Geophysics and Seismology Commons^™

Mapping Thunder Sources By Inverting Acoustic And Electromagnetic Observations, J. F. Anderson, J. B. Johnson, R. O. Arechiga, R. J. Thomas

Geosciences Faculty Publications and Presentations

We present a new method of locating current flow in lightning strikes by inversion of thunder recordings constrained by Lightning Mapping Array observations. First, radio frequency (RF) pulses are connected to reconstruct conductive channels created by leaders. Then, acoustic signals that would be produced by current flow through each channel are forward modeled. The recorded thunder is considered to consist of a weighted superposition of these acoustic signals. We calculate the posterior distribution of acoustic source energy for each channel with a Markov Chain Monte Carlo inversion that fits power envelopes of modeled and recorded thunder; these results show which …

Analyst A: Alternatives In Analysis Of The Utexas1 Surface Wave Dataset, Paul Michaels

Paul Michaels

In February of 2011 an earthquake event caused significant damage and loss of life in Christchurch, New Zealand. Such an event serves as motivation for improved foundation design and characterization of the shallow subsurface. In January of 2013, University of Texas engineers acquired surface wave data which has been made available to the ASCE GeoInstitute Geophysical Engineering Committee for a benchmark project. Participants were invited to process and interpret the common data set. This paper reports the results designated as those of "Analyst A". The active vibroseis and sledgehammer data were combined to produce a composite Rayleigh wave dispersion curve. …

Earthquake And Tsunami Forecasts: Relation Of Slow Slip Events To Subsequent Earthquake Rupture, Timothy H. Dixon, Yan Jiang, Rocco Malservisi, Robert Mccaffrey, Nicholas Voss, Marino Protti, Victor Gonzalez

Geology Faculty Publications and Presentations

The 5 September 2012 Mw 7.6 earthquake on the Costa Rica subduction plate boundary followed a 62-y interseismic period. High-precision GPS recorded numerous slow slip events (SSEs) in the decade leading up to the earthquake, both up-dip and down-dip of seismic rupture. Deeper SSEs were larger than shallower ones and, if characteristic of the interseismic period, release most locking down-dip of the earthquake, limiting down-dip rupture and earthquake magnitude. Shallower SSEs were smaller, accounting for some but not all interseismic locking. One SSE occurred several months before the earthquake, but changes in Mohr–Coulomb failure stress were probably too small to …

The Assessment Of Geothermal Potential Of Turkey By Means Of Heat Flow Estimation, Uğur Akin, Emin U. Ulugergerli̇, Semih Kutlu

Bulletin of the Mineral Research and Exploration

In this study, the heat flow distribution of Turkey was investigated in the interest of exploring new geothermal fields in addition to known ones. For this purposes, the geothermal gradient was estimated from the Curie point depth map obtained from airborne magnetic data by means of power spectrum method. By multiplying geothermal gradient with thermal conductivity values, the heat flow map of Turkey was obtained. The average value in the heat flow map of Turkey was determined as 74 mW/m². It points out existence of resources of geothermal energy larger than the average of the world resources. in …

Quantifying The Basal Conditions Of A Mountain Glacier Using A Targeted Full-Waveform Inversion: Bench Glacier, Alaska, Usa, E. Babcock, J. Bradford

John H. Bradford

Glacier dynamics are inextricably linked to the basal conditions of glaciers. Seismic reflection methods can image the glacier bed under certain conditions. However, where a seismically thin layer of material is present at the bed, traditional analyses may fail to fully characterize bed properties. We use a targeted full-waveform inversion algorithm to quantify the basal-layer parameters of a mountain glacier: thickness (d), P-wave velocity (α) and density (ρ). We simultaneously invert for the seismic quality factor (Q) of the bulk glacier ice. The inversion seeks to minimize the difference between the data and a one-dimensional reflectivity algorithm using a gradient-based …

Development And Application Of Tools For Avalanche Forecasting, Avalanche Detection, And Snowpack Characterization, Scott Christopher Havens

Boise State University Theses and Dissertations

Avalanche formation is a complex interaction between the snowpack, weather, and terrain. However, detailed observations typically can only be made at a single point and must be extrapolated over the slope or regional scale. This study aims to provide avalanche forecasters with tools to evaluate the snowpack, avalanche hazard, and avalanche occurrence when manual observations are not feasible.

Avalanches that occur within the new storm snow are a prevalent problem for the avalanche forecasters with the Idaho Transportation Department (ITD) along Highway 21. We have implemented a real time SNOw Slope Stability (SNOSS) model that provides an index to the …

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 …

Refraction Microtremor Analysis Of Areas Surrounding California State University San Bernardino, Malcolm D. Thomas

Electronic Theses, Projects, and Dissertations

The San Andreas Fault stretches for over 800 miles through California. Along the foothills of the San Bernardino Mountains, areas in close proximity to the San Andreas Fault Zone may be subject to site amplification of ground motion caused by seismic activity via wave propagation through the subsurface. These seismic hazards are being addressed via the Alquist-Priolo Earthquake Faulting Zone Act and the National Earthquake Hazards Reduction Program (NEHRP). Shear wave velocity of the subsurface has served as a proxy for ground motion amplification and is therefore a useful parameter to help analyze and reduce seismic hazards. Low shear wave …

Urban Seismology For Groundwater Characterization In A Developing Country: Challenges And Rewards, John H. Bradford, Kyle Lindsay, Steve Silliman, Nicaise Yalo, Moussa Boukari

Geosciences Faculty Publications and Presentations

The coastal city of Cotonou in the developing country of Bénin, West Africa, is a large population center that is facing a serious threat to the sustainability of its freshwater supply. The city relies on the Godomey aquifer for domestic water, but the aquifer is undergoing saltwater intrusion. This problem is likely to worsen without significant steps to improve management of the water supply. Aquifer continuity and saltwater flow paths are poorly understood, but that information is critical to ensure sustainable access to freshwater in this growing urban center. In January 2012, a two-year geophysical investigation was begun with the …

Quantifying The Basal Conditions Of A Mountain Glacier Using A Targeted Full-Waveform Inversion: Bench Glacier, Alaska, Usa, E. Babcock, J. Bradford

Geosciences Faculty Publications and Presentations

Glacier dynamics are inextricably linked to the basal conditions of glaciers. Seismic reflection methods can image the glacier bed under certain conditions. However, where a seismically thin layer of material is present at the bed, traditional analyses may fail to fully characterize bed properties. We use a targeted full-waveform inversion algorithm to quantify the basal-layer parameters of a mountain glacier: thickness (d), P-wave velocity (α) and density (ρ). We simultaneously invert for the seismic quality factor (Q) of the bulk glacier ice. The inversion seeks to minimize the difference between the data …

Turbidity-Based Sediment Monitoring In Northern Thailand: Hysteresis, Variability, And Uncertainty, Shawn G. Benner, Spencer H. Wood

Geosciences Faculty Publications and Presentations

Annual total suspended solid (TSS) loads in the Mae Sa River in northern Thailand, determined with an automated, turbidity-based monitoring approach, were approximately 62,000, 33,000, and 14,000 Mg during the three years of observation. These loads were equivalent to basin yields of 839 (603-1170), 445 (217-462), and 192 (108-222) Mg km^-2 for the 74.16-km² catchment during 2006, 2007, and 2008, respectively. The yearly uncertainty ranges indicate our loads may be underestimated by 38-43% or overestimated by 28-33%. In determining the annual loads, discharge (Q) and turbidity (T) values were compared against 333 hand-sampled total suspended solid concentrations (TSS) …

Warm Water Benthic Foraminifera Document The Pennsylvanian-Permian Warming And Cooling Events – The Record From The Western Pangea Tropical Shelves, Vladimir Davydov

Geosciences Faculty Publications and Presentations

Shallow warm water benthic foraminifera (SWWBF), including all larger fusulinids (symbiont-bearing benthic foraminifera), are among the best indicators of paleoclimate and paleogeography in the Carboniferous and Permian. The distribution of benthic foraminifera in space and time constrain important tectonic, paleogeographic and climatic events at a global scale. The North American shelves during Pennsylvanian and Permian time - though geographically within the tropical belt - are characterized by temperate environments with significantly lower foraminifera diversification and rare occurrences of warm water Tethyan forms, that are in general appear in the region as a migration entities. Such environments allow documentation of warming …

From ~1.5 Ma To Today: Insights Into The Southern San Andreas Fault System From 3d Mechanical Models, Laura Fattaruso

Masters Theses

Three-dimensional mechanical simulations of the San Andreas fault (SAF) within the Coachella Valley in California produce deformation that match geologic observations and demonstrate the impact of fault geometry on uplift patterns. Most models that include the Coachella Valley segment of the SAF have assumed a vertical orientation, but recent studies suggest that this segment dips 60-70° northeast. We compare models with varied fault geometry and evaluate how well they reproduce observed uplift patterns. Our model with a dipping SAF matches geologic observations, while models containing a vertical fault do not. This suggests that the active Coachella Valley segment of the …

Comparing Near-Regional And Local Measurements Of Infrasound From Mount Erebus, Antarctica: Implications For Monitoring, A. L. Dabrowa, D. N. Green, J. B. Johnson, J. C. Phillips, A. C. Rust

Geosciences Faculty Publications and Presentations

Local (100s of meters from vent) monitoring of volcanic infrasound is a common tool at volcanoes characterized by frequent low-magnitude eruptions, but it is generally not safe or practical to have sensors so close to the vent during more intense eruptions. To investigate the potential and limitations of monitoring at near-regional ranges (10s of km) we studied infrasound detection and propagation at Mount Erebus, Antarctica. This site has both a good local monitoring network and an additional International Monitoring System infrasound array, IS55, located 25 km away. We compared data recorded at IS55 with a set of 117 known Strombolian …

Introduction To An Open Community Infrasound Dataset From The Actively Erupting Sakurajima Volcano, Japan, David Fee, Akihiko Yokoo, Jeffrey B. Johnson

Geosciences Faculty Publications and Presentations

Active volcanoes are significant sources of seismic and acoustic radiation. Extensive work has shown that infrasound is an effective tool to study and monitor active volcanoes. Infrasound is now a regular tool utilized by volcano observatories to aid in volcano monitoring and hazard mitigation. Infrasound‐based studies are able to provide important information on eruption dynamics and to develop quantitative models of volcanic eruptions. In addition, volcanoes provide excellent acoustic sources for atmospheric propagation studies and can be used to infer atmospheric dynamics and structure (see Johnson and Ripepe, 2011; Fee and Matoza, 2013 for recent reviews on volcano infrasound). The …

Large-Scale Mechanical Buckle Fold Development And The Initiation Of Tensile Fractures, Andreas Eckert, Peter Connolly, Xiaolong Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Tensile failure associated with buckle folding is commonly associated to the distribution of outer arc extension but has also been observed on fold limbs. This study investigates whether tensile stresses and associated failure can be explained by the process of buckling under realistic in situ stress conditions. A 2-D plane strain finite element modeling approach is used to study single-layer buckle folds with a Maxwell viscoelastic rheology. A variety of material parameters are considered and their influence on the initiation of tensile stresses during the various stages of deformation is analyzed. It is concluded that the buckling process determines the …

Application Of The Monopole Source To Quantify Explosive Flux During Vulcanian Explosions At Sakurajima Volcano (Japan), Jeffrey B. Johnson, Alex J. C. Miller

Geosciences Faculty Publications and Presentations

A primary goal in volcano seismology is to characterize source motions internal to a volcano in terms of their representative forces. In a similar manner, much volcano infrasound research strives to recover eruptive force time histories corresponding to material accelerations occurring at Earth’s free surface. These motions may correspond to explosive emission of gas and pyroclasts (e.g., Banister, 1984), rapid ground distensions of a volcanic dome (e.g., Johnson and Lees, 2010), and/or gravity driven rock fall or pyroclastic flows (e.g., Yamasato, 1997). When free surface motion is unsteady it imposes stresses upon the surrounding atmosphere, which are propagated as acoustic …

Eocene-Oligocene Latitudinal Climate Gradients In North America Inferred From Stable Isotope Ratios In Perissodactyl Tooth Enamel, Alessandro Zanazzi, Emily Judd, Andrew Fletcher, Harold Bryant, Matthew J. Kohn

Geosciences Faculty Publications and Presentations

The Eocene-Oligocene transition (~ 34 Ma) was one of the most pronounced episodes of climate change of the Cenozoic. In order to investigate this episode of global climate cooling in North America, we analyzed the carbon and oxygen stable isotope composition of the carbonate component of 19 perissodactyl (horse and rhino) tooth enamel samples from the Eocene-Oligocene rocks of the Cypress Hills Formation (southwestern Saskatchewan, Canada); we then compared the results with previously published data from the US Great Plains (Nebraska, South Dakota, and Wyoming).

Average (± 1σ) perissodactyl enamel δ¹³C values (vs. V-PDB) in the Eocene (-8.8 …

Explosive Dome Eruptions Modulated By Periodic Gas-Driven Inflation, Jeffrey B. Johnson, J. J. Lyons, B. J. Andrews, J. M. Lees

Geosciences Faculty Publications and Presentations

Volcan Santiaguito (Guatemala) “breathes” with extraordinary regularity as the edifice's conduit system accumulates free gas, which periodically vents to the atmosphere. Periodic pressurization controls explosion timing, which nearly always occurs at peak inflation, as detected with tiltmeters. Tilt cycles in January 2012 reveal regular 26 ± 6 min inflation/deflation cycles corresponding to at least ~10¹ kg/s of gas fluxing the system. Very long period (VLP) earthquakes presage explosions and occur during cycles when inflation rates are most rapid. VLPs locate ~300 m below the vent and indicate mobilization of volatiles, which ascend at ~50 m/s. Rapid gas ascent feeds …

Seismicity Processes In The Charlevoix Seismic Zone, Eastern Canada, Azadeh Fereidoni

Electronic Thesis and Dissertation Repository

The Charlevoix Seismic Zone (CSZ) is the most seismically active region in eastern Canada, based on the historical and current rate of activity. Several papers contend that the current seismicity in the CSZ represents long-lived aftershock sequences of the 1663 M~7 earthquake, in which the aftershock activity has persisted for hundreds of years. The aim of this thesis is to explore the influence of the 1663 earthquake on the current seismicity in the CSZ. The first part of the thesis has focused on developing a comprehensive earthquake database required for analysis of seismicity. The second part of the thesis has …

Interseismic Locking On The Hikurangi Subduction Zone: Uncertainties From Slow-Slip Events, Robert Mccaffrey

Geology Faculty Publications and Presentations

lnterseismic locking on the Hikurangi subduction zone in New Zealand is examined in light of alternative assumed locking distributions and the impact of transients (slow-slip and volcanic sources) on temporal and spatial resolution. The modern pattern of locking in the north is poorly resolved and, based on simulations of possible transient behavior, may be an ephemeral feature of the subduction cycle. While there appears to be some contemporary locking in the northern half of the Hikurangi subduction zone (HSZ), its location is model dependent, and hence, its relationship to structure, slow-slip, or any transition zone there is unclear. Simulations of …

Geogram 2014, David J. Keeling Editor, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.

Particle Swarms In Confining Geometries, Eric Robert Boomsma

Open Access Dissertations

The transport of micro- and nano-particles in subsurface fluid deposits is an area of increasing interest due to the rising use of these particles for consumer and industrial purposes. Subsurface particle transport is complicated by the presence of fractures and fracture networks which govern the paths that particles will be able to take. In this thesis, subsurface particle transport will be investigated using particle swarms; collections of hydro-dynamically interacting particles which exhibit group behavior. The effects of fluid viscosity, particle properties, fracture geometry, and fracture aperture on swarm behavior were experimentally investigated. ^ Swarm parameters were examined in time with …

Gps Constraints On The Mw = 7.5 Ometepec Earthquake Sequence, Southern Mexico: Coseismic And Post-Seismic Deformation, Shannon E. Graham, Charles Demets, Enrique Cabral-Cano, Vladimir Kostoglodov, Andrea Walpersdorf, Nathalie Cotte, Michael Brudzinski, Robert Mccaffrey, Luis Salazar-Tlaczani

Geology Faculty Publications and Presentations

We use continuous GPS measurements from 31 stations in southernMexico to model coseismic slip and post-seismic deformation from the 2012 March 20 Mw = 7.5 Ometepec earthquake, the first large thrust earthquake to occur below central Mexico during the modern GPS era. Coseismic offsets ranging from ∼280 mm near the epicentre to 5 mm or less at sites far from the epicentre are fit best by a rupture focused between ∼15 and 35 km depth, consistent with an independent seismological estimate. The corresponding geodetic moment of 1.4 × 10²⁰ N·m is within 10 per cent of two independent seismic …

The Spatial Cross-Correlation Method For Dispersive Surface Waves, Andrew P. Lamb, Kasper Van Wijk, Lee M. Liberty, T. Dylan Mikesell

Geosciences Faculty Publications and Presentations

Dispersive surface waves are routinely used to estimate the subsurface shear-wave velocity distribution, at all length scales. In the well-known Spatial Autocorrelation method, dispersion information is gained from the correlation of seismic noise signals recorded on the vertical (or radial) components. We demonstrate practical advantages of including the cross-correlation between radial and vertical components of the wavefield in a spatial cross-correlation method. The addition of cross-correlation information increases the resolution and robustness of the phase velocity dispersion information, as demonstrated in numerical simulations and a near-surface field study with active seismic sources, where our method confirms the presence of a …

Luminescence Dating Without Sand Lenses: An Application Of Osl To Coarse-Grained Alluvial Fan Deposits Of The Lost River Range, Idaho, Usa, M. K. Kenworthy, T. M. Rittenour, J. L. Pierce, N. A. Sutfin, W. D. Sharp

Geosciences Faculty Publications and Presentations

Optically stimulated luminescence (OSL) dating is increasingly used to estimate the age of fluvial deposits. A significant limitation, however, has been that conventional techniques of sampling and dose rate estimation are suitable only for thick (>60 cm) layers consisting of sand size or finer grains. Application of OSL dating to deposits lacking such layers remains a significant challenge. Alluvial fans along the western front of the Lost River Range in east-central Idaho, USA are one example. Deposits are typically pebble to cobble sheetflood gravels with a sandy matrix but thin to absent sand lenses. As a result, the majority …

Calculating The Velocity Of A Fast-Moving Snow Avalanche Using An Infrasound Array, Scott Havens, Hans-Peter Marshall, Jeffrey B. Johnson, Bill Nicholson

Geosciences Faculty Publications and Presentations

On 19 January 2012, a large D3 avalanche (approximately 10³ t) was recorded with an infrasound array ideally situated for observing the avalanche velocity. The avalanche crossed Highway 21 in Central Idaho during the largest avalanche cycle in the 15 years of recorded history and deposited approximately 8 m of snow on the roadway. Possible source locations along the avalanche path were estimated at 0.5 s intervals and were used to calculate the avalanche velocity during the 64 s event. Approximately 10 s prior to the main avalanche signal, a small infrasound signal originated from the direction of the …

Magnitude Estimation For Earthquake And Tsunami Early Warning Systems, Attieh Eshaghi

Electronic Thesis and Dissertation Repository

In this study, different magnitude estimation methods were investigated for application to earthquake early warning (EEW) and tsunami early warning systems. This integrated study is divided into two main parts. First, I used strong motion accelerograms recorded by borehole and surface stations from the Kiban Kyoshin network (KiK-net) for Japanese earthquakes with moment magnitude (M) ≥ 5.0 in order to develop ground motion prediction equations (GMPEs). I developed new GMPEs for peak ground acceleration (PGA) and peak ground velocity (PGV) using two different catalogs. The first catalog included earthquakes with 5.0 ≤ M ≤ 8.1 from 1998-2010. In …

Postglacial Early Permian (Late Sakmarian– Early Artinskian) Shallow-Marine Carbonate Deposition Along A 2000 Km Transect From Timor To West Australia, Vladimir I. Davydov

Geosciences Faculty Publications and Presentations

Late Sakmarian to early Artinskian (Early Permian) carbonate deposition was widespread in the marine intracratonic rift basins that extended into the interior of Eastern Gondwana from Timor in the north to the northern Perth Basin in the south. These basins spanned about 20° of paleolatitude (approximately 35°S to 55°S). This study describes the type section of the Maubisse Limestone in Timor-Leste, and compares this unit with carbonate sections in the Canning Basin (Nura Nura Member of the Poole Sandstone), the Southern Carnarvon Basin (Callytharra Formation) and the northern Perth Basin (Fossil Cliff Member of the Holmwood Shale). The carbonate units …

Discovery Of Shallow-Marine Biofacies Conodonts In A Bioherm Within The Carboniferous-Permian Transition In The Omalon Massif, Ne Russia Near The North Paleo-Pole: Correlation With A Warming Spike In The Southern Hemisphere, Vladimir I. Davydov, Alexander S. Biakov

Geosciences Faculty Publications and Presentations

The conodont genera Hindeodus and Streptognathodus are reported for the first time within the Carboniferous-Permian transition in the northern high latitudes of the Paren’ River, Omolon Massif, NE Russia. Several fossil groups, including brachiopods, bivalves, scaphopods and microgastropods were found to be prolific in the invertebrate-dominated bioherms. These bioherms occur within predominantly siliciclastic sequences with extremely poor fauna, whereas in the studied bioherms the diversity of the bivalves and brachiopods exceeded observed diversity elsewhere in coeval facies in NE Russia. The bioherms are biostratigraphically constrained as uppermost Pennsylvanian to lowermost Cisuralian based on ammonoids. The very unusual peak of bivalve …