bluuebunny/crossref_metadata_2025 huggingface dataset:
IS POOR QUALITY SLEEP PRESENT IN OLDER ADULTS WITH WORSE SOCIAL AND HEALTH STATUS?
Authors: Mota Sonia Gonçalves da , Jesus Isabela Thaís Machado de , Inouye Keika , Macedo Marcela Naiara Graciani Fumagale , Brito Tábatta Renata Pereira de , Santos-Orlandi Ariene Angelini dos
Published: September 2021

ABSTRACT Objective: to analyze the relationship among sleep and sociodemographic aspects, health, frailty, performance in activities of daily living, cognitive performance and depressive symptoms of older residents in the community. Method: a cross-sectional, quantitative study was conducted with 81 older adults residents in the area covered by a Family Health Unit in the city of São Carlos (SP), Brazil. Data collection occurred in 2019, through the application of the following instruments: questionnaire for socioeconomic and health characterization of the older adult, Pittsburgh Sleep Quality Index, Frailty Phenotype proposed by Linda Fried, Mini Mental State Examination, Geriatric Depression Scale, Katz Index and Lawton Scale. Participants were divided into comparative groups according to sleep quality scores. Fisher's exact and Pearson's χ2 were used. A significance level of 5% was adopted. Results: 50.6% of the older adults had poor quality sleep (n=41), followed by 33.3% of older adults with good quality sleep (n=27) and 16.1% had sleep disorders (n=13). There was a relationship between sleep quality and sex (p=0.008), work status (p=0.001), self-assessment of health (p=0.013), falls (p=0.034), pain (p=0.012), frailty level (p=0.026) and the slow gait criterion (p<0.001). Conclusion: there was a higher prevalence of poor quality sleep and sleep disorders in older patients, who do not work outside the home, who evaluated their health as regular or poor, who suffered falls in the last year and who complained of pain, frailty and slow gait.
Socioeconomic inequalities in the use of dental services in Brazil: an analysis of the 2019 National Health Survey
Authors: Fagundes Maria Laura Braccini , Bastos Lucelen Fontoura , Amaral Júnior Orlando Luiz do , Menegazzo Gabriele Rissotto , Cunha Amanda Ramos da , Stein Caroline , Abreu Lucas Guimarães , Hugo Fernando Neves , Giordani Jessye Melgarejo do Amaral , Malta Deborah Carvalho , Iser Betine Pinto Moehlecke
Published: September 2021

ABSTRACT: Objective: To describe the prevalence of use of dental services in Brazil according to states and the Federal District and its relationship with socioeconomic variables and types of services, based on the 2019 National Health Survey. Methods: This is a cross-sectional population-based study using data from the 2019 National Health Survey, which included 88,531 participants aged 18 or older. We assessed variables related to the use of dental health services according to sociodemographic and behavioral characteristics through multivariate analysis, using a Poisson regression model with robust variance. Results: The use of dental services in the year prior to the interview was higher among adults (53.2%, confidence interval — 95%CI 52.5–53.9) than older adults (34.3%, 95%CI 33.2–34.4). The multivariate analysis revealed that the use of dental services was greater in people with better schooling (prevalence ratio — PR=2.02, 95%CI 1.87–2.18) and higher income (PR=1.54, 95%CI 1.45–1.64). States from the Southeast, Midwest, and South regions presented the highest percentages of individuals who visited a dentist in the previous year — between 49.0 and 57.6% of the population. Conclusion: Inequalities were found in the use of dental health services among the adult and older adult population, with regional differences; the use was higher among women, younger individuals, those with better schooling, higher income, healthier behaviors, better self-perceived oral health status, and who paid for their last dental treatment.
Prevalence of exposure to violence among adults – Brazil, 2019
Authors: Mascarenhas Márcio Dênis Medeiros , Melo Ariel de Sousa , Rodrigues Malvina Thais Pacheco , Bahia Camila Alves , Lima Cheila Marina , Corassa Rafael Bello , Andrade Fabiana Martins Dias de , Malta Deborah Carvalho
Published: September 2021

ABSTRACT: Objective: To estimate the prevalence of exposure to violence, characterizing its magnitude, types and occurrence in the adult population in Brazil. Methods: Cross-sectional study with data from the National Health Survey conducted in 2019. The prevalence of violence in the last 12 months and respective 95% confidence intervals (95%CI) were estimated according to sociodemographic variables. Crude prevalence ratios were estimated by Poisson regression. Results: The prevalence of exposure to violence among adults in Brazil was 18.3% (95%CI 17.8–18.8), with a significantly higher frequency among women (19.4%; 95%CI 18.7–20.0), in the 18–29 age group (27.0%; 95%CI 25.7–28.4), in self-declared black people (20.6%; 95%CI 19.3–21.9) and mixed race (19.3%; 95%CI 18.6–20.1) and among inhabitants of the Northeast region (18.7%; 95%CI 18.0–19.5). Among the victims of violence, 15.6% (95%CI 14.2–17.0) sought health care, of which (91.2%; 95%CI 88.1–93.6) were attended. The most reported types of violence were: psychological (17.4%; 95%CI 16.9–17.9), physical (4.1%; 95%CI 3.9–4.4) and sexual (0.8%; 95%CI 0.7–0.9). Men were more exposed to violence with the use of firearms or sharp targets, while women were the predominant victims for all other types and mechanisms of violence. The aggressor most cited was the intimate partner, the most frequent place of occurrence of violence being the residence and public streets/places. Conclusion: In Brazil, violence affected one in five adults. Women, young people and people with black skin were the population segments most exposed to violence, which should be a priority in prevention actions.
Políticas públicas para la reducción de accidentes de tránsito por el consumo de alcohol en la Argentina
Authors: Celleri Milagros , Brunelli Maximiliano , Cesan Marianela , De Lellis Martín
Published: September 2021

En Argentina, cada año mueren alrededor de 5 000 personas en siniestros viales y conducir bajo los efectos del alcohol es uno de los principales factores de riesgo. El objetivo de la presente revisión fue analizar qué medidas han sido efectivas en reducir la siniestralidad vial relacionada al consumo de alcohol en el mundo y cuáles de las políticas relevadas se implementan y con qué resultados en nuestro país. Se realizó la búsqueda en Psycinfo, Dialnet, Lilacs, Scielo y Pubmed. Se constató que en nuestro país se aplican algunas políticas públicas que han demostrado ser eficaces, aunque no se conocen los resultados de su implementación en nuestra población. Se identificaron también acciones realizadas que no cuentan, al menos por el momento, con evidencia suficiente que justifique su implementación. A partir de los resultados hallados se sugiere desarrollar investigaciones que generen evidencias consistentes ante este grave problema de salud.
Mathematical methods of financial transaction evaluation for fraud
Authors:   Perm State University, Radionova Marina Vladimirovna , Korzukhin Anton Aleksandrovich ,   Delivery Club Ltd, Saushev Nikita Andreevich ,   National Research University “Higher School of Economics” (Perm Branch)
Published: September 2021

An increase in the number of the financial transaction is currently observed, which triggers more financial frauds and more losses from the cyber attacks in the global economy. Detection of the deviant transactions is a burning issue for modern studies because all bank system participants are looking for minimizing the risks which could arise from the vulnerabilities in online transaction. An increase in the financial losses caused by the financial fraud updates the importance of the mathematical methods to analyze the real data. The purpose of the present study is to develop and to define the best mathematical model to predict fraudulent transactions. The novelty of the study lies in designing different binary choice models based on the panel data to predict the deviant transactions, as well as to compare the econometric models with the models based on the neural networks and tree ensembles and in justifying the choice of the best model. Methodologically, the study applies correlational analysis methods, econometric and neural network methods, decision tree ensembles. The most significant results referred to the scientific novelty of the research are as follows: 1) panel data-based financial transactions have been econometrically analyzed within probit- and logit-models with fixed or random effects; 2) neural network methods and tree ensemble-based method have been applied to predict fraudulent transactions; 3) designed mathematical models have been comparatively analyzed, and the model giving the best result in detecting the fraudulent transaction has been defined. Further research is connected with more profound study of the impact of different factors to check the financial transactions for their fraud nature.
El ciclo de la calle. Reivindicaciones, experiencias y prácticas de personas callejeras en Bogotá
Authors: Camacho Mariño Nataly
Published: September 2021

La vida en calle es una experiencia múltiple y compleja para las personas que la viven. Una entidad de espacios, tiempos, prácticas y relaciones sociales constituye lo que estas personas —que se denominan callejeras— llaman la “calle”. A través de una apuesta etnográfica, este artículo busca analizar la complejidad de estas experiencias y prácticas en la ciudad de Bogotá, explorar el punto de vista de las personas callejeras —y así sus reivindicaciones—,y problematizar el desfase, los desajustes, entre la mirada sobre su propia condición de vida y cierta mirada institucional y dominante.
Variant (E484K) ALERT - Ligation-Dependent Loop-Mediated Isothermal Amplification v1
Authors: Bektas Ali , Jayaprakash Anitha
Published: September 2021

A 2-hour, 2-temperature protocol, using RNA templated DNA ligation, for the visual detection of the E484K mutation of concern pertaining to SARS-CoV-2. N.B. This is the first version of this protocol, stay tuned for increased sensitivity and multiplexing (A.B.)
Risk factors for perinatal loss - reality or fiction?
Authors: Bezhenar V. F. , Ivanova L. A. , Tatarova N. A. , Korshunov M. Yu.
Published: September 2021

Aim: to identify factors predisposing to perinatal losses, assessment of which is available at the first (only) visit of pregnant woman in antenatal clinic.

Materials and Methods. A retrospective analysis of the medical records of 964 women who performed delivery in 2009-2019 in 15 obstetric facilities was carried out. The patients were divided into 2 groups: the main group included 457 women with perinatal losses (stillbirth - 328 children, and 129 children with early neonatal death); the control group consisted of 507 women, whose children survived 7 days during postnatal period. We analyzed parameters routinely determined by an obstetrician-gynecologist at the first visit of woman during within ongoing pregnancy (regardless of gestation age), namely, social status, anamnesis, data of initial examination.

Results. The following significant differences were revealed in pregnant women from the main group: a younger age of pregnancy; no registered marriage and permanent job as well as primary and secondary education; smoking, alcohol and drug use; concurrent diabetes mellitus, hypertensive disorders, blood contact infections, obesity; older menarche age and younger sexual debut age; medical history contains infectious genital pathology, more often pregnancies and childbirths, two or more abortions before repeated childbirth, premature births.

Conclusion. Thus, the anamnestic indicators noted above can be used to create prognostic statistical systems and models to determine high risk of perinatal losses of any nature.
Modern view on the etiopathogenesis of heart rhythm disorders and methods of their correction in pregnant women
Authors: Useinova R. Kh. , Sulima A. N. , Rybalka A. N. , Beglitse D. A. , Rumyantseva Z. S. , Baskakov P. N. , Dizha M. A. , Dolya E. M.
Published: September 2021

Introduction. Issues of etiopathogenesis for various cardiovascular disorders in the structure of extragenital diseases during pregnancy pose an urgent problem and represent a global topic for further scientific research. Due to the high frequency of heart rhythm disorders in pregnant women, it is necessary to improve their management.

Aim: to analyze data from the current literature on the etiopathogenesis of arrhythmias during gestation and effective methods of their correction.

Materials and Methods. Literature sources of electronic databases PubMed/MEDLINE, Medscape, Google Scholar, Embase, Ovid Healthstar, Cochrane, eLibrary, CyberLeninka and scientific articles in peer-reviewed open access journals published across the last 25 years, including basic research on this pathology have been analyzed. The search in databases used keywords and their combinations in Russian and English: "arrhythmias", "arrhythmias in pregnancy", "pathogenesis of gestational arrhythmias".

Results. There have been analyzed major aspects of the etiology and pathogenesis of gestational arrhythmias as well as potential causes for developing first-time rhythm disorders in pregnant women and features of the gestational period as a predictor of emerging arrhythmias in patients with pre-existing pathology of the cardiovascular system are determined. The article describes the most common rhythm disorders and acceptable ways to correct them, taking into account the latest recommendations and research in this area.

Conclusion. The authors concluded that the etiopathogenesis of rhythm disorders during pregnancy and their treatment methods require further examination.
Pregnancy in advanced age of mothers and fathers
Authors: Dadak C.
Published: September 2021

There is a higher incidence of infertility, chromosomal aberrations, poor results of in vitro fertilization, ectopic pregnancies, spontaneous abortion, preeclampsia, placenta previa, gestational diabetes mellitus, caesarean section, chronic diseases with higher rates of admission into intensive care units, and a higher rate of maternal mortality among women who delay pregnancy into advanced age. This is mainly due to socioeconomic causes as well as the increased use of contraceptives. Problems due to advanced maternal age arise also with egg donations. Only chromosome aberrations are related to the age of the donor. Paternal age also appears to play a significant role in the outcome of the pregnancy. However, opinions vary in the literature available. Counseling the couples should be addressed.
Features of nervous system damage in antiphospholipid syndrome
Authors: Voskresenskaya O. N. , Bitsadze V. O. , Khizroeva J. Kh. , Sukontseva T. A. , Tretyakova M. V. , Shkoda A. S. , Gris J.-C. , Elalamy I. , Rizzo G. , Blinov D. V. , Makatsariya A. D.
Published: September 2021

Antiphospholipid syndrome (APS) is an autoimmune process that increases the risk of arterial and venous thrombosis. The mechanism of damage to the central nervous system (CNS) can be not only due to thrombosis, but also antiphospholipid antibodies (APA) circulating in the peripheral blood. The latter can damage the cerebral vascular endothelium, alter the resistance of the blood-brain barrier and penetrate into the central nervous system, exerting a damaging effect on astroglia and neurons, as evidenced by the release of neurospecific proteins into the peripheral bloodstream. The role of APS in developing cerebral ischemia, migraine, epilepsy, chorea, transverse myelitis, multiple sclerosis, cognitive impairment and mental disorders, as well as the peripheral nervous system is described. It should also be noted about a role of APS for emerging neurological disorders in COVID-19, enabled apart from thrombogenesis due to APA via 2 potential mechanisms - molecular mimicry and neoepitope formation. Further study of the APS pathogenesis and interdisciplinary interaction are necessary to develop effective methods for patient management.
Possibilities of phototherapy use for correction of psychоvegetative disturbance in schoolchildren
Authors: Talitskaya O. E. , Vein A. M. , Shvarkov S. B. , Neudakhin E. V.
Published: September 2021

Efficiency of phototherapy (10 sessions each lasting 30 minutes in the morning hours, light intensity 3300 lux) in 40 children with psychovegetative disorders, clinically represented by cephalalgic syndrome of different types is evaluated. Clinical symptoms, mood, vegetative status, level of thyroid hormones, hydrocortisone, prolactin in the blood, and excretion of catecholamines with diurnal urea are analyzed. After the course of phototherapy in 92,5% of children positive changes in psychovegetative and neuroendocrine spheres were found. The most pronounced positive effect of phototherapy is found in the group of children with chronic exercise-induced headache. Optimizing modulating influence of phototherapy on the content of stress-realizing hormones in childs body, on vegetative homeostasis, increasing adaptability of body are determined. Use of phototherapy for correction of psychovegetative disorders in children is reasoned.
The Virginia earthquake of April 9, 1918
Authors: Watson Thomas L.
Published: September 2021

Summary of geology and conclusions

Since, from the reports received, the shock seems to have been most severe in the northern part of the Valley of Virginia, a very brief summary of the geology of the northern valley region is of some interest in seeking the probable cause of the earthquake. The Valley of Virginia is bounded on the southeast by the Blue Ridge, the central portion of which is composed of pre-Cambrian igneous rocks and on the northwest by the Valley Ridges subprovince of folded sedimentary rocks ranging up to Devonian and Mississippian in age.

The valley maintains an approximate width of twenty miles from the state boundary southwestward to nearly the latitude of Greenville, Augusta County (Map, Plate I). From near the latitude of Strasburg and Riverton to that a short distance south of Harrisonburg, the valley is divided lengthwise by Massanutten Mountain, which is synclinal in structure and composed of sedimentary rock ranging up to and including Devonian in age. The mountain extends southwestward for a distance of about forty-five miles, and divides the valley lengthwise into two narrow valleys which average from five to ten miles in width. The Massanutten syncline, however, which involves the Martinsburg shale (Ordovician) at the surface, continues for a considerable distance both to the northeast and to the southwest of the north and south ends of the mountain proper.

The valley bottom is developed on folded limestone and shales of Cambro-Ordovician age, underlain by quartzites, sandstones, and shales of Lower Cambrian age which, because of their structure and greater resistance, are exposed along the northwest flank of the Blue Ridge. No igneous rocks are known to occur in the valley proper north of the latitude of northern Rockingham County.

The valley rocks are faulted, but in some localities at least the faulting appears to be slight, since the displacement is frequently not great enough to cut one or more formations. Bassler has recognized faulting at Winchester, one of the localities of highest intensity (VI R.-F. scale), during the earthquake of April 9, 1918. He says:5 “Although the full geologic structure in the vicinity of Winchester could not be determined because of lack of continuous exposures, the quarries and other outcrops just west and east of the town indicate that by faulting a band of Lower Ordovician dolomitic limestones has been interpolated between a band of Stones River limestones on the west and argillaceous limestones and shales of Chambersburg and Martinsburg age on the east.”

Faulting occurs at the base of Little North Mountain along the northwest side of the valley, and along the northwest front of the Blue Ridge on the southeast side of the valley a great overthrust fault, which apparently follows the Blue Ridge, has a horizontal displacement in places of at least four miles.

It seems probable, therefore, that the seismic disturbance of April 9, 1918, had its origin in one or more of the faults which characterize the region.
Lumped mass method for Rayleigh waves
Authors: Lysmer John
Published: September 2021

abstract

A simple numerical method is developed for the analysis of generalized Rayleigh waves in multilayered elastic media. The method which completely avoids the use of displacement potentials leads to a simple eigenvalue problem which may be solved by generally available effective computer codes. Numerical results obtained by the method show excellent agreement with previously published solutions obtained by other theories.
Magnitude of the Inglewood, California, earthquake of June 21, 1920
Authors: Richter C. F.
Published: September 2021

abstract

Comparison with later earthquakes in the same area indicates a magnitude near 4.9 for the Inglewood, California, earthquake of June 21, 1920.
S velocities at near distances in western central California
Authors: Filson John
Published: September 2021

An observational study of S from near earthquakes in western central California has been conducted. The average velocity of a single direct S arrival at Berkeley (BRK) from 25 earthquakes within 108 km is 3.60 ± .05 km/sec. At Vineyard (VIN) the clearest arrival from 12 earthquakes within 97 km has a velocity of 3.00 ± .06 km/sec. A weaker, earlier arrival is observed at VIN for 50 km < Δ < 100 km indicating a velocity of 3.51 ± .06 km/sec. The two arrivals at VIN may be due to either a lateral or vertical rustal velocity contrast. The greater attenuation of the higher velocity arrival at VIN with respect to BRK may indicate the dimension of an anelastic zone associated with regional faulting. SH arrivals identified on records from an instrument with extended long-period response have been identified as SHn with a velocity of 4.5 ± .2 km/sec. Source motions inferred from S-particle motion at BRK show a strong orientation with the trend of the regional faulting.
The south-central Illinois earthquake of November 9, 1968: Macroseismic studies
Authors: Gordon David W. , Bennett Theron J. , Herrmann Robert B. , Rogers Albert M.
Published: September 2021

The November 9, 1968 earthquake in south-central Illinois occurred in the New Madrid zone, a seismic zone associated with northeast-trending geological structure. Landforms in the epicentral area consist of nearly flat, glacial lake plains surrounding low, loess-covered hills. An extensive post office canvass and a field inspection of the epicentral area indicate that the strongest shaking (MM VII) took place in the Wabash and Ohio Valleys and adjacent lowlands of south-central Illinois. Characteristic damage included broken chimneys, fallen plaster, and occasional instances of collapsed parapets and overthrown tombstones. Observed rotations of tombstones and other objects in the epicentral area suggest a quadrant distribution of clockwise and counter-clockwise rotations.
Ocean microseism measurements with a neutral bouyancy free-floating midwater seismometer
Authors: Bradner H. , de Jerphanion Louis G. , Langlois Richard
Published: September 2021

abstract

Seismometers in spherical aluminum pressure housings have been weighted to float stably at midwater depths in the ocean, and thus record water motions in a frequency band of 0.02 to 5 cps. Simultaneous records made with a midwater instrument at 1.2-km depth and a bottom instrument at 4.6-km depth showed coherence at spectral power peaks of leaky organ-pipe frequencies and additional coherence peaks at frequencies down to 0.025 cps. Twenty organ-pipe modes can be tentatively identified. The spectral power can be attributed almost entirely to microseismic motions in wave-guide modes. We conclude that the forcing functions for microseisms are broad enough so that deep ocean-bottom and midwater microseism spectral peak frequencies are characteristic of local bathymmetry.
Stationary phase approximation in focal mechanism determination
Authors: Chandra Umesh
Published: September 2021

abstract

Tests of the stationary phase approximation method applied to P waves for the determination of focal mechanisms have been carried through for eight earthquakes selected from different geographic locations and depth ranges. The results are found to be in close agreement with the solutions obtained from S-wave polarization data for four earthquakes and in reasonable agreement for three earthquakes. In general, however, the P polarities are more consistent with S-wave polarization solutions than with the solutions obtained by the present method. The stationary phase solutions agree with the P-wave spectrum solutions determined in a previous study. The method is applicable to shallow-focus earthquakes, and to earthquakes of large magnitude in which methods using S-wave polarization data and P-wave spectra are difficult to apply.
Discrimination of earthquakes and explosions by the rayleigh-wave spectral ratio
Authors: Derr John S.
Published: September 2021

Limited data from a long-period vertical seismometer and the prototype of a new mercury tiltmeter at the station, Harvard, Massachusetts, tend to confirm that the Rayleigh-wave spectral ratio of short- to long-period energy provides a useful discriminant for underground explosions in the Western United States at distances of from 28° to 38° in the magnitude range of 3.5 < Ms < 5.6. This corresponds to discrimination in the range of 5.0 < mb < 6.3. The same spectral ratio, however, does not discriminate the large Milrow event in the Aleutians from earthquakes in the same region, possibly because of differences in earthquake source mechanisms in different regions and because this explosion released significant tectonic strain. The Rayleigh spectral ratio complements the Mg — mb discriminant by providing a clear separation of earthquakes and explosions in some geographical regions where earthquakes are of low stress drop and generally strike-slip in mechanism.
Microearthquake seismicity and tectonics of Coastal Northern California
Authors: Seeber Leonardo , Barazangi Muawia , Nowroozi Ali
Published: September 2021

This paper demonstrates that high-gain, high-frequency portable seismographs operated for short intervals can provide unique data on the details of the current tectonic activity in a very small area. Five high-frequency, high-gain seismographs were operated at 25 sites along the coast of northern California during the summer of 1968. Eighty per cent of 160 microearthquakes located in the Cape Mendocino area occurred at depths between 15 and 35 km in a well-defined, horizontal seismic layer. These depths are significantly greater than those reported for other areas along the San Andreas fault system in California. Many of the earthquakes of the Cape Mendocino area occurred in sequences that have approximately the same magnitude versus length of faulting characteristics as other California earthquakes.

Consistent first-motion directions are recorded from microearthquakes located within suitably chosen subdivisions of the active area. Composite fault plane solutions indicate that right-lateral movement prevails on strike-slip faults that radiate from Cape Mendocino northwest toward the Gorda basin. This is evidence that the Gorda basin is undergoing internal deformation. Inland, east of Cape Mendocino, a significant component of thrust faulting prevails for all the composite fault plane solutions. Thrusting is predominant in the fault plane solution of the June 26 1968 earthquake located along the Gorda escarpement. In general, the pattern of slip is consistent with a north-south crustal shortening.

The Gorda escarpment, the Mattole River Valley, and the 1906 fault break northwest of Shelter Cove define a sharp bend that forms a possible connection between the Mendocino escarpment and the San Andreas fault. The distribution of hypocenters, relative travel times of P waves, and focal mechanisms strongly indicate that the above three features are surface expressions of an important structural boundary. The sharp bend in this boundary, which is concave toward the southwest, would tend to lock the dextral slip along the San Andreas fault and thus cause the regional north-south compression observed at Cape Mendocino.

The above conclusions support the hypothesis that dextral strike-slip motion along the San Andreas fault is currently being taken up by slip along the Mendocino escarpment as well as by slip along northwest trending faults in the Gorda basin.
Analysis of Rayleigh-wave multipath propagation at LASA
Authors: Capon Jack
Published: September 2021

An investigation has been made of the multipath propagation of Rayleigh waves by using data obtained from the large aperture seismic array (LASA). The use of the LASA in conjunction with a high-resolution analysis technique provides a greater angular resolution and accuracy than was previously possible for the analysis of the multipath propagation. Measurements have been made of this phenomenon for the Rayleigh waves of 26 events distributed at various azimuths and distances from LASA. On the bas of these measurements reasonably good conjectures are made concerning the actual propagation paths for groups in the 20- to 40-sec period range. It is shown that in almost all cases these propagation paths can be associated with refractions and reflections at the continental margins.
Strain effects of nuclear explosions in Nevada
Authors: Boucher Gary , Malone Stephen D. , Homuth E. Fred
Published: September 2021

abstract

The University of Nevada's three-component quartz-rod strain meter installation at Round Mountain, Nevada (38°42.1′N, 117°04.6′W) has recorded a number of underground nuclear explosions at the Nevada Test Site, beginning with the megaton-sized JORUM event September 16 1969. Both that explosion and the larger HANDLEY event on March 26 1970 produced static strain offsets of a few parts in 109 at Round Mountain. These offsets did not decay within the first few hours after the explosions. In both cases, the strain offsets were in the sense of ground extension radial to the shot point, which is inconsistent with the assumption of a pure compressive source of strain. The strain-change ellipse for the HANDLEY event was found to have a major strain axis of 11 × 10−9 extensional, oriented N 34°W, and a minor axis of 7.4 × 10−9 compressional. A single-component strain meter at Mina, Nevada, (38°26.3′N, 118°9.3′W) was operated for the HANDLEY event, and recorded a strain offset of 2.6 × 10−9 in the direction N 74°E. Strain offsets at the time of the largest collapse events following HANDLEY were observed at Round Mountain. These offsets had the same sense on each component as those following the explosion itself. This is interpreted as support for the hypothesis that the strain changes are tectonic in origin, and the explosion initiates the strain release. Small offsets were observed for three smaller explosions out of a total of 13 studied. The relationship between body-wave magnitude mb and maximum dynamic strains at Round Mountain may be described empirically by the equation Log S = − 13.4 + 1.10 mb. Because of its high sensitivity and stability, the Round Mountain strain meter is capable of obtaining useful measurements of dynamic and static strain effects of intermediate- to large-sized explosions, at distances ranging from 160 to 200 km.
Leaking modes in a crust with a surface layer
Authors: Dainty Anton M.
Published: September 2021

abstract

Dispersion curves, attenuation functions and excitation functions for an explosive source at depth for four different models of the crust are presented for the leaking modes P(+, −), P(−, +) and π1(−, +). One of the objectives of the calculations was to determine the effect of a surface, low-velocity layer on the dispersion curves and attenuation functions. For the mode P(+, −) (the fundamental leaking mode), the differences are slight, while more pronounced differences are found for the other modes.

The variation of the excitation function with depth of the source has been studied. For the modes P(+, −), P(−, +) low frequencies are enhanced and high frequencies suppressed for one of the models as the source depth increases. According to this study, a source deep in the crust should be a more efficient exciter of the mode P(+, −) (the most commonly seen mode) than a near-surface source.
The Koyna earthquake of December 10 1967: A multiple seismic event
Authors: Gupta Harsh K. , Rastogi B. K. , Narain Hari
Published: September 2021

abstract

The analysis of P waves recorded at seismological observatories and seismic arrays at teleseismic distances and strong motion seismographs located at Koyna Dam suggest the Koyna earthquake of December 10 1967 to be a complex multiple event. Six of the events could be identified, and the second and third events are located with respect to the initiation using the Gutenberg sine-curve method at distances of 6 and 17 km due south, the average rupture velocity being 3.4 km/sec. The findings are consistent with the field observations and the different origin times, epicenters and magnitudes reported for the earthquake. Seismic array records are found to be very useful in examining the multiplicity of seismic events.
Evaluation of computational algorithms for the Associated Legendre Polynomials by interval analysis
Authors: Wiggins Ralph A. , Saito Masanori
Published: September 2021

abstract

An interval arithmetic that consists of tracing the number of significant figures during each calculation is applied to computational algorithms for the Associated Legendre Polynomial, Pnm(cos ϑ). The results indicate that the interval arithmetic scheme is a good estimator for the propagation of round-off errors and that one particular algorithm [a recurrence relation that relates Pnm (cos ϑ) to Pnn(cos ϑ)] is by far the superior computational scheme.
Comparison of three methods for calibrating a Willmore geophone
Authors: Donato R. J.
Published: September 2021

abstract

This paper describes a simple method for calibrating a Willmore geophone without using a shake table. It is assumed that one of the mechanical parameters of the system is known—in this case, the mass. The results from this simplified method are compared with an a.c. bridge method in which the equivalent electrical impedance is measured and with another bridge method described by Willmore where the sensitivity is measured by a substitution method. The three methods give substantially the same sensitivity of 6.1 volts/cm/sec for the particular geophone, with an estimated accuracy of 2 per cent, and all agree to the manufacturer's approximate specification to within 7 per cent.
A source of major error in the digital analysis of World Wide Standard station seismograms
Authors: James David E. , Linde Alan T.
Published: September 2021

abstract

A critical requirement in the digitization of analogue seismograms is that the y axis of the digitizing device be parallel to the recorded direction of swing of the galvanometer. Small misalignment of the seismogram on the digitizing table can produce major errors in the results of Fourier analysis and other digital techniques. In the examples discussed, the direction of the galvanometer swing was not parallel to the recording drum axis (the nominal direction of swing). Fourier spectra and group velocities are presented for cases in which the seismogram is aligned with the x axis of the digitizer: (1) parallel to the trace; (2) normal to the drum axis; (3) correctly aligned, normal to the direction of galvanometer swing. If the alignment is incorrect, the errors in the results are significant at both short and long periods and lead to erroneous geophysical conclusions. The magnitude of the errors increases with both the degree of misalignment and the amplitude of the recorded signal.
The motion excited by an impulsive source in an elastic half-space with a surface obstacle
Authors: Aboudi Jacob
Published: September 2021

abstract

An elastic half-space having a surface obstacle of slightly different elastic constants whose deviation and shape of boundaries are small is considered. By combining a perturbation method and a finite difference solution, the motion of the half-space due to an impulsive source is given. Results show that Rayleigh and reflected waves are highly influenced by the existence of the obstacle and could give some indications for screening purposes of elastic waves.
Transformation of the earthquake displacement field for spherical earth—Static case
Authors: Wason Hans R. , Singh Sarva Jit
Published: September 2021

abstract

Explicit expressions for the static displacement field for a Volterra dislocation and a center of compression in an infinite homogeneous medium are obtained. Using an addition theorem, the field is transformed to a polar coordinate system with origin at the center of the Earth. Expressions for the discontinuity in the motion stress vector across the concentric spherical surface through the source are then obtained. These results can be used in studying the deformation of a multilayered spherical earth model induced by internal sources by the Thomson-Haskell matrix method which has so far been mostly applied to dynamic problems.
Virginia's two largest earthquakes—December 22, 1875 and May 31, 1897
Authors: Bollinger G. A. , Hopper Margaret G.
Published: September 2021

abstract

A study of the macroseismic effects associated with the two largest of Virginia's historic earthquakes, based primarily on journals and archival newspaper accounts, reveals that exceptionally large felt areas can be associated with moderate earthquakes in the middle Atlantic region. Occurring at opposite ends of the state, the two shocks exhibit similar effects to the north, which appear related to the surficial geology, but differing intensity distributions to the southwest, which may reflect the differences between the two areas that exist in the geological structure. Differences in focal depth and focal mechanism may also be contributing factors. The Giles County earthquake of May 31, 1897, in the folded Appalachian Province of western Virginia, is assigned a maximum intensity (MM) of VIII and a felt area of at least 280,000 square miles. The Chesterfield County earthquake of December 22, 1875, in the crystalline Piedmont Province near Richmond, had a maximum intensity (MM) of VII and a 50,000-square-mile felt region. In both cases the previously reported intensities and felt areas were found adequate. For the moderate seismicity of the Appalachians, an extremely long period, May 3 to June 6, of seismic and acoustic phenomena occurred in conjunction with the May 31, 1897 shock.
A new approach for preparation of quantitative seismicity maps as applied to Alpide Belt-Sunda Arc and adjoining areas
Authors: Kaila K. L. , Narain Hari
Published: September 2021

abstract

A new method is developed for preparation of quantitative seismicity maps of an area. In this method, the slope b of the cumlative regression curve log N = A − bM, is supposed to be variable from one region to another and not constant as assumed by Riznichenko (1958) in his seismostatistical method. Under such a premise of variable b, the seismicity at any place is defined as log of the area under the curve representing incremental number of earthquakes versus magnitude on linear graph paper, within the magnitude range M = M to M = Mmax. The log of the total area under such a curve from magnitude M = 0 to M = Mmax will represent A value on the cumulative regression curve, and the same can also be used as a measure of seismicity level in any region. Worldwide relations are established between N(occ) the cumulative number of earthquakes occurring in an area with magnitude 4 and above and those actually detected N(det). This enables one to define the ratio between log N(det) and log N(occ) as the detectability level D of an area. The constants A and b of the cumulative regression curves for various regions of the Earth (normalized to 2° × 2° grid area and 14-year period of earthquake observation) are found to be related to each other by the equation A = 6.35b − 1.41. Making use of this relation and the detectability level D, b and the normalized A values for every 2° × 2° grid area as at the equator can be calculated. These A or b values are then used to draw the seismicity maps for any region of the Earth.

Using this new approach, a quantitative seismicity map based on A values has been prepared for the entire Alpide Belt-Sunda Arc and adjoining areas. This seismicity map has not only brought out the regions of high and low seismicity in great detail, but, at the same time, it also shows the trends of these highs and lows very clearly. This map is then compared with regional seismic zoning maps prepared by other workers covering small portions of this seismic belt and the two pictures are seen to show very good agreement both qualitatively as well as quantitatively.
Elastic multipole theory and seismic moment
Authors: Randall M. J.
Published: September 2021

abstract

Relationships between dynamic and static elastic multipoles derived from a general solution of the elastic-wave equation allow the direct application of results from elastostatic theory to problems in earthquake mechanism. For any theoretical model, the impulse of wave displacement (with can easily be found from long-period seismograms) can be simply derived from the far-field static dilation.

Application to a generalized dislocation model shows that seismic moment is properly a tensor.
Upper mantle P-wave velocity structure in the Japan region from travel-time studies of deep earthquakes using a new analytical method
Authors: Kaila K. L. , Krishna V. G. , Narain Hari
Published: September 2021

abstract

The upper mantle P-wave velocity structure of the region of Japan has been studied in great detail from travel times of 107 earthquakes with focal depths varying from 40 to 600 km, using a new analytical method given by Kaila (1969). In southwestern Japan the P-wave velocity is found to be 7.88 km/sec at a 40-km depth, and it remains almost constant to a depth of 255 km. For northeastern Japan the velocity, determined as 7.88 km/sec at 40 km, increases linearly with moderate gradient to 8.14 km/sec at a 175-km depth. On the other hand, for central Japan the P-velocity is found to be 7.92 km/sec at a 40-km depth, and increases linearly with a high-velocity gradient to 8.33 km/sec at a depth of 180 km. Then, there is a slight decrease in the velocity gradient, but the velocity still increases linearly to 8.52 km/sec at a depth of 365 km. At this transition depth, there is a first-order velocity discontinuity—the velocity increasing from 8.52 to 9.10 km/sec. Below this depth, velocity again increases linearly from 9.10 to 9.99 km/sec at a depth of 600 km. Probable causes for these lateral-velocity inhomogeneities in the upper mantle of the Japan region are discussed.

Graphs have been drawn to show the variation with depth of Δ*, the epicentral distance to the inflection point, (Δ2 − Δ1), ptrue = ∂T/∂Δ and ap = (T − pΔ) at the inflection point, the latter acting as a calibration curve for earthquake focal-depth determination in Japan. Using this calibration curve, focal depths are redetermined for all of the earthquakes under study for central Japan, and the same are compared with the values reported in the International Seismological Summaries.
Long-period body-wave propagation from 4° to 13°
Authors: Helmberger Donald V.
Published: September 2021

Numerical seismograms are computed for a compressional pulse in a layered model. The simpler models consist of a fluid layer over a fluid half-space, a fluid layer over a solid half-space, and a solid layer over a solid half-space. Restricted portions of the theoretical response for a layered model approximating the Earth are constructed. Synthetic seismograms are generated using the pressure pulse appropriate for NTS events and the long-period instrument response. The interplay between the PL wave, the refracted wave along the lid, and the arrival from the base of the low-velocity zone is displayed. A detailed comparison between the synthetics and observations indicates a prominent low-velocity zone with appreciable seismic absorption. Observed regional wave-shape characteristics are displayed and a reconnaissance map of lateral variations along the top of the mantle presented.
The July 8, 1971 Chilean earthquake
Authors: Eisenberg A. , Husid Raul , Luco Juan E.
Published: September 2021

Observations on the destructive 1971 Chilean earthquake show that the epicenter and focal mechanism might be different from the one in 1965 in the same region. Field study shows that almost all damage was confined to poorly-built structures or to those that were not earthquake-resistant. Local high intensities are well correlated with the soil characteristics of alluvial valleys. Analyses of accelerograms at Santiago, about 140 km from the epicenter, show, as in 1965, rather high (15 to 17 per cent of g) values of ground accelerations for that distance.
Magnitude from short-period P-wave data
Authors: Veith K. F. , Clawson G. E.
Published: September 2021

abstract

An empirical surface-focus amplitude-distance curve, based on approximately 2400 short-period P-wave amplitudes from 43 large explosions at 19 different sites, and a corresponding curve based on geometrical spreading in the Herrin earth model are developed. The relative amplitude differences are inverted to obtain the Q structure of the mantle. Theoretical, deep-focus, amplitude-distance curves incorporating geometric spreading and attenuation are developed. Corresponding distance and depth amplitude-correction P factors are given for computing magnitude (mp). The correction factors are evaluated and are shown to provide a significantly improved basis for computing magnitude relative to the presently used Q factors which yield mb. Values of mp were normalized to be equal on the average to values of mb for a surface source; differences in attenuation factors generally make mb larger than mp for deep earthquakes.
Surface-wave dispersion in Byrd Land, Antarctica
Authors: Acharya H. K.
Published: September 2021

Assuming constant density and Poisson's ratio of 0.25, theoretical surface-wave dispersion has been computed for the Byrd Land area in Antarctica, where the velocity increases monotonically with depth. Comparison with observed dispersion indicates 8 to 10 per cent anisotropy in the ice cap. Such anisotropy was also detected from ultrasonic velocity measurements on snow cores.
A three-quarter watt seismic station
Authors: Muirhead K. J. , Simpson D. W.
Published: September 2021

A low-power, low-cost instrument using slow speed, direct recording on magnetic tape provides continuous unattended seismic recording in excess of 1 month. The seismic signal is recorded at two gain levels separated by 26 db with a total dynamic range of greater than 70 db. A high-accuracy crystal clock with fully coded digital output and a crystal stabilized radio for reference time-signal reception provide timing to better than 0.1 sec throughout the recording period. Total power consumption is less than 34 watts which enables operation for 1 month on dry cell batteries. The weight of the complete system including seismometer and batteries is less than 100 lb. Ten instruments have been used to record seismic signals ranging from localized microearthquake activity to explosions and teleseismic events.
A line source on a solid-solid interface—A study of the pseudo-Stoneley wave
Authors: Dampney C. N. G.
Published: September 2021

The displacement caused by a source on an interface between two solid semi-infinite elastic media presents an excellent study in interference between direct, head and interface waves. The solution herein derived provides fresh insight into the nature of pseudo-Stoneley interface waves. As well, the evolution of the head and direct waves is discerned as they move away from the interface.

The technique used to solve the problem demonstrates the simplicity of using Sherwood's (1958) method with generalized ray theory. The displacement is simply expressed in a closed form which can be rapidly evaluated and is straightforward to interpret physically.