Physical Sciences and Mathematics | Open Access Articles

Holocene Earthquakes And Right-Lateral Slip On The Left-Lateral Darrington-Devils Mountain Fault Zone, Northern Puget Sound, Washington, Stephen F. Personius, Richard W. Briggs, Alan R. Nelson, Elizabeth R. Schermer, J. Zebulon Maharrey, Brian L. Sherrod, Sarah A. Spaulding, Lee-Ann Bradley

Geology Faculty Publications

Sources of seismic hazard in the Puget Sound region of northwestern Washington include deep earthquakes associated with the Cascadia subduction zone, and shallow earthquakes associated with some of the numerous crustal (upper-plate) faults that crisscross the region. Our paleoseismic investigations on one of the more prominent crustal faults, the Darrington–Devils Mountain fault zone, included trenching of fault scarps developed on latest Pleistocene glacial sediments and analysis of cores from an adjacent wetland near Lake Creek, 14 km southeast of Mount Vernon, Washington. Trench excavations revealed evidence of a single earthquake, radiocarbon dated to ca. 2 ka, but extensive burrowing and …

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Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu

Geology Faculty Publications

Reconstruction of the Hirnantian (Late Ordovician) palaeotopography in South China is important for understanding the distribution pattern of the Hirnantian marine depositional environment. In this study, we reconstructed the Hirnantian palaeotopography in the Upper Yangtze region based on the rankings of the palaeo-water depths, which were inferred according to the lithofacies and biofacies characteristics of the sections. Data from 374 Hirnantian sections were collected and standardized through the online Geobiodiversity Database. The Ordinary Kriging interpolation method in the ArcGIS software was applied to create the continuous surface of the palaeo-water depths, i.e. the Hirnantian palaeotopography. Meanwhile, the line transect analysis …

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Hydroacoustic Investigations Of Submarine Landslides At West Mata Volcano, Lau Basin, Jacqueline Caplan-Auerbach, R. P. Dziak, D. R. Bohnenstiehl, W. W. Chadwick, T. -K. Lau

Geology Faculty Publications

Submarine landslides are an important process in volcano growth yet are rarely observed and poorly understood. We show that landslides occur frequently in association with the eruption of West Mata volcano in the NE Lau Basin. These events are identifiable in hydroacoustic data recorded between ~5 and 20 km from the volcano and may be recognized in spectrograms by the weak and strong powers at specific frequencies generated by multipathing of sound waves. The summation of direct and surface-reflected arrivals causes interference patterns in the spectrum that change with time as the landslide propagates. Observed frequencies are consistent with propagation …

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Multiple Migmatite Events And Cooling From Granulite Facies Metamorphism Within The Famatina Arc Margin Of Northwest Argentina, Sean R. Mulcahy, Sarah M. Roeske, William C. Mcclelland, Joshua R. Ellis, Fred Jourdan, Paul R. Renne, Jeffrey D. Vervoort, Graciela I. Vujovich

Geology Faculty Publications

The Famatina margin records an orogenic cycle of convergence, metamorphism, magmatism, and extension related to the accretion of the allochthonous Precordillera terrane. New structural, petrologic, and geochronologic data from the Loma de Las Chacras region demonstrate two distinct episodes of lower crustal migmatization. The first event preserves a counterclockwise pressure-temperature path in kyanite-K-feldspar pelitic migmatites that resulted in lower crustal migmatization via muscovite dehydration melting at ∼12 kbar and 868°C at 461 ±1.7 Ma. The shape of the pressure temperature path and timing of metamorphism are similar to those of regional midcrustal granulites and suggest pervasive Ordovician migmatization throughout the …

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Crustal Shortening, Exhumation, And Strain Localization In A Collisonal Orogen: The Bajo Pequeno Shear Zone, Sierra De Pie De Palo, Argentina, Joshua M. Garber, Sarah M. Roeske, Jessica Warren, Sean R. Mulcahy, William C. Mcclelland, Lauren J. Austin, Paul R. Renne, Graciela I. Vujovich

Geology Faculty Publications

The Bajo Pequeño Shear Zone (BPSZ) is a lower-crustal shear zone that records shortening and exhumation associated with the establishment of a new plate boundary, and its placement in a regional structural context suggests that local- to regional-scale strain localization occurred with progressive deformation. A kilometer-scale field and analytical cross section through the ~80 m thick BPSZ and its adjacent rocks indicates an early Devonian (405–400 Ma) phase of deformation on the western margin of Gondwanan continental crust. The earliest stages of the BPSZ, recorded by metamorphic and microstructural data, involved thrusting of a hotter orthogneiss over a relatively cool …

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Izu-Bonin-Mariana Rear Arc: The Missing Half Of The Subduction Factory, Yoshihiko Tamura, Abigail K. Barker, Cathy J. Busby, Julien L.R. Berger, Peter Blum, Everton M. Bongiolo, Gilles Guèrin, Manuela Bordiga, Graham D.M. Andrews, Susan M. Debari, James B. Gill, Cedric Hamelin, Jihui Jia, Eleanor H. John, Ann-Sophie Jonas, Martin Jutzeler, Myriam A.C. Kars, Zachary A. Kita, Kevin Konrad, Susan H. Mahony, Michelangelo Martini, Takashi Miyazaki, Robert J. Musgrave, Debora B. Nascimento, Alexander R.L. Nichols, Julia M. Ribeiro, Tomoki Sato, Julie C. Schindlbeck, Axel K. Schmitt, Susanne M. Straub, Maryline J. Vautravers, Yang Yang

Geology Faculty Publications

4GT) lies in the western part of the Izu fore-arc basin, ~60 km east of the arc-front volcano Aogashima, ~170 km west of the axis of the Izu-Bonin Trench, 1.5 km west of Ocean Drilling Program (ODP) Site 792, and at 1776 meters below sea level (mbsl). It was drilled as a 150 m deep geotechnical test hole for potential future deep drilling (5500 meters below seafloor [mbsf]) at proposed Site IBM-4 using the D/V Chikyu. Core from Site U1436 yielded a rich record of Late Pleistocene explosive volcanism, including distinctive black glassy mafic ash layers that may record large-volume …

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Full-Text Articles in Physical Sciences and Mathematics

Holocene Earthquakes And Right-Lateral Slip On The Left-Lateral Darrington-Devils Mountain Fault Zone, Northern Puget Sound, Washington, Stephen F. Personius, Richard W. Briggs, Alan R. Nelson, Elizabeth R. Schermer, J. Zebulon Maharrey, Brian L. Sherrod, Sarah A. Spaulding, Lee-Ann Bradley

Geology Faculty Publications

Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu

Geology Faculty Publications

Hydroacoustic Investigations Of Submarine Landslides At West Mata Volcano, Lau Basin, Jacqueline Caplan-Auerbach, R. P. Dziak, D. R. Bohnenstiehl, W. W. Chadwick, T. -K. Lau

Geology Faculty Publications

Multiple Migmatite Events And Cooling From Granulite Facies Metamorphism Within The Famatina Arc Margin Of Northwest Argentina, Sean R. Mulcahy, Sarah M. Roeske, William C. Mcclelland, Joshua R. Ellis, Fred Jourdan, Paul R. Renne, Jeffrey D. Vervoort, Graciela I. Vujovich

Geology Faculty Publications

Crustal Shortening, Exhumation, And Strain Localization In A Collisonal Orogen: The Bajo Pequeno Shear Zone, Sierra De Pie De Palo, Argentina, Joshua M. Garber, Sarah M. Roeske, Jessica Warren, Sean R. Mulcahy, William C. Mcclelland, Lauren J. Austin, Paul R. Renne, Graciela I. Vujovich

Geology Faculty Publications

Geology Faculty Publications