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Full-Text Articles in Physical Sciences and Mathematics

Exploring Background Noise With A Large-N Infrasound Array: Waterfalls, Thunderstorms, And Earthquakes, L. T. Scamfer, J. F. Anderson Dec 2023

Exploring Background Noise With A Large-N Infrasound Array: Waterfalls, Thunderstorms, And Earthquakes, L. T. Scamfer, J. F. Anderson

Geosciences Faculty Publications and Presentations

Ambient infrasound noise contains an abundance of information that is typically overlooked due to limitations of typical infrasound arrays. To evaluate the ability of large-N infrasound arrays to identify weak signals hidden in background noise, we examine data from a 22-element array in central Idaho, USA, spanning 58 days using a standard beamforming method. Our results include nearly continuous detections of diverse weak signals from infrasonic radiators, sometimes at surprising distances. We observe infrasound from both local (8 km) and distant (195 km) waterfalls. Thunderstorms and earthquakes are also notable sources, with distant thunderstorm infrasound observed from ∼800 to 900 …


Studying The Impact Of The Geospace Environment On Solar Lithosphere Coupling And Earthquake Activity, Dimitar Ouzounov, Galina Khachikyan Dec 2023

Studying The Impact Of The Geospace Environment On Solar Lithosphere Coupling And Earthquake Activity, Dimitar Ouzounov, Galina Khachikyan

Mathematics, Physics, and Computer Science Faculty Articles and Research

In solar–terrestrial physics, there is an open question: does a geomagnetic storm affect earthquakes? We expand research in this direction, analyzing the seismic situation after geomagnetic storms (GMs) accompanied by the precipitation of relativistic electrons from the outer radiation belt to form an additional radiation belt (RB) around lower geomagnetic lines. We consider four widely discussed cases in the literature for long-lived (weeks, months) RBs due to GMs and revealed that the 1/GMs 24 March 1991 with a new RB at L~2.6 was followed by an M7.0 earthquake in Alaska, 30 May 1991, near footprint L = 2.69; the 2/GMs …


Investigating Seismicity And Structure Of The Pecos, Texas Region Of The Delaware Basin Using A Temporary Nodal Network, Jenna Lynn Faith Dec 2023

Investigating Seismicity And Structure Of The Pecos, Texas Region Of The Delaware Basin Using A Temporary Nodal Network, Jenna Lynn Faith

Open Access Theses & Dissertations

With increasing earthquakes in the Delaware Basin since 2009, earthquake studies, including accurate hypocenters, are critically needed in the Delaware Basin to identify the structures producing earthquakes, and to determine if they are related to unconventional petroleum development and production. In 2018, with funding from the Texas Seismological Network (TexNet), the University of Texas at El Paso deployed and maintained a nodal network of 25 Magseis Fairfield Z-Land Generation 2 5-Hz seismic nodes in the Pecos, Texas region of the Delaware Basin, known as The Pecos Array. The network was deployed from November 2018 until the beginning of January 2020, …


Empirical Nonlinear Site Response Applicable To Greater Vancouver, British Columbia, Natalia Gomez Jaramillo Oct 2023

Empirical Nonlinear Site Response Applicable To Greater Vancouver, British Columbia, Natalia Gomez Jaramillo

Electronic Thesis and Dissertation Repository

In Greater Vancouver, strong earthquake shaking has not been recorded to quantify expected nonlinear soil response. Earthquake horizontal to vertical spectral ratios (eHVSR) are evaluated at seismic stations located at the edges or deeper center of sedimentary basins in Mexico City, the Kanto basin and Anchorage with available weak-to-strong motion recordings that have similar linear site response to Greater Vancouver to constrain the expected nonlinear soil response for future large earthquakes affecting Greater Vancouver. The empirical results confirm that the very low fundamental frequency (f0 < 0.6 Hz) at deep Fraser River delta sites will be less affected by strong shakings and suggest that for Fraser River delta edge sites the amplification at the predominant frequency (f1) could increase up to 1.77 times with a strong event. This thesis’ …


Cluster Scaling And Critical Points: A Cautionary Tale, W. Klein, Harvey Gould, Sakib Matin Sep 2023

Cluster Scaling And Critical Points: A Cautionary Tale, W. Klein, Harvey Gould, Sakib Matin

Physics

Many systems in nature are conjectured to exist at a critical point, including the brain and earthquake faults. The primary reason for this conjecture is that the distribution of clusters (avalanches of firing neurons in the brain or regions of slip in earthquake faults) can be described by a power law. Because there are other mechanisms such as 1/f noise that can produce power laws, other criteria that the cluster critical exponents must satisfy can be used to conclude whether or not the observed power-law behavior indicates an underlying critical point rather than an alternate mechanism. We show how a …


Hamiltonian Monte Carlo For Reconstructing Historical Earthquake-Induced Tsunamis, Jacob Paul Callahan Jun 2023

Hamiltonian Monte Carlo For Reconstructing Historical Earthquake-Induced Tsunamis, Jacob Paul Callahan

Theses and Dissertations

In many areas of the world, seismic hazards pose a great risk to both human and natural populations. In particular, earthquake-induced tsunamis are especially dangerous to many areas in the Pacific. The study and quantification of these seismic events can both help scientists better understand how these natural hazards occur and help at-risk populations make better preparations for these events. However, many events of interest occurred too long ago to be recorded by modern instruments, so data on these earthquakes are sparse and unreliable. To remedy this, a Bayesian method for reconstructing the source earthquakes for these historical tsunamis based …


A Method Of Reconstructing Historical Destructive Landslides Using Bayesian Inference, Raelynn Wonnacott May 2023

A Method Of Reconstructing Historical Destructive Landslides Using Bayesian Inference, Raelynn Wonnacott

Theses and Dissertations

Along with being one of the most populated regions of the world, Indonesia has one of the highest natural disaster rates worldwide. One such natural disaster that Indonesia is particularly prone to are tsunamis. Tsunamis are primarily caused by earthquakes, volcanoes, landslides and debris flows. To effectively allocate resources and create emergency plans we need an understanding of the risk factors of the region. Understanding the source events of destructive tsunamis of the past are critical to understanding the these risk factors. We expand upon previous work focusing on earthquake-generated tsunamis to consider landslide-generated tsunamis. Using Bayesian inference and modern …


The First Application Of The Luminescence Surface Exposure Dating Method On Active Fault Scarps In The Western Anatolia Extensional Province: The Manisa Fault As An Example, Mustafa Softa, Eren Şahi̇ner, Hasan Sözbi̇li̇r, Joel Qg Spencer, Mehmet Utku, Mehmet Fati̇h Büyüktopcu Jan 2023

The First Application Of The Luminescence Surface Exposure Dating Method On Active Fault Scarps In The Western Anatolia Extensional Province: The Manisa Fault As An Example, Mustafa Softa, Eren Şahi̇ner, Hasan Sözbi̇li̇r, Joel Qg Spencer, Mehmet Utku, Mehmet Fati̇h Büyüktopcu

Turkish Journal of Earth Sciences

While there has been significant research on the dating of paleoearthquakes using methods such as surface cosmogenic dating, and trench-based luminescence or radiocarbon dating, this paper focuses on implementing an alternative surface dating method using a fault scarp-based optically stimulated luminescence (OSL) dating approach. Hence for the first time, we investigated the Pleistocene to Holocene earthquake cycle of the Manisa Fault, one of the dip-slip active faults of the Western Anatolia extensional province, utilizing novel OSL surface exposure techniques. In this technique, OSL bleaching profiles on the fault surface are directly related to the exposure of the fresh fault scarps …


Closing The Modern Seismic Gap Along The Teton Fault Via Seismic Mapping Of Mass Transport Deposits In Jackson Lake, Wy, Callia Jacqueline Cortese Jan 2023

Closing The Modern Seismic Gap Along The Teton Fault Via Seismic Mapping Of Mass Transport Deposits In Jackson Lake, Wy, Callia Jacqueline Cortese

Theses and Dissertations--Earth and Environmental Sciences

Terrestrial paleoseismological records along the Teton fault have historically indicated two-to-three major post-Pinedale (~14 ka) earthquake events, leaving an unresolved 6-9 m offset along the modern scarp. Recent studies of Jenny Lake have augmented this record, but the triggering mechanism is still equivocal until new paleo-earthquake records are developed. The earthquake record of the Teton fault is complicated by quiescence from ~5 ka to present, demonstrating the need for additional paleoseismic investigations. Compressed, high-intensity radar pulse (CHIRP) reflection data from Jackson Lake indicates multiple potentially seismically-induced mass transport deposits (MTDs). At least six MTD Groups representing chronostratigraphic intervals were interpreted …


Analyzing Ground Motion Records With Cvi Fuzzy Art, Dustin Tanksley, Xinzhe Yuan, Genda Chen, Donald C. Wunsch Jan 2023

Analyzing Ground Motion Records With Cvi Fuzzy Art, Dustin Tanksley, Xinzhe Yuan, Genda Chen, Donald C. Wunsch

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper explores using Cluster Validity Indices Fuzzy Adaptative Resonance Theory (CVI Fuzzy ART) to cluster ground motion records (GMRs). Clustering the features extracted from a supervised network trained for predicting the structure damage results in less overfitting from the trained network. Using Cluster Validity Indices (CVIs) to evaluate the clustering gives feedback to how well the data is being classified, allowing further separation of the data. By using CVI Fuzzy ART in combination with features extracted from a trained Convolutional Neural Network (CNN), we were able to form additional clusters in the data. Within the primary clusters, accuracy was …


The Impact Of Subjective Risk Analysis On Real Estate Prices In The Nisqually Region Following The 2001 Nisqually Earthquake, Ryan Espedal Jan 2023

The Impact Of Subjective Risk Analysis On Real Estate Prices In The Nisqually Region Following The 2001 Nisqually Earthquake, Ryan Espedal

All Master's Theses

Earthquakes are an environmental hazard that pose great risks to communities almost every day. With earthquakes, the main cause of concern is physical destruction of property, however, there are also psychological effects that are researched and discussed much less. In 2001, the Nisqually area of western Washington experienced a substantial earthquake that produced minimal physical damage but caused a significant decrease in real estate prices. Studying single-family homes from 1986-2012, this research utilizes hedonic property models to measure the change in consumer’s subjective risk calculations with reference to real estate purchases after the Nisqually earthquake, measure the relationship between earthquake …


Induced Seismicity In The Raton Basin And Global Variability Of The 410-Km Discontinuity, Margaret E. Glasgow Nov 2022

Induced Seismicity In The Raton Basin And Global Variability Of The 410-Km Discontinuity, Margaret E. Glasgow

Earth and Planetary Sciences ETDs

Natural processes like mantle convection and plate tectonics dominate Earth’s seismic structure. Recently human activities have increasingly influenced the deformation of the shallow crust. In this dissertation, passive source seismology was used to constrain seismic discontinuities in the mantle transition zone and seismogenic structures in induced earthquake settings. Using a novel sampling method and uniform processing approach, I found the 410-km discontinuity is thermally and compositionally variable. Using a machine- learning approach, I found the three main zones of seismicity in the Raton Basin consist of short faults or fault segments with variable orientations. The zone that hosted a Mw …


Volcano And Tectonic Hazard Modeling Using Interdisciplinary Geophysical And Geodetic Methods, Mitchell Scott Hastings Nov 2022

Volcano And Tectonic Hazard Modeling Using Interdisciplinary Geophysical And Geodetic Methods, Mitchell Scott Hastings

USF Tampa Graduate Theses and Dissertations

Volcanic and tectonic hazards such as volcanic eruptions, earthquakes and tsunamis present risks to about ~45% of the global population. They have caused at least 1.5 trillion dollars in damages worldwide since the start of the 20th century, and the costs are accelerating as population increases. In this dissertation, new data are combined with existing information and novel modeling approaches to quantify volcanic, earthquake and tsunami hazards.

The Blackfoot Reservoir Volcanic Field (BRVF) is a bimodal volcanic field on southeastern margin of the Eastern Snake River Plain in Idaho. In the BRVF, gravity anomalies reveal two shallow silicic intrusions that …


The Role Of Fracture Branching In The Evolution Of Fracture Networks: An Outcrop Study Of The Jurassic Navajo Sandstone, Southern Utah, Benjamin E. Surpless, Caroline Mckeighan Aug 2022

The Role Of Fracture Branching In The Evolution Of Fracture Networks: An Outcrop Study Of The Jurassic Navajo Sandstone, Southern Utah, Benjamin E. Surpless, Caroline Mckeighan

Geosciences Faculty Research

Fractures strongly influence the permeability of geologic formations, and because most fractures in the subsurface are below the resolution of geophysical methods, predicting the spatial evolution of fracture networks is important for groundwater resources, oil and gas production, and geothermal energy. Previous researchers have established that variations in lithologic mechanical properties influence the propagation of joints and fractures in layered rocks under stable stress conditions, but few studies have addressed how instabilities in local stress fields, in conjunction with variations in rock mechanical properties, lead to fracture branching.

We investigate NE-striking fractures in the footwall of the west-dipping Sevier fault …


Analysis Of Seismicity And Related Seismic Risk In Muslim Countries: Case Studies From Afghanistan And Pakistan, Ikramuddin Bahram Aug 2022

Analysis Of Seismicity And Related Seismic Risk In Muslim Countries: Case Studies From Afghanistan And Pakistan, Ikramuddin Bahram

Graduate Theses and Dissertations

How communities respond to a natural hazard is influenced by how they perceive it. This dissertation evaluated the gap between intent and action regarding earthquake hazards in Muslim countries with a focus on Afghanistan and Pakistan. Cultural biases provided predictions of risk perceptions and risk-taking preferences that were often more powerful than measures of knowledge and experience. In Muslim communities, perception of risk was influenced by the teachings of Islam and related rituals, traditions, and culture.

This study evaluated the seismicity and earthquake hazard in Afghanistan and Pakistan. Assessments of seismic risk and perception of danger were conducted to examine …


Geology Online Lab Activities An Open Educational Resource For Community College Students And Instructors, Rondi Davies Mar 2022

Geology Online Lab Activities An Open Educational Resource For Community College Students And Instructors, Rondi Davies

Open Educational Resources

The online geology lab for community college students was developed by Dr. Rondi Davies, a faculty member at Queensborough Community College, City University New York, during two years of forced online synchronous learning brought on by the COVID-19 pandemic. This open educational resource collects many of Dr. Davies’ favorite open-access materials and supplements them with her own work within a single, cohesive laboratory manual intended for two-year, non-major college students from the New York area.

Dr. Davies wanted to develop labs that were fun, engaging, and that excited students about the subject, were relevant to their lives, helped them to …


Toward The Understanding Of The 2018 Arnold, Ne Earthquake Cluster: Relocation Of Hypocenters And Establishment Of New Gravity Base Stations, Kris Guthrie Mar 2022

Toward The Understanding Of The 2018 Arnold, Ne Earthquake Cluster: Relocation Of Hypocenters And Establishment Of New Gravity Base Stations, Kris Guthrie

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

In 2018, 27 unexpected earthquakes occurred in central Nebraska near Arnold. These earthquakes have no readily apparent cause and no evidence of the responsible fault system is seen at the surface. A joint analysis of vintage, regional gravity and magnetic datasets before the first earthquake revealed a lineament that could represent a pre-existing fault system. New high resolution potential fields data are needed to confidently map the subsurface features around the cluster. To design a survey and collect the data, the following tasks need to be addressed: [1] The earthquakes’ hypocenters need to be improved (relocated) to increase the efficiency …


Editorial: Geospace Observation Of Natural Hazards, Dimitar Ouzounov, Jann-Yenq Liu, Patrick T. Taylor, Katsumi Hattori Jan 2022

Editorial: Geospace Observation Of Natural Hazards, Dimitar Ouzounov, Jann-Yenq Liu, Patrick T. Taylor, Katsumi Hattori

Mathematics, Physics, and Computer Science Faculty Articles and Research

"This collection of technical papers aims to bring recent data from many sources into the study of natural hazards. They represent a multi-instrumental approach using both ground observations: Global Navigation Satellite System (GNSS); and Low Earth Orbiting Electromagnetic (LEO EM) satellites missions together with Earth Observations (EO), which could reveal new information. Results from latest satellite missions, [(NPP/NASA/NOAA(US), CENTINEL, Swarm/ESA (EU), HIMAWARI (JMA, Japan), FORMOSAT-5 (Taiwan, August 2017), CSES1 (China/Italy, Feb 2018), and FORMOSAT-7/COSMIC-2 (Taiwan/United States, May 2019)], are represented in this volume."


Stratigraphic Evidence Of Two Historical Tsunamis On The Semi-Arid Coast Of North-Central Chile, Jessica M. Depaolis, Tina Dura, Breanyn Macinnes, Lisa L. Ely, Marco Cisternas, Matías Carvajal, Hui Tang, Hermann M. Fritz, Cyntia Mizobe, Robert L. Wesson, Gino Figueroa, Nicole Brennan, Benjamin P. Horton, Jessica E. Pilarczyk, D. Reide Corbett, Benjamin C. Gill, Robert Weiss Aug 2021

Stratigraphic Evidence Of Two Historical Tsunamis On The Semi-Arid Coast Of North-Central Chile, Jessica M. Depaolis, Tina Dura, Breanyn Macinnes, Lisa L. Ely, Marco Cisternas, Matías Carvajal, Hui Tang, Hermann M. Fritz, Cyntia Mizobe, Robert L. Wesson, Gino Figueroa, Nicole Brennan, Benjamin P. Horton, Jessica E. Pilarczyk, D. Reide Corbett, Benjamin C. Gill, Robert Weiss

Geological Sciences Faculty Scholarship

On September 16, 2015, a Mw 8.3 earthquake struck the north-central Chile coast, triggering a tsunami observed along 500 km of coastline, between Huasco (28.5°S) and San Antonio (33.5°S). This tsunami provided a unique opportunity to examine the nature of tsunami deposits in a semi-arid, siliciclastic environment where stratigraphic and sedimentological records of past tsunamis are difficult to distinguish. To improve our ability to identify such evidence, we targeted one of the few low-energy, organic-rich depositional environments in north-central Chile: Pachingo marsh in Tongoy Bay (30.3°S).

We found sedimentary evidence of the 2015 and one previous tsunami as tabular …


Diatoms Of The Intertidal Environments Of Willapa Bay, Washington, Usa As A Sea-Level Indicator, Isabel Hong, Benjamin P. Horton, Andrea D. Hawkes, Robert J. O.Donnell Iii, Jason S. Padgett, Tina Dura, Simon E. Engelhart Aug 2021

Diatoms Of The Intertidal Environments Of Willapa Bay, Washington, Usa As A Sea-Level Indicator, Isabel Hong, Benjamin P. Horton, Andrea D. Hawkes, Robert J. O.Donnell Iii, Jason S. Padgett, Tina Dura, Simon E. Engelhart

Geological Sciences Faculty Scholarship

An understanding of the modern relationship between diatom species and elevation is a prerequisite for using fossil diatoms to reconstruct relative sea level (RSL). We described modern diatom distributions from seven transects covering unvegetated subtidal environments to forested uplands from four tidal wetland sites (Smith Creek, Bone River, Niawiakum River, and Naselle River) of Willapa Bay, Washington, USA. We compared our diatom dataset (320 species from 104 samples) to a series of environmental variables (elevation, grain-size, total organic carbon (TOCSOM), and porewater salinity) using hierarchical clustering and ordination. While no single variable consistently explains variations in diatom assemblages …


Translating Risk Information To Protective Action: Examining Household Response To Information About Earthquake Hazards And Risk, Carson C. Macpherson-Krutsky Aug 2021

Translating Risk Information To Protective Action: Examining Household Response To Information About Earthquake Hazards And Risk, Carson C. Macpherson-Krutsky

Boise State University Theses and Dissertations

Natural hazards have been a part of the landscape since its existence, but they are becoming more devastating as they intersect with growing populations and as climate change increases their frequency and intensity. As these changes occur, the need to understand how to reduce disaster impacts becomes paramount. Despite growing concern and increasing costs of disasters over the past decade, household preparedness, which is at the foundation of disaster readiness, has seen little to no improvement. Using two research experiments, we adopt the Protective Action Decision Model (PADM; Lindell & Perry, 2004; 2012) as a framework to investigate what motivates …


An Exploration Of Passive Seismology: Applying Seismic Methods For Traditional And Exotic Source Characterization, David Lewis Guenaga Aug 2021

An Exploration Of Passive Seismology: Applying Seismic Methods For Traditional And Exotic Source Characterization, David Lewis Guenaga

Open Access Theses & Dissertations

As seismology continues to develop both theoretical and observational, so does its ability to be used in various applications. In this Dissertation, I develop and apply new approaches to five distinct projects (chapters 2-6), leveraging large and small high-quality targeted datasets to decipher fundamental and applied processes utilizing the full seismic wavefield. The first chapter introduces this Dissertation by providing broad context, continuity, and technical information about each of the five projects. Specifically, chapter 2 explores a seismic sensorâ??s ability to detect opera in Oak Ridge National Laboratory, TN, using a misfit power spectral density detector. Chapter 3 outlines work …


Changes In Tropospheric Ozone Associated With Strong Earthquakes And Possible Mechanism, Feng Jing, Ramesh P. Singh May 2021

Changes In Tropospheric Ozone Associated With Strong Earthquakes And Possible Mechanism, Feng Jing, Ramesh P. Singh

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The index of ozone anomaly (IOA) has been proposed to detect changes in tropospheric ozone associated with strong earthquakes. The tropospheric ozone prior and after the 2008 Wenchuan earthquake has been analyzed using IOA. Atmospheric infrared sounder ozone volume mixing ratio (O3 VMR) at different pressure levels (600, 500, 400, 300, 200 hPa) for an 18-year period 2003–2020 has been considered to identify the unique behavior associated with the strong earthquakes. Our results show distinct enhancement in tropospheric ozone occurred 5 d (7 May 2008) prior to the main event and distributed along the Longmenshan fault zone. An enhancement in …


A Broad, Distributed Active Fault Zone Lies Beneath Salt Lake City, Utah, Lee M. Liberty, James St. Clair, Adam P. Mckean Apr 2021

A Broad, Distributed Active Fault Zone Lies Beneath Salt Lake City, Utah, Lee M. Liberty, James St. Clair, Adam P. Mckean

Geosciences Faculty Publications and Presentations

Although the Wasatch fault is currently known to have a high‐seismic hazard from motion along range‐bounding faults, new seismic data reveal faulted and folded 13,000–30,000‐yr‐old Lake Bonneville strata beneath Salt Lake City (SLC). Coupled with previous excavation trench, borehole, and other geologic and geophysical observations, we conclude that a zone of latest Pleistocene and/or Holocene faulting and folding kinematically links the East Bench and Warm Springs faults through a 3 km wide relay structure and transfer zone. We characterize faults beneath downtown SLC as active, and these faults may displace or deform the ground surface during an earthquake. Through offset …


The 31 March 2020 MW 6.5 Stanley, Idaho, Earthquake: Seismotectonics And Preliminary Aftershock Analysis, Lee M. Liberty, Zachary M. Lifton, T. Dylan Mikesell Mar 2021

The 31 March 2020 MW 6.5 Stanley, Idaho, Earthquake: Seismotectonics And Preliminary Aftershock Analysis, Lee M. Liberty, Zachary M. Lifton, T. Dylan Mikesell

Geosciences Faculty Publications and Presentations

We report on the tectonic framework, seismicity, and aftershock monitoring efforts related to the 31 March 2020 Mw 6.5 Stanley, Idaho, earthquake. The earthquake sequence has produced both strike-slip and dip-slip motion, with minimal surface displacement or damage. The earthquake occurred at the northern limits of the Sawtooth normal fault. This fault separates the Centennial tectonic belt, a zone of active seismicity within the Basin and Range Province, from the Idaho batholith to the west and Challis volcanic belt to the north and east. We show evidence for a potential kinematic link between the northeast-dipping Sawtooth fault and the …


From Hector Mine M7.1 To Ridgecrest M7.1 Earthquake. A Look From A 20-Year Perspective, Sergey Pulinets, Marina Tsidilina, Dimitar Ouzounov, Dmitry Davidenko Feb 2021

From Hector Mine M7.1 To Ridgecrest M7.1 Earthquake. A Look From A 20-Year Perspective, Sergey Pulinets, Marina Tsidilina, Dimitar Ouzounov, Dmitry Davidenko

Mathematics, Physics, and Computer Science Faculty Articles and Research

The paper provides a comparative analysis of precursory phenomena in the ionosphere and atmosphere for two strong earthquakes of the same magnitude M7.1 that happened in the same region (North-East from Los Angeles) within a time span of 20 years, the Hector Mine and Ridgecrest earthquakes. Regardless of the similarity of their location (South-Eastern California, near 160 km one from another), there was one essential difference: the Hector Mine earthquake happened during geomagnetically disturbed conditions (essential in the sense of ionospheric precursors identification). In contrast, the quiet geomagnetic conditions characterized the period around the time of the Ridgecrest earthquake. The …


Resonant Frequency Derived From The Rayleigh‐Wave Dispersion Image: The High‐Impedance Boundary Problem, Lee M. Liberty, James St. Clair, T. Dylan Mikesell, William D. Schermerhorn Feb 2021

Resonant Frequency Derived From The Rayleigh‐Wave Dispersion Image: The High‐Impedance Boundary Problem, Lee M. Liberty, James St. Clair, T. Dylan Mikesell, William D. Schermerhorn

Geosciences Faculty Publications and Presentations

We present a simple and automated approach to estimate primary site‐response resonance, layer thickness, and shear‐wave velocity directly from a dispersion image for a layer over half‐space problem. We demonstrate this for high‐impedance boundary conditions that lie in the upper tens of meters. Our approach eliminates the need for time‐consuming dispersion curve picking and 1D shear‐wave velocity inversion for large data volumes that can capture velocity structure in profile. We highlight important relationships between dispersion characteristics and resonance parameters through synthetic modeling and field data acquired over Atlantic Coastal Plain sediments. In this environment, shallow soil conditions are critical to …


Tsunami Hazard, Warning, And Risk Reduction In Italy And The Mediterranean Sea: State Of The Art, Gaps, And Future Solutions, Stefano Lorito, Alessandro Amato, Lorenzo Cugliari, Fabrizio Romano, Roberto Tonini, Cecilia Valbonesi, Manuela Volpe Jan 2021

Tsunami Hazard, Warning, And Risk Reduction In Italy And The Mediterranean Sea: State Of The Art, Gaps, And Future Solutions, Stefano Lorito, Alessandro Amato, Lorenzo Cugliari, Fabrizio Romano, Roberto Tonini, Cecilia Valbonesi, Manuela Volpe

Turkish Journal of Earth Sciences

Historical catalogues show evidence for about 300 tsunamis in European coastal waters since 1600 BC, and tsunami hazard models like the NEAMTHM18 provide the probability of future inundation from earthquake-induced tsunamis. A recent wake-up call came from the 2020 Mw7.0 Samos-İzmir earthquake and the following moderate, damaging tsunami. Five accredited Tsunami Service Providers (TSPs) run by IPMA (Portugal), CENALT (France), INGV (Italy), NOA (Greece), and KOERI (Turkey), and several national centers monitor the seismicity and provide tsunami alerts in the framework of the UNESCO Tsunami Early Warning and Mitigation System in the North-eastern Atlantic, the Mediterranean and connected seas (NEAMTWS). …


Improving The Robustness Of The Advanced Ligo Detectors To Earthquakes, Eyal Schwartz, A. Pele, J. Warner, B. Lantz, Joseph Betzwieser, K. L. Dooley, S. Biscans, K. E. Ramirez Nov 2020

Improving The Robustness Of The Advanced Ligo Detectors To Earthquakes, Eyal Schwartz, A. Pele, J. Warner, B. Lantz, Joseph Betzwieser, K. L. Dooley, S. Biscans, K. E. Ramirez

Physics and Astronomy Faculty Publications and Presentations

Teleseismic, or distant, earthquakes regularly disrupt the operation of ground–based gravitational wave detectors such as Advanced LIGO. Here, we present EQ mode, a new global control scheme, consisting of an automated sequence of optimized control filters that reduces and coordinates the motion of the seismic isolation platforms during earthquakes. This, in turn, suppresses the differential motion of the interferometer arms with respect to one another, resulting in a reduction of DARM signal at frequencies below 100 mHz. Our method greatly improved the interferometers' capability to remain operational during earthquakes, with ground velocities up to 3.9 μm s−1 rms …


A Method For Reconstructing Historical Destructive Earthquakes Using Bayesian Inference, Hayden J. Ringer Aug 2020

A Method For Reconstructing Historical Destructive Earthquakes Using Bayesian Inference, Hayden J. Ringer

Theses and Dissertations

Seismic hazard analysis is concerned with estimating risk to human populations due to earthquakes and the other natural disasters that they cause. In many parts of the world, earthquake-generated tsunamis are especially dangerous. Assessing the risk for seismic disasters relies on historical data that indicate which fault zones are capable of supporting significant earthquakes. Due to the nature of geologic time scales, the era of seismological data collection with modern instruments has captured only a part of the Earth's seismic hot zones. However, non-instrumental records, such as anecdotal accounts in newspapers, personal journals, or oral tradition, provide limited information on …