Improving teleseismic event locations using a three-dimensional Earth model

1996 ◽  
Vol 86 (3) ◽  
pp. 788-796 ◽  
Author(s):  
Gideon P. Smith ◽  
Göran Ekström
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
The United States ◽  
Earth Model ◽  
Published Data ◽  
S Wave ◽  
Origin Time ◽  
Data Set ◽  
Station Corrections ◽  
Earth Models

Abstract A comparison is made between seismic event locations derived from standard spherically symmetric Earth models (JB, PREM, IASP91) and a recent Earth model (S&P12/WM13) that incorporates large-scale lateral heterogeneity of P- and S-wave velocities in the mantle. Events with known hypocentral coordinates are located in the different Earth models using standard methods. Two sets of events are considered: a data set of 26 explosions, including primarily nuclear weapons test explosions and peaceful nuclear explosions in the United States and former USSR; and a published data set of 82 well-located earthquakes with a more even global distribution. IASP91 and PREM are shown to offer similar errors in event location and origin time estimates with respect to the JB model. The three-dimensional (3D) model S&P12/WM13 offers improvement in event locations over all three one-dimensional (1D) models with, or without, station corrections. For the explosion events, the average mislocation distance is reduced by approximately 40%; for the earthquakes, the improvements are smaller. Corrections for crustal thickness beneath source and receiver are found to be of similar magnitude to the mantle corrections, but use of station corrections together with the three-dimensional mantle model provide the best locations.

Preliminary Results from the Air Mass Transformation Experiment (AMTEX)

1976 ◽  
Vol 57 (11) ◽  
pp. 1346-1355 ◽  
Author(s):  
D. H. Lenschow ◽  
E. M. Agee
Keyword(s):  
United States ◽  
Experimental Period ◽  
The United States ◽  
Published Data ◽  
Data Set ◽  
Air Mass ◽  
Preliminary Results ◽  
Cold Air Outbreak ◽  
Transformation Experiment ◽  
Transformation Processes

The field phases of AMTEX, a GARP subprogram on air-sea interaction implemented by Japan, were conducted over the East China Sea in the environs of Okinawa, Japan, during the last two weeks of February in 1974 and 1975. Investigators from Australia, Canada, and the United States also participated in this experiment. The weather was generally very favorable for this study of air mass transformation processes in 1975 because of an extensive cold air outbreak during most of the experimental period. A basic synoptic data set was obtained from 6 h soundings from an array of aerological stations centered at Okinawa. In addition, satellite, hourly surface and surface marine, oceanographic, boundary layer, radiation, radar, cloud physics, and aircraft data were obtained and have been or will be available in published data reports or on magnetic tape. Preliminary results from 1974 and 1975 reported at the Fourth AMTEX Study Conference and joint United States–Japan Cooperative Science Program Seminar, “Air Mass Transformation Processes over the Kuroshio in Winter,” held in Tokyo, 26–30 September 1975, are presented and discussed.

Structure of the Séchilienne unstable slope from large-scale three-dimensional electrical tomography using a Resistivity Distributed Automated System (R-DAS)

2019 ◽  
Vol 219 (1) ◽  
pp. 129-147 ◽  
Author(s):  
M Lajaunie ◽  
J Gance ◽  
P Nevers ◽  
J-P Malet ◽  
C Bertrand ◽  
...  
Keyword(s):  
Large Scale ◽  
Electrical Potential ◽  
Three Dimensional ◽  
Automated System ◽  
Data Uncertainty ◽  
Complex Data ◽  
Electrical Tomography ◽  
Data Set ◽  
Resistivity Model ◽  
Unstable Slope

SUMMARY This work presents a 3-D resistivity model of the Séchilienne unstable slope acquired with a network of portable resistivimeters in summer 2017. The instrumentation consisted in distributed measuring systems (IRIS Instruments FullWaver) to measure the spatial variations of electrical potential. 23 V-FullWaver receivers with two 50 m dipoles have been deployed over an area of circa 2 km2; the current was injected between a fixed remote electrode and a mobile electrode grounded successively at 30 locations. The data uncertainty has been evaluated in relation to the accuracy of electrodes positioning. The software package BERT (Boundless Electrical Resistivity Tomography) is used to invert the apparent resistivity and model the complex data set providing the first 3-D resistivity model of the slope. Stability tests and synthetic tests are realized to assess the interpretability of the inverted models. The 3-D resistivity model is interpreted up to a depth of 500 m; it allows identifying resistive and conductive anomalies related to the main geological and hydrogeological structures shaping the slope. The high fracturation of the rock in the most active zone of the landslide appears as a resistive anomaly where the highest resistivity values are located close to the faults. A major drain formed by a fault in the unaltered micaschist is identified through the discharge of a perched aquifer along the conductive zone producing an important conductive anomaly contrasting with the unaltered micaschist.

Competitive Effects of Front-of-Package Nutrition Labeling Adoption on Nutritional Quality: Evidence from Facts Up Front–Style Labels

2020 ◽  
Vol 84 (6) ◽  
pp. 3-21 ◽  
Author(s):  
Joon Ho Lim ◽  
Rishika Rishika ◽  
Ramkumar Janakiraman ◽  
P.K. Kannan
Keyword(s):  
Nutritional Quality ◽  
Large Scale ◽  
Product Category ◽  
Underlying Mechanism ◽  
The United States ◽  
Product Line ◽  
Nutrition Labeling ◽  
Competitive Response ◽  
Data Set ◽  
Packaged Food

“Facts Up Front” nutrition labels are a front-of-package (FOP) nutrition labeling system that presents key nutrient information on the front of packaged food and beverage products in an easy-to-read format. The authors conduct a large-scale empirical study to examine the effect of adoption of FOP labeling on products’ nutritional quality. The authors assemble a unique data set on packaged food products in the United States across 44 categories over 16 years. By using a difference-in-differences estimator, the authors find that FOP adoption in a product category leads to an improvement in the nutritional quality of other products in that category. This competitive response is stronger for premium brands and brands with narrower product line breadth as well as for categories involving unhealthy products and those that are more competitive in nature. The authors offer evidence regarding the role of nutrition information salience as the underlying mechanism; they also perform supplementary analyses to rule out potential self-selection issues and conduct a battery of robustness checks and falsification tests. The authors discuss the implications of the findings for public policy makers, consumers, manufacturers, and food retailers.

Analytic investigations of the effects of near‐surface three‐dimensional galvanic scatterers on MT tensor decompositions

Geophysics ◽  
1991 ◽  
Vol 56 (4) ◽  
pp. 496-518 ◽  
Author(s):  
R. W. Groom ◽  
R. C. Bailey
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Magnetic Scattering ◽  
Impedance Tensor ◽  
Data Set ◽  
Near Surface ◽  
Eigenvalue Estimates ◽  
Polarization Azimuth ◽  
Local Current ◽  
Scattering Operators

An outcropping hemispherical inhomogeneity embedded in a two‐dimensional (2-D) earth is used to model the effects of three‐dimensional (3-D) near‐surface electromagnetic (EM) “static” distortion. Analytical solutions are first derived for the galvanic electric and magnetic scattering operators of the heterogeneity. To represent the local distortion by 3-D structures of fields which were produced by a large‐scale 2-D structure, these 3-D scattering operators are applied to 2-D electric and magnetic fields derived by numerical modeling to synthesize an MT data set. Synthetic noise is also included in the data. These synthetic data are used to study the parameters recovered by several published methods for decomposing or parameterizing the measured MT impedance tensor. The stability of these parameters in the presence of noise is also examined. The parameterizations studied include the conventional 2-D parameterization (Swift, 1967), Eggers’s (1982) and Spitz’s (1985) eigenstate formulations, LaTorraca et al.’s (1986) SVD decomposition, and the Groom and Bailey (1989) method designed specifically for 3-D galvanic electric scattering. The relationships between the impedance or eigenvalue estimates of each method and the true regional impedances are examined, as are the azimuthal (e.g., regional 2-D strike, eigenvector orientation and local strike) and ellipticity parameters. The 3-D structure causes the conventional 2-D estimates of impedances to be site‐dependent mixtures of the regional impedance responses, with the strike estimate being strongly determined by the orientation of the local current. For strong 3-D electric scattering, the local current polarization azimuth is mainly determined by the local 3-D scattering rather than the regional currents. There are strong similarities among the 2-D rotation estimates of impedance and the eigenvalue estimates of impedance both by Eggers’s and Spitz’s first parameterization as well as the characteristic values of LaTorraca et al. There are striking similarities among the conventional estimate of strike, the orientations given by the Eggers’s, Spitz’s (Q), and LaTorraca et al.’s decompositions, as well as the estimate of local current polarization azimuth given by Groom and Bailey. It was found that one of the ellipticities of Eggers, LaTorraca et al., and Spitz is identically zero for all sites and all periods, indicating that one eigenvalue or characteristic value is linearly polarized. There is strong evidence that this eigenvalue is related to the local current. For these three methods, the other ellipticity differs from zero only when there are significant differences in the phases of the regional 2-D impedances (i.e., strong 2-D inductive effects), implying the second ellipticity indicates a multidimensional inductive response. Spitz’s second parameterization (U), and the Groom and Bailey decomposition, were able to recover information regarding the actual regional 2-D strike and the separate character of the 2-D regional impedances. Unconstrained, both methods can suffer from noise in their ability to resolve structural information especially when the current distortion causes the impedance tensor to be approximately singular. The method of Groom and Bailey, designed specifically for quantifying the fit of the measured tensors to the physics of the parameterization, constraining a model, and resolving parameters, can recover much of the information in the two regional impedances and some information about the local structure.

scholarly journals Development of three-dimensional wetting and drying algorithm for the Geophysical Scale Transport Multi-Block Hydrodynamic Sediment and Water Quality Transport Modeling System (GSMB)

2021 ◽  
Author(s):  
Ray Chapman ◽  
Phu Luong ◽  
Sung-Chan Kim ◽  
Earl Hayter
Keyword(s):  
Water Quality ◽  
Water Wave ◽  
Large Scale ◽  
Three Dimensional ◽  
The United States ◽  
Technical Note ◽  
Three Dimensions ◽  
Transport Modeling ◽  
Two Dimensional ◽  
Wetting And Drying

The Environmental Laboratory (EL) and the Coastal and Hydraulics Laboratory (CHL) have jointly completed a number of large-scale hydrodynamic, sediment and water quality transport studies. EL and CHL have successfully executed these studies utilizing the Geophysical Scale Transport Modeling System (GSMB). The model framework of GSMB is composed of multiple process models as shown in Figure 1. Figure 1 shows that the United States Army Corps of Engineers (USACE) accepted wave, hydrodynamic, sediment and water quality transport models are directly and indirectly linked within the GSMB framework. The components of GSMB are the two-dimensional (2D) deep-water wave action model (WAM) (Komen et al. 1994, Jensen et al. 2012), data from meteorological model (MET) (e.g., Saha et al. 2010 - http://journals.ametsoc.org/doi/pdf/10.1175/2010BAMS3001.1), shallow water wave models (STWAVE) (Smith et al. 1999), Coastal Modeling System wave (CMS-WAVE) (Lin et al. 2008), the large-scale, unstructured two-dimensional Advanced Circulation (2D ADCIRC) hydrodynamic model (http://www.adcirc.org), and the regional scale models, Curvilinear Hydrodynamics in three dimensions-Multi-Block (CH3D-MB) (Luong and Chapman 2009), which is the multi-block (MB) version of Curvilinear Hydrodynamics in three-dimensions-Waterways Experiments Station (CH3D-WES) (Chapman et al. 1996, Chapman et al. 2009), MB CH3D-SEDZLJ sediment transport model (Hayter et al. 2012), and CE-QUAL Management - ICM water quality model (Bunch et al. 2003, Cerco and Cole 1994). Task 1 of the DOER project, “Modeling Transport in Wetting/Drying and Vegetated Regions,” is to implement and test three-dimensional (3D) wetting and drying (W/D) within GSMB. This technical note describes the methods and results of Task 1. The original W/D routines were restricted to a single vertical layer or depth-averaged simulations. In order to retain the required 3D or multi-layer capability of MB-CH3D, a multi-block version with variable block layers was developed (Chapman and Luong 2009). This approach requires a combination of grid decomposition, MB, and Message Passing Interface (MPI) communication (Snir et al. 1998). The MB single layer W/D has demonstrated itself as an effective tool in hyper-tide environments, such as Cook Inlet, Alaska (Hayter et al. 2012). The code modifications, implementation, and testing of a fully 3D W/D are described in the following sections of this technical note.

scholarly journals JUSTFAIR: Judicial System Transparency through Federal Archive Inferred Records

2020 ◽  
Author(s):  
Maria-Veronica Ciocanel ◽  
Chad M. Topaz ◽  
Rebecca Santorella ◽  
Shilad Sen ◽  
Christian Michael Smith ◽  
...  
Keyword(s):  
Large Scale ◽  
Federal District ◽  
The United States ◽  
Judicial System ◽  
Public Access ◽  
Data Set ◽  
Scale Free ◽  
The Public ◽  
Sentencing Decisions ◽  
Constitutional Right

In the Unites States, the public has a constitutional right to access criminal trial proceedings. In practice, it can be difficult or impossible for the public to exercise this right. We present JUSTFAIR: Judicial System Transparency through Federal Archive Inferred Records, a database of criminal sentencing decisions made in federal district courts. We have compiled this data set from public sources including the United States Sentencing Commission, the Federal Judicial Center, the Public Access to Court Electronic Records system, and Wikipedia. With nearly 600,000 records from the years 2001 - 2018, JUSTFAIR is the first large scale, free, public database that links information about defendants and their demographic characteristics with information about their federal crimes, their sentences, and, crucially, the identity of the sentencing judge.

Similarities of the Scotia and Caribbean Plates: Implications for a common plate tectonic history?!

2021 ◽  
Author(s):  
Christian Burmeister ◽  
Paul Wintersteller ◽  
Martin Meschede
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Plate Tectonic ◽  
Data Set ◽  
Scotia Sea ◽  
Passive Margins ◽  
Tectonic History ◽  
Position Index ◽  
Detailed Interpretation ◽  
Oceanic Plates

<p>The active volcanic arcs of the Scotia Plate and Caribbean Plate are two prominent features along the otherwise passive margins of the Atlantic Ocean, where subduction processes of oceanic crust is verifiable. Both arcs have been, and continue to be, important oceanic gateways during their formation. Trapped between the large continental plates of North- and South America, as well as Antarctica, the two significantly smaller oceanic plates show striking similarities in size, shape, plate margins and morphology, although formed at different times and locations during Earth’s history.</p><p>Structural analyses of the seafloor are based on bathymetric datasets by multibeam-echosounders (MBES), including data of the Global Multi Resolution Topography (GMRT), Alfred Wegener Institute (AWI), MARUM/Uni-Bremen, Geomar/Uni-Kiel, Uni-Hamburg and the British Antarctic Survey (BAS). Bathymetric data were processed to create maps of ocean floor morphology with resolution of 150-250 meters in accuracy. The Benthic Terrain Modeler 3.0 (BTM), amongst other GIS based tools, was utilized to analyse the geomorphometry of both plates. Furthermore, we used the bathymetric datasets for three-dimensional modelling of the seafloor to examine large-scale-structures in more detail.</p><p>The modelling of ship-based bathymetric datasets, in combination with the GEBCO 2014 global 30 arc-second interval grid, included in the GMRT bathymetric database, delivered detailed bathymetric maps of the study area. With the help of the fine- and broad-scale bathymetric position index (BPI), comparable to the topographic position index (Weiss, 2001), we present the first detailed interpretation of combined bathymetric datasets of the Scotia Sea, including the entire Scotia Plate and adjacent areas, such as the East Scotia Plate. We identified typical morphological features of the abyss, based on the determination of steep and broad slopes, ridges, boulders, flat plains or flat ridge tops and depressions in various scales. Additional data analyses of gravimetric and magnetic properties of the crust should help to understand the plate tectonic history of both areas in more detail.</p><p><br>References: <br>Ryan, W. B. F; Carbotte, S.M.; Coplan, J.; O'Hara, S.; Melkonian, A.; Arko, R.; Weissel, R.A.; Ferrini, V.; Goodwillie, A.; Nitsche, F.; Bonczkowski, J. and Zemsky, R. (2009): Global Multi-Resolution Topography (GMRT) synthesis data set, Geochem. Geophys. Geosyst., 10, Q03014, doi:10.1029/2008GC002332.</p><p>Walbridge, S.; Slocum, N.; Pobuda, M.; Wright, D.J. (2018): Unified Geomorphological Analysis Workflows with Benthic Terrain Modeler. Geosciences 2018, 8, 94. doi: 10.3390/geosciences8030094</p><p>Weiss, A. D. (2001): Topographic Positions and Landforms Analysis (Conference Poster). Proceedings of the 21st Annual ESRI User Conference. San Diego, CA, July 9-13.</p>

scholarly journals EXISTING STRATEGIES FOR ELECTRONIC DATA COLLECTION BY ELDER ABUSE MULTI-DISCIPLINARY TEAMS

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S423-S423
Author(s):  
Tony Rosen ◽  
David Burnes ◽  
Darin Kirchin ◽  
Alyssa Elman ◽  
Risa Breckman ◽  
...  
Keyword(s):  
Data Collection ◽  
Social Services ◽  
Large Scale ◽  
Elder Abuse ◽  
The United States ◽  
Third Party ◽  
Snowball Sampling ◽  
Electronic Data ◽  
Data Set ◽  
Electronic Data Collection

Abstract Elder abuse cases often require integrated responses from social services, medicine, civil legal, and criminal justice. Multi-disciplinary teams (MDTs), which meet periodically to discuss and coordinate interventions for complex cases, have developed in many communities. Little is known about how these MDTs collect case-level data. Our objective was to describe existing strategies of case-level electronic data collection conducted by MDTs across the United States as a preliminary step in developing a comprehensive database strategy. To identify MDTs currently collecting data electronically, we used a snowball sampling approach discussing with national leaders. We also sent an e-mail to the National Center for Elder Abuse listserv inviting participation. We identified and reviewed 11 databases from MDTs. Strategies for and comprehensiveness of data collection varied widely. Databases used ranged from a simple spreadsheet to a customized Microsoft Access database to large databases designed and managed by a third-party vendor. Total data fields collected ranged from 12-338. Types of data included intake/baseline case/client information, case tracking/follow-up, and case closure/outcomes. Information tracked by many MDTs, such as type of mistreatment, was not captured in a single standard fashion. Documentation about data entry processes varied from absent to detailed. We concluded that MDTs currently use widely varied strategies to track data electronically and are not capturing data in a standardized fashion. Many MDTs collect only minimal data. Based on this, we have developed recommendations for a minimum data set and optimal data structure. If widely adopted, this would potentially improve ability to conduct large-scale comparative research.

scholarly journals Updates to the Regional Seismic Travel Time (RSTT) Model: 1. Tomography

2020 ◽  
Author(s):  
Michael L. Begnaud ◽  
Stephen C. Myers ◽  
Brian Young ◽  
James R. Hipp ◽  
Doug Dodge ◽  
...  
Keyword(s):  
Travel Time ◽  
Seismic Velocity ◽  
Three Dimensional ◽  
Computer Software ◽  
Velocity Model ◽  
Travel Times ◽  
Crust And Upper Mantle ◽  
Data Set ◽  
Earth Models ◽  
Regional Phases

Abstract A function of global monitoring of nuclear explosions is the development of Earth models for predicting seismic travel times for more accurate calculation of event locations. Most monitoring agencies rely on fast, distance-dependent one-dimensional (1D) Earth models to calculate seismic event locations quickly and in near real-time. RSTT (Regional Seismic Travel Time) is a seismic velocity model and computer software package that captures the major effects of three-dimensional crust and upper mantle structure on regional seismic travel times, while still allowing for fast prediction speed (milliseconds). We describe updates to the RSTT model using a refined data set of regional phases (i.e., Pn, Pg, Sn, Lg) using the Bayesloc relative relocation algorithm. The tomographic inversion shown here acts to refine the previous RSTT public model (rstt201404um) and displays significant features related to areas of global tectonic complexity as well as further reduction in arrival residual values. Validation of the updated RSTT model demonstrates significant reduction in median epicenter mislocation (15.3 km) using all regional phases compared to the iasp91 1D model (22.1 km) as well as to the current station correction approach used at the Comprehensive Nuclear-Test-Ban Treaty Organization International Data Centre (18.9 km).

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