Tectonics and Structure | Open Access Articles

Probabilistic Tsunami Hazard Assessment At Seaside, Oregon, For Near- And Far-Field Seismic Sources, Frank González, Eric L. Geist, Bruce Jaffe, Utku Kânoğlu, Harold O. Mofjeld, Costas Synolakis, Vasily V. Titov, Diego Rodriguez Arcas, Douglas Bellomo, David Carlton, Thomas Horning, Jeff Johnson, Jean Newman, Thomas Parsons, Robert Peters, Curt D. Peterson, George Priest, Angie Venturato, Joseph Weber, Florence L. Wong, Ahmet Yalçıner

Geology Faculty Publications and Presentations

The first probabilistic tsunami flooding maps have been developed. The methodology, called probabilistic tsunami hazard assessment (PTHA), integrates tsunami inundation modeling with methods of probabilistic seismic hazard assessment (PSHA). Application of the methodology to Seaside, Oregon, has yielded estimates of the spatial distribution of 100- and 500-year maximum tsunami amplitudes, i.e., amplitudes with 1% and 0.2% annual probability of exceedance. The 100-year tsunami is generated most frequently by far-field sources in the Alaska-Aleutian Subduction Zone and is characterized by maximum amplitudes that do not exceed 4 m, with an inland extent of less than 500 m. In contrast, the 500-year …

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Understanding Paleoclimate And Human Evolution Through The Hominin Sites And Paleolakes Drilling Project, Andrew Cohen, Ramon Arrowsmith, Anna K. Behrensmeyer, Christopher Campisano, Craig Feibel, Shimeles Fisseha, Roy Johnson, Zelalem Bedaso, Charles Lockwood, Emma Mbua, Daniel Olago, Richard Potts, Kaye Reed, Robin Renaut, Jean-Jacques Tiercelin, Mohammed Umer

Geology Faculty Publications

Understanding the evolution of humans and our close relatives is one of the enduring scientific issues of modern times. Since the time of Charles Darwin, scientists have speculated on how and when we evolved and what conditions drove this evolutionary story. The detective work required to address these questions is necessarily interdisciplinary, involving research in anthropology, archaeology, human genetics and genomics, and the earth sciences. In addition to the difficult tasks of finding, describing, and interpreting hominin fossils (the taxonomic tribe which includes Homo sapiens and our close fossil relatives from the last 6 Ma), much of modern geological research …

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Collaborative Research: Erosional Forcing Of Late Quaternary Compressive Strain, West Central Taiwan, Phaedra Upton

University of Maine Office of Research Administration: Grant Reports

The concept of steady-state growth of compressive orogens is one of the most accepted ideas in continental tectonics developed in the last two decades, yet surprisingly few direct data exist to test the models that have been advanced. Testing and refining the concept of steady-state mountain building requires identification of cases of transient response and dynamic feedback in compressive orogens, and documentation of the spatial and temporal scales at which crustal deformation responds to erosion. This project takes advantage of a unique natural experiment in the active fold-thrust belt of west-central Taiwan where enough modern seismologic, geodetic, structural and geochronologic …

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Moment Release Rate Of Cascadia Tremor Constrained By Gps, Ana C. Aguiar, Timothy I. Melbourne, Craig W. Scrivner

All Faculty Scholarship for the College of the Sciences

A comparison of GPS and seismic analyses of 23 distinct episodic tremor and slip events, located throughout the Cascadia subduction zone over an 11-year period, yields a highly linear relationship between moment release, as estimated from GPS, and total duration of nonvolcanic tremor, as summed from regional seismic arrays. The events last 1–5 weeks, typically produce ~5 mm of static forearc deformation, and show cumulative totals of tremor that range from 40 to 280 h. Moment released by each event is estimated by inverting GPS-measured deformation, which is sensitive to all rates of tremor-synchronous faulting, including aseismic creep, for total …

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Analysis Of Deni̇zli̇ Earthquakes According To Their Activity And Cumulative Activity Terms, Mehmet Utku

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Paragneiss Zircon Geochronology And Trace Element Geochemistry, North Qaidam Hp/Uhp Terrane, Western China, Chris G. Mattinson, Joseph L. Wooden, Jian-Xin Zhang, D. K. Bird

All Faculty Scholarship for the College of the Sciences

In the southeastern part of the North Qaidam terrane, near Dulan, paragneiss hosts minor peridotite and UHP eclogite. Zircon geochronology and trace element geochemistry of three paragneiss samples (located within a ∼3 km transect) indicates that eclogite-facies metamorphism resulted in variable degrees of zircon growth and recrystallization in the three samples. Inherited zircon core age groups at 1.8 and 2.5 Ga suggest that the protoliths of these rocks may have received sediments from the Yangtze or North China cratons. Mineral inclusions, depletion in HREE, and absence of negative Eu anomalies indicate that zircon U-Pb ages of 431 ± 5 Ma …

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Tectonics Of Quaternary Travertine Accumulation At Al-Fatha Area In Middle Iraq, Ibrahim S. Al- Jumaily, Nazar M.S. Numan

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Kinematic Behavior Of Southern Alaska Constrained By Westward Decreasing Postglacial Slip Rates On The Denali Fault, Alaska, A.-S. Mériaux, K. Sieh, R. C. Finkel, Charles M. Rubin, M. H. Taylor, A. J. Meltzner, F. J. Ryerson

All Faculty Scholarship for the College of the Sciences

Long‐term slip rates for the Denali Fault in southern Alaska are derived using ¹⁰Be cosmogenic radionuclide (CRN) dating of offset glacial moraines at two sites. Correction of ¹⁰Be CRN model ages for the effect of snow shielding uses historical, regional snow cover data scaled to the site altitudes. To integrate the time variation of snow cover, we included the relative changes in effective wetness over the last 11 ka, derived from lake‐level records and δ ¹⁸O variations from Alaskan lakes. The moraine CRN model ages are normally distributed around an average of 12.1 ± 1.0 ka (n …

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Basal Mechanics Of Ice Streams: Insights From The Stick-Slip Motion Of Whillans Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley, Robert A. Bindschadler, Matt A. King

All Faculty Scholarship for the College of the Sciences

The downstream portion of Whillans Ice Stream, West Antarctica, moves primarily by stick-slip motion. The observation of stick-slip motion suggests that the bed is governed by velocity-weakening physics and that the basal physics is more unstable than suggested by laboratory studies. The stick-slip cycle of Whillans Ice Plain exhibits substantial variability in both the duration of sticky periods and in slip magnitude. To understand this variability, we modeled the forces acting on the ice stream during the stick phase of the stick-slip cycle. The ocean tides introduce changes in the rate at which stress is applied to the ice plain. …

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Exhumation Of The Inyo Mountains, California: Implications For The Timing Of Extension Along The Western Boundary Of The Basin And Range Province And Distribution Of Dextral Fault Slip Rates Across The Eastern California Shear Zone, Jeffrey Lee, Daniel F. Stockli, Lewis A. Owen, Robert C. Finkel, Roman Kislitsyn

All Faculty Scholarship for the College of the Sciences

New geologic mapping, tectonic geomorphologic, ¹⁰Be terrestrial cosmogenic nuclide, and (U-Th)/He zircon and apatite thermochronometric data provide the first numerical constraints on late Cretaceous to late Quaternary exhumation of the Inyo Mountains and vertical slip and horizontal extension rates across the eastern Inyo fault zone, California. The east-dipping eastern Inyo fault zone bounds the eastern flank of the Inyo Mountains, a prominent geomorphic feature within the western Basin and Range Province and eastern California shear zone. (U-Th)/He zircon and apatite thermochronometry yield age patterns across the range that are interpreted as indicating: (1) two episodes of moderate to rapid …

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Arkosic Rocks From The San Andreas Fault Observatory At Depth (Safod)Borehole, Central California, S. D. Springer, J. P. Evans, J. I. Garver, D. Kirschner, Susanne U. Janecke

Susanne U. Janecke

http://lithosphere.geoscienceworld.org/content/1/4/206 The San Andreas Fault Observatory at Depth (SAFOD) drill hole encountered indurated, high-seismic-velocity arkosic sedimentary rocks west of the active trace of the San Andreas fault in central California. The arkosic rocks are juxtaposed against granitic rocks of the Salinian block to the southwest and against fine-grained Great Valley Group and Jurassic Franciscan rocks to the northeast. We identify three distinct lithologic units using cuttings, core petrography, electrical resistivity image logs, zircon fission-track analyses, and borehole-based geophysical logs. The upper arkose occurs from 1920 to 2530 m measured depth (mmd) in the borehole and is composed of five structural …

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Geodynamics Of Terrane Accretion Within Southern Alaska, Benjamin Patrick Hooks

Electronic Theses and Dissertations

The subduction and accretion of an exotic terrane at the southern margin of Alaska is driving uplift of the St. Elias and Alaska Ranges, and is responsible for some of the largest strain releases in history. Here are presented results from numerical models conditioned by geological observations that reproduce the tectonic landscape, deformation, and strain patterns at macro- (1000-km) and meso- (<100 >km) scales. These models utilize completely coupled thermal and mechanical solutions that account for the development of heterogeneities to both the thermal and rheological structure of the lithosphere. Perturbation to the thermal structure related to flattening of the …

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In Situ Element Quantification In The Hydrothermal Diamond Anvil Cell Using Synchrotron X-Ray Fluorescence With Applications Toward Subduction Zone Processes, Steven Joseph Maglio

UNLV Theses, Dissertations, Professional Papers, and Capstones

Yttrium is used in geochemical investigations of arc volcanics and metamorphic geothermometers. The ability to use Y as a geochemical tool is predicated on an understanding of the mobility of Y during fluid-saturated conditions attending metamorphic and igneous processes. The goal of this work was to use the hydrothermal diamond anvil cell (HDAC) and synchrotron radiation X-ray fluorescence to quantify, in situ, the concentration of Y in aqueous fluids at 2-5 GPa and 650 - 800 °C; conditions likely at the oceanic lithosphere - mantle wedge interface in subduction zones. Previous studies have used modified diamond anvils which limits their …

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Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer

Phillip G Resor

Slip heterogeneity reflects the fundamental physics of earthquake rupture and has been attributed to strong fault patches termed asperities or barriers. We propose that variations in fault-surface orientation due to slip-parallel corrugations may act as geometric asperities and barriers, generating variations in incremental (i.e. due to a single earthquake) slip across a fault surface. We evaluate this hypothesis using observations from the Arkitsa normal fault exposure in central Greece. A scan of the Arkitsa fault surface with 1-m spatial resolution and mm-scale precision reveals corrugations made up of 1–5 m wide synforms, antiforms, and nearly planar fault sections with long …

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Geology Faculty Publications and Presentations

Geology Faculty Publications

Collaborative Research: Erosional Forcing Of Late Quaternary Compressive Strain, West Central Taiwan, Phaedra Upton

University of Maine Office of Research Administration: Grant Reports

Moment Release Rate Of Cascadia Tremor Constrained By Gps, Ana C. Aguiar, Timothy I. Melbourne, Craig W. Scrivner

All Faculty Scholarship for the College of the Sciences

Analysis Of Deni̇zli̇ Earthquakes According To Their Activity And Cumulative Activity Terms, Mehmet Utku

Bulletin of the Mineral Research and Exploration

Paragneiss Zircon Geochronology And Trace Element Geochemistry, North Qaidam Hp/Uhp Terrane, Western China, Chris G. Mattinson, Joseph L. Wooden, Jian-Xin Zhang, D. K. Bird

All Faculty Scholarship for the College of the Sciences

Tectonics Of Quaternary Travertine Accumulation At Al-Fatha Area In Middle Iraq, Ibrahim S. Al- Jumaily, Nazar M.S. Numan

Bulletin of the Mineral Research and Exploration

Kinematic Behavior Of Southern Alaska Constrained By Westward Decreasing Postglacial Slip Rates On The Denali Fault, Alaska, A.-S. Mériaux, K. Sieh, R. C. Finkel, Charles M. Rubin, M. H. Taylor, A. J. Meltzner, F. J. Ryerson

All Faculty Scholarship for the College of the Sciences

Basal Mechanics Of Ice Streams: Insights From The Stick-Slip Motion Of Whillans Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley, Robert A. Bindschadler, Matt A. King

All Faculty Scholarship for the College of the Sciences

All Faculty Scholarship for the College of the Sciences

Arkosic Rocks From The San Andreas Fault Observatory At Depth (Safod)Borehole, Central California, S. D. Springer, J. P. Evans, J. I. Garver, D. Kirschner, Susanne U. Janecke

Susanne U. Janecke

Geodynamics Of Terrane Accretion Within Southern Alaska, Benjamin Patrick Hooks

Electronic Theses and Dissertations

In Situ Element Quantification In The Hydrothermal Diamond Anvil Cell Using Synchrotron X-Ray Fluorescence With Applications Toward Subduction Zone Processes, Steven Joseph Maglio

UNLV Theses, Dissertations, Professional Papers, and Capstones

Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer

Phillip G Resor