bluuebunny/crossref_metadata_2025 huggingface dataset:
Scottish Inshore Fisheries Integrated Data System (SIFIDS): work package 8B final report identifying fishing activities and their associated drivers
Authors:   University of St Andrews, Mendo Tania , Smout Sophie ,   University of St Andrews, Ransijn Johanna ,   University of St Andrews, Durbach Ian ,   University of St Andrews, McCann Paddy ,   University of St Andrews, Crowe Swithun ,   University of St Andrews, Carulla Fàbrega Ariadna , de Prado Irene , James Mark ,   University of St Andrews
Published: July 2021

[Extract from Executive Summary] This Work Package (WP8B) of the SIFIDS project focused on vessels that are 12 m or under in length, use static gear (pots or creels), and primarily target lobsters (Homarus gammarus), crabs (Cancer pagurus and Necora puber), and prawns (Nephrops norvegicus). WP8B had two principal objectives: 1. Identify fishing activity profiles for static gear vessels in the inshore fleet prosecuting lobsters, crabs and nephrops. 2. Incorporate effort, biological data, socio-economic data, environmental data to understand fishing behaviour
Pragmatic Options of the Dialogical Text as a Language Unit
Authors: Shpilnaya Nadezhda
Published: July 2021

The purpose of the article is to analyse pragmatic variants of a dialogical text as a language unit. It is assumed that the pragmatic context of the dialogical text (dialogue) actualizing is associated with either informative or phatic intentions. Informative and phatic dialogues appear as pragmatic allotext of a dialogical text. The research methodology is based on the synthesis of derivational and anthropocentric language theories. The process of creating a dialogical text is considered, on the one hand, as a derivational process due to the suppositional relationship between the lexeme and the text, and on the other hand, as a process of interpreting the text in the pragmatic context of its actualization. The material for the study was the recording of oral and written speech of regular native speakers in an informal communication situation. The total number of analyzed speech patterns was 140 dialogic texts – 70 texts of each communication type. It is stated that the pragmatic actualization of the dialogical text is associated with the realization of paradigmatic and syntagmatic connections of lexemes. It is revealed that the syntagmatic model of a dialogical text genesis in informative communication is an adjoining model. A paradigmatic model of dialogic text genesis in informative communication is synonymy. In phatic communication, an attachment model was identified as a syntagmatic model of the genesis of a dialogical text. The paradigmatic model for the production of dialogic text in phatic communication is a homonym model.
Preputial Stones as a Rare Complication of Buried Penis: A Case Report
Authors: Kim Si Hyun , Kim Doo Sang
Published: July 2021

Preputial calculi are a very rare manifestation of urolithiasis that occur most often in uncircumcised elderly males with poor hygiene and low socioeconomic status. Here, we present a case of preputial calculi in a 13-year-old boy with a buried penis. No penile shaft was observed and hard materials palpated around the penile foreskin. Imaging examinations showed several stones around the penis and surgical correction was indicated. The stones were removed and a circumferential incision along the coronal edge allowed for degloving with rotated skin flaps. Surgical removal of the stones and reconstruction was performed to promote hygiene and prevent future infection.
Thermal performance of mortars/concretes containing calcined marl as alternative pozzolan
Authors: Akgün Yasemin
Published: July 2021

The solutions to the increasing problem regarding the energy demand of the world have been expected from the building sector with their consumption of a high amount of energy. Producing environmentally friendly and energy-efficient blended cements and using materials with high thermal performance in terms of insulation and thermal energy storage in buildings are some of these solutions. Calcined marl at the optimum temperature is an alternative pozzolan for blended cement production. The main purpose of this study is to determine how the thermal performance and mechanical properties of mortar/concrete are affected by using calcined marl as alternative pozzolan. For this purpose, mortars/concretes containing calcined marl blended cements were produced. The calcined marl replacement ratios of blended cements were 0, 10, 30 and 50 wt.%. In the study, the strengths and thermal performances of mortars/concretes containing calcined marl blended cements were determined. The test results were compared among themselves and with each other. From the test results, it was concluded that the thermal performances of the mortars/concretes containing calcined marl blended cements could be improved up to 50% replacement ratio without compromising the strength of considered materials.
Safety margin from characteristic values in settlement calculations of embankments on clay
Authors: López Ramírez Alejandra , Löfman Monica Susanne , Korkiala-Tanttu Leena
Published: July 2021

Settlement calculations in serviceability limit state (SLS) design of embankments require the estimation of characteristic values of soil properties to account for different sources of uncertainty. The upcoming revised version of EN 1997-1:2004 (Eurocode 7) presents a statistically based equation to determine characteristic values of soil properties with the aim of providing a more consistent safety margin. The aim of this study is to quantify the safety margin in settlement calculations using this equation and performing probabilistic analyses. Four different cases of embankments on soft soil with different soil conditions were considered, including significant non-linear stress–strain behaviour. This allowed evaluation of the consistency of the safety margin from statistically derived characteristic values for different soil conditions. Probabilistic analyses were performed using Monte Carlo simulations to determine the statistics of total settlements. The safety margin was then defined based on the distance between the settlement from characteristic values and the mean settlement value of the simulations. The quantified safety margin was not consistent among the cases, which may be related to varying levels of non-linear compressibility and degree of consolidation. Moreover, for some cases, the safety margin might be too conservative for SLS design of embankments.
A fuzzy multi-objective multiple-pollutant model for rivers using an ant colony algorithm
Authors: Ghorbani Mohammad Kazem , Afshar Abbas , Hamidifar Hossein , Reddy Manne Janga
Published: July 2021

A fuzzy multi-objective optimisation model was investigated for water quality management in a river under uncertain conditions. In this study, to deal with multiple pollutants simultaneously, the National Sanitation Foundation's water quality index was considered as one of the model's objective functions based on fuzzy set theory. This made it possible to investigate the overall effect of uncertainties on simultaneous changes. Another objective function was the total treatment costs for wastewater discharged into the river. A water quality simulation model and a non-dominated-archiving ant colony optimisation algorithm were used to determine the values of water quality parameters and the model's optimal solutions, respectively. Furthermore, a simulation–optimisation approach was adopted for facilitating the problem-solving process and applied to a hypothetical case study resembling a river system in Iran. The results show that the proposed model significantly reduced the total wastewater treatment costs compared with a similar single-objective model with a more cautious and a cost-effective approach. Although the treatment costs were increased compared with the similar deterministic model, more feasible approach was taken by considering the uncertainties associated with the objectives. With suitable modifications, the model could be easily adapted for other river systems.
Governance, human agency and other blindspots in active transport practice — and research
Authors: Sagaris Lake
Published: July 2021

At the root of the multiple, diverse and multi-scalar challenges facing the living systems we call cities likes a single enormous knot: figuring out how to live together very differently, in light of climate crisis, pandemics, loss of biodiversity and other life-threatening conditions. Active transport has an important role to play in showing ways of living better with lower consumption, improving health and, in many contexts, social equality. This requires more attention to interdisciplinary methodologies, social movements and civil society, and the governance arrangements necessary to facilitate or at least permit significant social change.
Análisis numérico de los mapas de patrones de flujo del refrigerante R600a en un colector/evaporador de una bomba de calor asistida por energía solar
Authors: Quitiaquez William , Cortez Eduardo , Anchapaxi Karen , Isaza-Roldán C.A. , Nieto-Londoño César , Quitiaquez Patricio , Toapanta-Ramos Fernando
Published: July 2021

En la presente investigación se detallan los mapas de patrones de flujo que se generan en una tubería horizontal de un colector/evaporador componente de una bomba de calor de expansión directa asistida por energía solar, utilizando el refrigerante R600a como fluido de trabajo. El estudio se realizó en una tubería de 3,8 mm de diámetro interno y 1000 mm de longitud, las velocidades de masa variaron entre 197,59 y 267,26 kg·m-2·s-1, el flujo de calor entre 72,83 y 488,27 W·m-2, durante las pruebas experimentales se presentó una radiación solar incidente entre 0 y 652,9 W·m-2. Se consideró para el análisis la correlación de Wojtan, Ursenbacher y Thome, el modelo utilizado no requiere de cálculos iterativos, además, plantea un análisis detallado de las diferentes zonas presentes a lo largo de la tubería, evidenciando una mayor precisión en los resultados. Las zonas predominantes en los resultados de este estudio son intermitente, anular y secado, encontrados en las cinco pruebas, sin embargo, por las condiciones de trabajo en todas las pruebas a excepción de la prueba A, se encontró el flujo niebla y estratificado-ondulado.
Academic Dishonesty and Research Productivity in a Changing Higher Education Environment. The Case of India’s Engineering Institutions
Authors: Bakthavatchaalam Venkat , Miles Mike , Machado-Taylor Maria de Lourdes , Sa Maria Jose
Published: July 2021

The Indian academic system is in a period of rapid transition, evidenced by the increasing number of higher education institutions, students and academics. However, very few studies have explored academics’ research productivity and the various factors influencing it. Even those few studies have largely ignored the influences of indigenous factors and academic dishonesty on research productivity. Using a mixed-method approach, this research explores how the changing academic environment influences academics’ research productivity in South Indian engineering institutions established after 1990. Important demographic factors influencing research productivity have been identified. The results show that indigenous factors play a major role in motivating the academics to conduct research, whereas corruption / academic dishonesty, thought to be prevalent at all levels in the higher educational system, tend to reduce their research motivation. The research shows the complex interconnections between the changing academic environment, indigenous factors and academic dishonesty, and their influence on academics’ research. The results of this work can be used for informing future higher education policy-making in terms of increasing research productivity and decreasing a range of academic dishonesty in the context of a rapidly changing academic system.
Measuring Parental Control and Its Relationship to Cognitive Abilities of Early-Grade Students
Authors: Lanina Ekaterina , Bochaver Aleksandra , Antipkina Inna
Published: July 2021

The article presents a tool for assessing the parental regulation of children’s behavior at the start of the school. The questionnaire assesses the implementation by parents of two typical control functions (direct control of the child’s behavior and communicative mediation between the child and the environment), as well as a poorly studied construct — parental control over digital devices (“gadgets”) that the child uses. It was demonstrated that the severity of parental control is sensitive to the characteristics of parents (higher education, age, number of children in the family) and the characteristics of the child (cognitive achievements at the start of the school).
Measuring Basic Mathematical Literacy in Elementary School
Authors: Federiakin Denis , Larina Galina , Kardanova Elena
Published: July 2021

Measuring mathematical literacy is not easy as this construct is multicomponent and tasks often involve a lot of reading. As a rule, intended users of measurement results want information about the overall level of respondents’ mathematical literacy as well as its specific components. According to educational and psychological testing standards, reporting overall scores together with subscores simultaneously requires additional psychometric evaluation to provide evidence for validity of all scores reported. A study performed shows that PROGRESS-ML, a test measuring basic mathematical literacy in elementary school pupils, can be used as a one-dimensional measure, allowing overall test scores to be reported. Meanwhile, reading skills do not contribute significantly to the likelihood of item response, and subscores can be reported as complementary to the total score.
Psychometric Properties of the Russian-Language Version of the Early Parental Attitudes Questionnaire (EPAQ) Designed to Assess Intuitive Theories of Parenting
Authors: Bukhalenkova Daria , Veraksa Aleksander , Gavrilova Margarita , Kartushina Natalya
Published: July 2021

Psychometric properties of the Russian-language version of the Early Parental Attitudes Questionnaire (EPAQ), an instrument for assessing intuitive theories of parenting, were tested on 1,928 parents of children aged 1–7. Assessment of the questionnaire’s reliability (internal consistency) using the Cronbach’s alpha coefficient showed that the scales were not homogeneous. Confirmatory factor analysis revealed that the data obtained in the Russian sample was only partially consistent with the original three-scale model obtained in American parents. The questionnaire’s factor structure, determined using the exploratory factor analysis, was interpreted from the perspective of the adults’ beliefs on parenting and child development that are widespread in Russia. Additional adaptation is needed to improve the reliability of the Russian-language version of the questionnaire and to allow its further use.
El alumnado de educación secundaria frente a las noticias falsas: resultados de una intervención didáctica
Authors: López-Flamarique Maite , Planillo Artola Sandra
Published: July 2021

Las redes sociales se han convertido en una de las principales fuentes de información, especialmente entre los más jóvenes. Al mismo tiempo, se ha incrementado la producción y circulación de información falsa o fake news a través de las redes. En este contexto, resulta crucial que los jóvenes adquieran estrategias y competencias para realizar una lectura crítica de la información que consumen. Este estudio busca analizar el comportamiento del alumnado de secundaria ante la información falsa y el efecto de una intervención didáctica, realizada online durante la pandemia de la covid-19, cuyo objetivo era que el alumnado desarrollara competencias para detectar noticias falsas. Se trata de una investigación participativa con un diseño de pre-test y post-test. Los resultados muestran que el alumnado incrementó su competencia para identificar algunos tipos de falsedad como la información no probada y la información tergiversada, si bien tuvo problemas para reconocer información descontextualizada o el uso de lenguaje discriminatorio. Las estrategias que más utilizó son la comprobación de datos en internet y el uso de verificadores. Se observaron comportamientos diferenciados entre el alumnado que identificó la información falsa y el que no lo hizo. Las conclusiones apuntan a la necesidad de trabajar en el aula de forma integral, extensiva y transversal la evaluación de la información partiendo de las habilidades que el alumnado ya posee.
How is the practice to use the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool in systematic reviews: a meta-epidemiological study protocol v1
Authors: Banno Masahiro , Tsujimoto Yasushi , Ariie Takashi , Okazaki Yuji , Shimamura Yoshinosuke , Kamijo Kyosuke , Kataoka Yuki
Published: July 2021

ABSTRACT Objectives. To evaluate the practice to use the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool in systematic reviews (SRs) including non-randomized studies of interventions (NRSI). Methods. This study is a meta-epidemiological study. We will include SRs, which include NRSI, and which used the ROBINS-I tool to assess the risk of bias (RoB) for NRSI. We will exclude SRs if the results have no NRSI even if review authors plan to include NRSI. We will exclude protocols. We will limit SRs published since 2020. We will search PubMed to collect eligible SRs using the search term “ROBINS[tiab]” AND the Systematic Review filter. We will perform random sampling and collect 100 samples from eligible non-Cochrane reviews. We will investigate eligible Cochrane reviews and the 100 non-Cochrane reviews and compare the characteristics. Ethics & Dissemination. This study does not need ethical approval. We registered this study protocol. We will publish the findings in a peer-reviewed journal and may present them at conferences. Discussion. This study will clarify how is the practice to assess the RoB for non-randomized studies of interventions. The results will inform the researchers, reviewers, and readers of the points that need special attention. Registration: Protocols.io
Comparative Analysis of Intensity of Traits Limiting the Professional and Psychological Fitness of Internal Affairs Officers
Authors: Goncharova N.A. , Kalashnik A.A. , Sitnikov V.L.
Published: July 2021

The article discusses the results of a comparative study of intensity of personality traits that limit the professional and psychological fitness of internal affairs officers and determine the prognosis factors for one's individual development in this field. Within the scope of the study we compared the applicants' parameters of motivational profile, emotional and volitional self-control, personality characteristics as well as their mental faculties. As a result, certain reliably significant traits have been found which limit one's possibilities for effective professional performance. The results obtained in the comparative and factor analysis made it possible to establish a combination of determining factors that limit one's professional and psychological fitness. A factor structure of limiting traits has been revealed, making up more than 60 per cent of total variance. It is represented by low self-control, poor mental faculties, addictive behavior, poorly developed feeling of justice, passive personality orientation, anxiety-depressive disorders and social immaturity of personality.
Self-Control Peculiarities of Men with Alcohol Dependence
Authors: Vlasova N.V. , Lanovaya A.M.
Published: July 2021

The article presents the results of an empirical research of self-regulation peculiarities of men with alcohol dependence. Self-regulation is defined as a system process which is comprised of initiation, planning and modeling processes, evaluation and correction of one's external and internal activities in accordance with goals. In case of alcohol dependence as one of the forms of destructive addictive behavior, serious disorders occur in one's personality sphere. Firstly, negative changes emerge in all mental processes. Secondly, alcohol abuse leads to disorders in the emotional sphere. Addicts are liable to aggressive and uncontrolled acts. The empirical study that aimed to detect peculiarities in self-regulation altered by the establishing alcohol dependence. The experimental group included 40 men diagnosed with the second and third stages of alcoholism. The results of the empirical study can be used in preventive programs based on techniques of developing self-regulation.
Automatic phase pickers: Their present use and future prospects
Authors: Allen Rex
Published: July 2021

abstract

Automatic phase-picking algorithms are designed to detect a seismic signal on a single trace and to time the arrival of the signal precisely. Because of the requirement for precise timing, a phase-picking algorithm is inherently less sensitive than one designed only to detect the presence of a signal, but still can approach the performance of a skilled analyst. A typical algorithm filters the input data and then generates a function characterizing the seismic time series. This function may be as simple as the absolute value of the series, or it may be quite complex. Event detection is accomplished by comparing the function or its short-term average (STA) with a threshold value (THR), which is commonly some multiple of a long-term average (LTA) of a characteristic function. If the STA exceeds THR, a trigger is declared. If the event passes simple criteria, it is reported. Sensitivity, expected timing error, false-trigger rate, and false-report rate are interrelated measures of performance controlled by choice of the characteristic function and several operating parameters. At present, computational power limits most systems to one-pass, time-domain algorithms. Rapidly advancing semi-conductor technology, however, will make possible much more powerful multi-pass approaches incorporating frequency-domain detection and pseudo-offline timing.
The 23 November 1980 southern Italy earthquake
Authors: Del Pezzo Edoardo , Iannaccone Giovanni , Martini Marcello , Scarpa Roberto
Published: July 2021

abstract

The seismic activity associated with the catastrophic southern Italy earthquake was monitored by 11 seismic stations operating before this event, within an epicentral distance of 200 km, and by 32 additional short-period seismometers installed soon after the main shock. The hypocenter of this event was located at 40°46′N and 15°18′E, at 16 km depth. The fault-plane solution reveals normal faulting, with tensile axis dipping 18° and oriented orthogonal to the axis of the Apennines chain. This mechanism is in good agreement with the stress pattern inferred from some previous earthquakes and the local seismotectonics.

The hypocenter locations of more than 600 aftershocks, with local magnitudes greater than 2.4, show a pronounced alignment extending for about 70 km, oriented north 120° and scattered laterally less than 15 km. These events are mostly concentrated between 8 and 16 km depth. A cluster of aftershocks occurred close to the hypocenter of the main shock covering a region elongated 25 km which corresponds also to the highly damaged area. No significant spreading of the aftershock area with time is observed, but one of the events with higher magnitude (ML = 4.8, 14 February 1981) is displaced 20 km NW from the tip of the aftershock region. The time evolution of the number of aftershocks fits well Omori's hyperbolic law with a decay coeffcient of 1.07 ± 0.06.

The possibility of a future delayed multiple sequence of large events, as already observed in the past along the central and southern Apennines, is discussed. In particular, a relatively high seismic potential seems to exist along the northern boundary of the 1980 rupture segment.
Effect of distance on local magnitudes found from strong-motion records
Authors: Jennings Paul C. , Kanamori Hiroo
Published: July 2021

abstract

Values of local magnitude ML, are calculated from 56 strong-motion accelerograms recorded in the Imperial Valley earthquake of 15 October 1979 according to procedures developed earlier (Kanamori and Jennings, 1978). These data, plus similar data from the San Fernando earthquake of 9 February 1971 and additional, less numerous data from several other California earthquakes, are used to investigate the use of different measures of distance in near-field determinations of ML: this investigation has relevance for similar uses of distances in determining seismic design criteria. In addition, the consistency of the values of ML found from the strong-motion data is examined from the viewpoint of assessing the need for any correction in the standard attenuation curve, −log10A0(Δ).

It was found that the most consistent values of ML result when distance is measured to the closest point on the surface trace of the fault if a site lies within a circle with diameter equal to the extent of faulting and centered on the center of faulting (center of energy release). Outside this circle, the distance measured to the center of the circle is recommended.

A consistent trend in the values of ML found from strong-motion records is seen in the data. The values start, at zero distance, at essentially the far-field value and then decrease to −1/4 unit at about 20 km. Then they rise to +1/4 unit at 50 to 60 km. A smooth revision to the standard attenuation curve is presented which removes this systematic trend.
Building damage at Charleston, South Carolina, associated with the 1886 earthquake
Authors: Robinson Andrew , Talwani Pradeep
Published: July 2021

abstract

Following the Modified Mercalli Intensity X 31 August 1886 earthquake, a privately published report described the damage sustained by each of the approximately 7,000 buildings in Charleston, South Carolina. We have examined this report to seek the factors that contributed to the observed damage. An analysis of the data suggests that the type of material used in the construction was the most important single factor and the site location (made versus solid ground) a secondary one. Over 80 per cent of the damaged buildings were of brick construction. Only a slightly higher proportion of brick buildings located on made ground (69 per cent) suffered compared to those located on firm ground (63 per cent). Only 7 per cent of wood frame structures sustained damage, of these 96 per cent were located on made ground.
Numerical evaluation of near-field, high-frequency radiation from quasi-dynamic circular faults
Authors: Campillo Michel
Published: July 2021

abstract

We compute the near-field, high-frequency radiation from a circular crack expanding with constant rupture velocity and discuss the characteristics of the stopping phases. We then introduce rupture velocity jumps in the fracture process. The computed accelerations show the dominant role played by the rupture front kinematics. The high acceleration pulses are associated with sudden changes of the rupture velocity. For a sudden jump (or a sudden stop), there is no theoretical high-frequency limit to the spectral density of acceleration. In order to account for fmax, we introduce a smooth deceleration of the rupture front over a time t′ in place of a sudden stop. This results in a spectral fall-off for frequencies greater than 1/t′ and supports the interpretation of fmax as a source effect.
Maximum likelihood estimation of b values for magnitude grouped data
Authors: Bender Bernice
Published: July 2021

abstract

The b value estimated by fitting a set of observed earthquake magnitudes to the magnitude-frequency relationship, log N(m) = a - bm, where N(m) = number of earthquakes exceeding magnitude m, is correlated with the fitting technique used. Both so-called interval and cumulative least-squares fits to the formula log N(m) = a - bm tend statistically to estimate too low a b value, because they cannot include magnitudes above the maximum observed. Maximum likelihood formulas (Aki, Utsu, and Page) for exact or continuous magnitudes give biased results if they are applied to interval data, with the bias increasing as interval size increases. The bias is small at magnitude intervals Δm = 0.1, but significant if the formulas are applied to magnitudes which have been recovered from historic intensity data at intervals of 0.6 magnitude unit. Corrections for interval size can be applied to the continuous data formulas to make them equivalent to the formula derived specifically for grouped data (e.g., Karnik, 1971). A simpler form of the grouped data formula is derived here and shows the role of interval size and maximum magnitude on the b value obtained. This paper also shows how, given a population value of b, to calculate the distribution of the estimated b values. Conversely, this paper derives an a posteriori distribution for the population b value, given the magnitudes of an observed set of earthquakes.

The distribution of b values fitted by various techniques is illustrated for a number of cases. Several illustrations of probabilistic ground motions calculated for a range of b values show that a small fractional change in the assumed b value can have a substantially larger fractional effect on the ground motion calculated.
A specific barrier model for the quantitative description of inhomogeneous faulting and the prediction of strong ground motion. Part II. Applications of the model
Authors: Papageorgiou Apostolos S. , Aki Keiiti
Published: July 2021

abstract

The specific barrier model, which was described in detail by Papageorgiou and Aki (1983), is applied to a set of five moderate to strong Californian earthquakes: Kern County (1952); San Fernando (1971); Borrego Mountain (1968); Long Beach (1933); and Parkfield (1966). Source parameters such as barrier intervals, local stress drops, cohesive zone size, and cohesive stress are inferred. The analysis of the San Fernando earthquake of 1971 revealed a strong frequency dependence of Qβ, suggesting that the high frequencies may not be as strongly attenuated as initially thought. This suggests that the fall-off at high frequencies of observed spectra at a site may not be a propagation path effect but primarily a source effect. The cut-off frequency observed on the source acceleration power spectra of all the events analyzed in this paper, is interpreted in terms of the cohesive zone size and cohesive stress which arrest the localized fractures that occur on the fault plane. It was found that the barrier interval, as inferred by the specific barrier model, increases with the increase in maximum slip. The ratio of the latter to the former represents the local strain drop and was found to increase slightly (factor of 2) with earthquake size. This verifies the relation between barrier interval and maximum slip which has been observed by Aki et al. (1977) who inferred the barrier interval by different methods (i.e., surface measurement of fault slip, seismic measurement of rise time, scaling law of seismic spectrum). Striking similarities with respect to source parameters were found between the Fort Tejon (1857) and Kern County (1952) earthquakes as well as between the Long Beach (1933) and Parkfield (1966) earthquakes. The former are characterized by long barrier intervals and large slips while the latter are characterized by short barrier intervals and small slips. San Fernando (1971) and Borrego Mountain (1968) earthquakes lie in between these two extremes.
Possibility of induced seismicity in the vicinity of the Sleepy Hollow oil Field, southwestern Nebraska
Authors: Rothe George H. , Lui Chung-Yao
Published: July 2021

An array of four seismographs operating in northwestern Kansas and southwestern Nebraska detected 31 earthquakes in the magnitude range 0.6 to 2.9 from March 1979 to March 1980. Of these, 22 were recorded at enough stations to allow accurate location, and at least three of them were felt by local residents. Sixteen of the located events occurred in the immediate vicinity of the most productive oil field in Nebraska: the Sleepy Hollow Field. A mail canvass revealed a well-constrained “felt” area about 10 km across which coincides remarkably well with the oil field. Water injection has been used as a method of enhanced recovery in this field since 1966. Some of the earthquakes occurred on possible downward extensions of faults in the deeper sedimentary rocks and granite basement, implying that some of the seismicity may be induced. Deeper events and other supporting data, however, suggest current tectonic activity on the Chadron-Cambridge Arch. The recently installed eight-station Sleepy Hollow Seismic Network should provide the data necessary to test these hypotheses.
Interpretation of seismic reflection profiling data for the structure of the San Andreas fault zone
Authors: Feng R. , McEvilly T. V.
Published: July 2021

A seismic reflection profile crossing the San Andreas fault zone in central California was conducted in 1978. Results are complicated by the extreme lateral heterogeneity and low velocities in the fault zone. Other evidence for severe lateral velocity change across the fault zone lies in hypocenter bias and nodal plane distortion for earthquakes on the fault. Conventional interpretation and processing methods for reflection data are hard-pressed in this situation. Using the inverse ray method of May and Covey (1981), with an initial model derived from a variety of data and the impedance contrasts inferred from the preserved amplitude stacked section, an iterative inversion process yields a velocity model which, while clearly nonunique, is consistent with the various lines of evidence on the fault zone structure.
Source dimensions and stress drops of small earthquakes near Parkfield, California
Authors: O'Neill M. E.
Published: July 2021

Source dimensions and stress drops of 30 small Parkfield, California, earthquakes with coda duration magnitudes between 1.2 and 3.9 have been estimated from measurements on short-period velocity-transducer seismograms. Times from the initial onset to the first zero crossing, corrected for attenuation and instrument response, have been interpreted in terms of a circular source model in which rupture expands radially outward from a point until it stops abruptly at radius a. For each earthquake, duration magnitude MD gave an estimate of seismic moment MO and MO and a together gave an estimate of static stress drop.

All 30 earthquakes are located on a 6-km-long segment of the San Andreas fault at a depth range of about 8 to 13 km. Source radius systemically increases with magnitude from about 70 m for events near MD 1.4 to about 600 m for an event of MD 3.9. Static stress drop ranges from about 2 to 30 bars and is not strongly correlated with magnitude. Static stress drop does appear to be spatially dependent; the earthquakes with stress drops greater than 20 bars are concentrated in a small region close to the hypocenter of the magnitude 512 1966 Parkfield earthquake.
Dependence of sediment-filled valley response on input amplitude and valley properties
Authors: Tucker B. E. , King J. L.
Published: July 2021

For three sediment-filled valleys, average site responses were experimentally determined and found to apply, to within ±0.25 log units, to earthquakes at any azimuth and to S waves and coda waves; for one of these valleys, ground accelerations were measured over the range 10−5 to 0.2 g, and no significant differences in site responses were apparent. In two valleys with sediment-basement impedance contrasts of 5:1 and 6:1, average site amplification is as much as a factor of five in certain frequency bands. In another valley, with a sediment-basement impedance contrast of 3:1, sediment amplification is about a factor of two. The duration of motion on the valley sediments, in narrow frequency bands, is equal to that on the bordering rock, implying that the observed amplification is not due to a high-Q resonance of the sediments.
Foreshock and aftershock activity of the 1976 Mesa de Andrade, Mexico, earthquake
Authors: Gonzalez J. Javier , Nava F. Alejandro , Reyes C. Alfonso
Published: July 2021

Study of the aftershocks of the 7 December 1976, Mesa de Andrade, earthquake (ML = 5.3, MS = 5.7) on the Cerro Prieto fault in the Colorado River Delta, indicates a simple strike-slip transform fault mechanism. The fault plane defined by aftershocks is essentially vertical with a surface projection 1.5 km southwest of the surface trace of the Cerro Prieto fault. The main shock was complex and consisted of two large events. Aftershock hypocenters are distributed in two clusters separated by a gap suggestive of an unbroken barrier.

Station corrections of about 0.7 sec are indicated for arrival-time locations using stations both on the deltaic sediments and on the surrounding basement outcroppings (assuming a flat-layered velocity model). Differences of some 10 to 15 km are found between epicenters obtained using only United States stations and epicenters obtained with the addition of Mexican local stations.

Foreshock activity, recorded on a portable seismic network, was located in a zone coincident with the northern aftershock cluster. The abrupt onset of foreshock activity emphasizes the importance of continuous monitoring of the Colorado River Delta area in any scheme of earthquake risk studies.
A catalog of shallow earthquakes of Mexico from 1900 to 1981
Authors: Singh S. K. , Rodríguez M. , Espindola J. M.
Published: July 2021

A catalog of shallow earthquakes (depth ≦ 65 km) of Mexico (15° to 20°N, 94.5° to 105.5°W) covering the period 1900 to 1981 is presented. The catalog includes only those events whose magnitudes (M, Ms, or magnitude from Pasadena) are ≧5.9. It is most likely complete for shocks with Ms ≧6.5 from July 1906 to December 1981. For many shocks, Ms has been determined from Uppsala bulletins and/or Uppsala and Göttingen Wiechert Seismograms. The statistics of incremental frequency n(Ms) shows a peak at Ms ≃ 7.7, reinforcing a previous observation by Singh et al. (1981). In the range 6.4 ≦ Ms ≦ 7.5, the observed n(Ms) deviates significantly from an exponential distribution. The catalog provides a basis for further statistical analysis of earthquakes in Mexico.
Late quaternary history of the Stillwater seismic gap, Nevada
Authors: Wallace Robert E. , Whitney Robert A.
Published: July 2021

Fault scarps that formed during the 1915 and 1954 earthquakes in central Nevada are roughly aligned, but are separated by a gap of 40 km. The gap contains no historical scarps and has been termed the Stillwater seismic gap. The abundance, size, and distribution of prehistorical fault scarps is similar in the Stillwater seismic gap and the 1915 and 1954 earthquake areas, and overall height and long-term uplift rates of range blocks are similar throughout the area studied; thus, the faults in the gap do not appear to be locked or appreciably more or less active on a long-term basis than those in areas of the 1915 and 1954 earthquakes. None of the scarps in the gap is likely younger than about 300 yr, so that no major earthquake occurred in that period.

The Stillwater seismic gap is part of the central Nevada-eastern California seismic belt, where large-scale surface faulting events have occurred at intervals of a few years to a few decades in a pattern that suggests incremental filling of the belt. If that pattern of belt-filling continues, the Stillwater gap is a likely site for future major faulting, but the low level of seismicity in the gap area suggests that the next major earthquake there is not imminent.
A new asymptotic method for the modeling of near-field accelerograms
Authors: Bernard P. , Madariaga R.
Published: July 2021

We study high-frequency radiation from a dislocation model of rupture propagation at the earthquake source. We demonstrate that in this case all the radiation emanates from the rupture front and, by a change of variables, that at any instant of time the high-frequency waves reaching an observer come from a line on the fault plane that we call isochrone. An asymptotic approximation to near-source velocity and acceleration is obtained that involves a simple integration along the isochrones for every time step. It is shown that wave front discontinuities (critical or stopping phases) are radiated every time an isochrone becomes tangent to a barrier. This leads to what we call the critical ray approximation which is given in a closed form. The previous results are compared with discrete wavenumber synthetics obtained by Bouchon (1982) for the Gilroy 6 recording of the Coyote Lake earthquake of 1980. The fit between the asymptotic and full numerical method is extremely good. The critical ray approximation permits the identification of different phases in Bouchon's synthetics and the prediction of the behavior of the signal in the vicinity of their arrival time.
Stress analysis of rectangular walls under seismically induced hydrodynamic loads
Authors: Haroun Medhat. A.
Published: July 2021

Seismically induced bending moments in the walls of rectangular concrete liquid storage tanks are evaluated. The tank is assumed to be subjected to simultaneous horizontal and vertical components of earthquake excitations. The liquid is assumed to be homogeneous, inviscid, and incompressible. Hydrodynamic pressures are calculated using the classical potential flow approach and are compared with those obtained from approximate analyses. Typical systems of loadings are identified and applied on the walls which are assumed to behave as elastic plates. Analytical expressions for the computation of internal moments are presented, and numerical values of moment coefficients are tabulated for use in seismic design analysis of tank walls.
Source parameters for aftershocks of the Oroville, California, earthquake
Authors: Fletcher Jon , Boatwright John , Haar Linda , Hanks Thomas , McGarr Art
Published: July 2021

A suite of 111 strong-motion accelerograms for 14 aftershocks of the Oroville, California, earthquake (ML = 5.7, 1 August 1975) that range in local magnitude (ML) from 2.8 to 5.2 has been analyzed to obtain estimates of seismic moment (Mo), source radius (ro), and stress drop (Δσ) in addition to the focal parameters of location, depth, and fault-plane solution. This data set, which is unusually complete for near-source (Δ ≲ 20 km) on-scale readings, allows for greater precision in the calculation of various measures of stress difference as represented by the Brune stress drop, the apparent stress, the arms stress drop, and the dynamic stress drop. In addition, the seismicity following each aftershock and state-of-stress seem to correlate with particular estimates of stress drop.

Seismic moments were calculated from the asymptotic long-period spectral levels which were corrected for the radiation pattern of a double-couple point source. They range from 1.4 × 1021 dyne-cm for a ML = 2.8 shock to 3.3 × 1023 dyne-cm for a ML = 5.1 event. A least-squares fit between ML and the logarithm Mo yields

log M 0 = ( 1.36 ± 0.22 ) M L + ( 16.8 ± 1.1 ) for M L ≧ 4.3

and

log ⁡ M 0 = ( 1.1 ± 0.14 ) M L + ( 18 ± 0.51 ) for M L ≦ 4.1.

These relationships are qualitatively in agreement with the response of the Wood-Anderson instrument to a Brune pulse. Stress drops from the Brune formulation range about 14 to 170 bars. Stress drop is correlated with depth in that the deepest events have the largest stress drops and no large stress drops occur at the shallow depths. Apparent stresses are smaller than the Brune stress drops and show a weaker depth dependence over the depth interval for which they are available. The stress drop calculated from the rms of acceleration (arms) was approximately constant at about 90 bars for 5 of the 7 larger events analyzed; the two high values of 160 and 190 bars were obtained only for the two events which had marked aftershock sequences of their own. These results may be interpreted in terms of the state-of-stress, simple fracture criteria, and mechanisms for the generation of aftershocks. The increase with depth of the envelope of the Brune stress drops may be caused by an increase in shear stress from overburden pressure. Smaller stress drop events can occur at any depth interval. The causal mechanism of aftershocks is not known, but probably includes a change in the frictional properties of the fault, suggesting that the arms stress drop is a measure of the frictional or dynamic stress release.
Estimates of short-periodQvalues and seismic moments from coda waves for earthquakes of the Beijing and Yun-nan regions of China
Authors: Chen Peishan , Nuttli Otto W. , Ye Wenhua , Qin Jiazheng
Published: July 2021

Coda waves are used to determine the Q value of short-period waves in the Beijing area and in Yun-nan Province, China, and the seismic moments of the earthquakes studied. For the Beijing area the Q0, or 1-Hz value, is found to be approximately 400, with little or no indication of frequency dependence of Q for frequencies near 1 Hz in that region. For Yun-nan Province, the Q0 value is about 180, and the data suggest that Q(f) = Q0f0.2, where f is wave frequency. These values are in fairly good agreement with short-period Q estimates made for those regions by Chen and Nuttli (1984), on the basis of attenuation of seismic intensity values.

Hermann's (1980) application of Aki's (1969) coda wave theory is extended, to provide simple equations for calculating master curves for coda wave studies. Two types of master curves provide independent estimates of Q0 and of the dependency of Q on wave frequency. For the data analyzed the two methods gave similar results. A third type of master curves gives estimates of the seismic moments of the earthquakes studied. The moments obtained by this means agree with values obtained by the conventional methods of analysis that use the spectrum of body waves or surface waves.
Statistical aspects of New England seismicity from 1975 to 1982 and implications for past and future earthquake activity
Authors: Ebel John E.
Published: July 2021

The seismicity of New England from 1 October 1975 to 30 November 1982 has been studied to determine how well it represents past seismicity and what it might imply about future earthquakes. Just over 100 earthquakes with magnitudes between 2.0 and 4.7 were recorded during this modern time period, while the historic earthquake catalog of Chiburis (1981) lists 760 earthquakes in New England from 1568 to 1975, the largest having maximum Modified Mercalli intensity VII shaking. The spatial distribution of the recent seismicity reproduces that for the historical seismicity patterns quite well, with the larger earthquakes in the modern record having preferentially occurred along coastal and lowland New England or in central New Hampshire. Space-time plots show that the seismicity displays considerable spatial variation, and that there are only vague hints of migrations of epicenters. The number of earthquakes as well as the amount of seismic energy release appear essentially random in time, and the recurrence curve for the modern time period (log number of events versus magnitude) is a straight line for events between magnitudes 2 and 4.5 with a b value of 0.84 (±0.03). The sizes of the largest earthquakes in the historic record are those which would be expected by extrapolating the present seismicity rate backward in time using a Gumbel type I distribution. One major discrepancy between the statistics of the recent and historic catalogs is that the latter does not have as many moderate (magnitudes 5 to 5.8) earthquakes as would be expected from the recent data. This discrepancy could be due to inaccuracies in the historic catalog, to unusually high recent seismicity or to a real historical shortage of such moderate magnitude earthquakes. Large earthquakes may be more likely to happen in areas of past and present high seismicity, especially in central and southern New Hampshire, along coastal Maine, and along the south coast to New England.