Geophysics and Seismology Commons^™

Three-Dimensional Stochastic Estimation Of Porosity Distribution: Benefits Of Using Ground-Penetrating Radar Velocity Tomograms In Simulated-Annealing-Based Or Bayesian Sequential Simulation Approaches, Baptiste Dafflon, Warren Barrash

CGISS Publications and Presentations

Estimation of the three-dimensional (3-D) distribution of hydrologic properties and related uncertainty is a key for improved predictions of hydrologic processes in the subsurface. However it is difficult to gain high-quality and high-density hydrologic information from the subsurface. In this regard a promising strategy is to use high-resolution geophysical data (that are relatively sensitive to variations of a hydrologic parameter of interest) to supplement direct hydrologic information from measurements in wells (e.g., logs, vertical profiles) and then generate stochastic simulations of the distribution of the hydrologic property conditioned on the hydrologic and geophysical data. In this study we develop and …

Monitoring Glacier Surface Seismicity In Time And Space Using Rayleigh Waves, T. D. Mikesell, Kasper Van Wijk, Matthew M. Haney, John H. Bradford, Hans-Peter Marshall, Joel T. Harper

CGISS Publications and Presentations

Sliding glaciers and brittle ice failure generate seismic body and surface wave energy characteristic to the source mechanism. Here we analyze continuous seismic recordings from an array of nine short-period passive seismometers located on Bench Glacier, Alaska (USA) (61.033°N, 145.687°W). We focus on the arrival-time and amplitude information of the dominant Rayleigh wave phase. Over a 46-hour period we detect thousands of events using a cross-correlation based event identification method. Travel-time inversion of a subset of events (7% of the total) defines an active crevasse, propagating more than 200 meters in three hours. From the Rayleigh wave amplitudes, we estimate …

Seismic Detection Of A Low-Velocity Layer Atop The 410-Km Discontinuity: Verification Of An Electromagnetically Detected Layer Of Partial-Melt Atop The 410-Km Discontinuity Beneath Se Arizona, Dwight W. Townsend

Physics

No abstract provided.

Structure And Rheology Of The Sandhill Corner Shear Zone, Norumbega Fault System, Maine: A Study Of A Fault From The Base Of The Seismogenic Zone, Nancy Ann Price

Electronic Theses and Dissertations

Determining the structure and rheology of a seismogenic fault at frictional-to-viscous transition (FVT) depths is vital for understanding its strength and behavior. Few studies describe a fault from within this depth level, so the architecture of a shear zone at these depths as well as the effect of transient coseismic and postseismic deformation on the rheology of the shear zone is poorly-understood. The Sandhill Corner strand of the Paleozoic Norumbega fault system of Maine is the one of the few known examples of a subvertical, strike-slip fault exhumed from FVT depths. Using a suite of samples collected from the Sandhill …

Subsurface Characterization Using Head-Wave Artifacts In Seismic Interferometry, Thomas Dylan Mikesell

Boise State University Theses and Dissertations

Seismologists continually work to improve images of the Earth's interior. One new approach is seismic interferometry, which involves cross-correlating the seismic wave field recorded at two receivers to generate data as if one of the receivers was a source. Over the past decade, seismic interferometry has become an established technique to estimate the surface-wave part of the impulse response between two receivers; however, practical limitations in the source-energy distribution have made body-wave recovery difficult and causes spurious energy in the estimated impulse response. Rather than suppress such spurious energy, it can be useful to analyze coherent spurious events to help …

Non-Destructively Mapping The In-Situ Hydrologic Properties Of Snow, Firn, And Glacial Ice With Georadar, Joel Matthew Brown

Boise State University Theses and Dissertations

Ground penetrating radar (GPR) is a useful tool for studying the in-situ properties of glacial ice, firn, and snowpacks. The main focus of this dissertation is improving and expanding methods employed when collecting, processing, and understanding GPR data collected in the Cryosphere, or the snow and ice covered areas of the earth. The data used herein were collected on the Greenland Ice Sheet (GrIS) and on seasonal snowpacks of Western Montana, USA. This document has three sub-topics.

The first sub-topic is comparing the spatial variability of GPR data to the spatial variability of core data collected in two locations within …

A Field Proof-Of-Concept Of Aquifer Imaging Using 3-D Transient Hydraulic Tomography With Modular, Temporarily-Emplaced Equipment, Michael Cardiff, Warren Barrash, Peter K. Kitanidis

CGISS Publications and Presentations

Hydraulic tomography is a field scale aquifer characterization method capable of estimating 3-D heterogeneous parameter distributions, and is directly sensitive to hydraulic conductivity (K), thus providing a useful data source for improving flow and transport models. We present results from a proof-of-concept field and modeling study in which we apply 3-D transient hydraulic tomography (3DTHT) to the relatively high-K and moderately heterogeneous unconfined aquifer at the Boise Hydrogeophysical Research Site. Short-duration (20 min) partially penetrating pumping tests, for which observed responses do not reach steady state, are used as the aquifer stimulation. To collect field data, we utilize a system …

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 …

Reservoir Potential Of Sands Formed In Glaciomarine Environments: An Analog Study Based On Cenozoic Examples From Mcmurdo Sound, Antarctica, Christopher R. Fielding, Brian A. Blackstone, Tracy D. Frank, Zi Gui

Department of Earth and Atmospheric Sciences: Faculty Publications

This paper provides documentation of unexpectedly high-reservoir-quality glaciomarine sands found in the Cenozoic succession beneath McMurdo Sound, Antarctica, as an analogue study for evaluations of hydrocarbon prospectivity in basins elsewhere. The Oligocene to Lower Miocene succession of the Victoria Land Basin, an extant portion of the West Antarctic Rift System, comprises diamictites, mudrocks, and sandstones with minor conglomerates. These lithologies are arranged in repetitive stacking patterns (cycles), interpreted to record repeated advance and retreat of glaciers into and out of the basin, with attendant eustatic and isostatic effects. Phases of ice retreat within the cycles comprise an array of mudrocks, …

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 …

The Pkp Caustic At The Trinity College Seismograph Station (Tcct) From The Sumbawa-Indonesia Earthquake On November 8th, 2009, Daniel Echavarria

Senior Theses and Projects

On November 8^th, 2009 the Trinity College Seismograph Station (TCCT) recorded an earthquake of magnitude Mw = 6.7 with body wave amplitudes that were larger than expected. This earthquake, located in Sumbawa-Indonesia, generated similar body wave amplitudes as earthquakes of the same magnitude (Mw = 6.7) and comparable depth (shallow focus: 0th, 2010 and the Alaska earthquake on July 18^th, 2010. The large body wave amplitudes were caused by a set of consecutive PKP waves that constructively interfered. The distance from the Sumbawa-Indonesia earthquake to TCCT of 144.96° falls between the lower and higher estimates for …

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 …

Hillslope Asymmetry Maps Reveal Widespread, Multi-Scale Organization, Michael J. Poulos, Jennifer L. Pierce, Alejandro N. Flores, Shawn G. Benner

Geosciences Faculty Publications and Presentations

Hillslope asymmetry is the condition in which oppositely-facing hillslopes within an area have differing average slope angles, and indicates aspect-related variability in hillslope evolution. As such, the presence, orientation and magnitude of asymmetry may be a useful diagnostic for understanding process dominance. We present a new method for quantifying and mapping the spatial distribution of hillslope asymmetry across large areas. Resulting maps for the American Cordillera of the Western Hemisphere and the western United States reveal that hillslope asymmetry is widespread, with distinct trends at continental to drainage scales. Spatial patterns of asymmetry correlate with latitude along the American Cordillera, …

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

Mean Atlantic Meridional Overturning Circulation Across 26.5° N From Eddy-Resolving Simulations Compared To Observations, Xiaobiao Xu, William J. Schmitz Jr., Harley E. Hurlburt, Patrick J. Hogan

Faculty Publications

Observations along 26.5 degrees N are used to examine the time mean structure of the Atlantic meridional overturning circulation (AMOC) in eddy-resolving simulations with the Hybrid Coordinate Ocean Model (HYCOM). The model results yield a 5 year mean AMOC transport of 18.2 Sv, compared to 18.4 Sv based on data. The modeled northward limb of the AMOC has a vertical structure similar to observations. The southward limb is shallower than observed but deeper than other ocean general circulation models and includes a secondary transport maximum near 4000 m corresponding to Nordic Seas Overflow Water. The modeled flow through the Florida …

Studies Of Aftershock Sequences Of Large Subduction Zone Earthquakes, Armick Ivanian

Electronic Thesis and Dissertation Repository

Amongst the different types of earthquakes, it is observed that the mega-thrust earthquakes, which occur in subduction zones, are the most devastating. The aftershock sequences following the mega-thrust earthquakes can also increase the level of seismic hazard, even in remote areas away from the mainshock fault zone. This thesis examines the statistical parameters of aftershock sequences of large subduction zone earthquakes that have occurred in the western and eastern Pacific Ocean. These parameters are vital for seismic hazard assessment of regions located near subduction zones. The results show that, on average, the Gutenberg-Richter exponent—the b-value—is markedly higher in the …

Scaling Relationships Of Source Parameters For Slow Slip Events, Haiying Gao, David A. Schmidt, Ray J. Weldon Ii

Haiying Gao

To better understand the physical mechanisms of slow slip events (SSEs) detected worldwide, we explore the scaling relationships of various source parameters and compare them with similar scaling laws for earthquakes. These scaling relationships highlight differences and similarities between slow slip events and earthquakes and hold implications for the degree of heterogeneity and fault-healing characteristics. That static drop remains constant for different-sized events as is observed for earthquakes. However, the static stress drop of slow slop events is within a range of 0.01-1.0 MPa, 1-2 orders of magnitiude lower than that found for earthquakes, which could be related to the …

Georadar-Derived Estimates Of Firn Density In The Percolation Zone, Western Greenland Ice Sheet, Joel Brown, John Bradford, Joel Harper, W. Tad Pfeffer, Neil Humphrey, Ellen Mosley-Thompson

CGISS Publications and Presentations

Greater understanding of variations in firn densification is needed to distinguish between dynamic and melt-driven elevation changes on the Greenland ice sheet. This is especially true in Greenland’s percolation zone, where firn density profiles are poorly documented because few ice cores are extracted in regions with surface melt. We used georadar to investigate firn density variations with depth along a ~70 km transect through a portion of the accumulation area in western Greenland that partially melts. We estimated electromagnetic wave velocity by inverting reflection traveltimes picked from common midpoint gathers. We followed a procedure designed to find the simplest velocity …

Relationships Between Earthquake Ground Motions And Modified Mercalli Intensity, Andrea Sweny

Electronic Thesis and Dissertation Repository

With widespread Internet use, web-based earthquake reports are a valuable source of felt intensitydata with broad geographical coverage. Paired with ground motion data, Internet surveys like theUSGS Did You Feel It? (DYFI) website can be used to derive relationships between ground motionparameters and Modified Mercalli Intensity (MMI). These are particularly important for regionswith sparse seismographic coverage where the quality and density of intensity data may be superiorto ground motion data. MMI-ground motion relationships are also needed to infer ground motionsof historical earthquakes.

Using well-documented earthquakes in across North America, we analyze correlations betweenfelt intensity and ground motions, including peak ground …

Geophysical And Geological Analysis Of The Collingwood Member Of The Trenton Formation, Ryan M. Banas

Dissertations, Master's Theses and Master's Reports - Open

The Collingwood Member is a mid to late Ordovician self-sourced reservoir deposited across the northern Michigan Basin and parts of Ontario, Canada. Although it had been previously studied in Canada, there has been relatively little data available from the Michigan subsurface. Recent commercial interest in the Collingwood has resulted in the drilling and production of several wells in the state of Michigan.

An analysis of core samples, measured laboratory data, and petrophysical logs has yielded both a quantitative and qualitative understanding of the formation in the Michigan Basin. The Collingwood is a low permeability and low porosity carbonate package that …