pressure (UHP) belt is modeled. The gneiss contains the assemblage Bt + Pl + Kfs + Grt + Ky + Qtz + Rt + Ap. An equilibrium assemblage diagram constructed for the sample's pelitic bulk composition predicts the observed assemblage to form at ~ 11-15 kbar and ~810-870 °C. The diagram predicts predicts ~2-8 vol% melt in the observed assemblage. Predicted mineral abundances closely match observed values, with 8-18 vol % garnet and 0-10 …

Rock Glaciers In The Eastern Cascades, Washington, Mark Weidenaar

Undergraduate Honors Theses

The eastern portion of Washington State's Cascade Range is a place not previously examined for rock glaciers, due to proximity to the Pacific Ocean and its associated marine­-influenced climate. The objectives of this study were to determine spatial, activity, and genesis patterns, and paleoclimatic implications of Eastern Cascade rock glaciers. Using Google Earth, I found l 03 rock glaciers in the study area. Rock glaciers are more common further east of the Cascade crest and more north in latitude, with the largest concentrations occurring east of Lake Chelan (22) and in the Pasayten Wilderness (28) in the North Cascades. None …

Rock Glaciers In The Eastern Cascades, Washington, Mark Weidenaar

Undergraduate Honors Theses

The eastern portion of Washington State's Cascade Range is a place not previously examined for rock glaciers, due to proximity to the Pacific Ocean and its associated marine-influenced climate. The objectives of this study were to determine spatial, activity, and genesis patterns, and paleoclimatic implications of Eastern Cascade rock glaciers. Using Google Earth, I found 103 rock glaciers in the study area. Rock glaciers are more common further east of the Cascade crest and more north in latitude, with the largest concentrations occurring east of Lake Chelan (22) and in the Pasayten Wilderness (28) in the North Cascades. None were …

Comparison Of Earthquake Source Models For The 2011 Tohoku Event Using Tsunami Simulations And Near‐Field Observations, Breanyn T. Macinnes, Aditya Riadi Gusman, Randall J. Leveque, Yuichiro Tanioka

All Faculty Scholarship for the College of the Sciences

Selection of the earthquake source used in tsunami models of the 2011 Tohoku event affects the simulated tsunami waveform across the near field. Different earthquake sources, based on inversions of seismic waveforms, tsunami waveforms, and Global Positioning System (GPS) data, give distinguishable patterns of simulated tsunami heights in many locations in Tohoku and at near‐field Deep‐ocean Assessment and Reporting of Tsunamis (DART) buoys. We compared 10 sources proposed by different research groups using the GeoClaw code to simulate the resulting tsunami. Several simulations accurately reproduced observations at simulation sites with high grid resolution. Many earthquake sources produced results within 20% …

Pliocene Sinistral Slip Across The Adobe Hills, Eastern California-Western Nevada: Kinematics Of Fault Slip Transfer Across The Mina Deflection, Sarah Nagorsen-Rinke, Jeffrey Lee, Andrew Calvert

All Faculty Scholarship for the College of the Sciences

The Adobe Hills region (California and Nevada, USA) is a faulted volcanic field located within the western Mina deflection, a right-stepping zone of faults that connects the northern Eastern California shear zone (ECSZ) to the south with the Walker Lane belt (WLB) to the north. New detailed geologic mapping, structural studies, and ⁴⁰Ar/³⁹Ar geochronology in the Adobe Hills allow us to calculate fault slip rates and test predictions for the kinematics of fault slip transfer into the Mina deflection. The Adobe Hills are dominated by Pliocene tuffaceous sandstone, basaltic lavas that yield ⁴⁰Ar/³⁹Ar ages …

Feasibility Of Seismic Monitoring To Identify Avalanche Activity: Snoqualmie Pass, Wa, Kathryn Johnston

All Master's Theses

Avalanches across the Interstate-90 corridor over Snoqualmie Pass, in Washington State, are a concern for winter travelers and backcountry recreation. The temporary closure of the interstate for avalanche mitigation work also affects commerce by delaying transportation of merchandise. The study of seismic signals associated with snow avalanches could allow for greater understanding of avalanche properties, while remote sensing of avalanche activity could help established avalanche control programs and regional avalanche centers with forecasting and mitigation efforts. Two seismic stations were installed near the Alpental ski area on Snoqualmie Pass and recorded seismic activity throughout the winters of 2009-2010 and 2010-2011. …

Lidar Assessment Of Sediment Transport Related To The Removal Of The Marmot Dam, Sandy River, Oregon, Carl Daniel Matzek

All Master's Theses

Four Aerial LiDAR survey were used to examine the impacts of the 2007 removal of the Marmot Dam on the Sandy River, Oregon. Geomorphic Change Detection software was used to answer three project goals: 1) to investigate how the dam removal affected sediment distribution in the lower reach of the river, several km downstream of the dam, 2) to determine whether the pulse of sediment from the dam removal created a detectable, successive downstream accumulation of sediment through time, and 3) to assess the effect of natural high-flow events on the sediment distribution related to the dam removal. The results …

Geomorphology Of Deposits From The 2004 Indian Ocean Tsunami, Tamil Nadu, Southeastern India, Patrick Alan Johnston

All Master's Theses

In low latitudes, geologically suitable repositories for tsunami deposits are not well defined. This project characterizes the geomorphic environments on the southeastern coast of India that preserved depositional evidence of the catastrophic tsunami created by the M_w9.0-9.3 Sumatra-Andaman earthquake on December 26, 2004. The Indian coast is particularly interesting because it is approximately 1300 km from the subduction-zone source of tsunamis across the Indian Ocean, and therefore only the largest events are capable of reaching it. The main objective of this study was to identify the settings where recognizable tsunami deposits from the 2004 event have been preferentially …

Black Carbon Measurements Of Snow And Ice Using The Single Particle Soot Photometer: Method Development And An Ad 1852-1999 Record Of Atmospheric Black Carbon From A Mount Logan Ice Core, James Andrew Menking

All Master's Theses

Black carbon (BC), produced by the combustion of fossil and biofuels, warms the climate by absorbing solar radiation when in the atmosphere and by reducing the albedo of snow and ice when deposited. Measuring BC in snow and ice is important for estimating albedo reduction and developing historical records of BC concentration. Experiments were conducted to further develop a method for measuring BC in snow and ice using the Single Particle Soot Photometer (SP2). Results suggest the optimal procedures for sample storage, treatment, and nebulization, and analysis and calibration of BC concentrations measured using the SP2 coupled to a CETAC …

Paleoseismologic Evidence For Holocene Activity On The Pinto Mountain Fault, Twentynine Palms, California, Ana Maria Cadena

All Master's Theses

Excavations across the Pinto Mountain fault in Twentynine Palms, California exposed faulted strata across a 32-m wide zone. Trench wall exposures revealed clear evidence for five ground-rupturing events during the Holocene, and two additional events in the late Pleistocene. Optically stimulated luminescence ages from alluvial sediments suggest that the most recent event occurred between 1.7-2.9 ka B.P. and the penultimate event between 2.7-4.2 ka B.P.. Prior to the penultimate event, there were five ground-rupturing earthquakes on the eastern Pinto Mountain fault between 3.5-13.6 ka B.P.. The average recurrence interval since 13.3-13.6 ka B.P. is 1510-1680 years, and 1200-1500 years in …

The Roles Of Humans And Climatic Variation On The Fire History Of Subalpine Meadows - Mount Rainer National Park (Washington), Michael Louis Lukens

All Master's Theses

With the creation of Mount Rainier National Park (MORA) in 1899 came the active management of the park's landscapes and a heavy emphasis on fire suppression. Today managers at MORA have made returning fire to the park's landscapes a top priority. In order to achieve this goal, and to make more informed decisions in regard to the application of fire, land managers at MORA need to better understand past fire occurrences and the drivers of fire activity on the mountain. To address this problem, analysis of macroscopic charcoal preserved in lake sediments was used to reconstruct the fire history for …

Characterization Of Mass Wasting Through The Spectral Analysis Of Lidar Imagery: Owyhee River, Southeastern Oregon, Christopher Earl Markley

All Master's Theses

Quantifying landslide character is an important aspect of understanding hillslope-channel interactions. Spectral analysis of high-resolution, LiDAR derived, DEMs was carried out following methods described by Booth et al. (2009) to determine the characteristic spectral signature inherent in different styles of landslides in the Owyhee River Canyon in southeastern Oregon. The main factor in landslide generation in this location is a lithologic contact in which a coherent basaltic caprock overlies relatively weak sediments where most of the landslide failure surfaces originated. Changes in spectral power distribution through time were quantified by comparing a sequence of adjacent rotational landslides of apparent different …

Geochemical Constraints On Groundwater Recharge In The Royal Slope Area, Grant County, Washington, Zoe Danielle Weis

All Master's Theses

Groundwater, the primary source for potable water in the Columbia Plateau, has experienced significant declines over the past 25 years. Groundwater geochemistry and multivariable statistics were employed to identify and characterize the hydrofacies present, constrain recharge sources, and assess mixing of groundwater in the Royal Slope area of the Columbia Plateau. Geochemical analyses for major ions, stable isotopes, and radiogenic isotopes (14C and tritium) for age dating were performed on groundwater samples collected in 2010 from 24 wells in the study area. The results confirmed that the groundwater evolution in the study area follows the typical Columbia River Basalt Group …

Gps Constraints On Indo-Asian Convergence In The Bhutan Himalaya: Segmentation And Potential For A 8.2-8.8 Mw Earthquake, Dowchu Drukpa, Phuntsho Pelgay, Anjan Bhattacharya, Phillipe Vernant, Walter Szeliga, Roser Bilham

Faculty Scholarship for the Cascadia Hazards Institute

The seismogenic setting of Bhutan is unusual due to its lower-than-average 20th century seismic moment release (Drukpa et al. 2006), its absence of a reliable historical record, and its unusual location near the Shillong plateau where a great earthquake in 1897 resulted in ≈10 m of N/S shortening of the Indian plate to its south (Gahalaut et al. 2011). Despite these indicators that lower than normal convergence velocities should currently prevail, the GPS velocity between Shillong and Lhasa suggests that convergence in Sikkim and Bhutan occurs at velocities exceeding 20 mm/yr. GPS points between the Greater Himalaya and the Shillong …

Predictability Of Biomass Burning In Response To Climate Changes, A.-L. Daniau, Megan Walsh

All Faculty Scholarship for the College of the Sciences

Climate is an important control on biomass burning, but the sensitivity of fire to changes in temperature and moisture balance has not been quantified. We analyze sedimentary charcoal records to show that the changes in fire regime over the past 21,000 yrs are predictable from changes in regional climates. Analyses of paleo- fire data show that fire increases monotonically with changes in temperature and peaks at intermediate moisture levels, and that temperature is quantitatively the most important driver of changes in biomass burning over the past 21,000 yrs. Given that a similar relationship between climate drivers and fire emerges from …

Interseismic Strain Accumulation Along The Western Boundary Of The Indian Subcontinent, Walter Szeliga, Roger Bilham, Din Mohammad Kakar, Sarosh H. Lodi

All Faculty Scholarship for the College of the Sciences

Despite an overall sinistral slip rate of ≈3 cm/yr, few major earthquakes have occurred in the past 200 years along the Chaman fault system, the western boundary of the India Plate with the Eurasia Plate. GPS and InSAR data reported here indicate sinistral shear velocities of 8–17 mm/yr across the westernmost branches of the fault system, suggesting that a significant fraction of the plate boundary slip is distributed in the fold and fault belt to the east. At its southernmost on‐land segment (≈26°N), near the triple junction between the Arabia, Eurasia, and India Plates, we find the velocity across the …

Global Estimates Of Mineral Dust Aerosol Iron And Aluminum Solubility That Account For Particle Size Using Diffusion-Controlled And Surface-Area-Controlled Approximations, Qin Han, Charles S. Zender, J. Keith Moore, Clifton S. Buck, Ying Chen, Anne Johansen, Christopher I. Measures

All Faculty Scholarship for the College of the Sciences

Mineral aerosol deposition is recognized as the dominant source of iron to the open ocean and the solubility of iron in the dust aerosol is highly variable, with measurements ranging from 0.01–80%. Global models have difficulty capturing the observed variations in solubility, and have ignored the solubility dependence on aerosol size. We introduce two idealized physical models to estimate the size dependence of mineral aerosol solubility: a diffusion‐controlled model and a surface‐area‐controlled model. These models produce differing time‐ and space‐varying solubility maps for aerosol Fe and Al given the dust age at deposition, size‐resolved dust entrainment fields, and the aerosol …

Atmospheric Circulation Change In The Central Himalayas Indicated By A High-Resolution Ice Core Deuterium Excess Record, Hongxi Pang, Shugui Hou, Susan Kaspari, Paul Mayewski, Douglas Introne, Valérie Masson-Delmotte, Jean Jouzel, Zhenchao Li, Yuanqing He, Sungmin Hong, Dahe Qin

All Faculty Scholarship for the College of the Sciences

Continuous measurements of both δD and δ18O were performed along a 108.8 m ice core recovered from the East Rongbuk Glacier on the northeast saddle of Mt. Qomolangma (Everest) (28.03° N, 86.96° E, 6518 m above sea level) in September 2002. They provide the first high-resolution historical record of deuterium excess (d) in the central Himalayas. In this paper, we focus on d variability from 1951 to 2001 and its relationship with large scale atmospheric circulation. The d record exhibits significant seasonal variations, with low values in summer and high values in winter, reflecting the atmospheric circulation shift between winter …

Bulk Rock Composition And Geochemistry Of Olivine-Hosted Melt Inclusions In The Grey Porri Tuff And Selected Lavas Of The Monte Dei Porri Volcano, Salina, Aeolian Islands, Southern Italy., Angela L. Doherty, Robert J. Bodnar, Benedetto De Vivo, Wendy A. Bohrson, Harvey E. Belkin, Antonia Messina, Robert J. Tracy

All Faculty Scholarship for the College of the Sciences

The Aeolian Islands are an arcuate chain of submarine seamounts and volcanic islands, lying just north of Sicily in southern Italy. The second largest of the islands, Salina, exhibits a wide range of compositional variation in its erupted products, from basaltic lavas to rhyolitic pumice. The Monte dei Porri eruptions occurred between 60 ka and 30 ka, following a period of approximately 60,000 years of repose. The bulk rock composition of the Monte dei Porri products range from basaltic-andesite scoria to andesitic pumice in the Grey Porri Tuff (GPT), with the Monte dei Porri lavas having basaltic-andesite compositions. The typical …

Magmatic Rifting And Active Volcanism Conference, Afar Rift Consortium, Anne E. Egger, Tyrone Rooney, Donna Shillington

Geological Sciences Faculty Scholarship

The Magmatic Rifting and Active Volcanism (MRAV) Conference took place in Addis Ababa, Ethiopia January 10-13, 2012, convened by members of the Afar Rift Consortium, an international team investigating active magmatism and deformation in the Afar region. Over 200 people from around the world attended. The conference participants primarily presented the results of work on ongoing rifting processes in Afar, but work was also presented that addressed other portions of the East African Rift, comparable rift settings elsewhere, rifting processes in general, and the hazards and resources associated with the East African Rift.

The scientific program outlined the current state …

Wilson Cycles, Tectonic Inheritance, And Rifting Of The North American Gulf Of Mexico Continental Margin, Audrey D. Huerta, Dennis L. Harry

Geological Sciences Faculty Scholarship

The tectonic evolution of the North American Gulf of Mexico continental margin is characterized by two Wilson cycles, i.e., repeated episodes of opening and closing of ocean basins along the same structural trend. This evolution includes (1) the Precambrian Grenville orogeny; (2) formation of a rift-transform margin during late Precambrian opening of the Iapetus Ocean; (3) the late Paleozoic Ouachita orogeny during assembly of Pangea; and (4) Mesozoic rifting during opening of the Gulf of Mexico. Unlike the Atlantic margins, where Wilson cycles were first recognized, breakup in the Gulf of Mexico did not initially focus within the orogen, but …

Size And Exhumation Rate Of Ultrahigh-Pressure Terranes Linked To Orogenic Stage, Andrew R.C. Kylander-Clark, Bradley R. Hacker, Chris G. Mattinson

All Faculty Scholarship for the College of the Sciences

A growing set of data indicates a stark contrast between the evolution of two types of ultrahigh-pressure (UHP) terranes: large terranes that evolved slowly (over 10–30 Myr), and small terranes that formed and were exhumed on timescales of < 10 Myr. Here we compare the characteristics – area, thickness, formation rate, exhumation rate, age, and tectonic setting – of these two endmember types of UHP terrane worldwide. We suggest that the two UHP terrane types may form during different orogenic stages because of variations in the buoyancy and traction forces due to different proportions of subducting crust and mantle lithosphere or to different rates of subduction. The initial stages of continent collision involve the subduction of thin continental crust or microcontinents, and thus tectonic forces are dominated by the density of the oceanic slab; subduction rates are rapid and subduction angles are initially steep. However, as collision matures, thicker and larger pieces of continental material are subducted, and the positive buoyancy of the down-going slab becomes more prominent; subduction angles become gentle and convergence slows. Assessing the validity of this hypothesis is critical to understanding the physical and chemical evolution of Earth's crust and mantle.

Included here is the post-print copy of this article. The final publication is available via ScienceDirect at http://www.sciencedirect.com/science/article/pii/S0012821X11007564

Holocene House Hunting: An Application Of Satellite Image Analysis Towards Locating Prehistoric Archeological Sites In Alaska's Brooks Range, Joseph Keeney

Undergraduate Honors Theses

In this study, satellite image analysis was applied to archeological sites at Lake Matcharak in the Brooks Range of Alaska. The Goal was to test whether or not satellite remote sensing, which has been successful in locating large-size archeological features, could be applied to small-size prehistoric features found in Arctic Alaska. Using 1-m resolution IKONOS and 30-m resolution ASTER DEM data, vegetation indices (NDVI and tasseled cap) and slope were generated and stacked into one image. Supervised and unsupervised classifications were then applied to the resulting image to look for spectral/slope characteristics that were unique to known site locations at …

Interseismic Strain Accumulation Along The Western Boundary Of The Indian Subcontinent, Walter Szeliga, Roger Bilham, Din Mohammad Kakar, Sarosh H. Lodi

Faculty Scholarship for the Cascadia Hazards Institute

Despite an overall sinistral slip rate of approximately 3 cm/yr, few major earthquakes have occurred in the past 200 years along the Chaman fault system, the western boundary of the India Plate with the Eurasia Plate. GPS and InSAR data reported here indicate sinistral shear velocities of 8-17 mm/yr across the westernmost branches of the fault system, suggesting that a significant fraction of the plate boundary slip is distributed in the fold and fault belt to the east. At its southernmost on-land segment, near the triple junction between the Arabia, Eurasia, and India Plates, we find the velocity across the …

Holocene Arroyo Cut And Fills Cycles, South-Central Washington, Matthew Ian Durkee

All Master's Theses

Ephemeral streams have cut deeply incised arroyos into alluvial and eolian sediments in many of the watersheds within the Yakima Training Center (YTC) military reservation, south-central Washington. The most recent channel incision episode along Selah Creek is primarily attributed to multiple failures of an irrigation reservoir dam during the winters of 1909 and 1910. The modern arroyo exposed evidence of at least one previous episode of arroyo incision to a depth of ~4 m that occurred just prior to 1530- 1340 cal yr BP. Filling of this paleo-arroyo with fine to coarse grained sand ceased between 650-103 cal yr BP. …

Applying Gis Metrics To Determine Degree Of Glacial Modification In Mountainous Landscapes, Carl Delbert Swanson Ii

All Master's Theses

The ability to quantitatively assess the degree of glaciation in mountainous areas can be a powerful tool in unraveling the evolution of landscapes, and provide key insights in regions where field research is difficult. Here we determine, test, and apply metrics that assess the relative degree of past glacial modification in mountainous landscapes. Results show that slope results can be used to quantitatively assess the degree to which an area is modified by glaciation. In particular, analysis of basins using slope frequency distribution curves and slope vs. elevation plots capture steeper slopes, flatter valley bottoms, cirques, and arêtes of glaciated …

Documenting The Origin Of Compositional Diversity Of Subduction Zone Magmatism, Alicudi, Aeolian Arc (Southern Tyrrhenian Sea, Italy) Using In Situ Plagioclase Data, Rachel Hunt

All Master's Theses

Processes that generate magma compositional diversity are important to document because composition affects degree of explosivity, which impacts hazard mitigation. Magnesium to silicon rich magmas are produced by processes such as magma recharge, assimilation, and fractional crystallization (RAFC) that occur in subvolcanic magma chamber(s). This study evaluates how magma chamber processes contribute to compositional diversity at Alicudi Volcano, Italy. Analytical and petrographic data from ten samples that span the subaerial history include whole rock major and trace elements and strontium/neodymium isotopes, and plagioclase textural types, major and trace elements, and strontium isotopes; numerical modeling was also conducted. Integration of these …

Documenting Magma Evolution Of The Fossa Delle Felci (Salina Island, South Tyrrhenian Sea) By Integrating In Situ Plagioclase Data With Quantitative Modeling, Aaron Mayfield

All Master's Theses

Compositional diversity occurs via processes dominated by recharge, assimilation and fractional crystallization (RAFC), quantification of which can provide insights into eruption catalysts, and therefore assist in hazard mitigation. This study evaluates the relative roles of RAFC processes in Fossa delle Felci (Salina Island, Italy) magmas, which span the basalt to dacite range (52-65 wt% SiO2). Integration of petrographic, whole rock, and in situ plagioclase data with quantitative magma chamber models suggests differentiation dominated by fractional crystallization and magma recharge/mixing in reservoirs located at different crustal levels. At ~12 km depth, magma evolved through crystallization of a pyroxene dominated assemblage; plagioclase …