Geophysics and Seismology Commons^™

Using Mineral Magnetism To Characterize Compositions Of Fe-Ti Oxide Phases Of The Sulphur Creek Lava Flow (Kulshan), Elika Zilis

WWU Honors College Senior Projects

The aim of this study is to examine variations in the composition of Fe-Ti oxide minerals in the Sulphur Creek lava flow (SE margin of Kulshan), using magnetic techniques and electron microscopy. Geochemical and petrological data from these rocks dated ~9.8 ka may be a product of two distinct magma pulses (Garvey, 2002) with two distinct compositions: andesitic basalt and basalt. The composition of cubic oxides (magnetite and ulvöspinel) is influenced by the geochemistry of the crystallizing magma and can be used to provide information about the chemical evolution of these magmas, but also to help frame future paleomagnetic studies …

Silicon And Oxygen In Earth’S Core: Applications Of Machine Learning To Metal-Silicate Equilibria And Core Formation, Ruben Keane

WWU Honors College Senior Projects

Within Earth’s core, light elements (Si, O, C, S, N, H) are known to make up a small fraction of the total mass of the core with respect to heavy elements. The degree to which these elements exist in the cores of terrestrial planets have geophysical and geochemical implications, most notably the presence of core convection and a geodynamo, thermal conductivity within the core, and core temperature. Comparison of the composition of chondrites to Earth’s mantle composition and the Preliminary Reference Earth Model have given an estimation of about 10 % light elements in Earth’s core. The concentrations of each …

Populations Of Major Phases In Glacier Peak Lavas, Charlotte Wall

Geology Graduate and Undergraduate Student Scholarship

Volcanoes can be studied through minerals that are present in their eruption products. These minerals can be studied through optical microscopy and geochemistry to better understand their origins and provide insight into which processes took place prior to eruption (i.e., fractionation of crystals, assimilation of the surrounding crust, magma mixing). In this study I examine mineral populations in dacite (lava of intermediate composition) from Dahkobed/Glacier Peak volcano in the north Cascade Arc. The samples consist of a felsic (high SiO2) host component and a mafic (low SiO2) inclusion component. To establish base mineral populations, minerals from both the host and …

Paleomagnetism And Rotation History Of The Blue Mountains, Oregon, Usa, Bernard A. Housen

Geology Faculty Publications

An important element in reconstructions of the Cordilleran margin of North America includes longstanding debate regarding the timing and amount of rotation of the Blue Mountains in eastern Oregon, and the origin of geometric features such as the Columbia Embayment, which was a subject of some of Bill Dickinson’s early research. Suppositions of significant clockwise rotation of the Blue Mountains derived from Dickinson’s work were confirmed in the 1980s by paleomagnetic results from Late Jurassic–Early Cretaceous plutonic rocks, and secondary directions from Permian–Triassic units of the Wallowa–Seven Devils arc that indicate ~60° clockwise rotation of the Blue Mountains.

This study …

Surface Slip During Large Owens Valley Fault Earthquakes, Elizabeth K. Haddon, Colin B. Amos, O. Zielke, A. S. Jayko, R. Bürgmann

Geology Faculty Publications

The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross‐correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) …

Unblocking Temperatures Of Viscous Remanent Magnetism In Displaced Granitic Boulders, Icicle Creek Glacial Moraines (Washington, Usa), Juliet G. Crider, Danika M. Globokar, Russ F. Burmester, Bernard A. Housen

Geology Faculty Publications

Viscous remanent magnetization (VRM) may partially overprint original magnetization in rocks displaced by geomorphic events. An established theoretical relationship between the time and temperature of acquisition of VRM and the time and temperature of demagnetization suggests that laboratory demagnetization (unblocking) of VRM can be used to estimate the displacement age of rocks. We test this hypothesis at four nested glacial moraines in the Icicle Creek drainage of central Washington, the ages of which were previously determined by cosmogenic surface exposure dating. The moraines are composed primarily of granodiorite boulders, and magnetic remanence is carried dominantly by magnetite. Both the maximum …

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 …

Post-Caledonian Brittle Fault Zones On The Hyperextended Sw Barents Sea Margin: New Insights Into Onshore And Offshore Margin Architecture, Kjetil Indrevær, Steffen G. Bergh, Jean-Baptiste Koehl, John-Are Hansen, Elizabeth R. Schermer, Arild Ingebrigtsen

Geology Faculty Publications

Onshore-offshore correlation of brittle faults and tectonic lineaments has been undertaken along the SW Barents Sea margin off northern Norway. The study has focused on onshore mapping of fault zones, the mapping of offshore fault complexes and associated basins from seismic interpretation, and the linkage of fault complexes onshore and offshore by integrating a high-resolution DEM, covering both onshore and offshore portions of the study area, and processed magnetic anomaly data. This study shows that both onshore and offshore brittle faults manifest themselves mainly as alternating NNE–SSW- and ENE–WSW-trending, steeply to moderately dipping, normal fault zones constituting at least two …

Late Holocene Rupture History Of The Alpine Fault In South Westland, New Zealand, Kelvin Berryman, Alan Cooper, Richard Norris, Pilar Villamor, Rupert Sutherland, Trevor Wright, Elizabeth R. Schermer, Robert Langridge, Glenn Biasi

Geology Faculty Publications

Abstract Strata and fault relationships revealed in five trenches excavated across the recent trace of the Alpine fault at the Haast, Okuru, and Turnbull Rivers, South Westland, New Zealand, record the three most recent surface-faulting events. Using back-stripping techniques to remove the three faulting events and the sedimentary units associated with the faulting restores the cross-sections to gravel-bed floodplains at the Haast and Okuru Rivers, at about A.D. 750. Horizontal and vertical offsets of stream channels and terrace risers reveal characteristic displacements of about 8–9 m dextral and up to 1 m vertical per event. Cumulative dextral displacement is 25 …

Insights Into Rock-Ice Avalanche Dynamics By Combined Analysis Of Seismic Recordings And A Numerical Avalanche Mode, Demian Schneider, Perry Bartelt, Jacqueline Caplan-Auerbach, Marc Christen, Christian Huggel, Brian W. Mcardell

Geology Faculty Publications

Rock‐ice avalanches larger than 1 × 10⁶ m³ are high‐magnitude, low‐frequency events that may occur in all ice‐covered, high mountain areas around the world and can cause extensive damage if they reach populated regions. The temporal and spatial evolution of the seismic signature from two events was analyzed, and recordings at selected stations were compared to numerical model results of avalanche propagation. The first event is a rock‐ice avalanche from Iliamna volcano in Alaska which serves as a “natural laboratory” with simple geometric conditions. The second one originated on Aoraki/Mt. Cook, New Zealand Southern Alps, and is characterized …

Recent Extreme Avalanches: Triggered By Climate Change?, Christian Huggel, Jacqueline Caplan-Auerbach, Rick Wessels

Geology Faculty Publications

On 25 September 2008, seismo meters operated by the Alaska Volcano Observatory (AVO) registered strong ground shaking. On the basis of previous experience with such large seismic signals, AVO personnel were able to rapidly identify the seismic event as an avalanche. Two days later, an AVO overflight of Iliamna volcano, near Alaska's Cook Inlet, confirmed that a massive chunk of glacial ice and rock had broken free from its position on the upper flanks of the volcano, generating a massive avalanche that could have buried an entire town had it occurred in a more populated area.

Rapidly moving rock, ice, …

Geomorphic Constraints On Listric Thrust Faulting: Implications For Active Deformation In The Mackenzie Basin, South Island, New Zealand, Colin Amos, Douglas W. Burbank, David C. Nobes, Stuart A. L. Read

Geology Faculty Publications

Deformed fluvial terraces preserved over active thrust-related folds record the kinematics of folding as fault slip accumulates on the underlying thrust. In the Mackenzie Basin of southern New Zealand, the kinematics revealed by folded fluvial terraces along the active Ostler and Irishman Creek fault zones are inconsistent with traditional models for thrust-related folding in which spatially uniform rock uplift typically occurs over planar fault ramps. Instead, warped and tilted terraces in the Mackenzie are characterized by broad, continuous backlimbs and abrupt forelimbs and suggest folding through progressive limb rotation. By relating this pattern of surface deformation to the underlying thrust …

Earthquake Triggering At Alaskan Volcanoes Following The 3 November 2002 Denali Fault Earthquake, Seth C. Moran, John A. Power, Scott D. Stihler, John J. Sa´Nchez, Jacqueline Caplan-Auerbach

Geology Faculty Publications

The 3 November 2002 M_W 7.9 Denali fault earthquake provided an excellent opportunity to investigate triggered earthquakes at Alaskan volcanoes. The Alaska Volcano Observatory operates short-period seismic networks on 24 historically active volcanoes in Alaska, 247–2159 km distant from the mainshock epicenter. We searched for evidence of triggered seismicity by examining the unfiltered waveforms for all stations in each volcano network for ~1 hr after the M_W 7.9 arrival time at each network and for significant increases in located earthquakes in the hours after the mainshock. We found compelling evidence for triggering only at the Katmai volcanic cluster …

Seismic And Acoustic Signals Detected At Loihi Seamount By The Hawaii Undersea Geo-Observatory, Jacqueline Caplan-Auerbach, F. Duennebier

Geology Faculty Publications

The Hawai'i Undersea Geo-Observatory (HUGO) is an ocean bottom observatory located on the summit of Lo'ihi seamount, Hawai'i. An electro-optical cable connects the HUGO junction box to a shore station on the Big Island of Hawaii, thereby enabling the first real-time monitoring of a submarine volcano. HUGO was active for 3 months in 1998, collecting nearly continuous, real-time data on a high-rate hydrophone. Signals detected during that time include local as well as teleseismic earthquakes, T phases from Pacific-wide earthquakes, landslides on the submarine flank of Kilauea, and eruption sounds from the current Kilauea eruption. The data do not indicate …

Hydroacoustic Detection Of Submarine Landslides On Kilauea Volcano, Jacqueline Caplan-Auerbach, Christopher G. Fox, Frederick K. Duennebier

Geology Faculty Publications

Landslides produced at the site where lava flows into the ocean at Kilauea volcano have been detected hydroacoustically. Up to 10 landslides per day were detected by a hydrophone on the Hawaii Undersea Geo-Observatory (HUGO), located 50 km south of the entry site. The largest of these landslides, partly subaerial events known as bench collapses, were detected by a network of hydrophones in the eastern Pacific, 5000–7000 km away from the source. The landslides display a characteristic spectral signature easily recognizable among other signals such as earthquake T-phases and anthropogenic noises. The fact that signals are detected at great distances …

Seismicity And Velocity Structure Of Loihi Seamount From The 1996 Earthquake Swarm, Jacqueline Caplan-Auerbach, F. K. Duennebier

Geology Faculty Publications

The largest earthquake swarm yet recorded on Loihi submarine volcano took place in July and August of 1996. The swarm consisted of two phases of seismic activity and was associated with the formation of a pit crater and additional faulting of Loihi’s summit platform. The first phase of activity was comprised of predominantly high-frequency events scattered over the southern flanks of the volcano. Following a day of seismic quiescence, the second phase of activity began, consisting of lower-frequency earthquakes with strong T-phases. The phase 2 events took place beneath Loihi’s summit, presumably marking the formation of the pit crater, Pele’s …