bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microearthquakes near the Sleepy Hollow oil field, southwestern Nebraska
Authors: Evans David G. , Steeples Don W. 
Published: July 2021

Abstract
Between April 1982 and June 1984, 311 earthquakes were detected, and 176 earthquakes were located in the vicinity of the Sleepy Hollow oil field, southwestern Nebraska. The oil field is being injected with water to enhance oil production, and the earthquakes may be related to production. There is geologic evidence, however, to suggest that the earthquakes are tectonic in origin and are related to uplift along the axis of the Cambridge Arch, on which the field is located. First motion data from these events do not yield a well-constrained fault plane solution. Furthermore, first motion detections are inconsistent for earthquakes with nearly coincident hypocenters, indicating that more than one faulting mechanism is active in the oil field. Injection pressures do not correlate well with earthquake occurrence.
A microseismicity survey of Axial Seamount, Juan de Fuca Ridge
Authors: Jacobson R. S. , Bibee L. D. , Embley R. W. , Hammond S. R. 
Published: July 2021

Abstract
An array of ocean bottom seismometers and hydrophones were deployed within the caldera of Axial Seamount, located at the intersection of the Cobb-Eickelberg Seamount Chain and the Juan de Fuca Ridge. Recent manned submersible dives have discovered the presence of two distinct hydrothermal vent fields. The objective of the microseismicity survey was to determine baseline information necessary for designing an optimal experiment to monitor seismicity associated with submarine volcanic and hydrothermal systems. With an instrument deployment period of eight days, over 1500 events were recorded and examined. Most events occurred within three periods of swarm activity. The location of the swarm events is believed to be within the low temperature vent field in the northwest portion of Axial's caldera. These impulsive, high-frequency events are interpreted to be tectonic in origin. No harmonic tremor-like events were observed on any of the instruments, indicating a lack of magmatic movement. Only nine local events were recorded on more than one instrument, and none of these could be located unambiguously. Monochromatic 20-Hz signals were also recorded and are interpreted to originate from whales observed in the immediate vicinity.
Regional variation of the short-period (1 to 10 second) source spectrum
Authors: Zhuo Yuru , Kanamori Hiroo 
Published: July 2021

AbstractWe determined m^b, the body-wave magnitude calculated from the maximum amplitude of short-period P waves, of 38 large earthquakes in various tectonic provinces. The data are divided into three groups: group 1 (subduction-zone thrust events); group 2 (nonsubduction-zone dip-slip and oblique-slip events); and group 3 (strike-slip events). Groups 2 and 3 include intraplate earthquakes. Comparison of m^b values for these three groups of events suggests that the source spectral amplitudes of intraplate events at a period of about 1.4 sec is 2 to 5 times larger than those of subduction-zone events with the same Mw. We also determined the source spectra of 28 large earthquakes (Mw = 6.5 to 7.7) directly from Global Digital Seismographic Network (GDSN) data, over a period range from 1 to 10 sec. At periods from 1 to 2 sec, the source spectral amplitudes of intraplate earthquakes are 2 to 4 times larger than those of subduction-zone events with the same Mw. The difference decreases as the period increases to 10 sec.
Seismic event detection and source location using single-station (three-component) data
Authors: Magotra N. , Ahmed N. , Chael E. 
Published: July 2021

AbstractThe seismic event detection and source location scheme presented in this paper uses single-station seismic data to analyze seismic events. To detect events, “the detection scheme” combines the signals on the horizontal components in a manner analogous to beam steering. Once an event is detected, “the location scheme” estimates the location of the source with respect to the receiver by estimating the polarization direction of the Pn phase. The range estimate is then obtained from the relative timing of different phases.
Quasi-periodic occurrence of earthquakes in the 1978-1986 Bishop-Mammoth Lakes sequence, eastern California
Authors: Savage J. C. , Cockerham Robert S. 
Published: July 2021

Abstract
In December 1984, Ryall and Hill noted that the five principal events in the Bishop-Mammoth Lakes earthquake sequence occurred at intervals of about 1.5 yr with a standard deviation for an individual event of 0.25 yr. Some data selection was involved in identifying the principal events, although the choices seemed reasonable. The recent Chalfant Valley earthquake (ML = 6.4; 21 July 1986) followed the last prior principal event in the Bishop-Mammoth Lakes sequence by 1.65 yr, and no important activity intervened except one aftershock from the prior event. Thus, the Chalfant Valley earthquake could have been forecast from the observed periodicity. However, the precision of the forecast (±0.8 yr for the 95 per cent confidence interval) is not sufficient to furnish convincing evidence that the Bishop-Mammoth Lakes sequence is quasi-periodic. Extrapolation of the trend established by the six previous events suggests that the next event in the Bishop-Mammoth Lakes sequence would be expected in December 1987 ± 0.7 yr (95 per cent confidence interval). The regularity of the Bishop-Mammoth Lakes sequence is comparable to that of the Parkfield, California, sequence (average interevent interval 20.8 yr with a standard deviation for an individual interval of 6.2 yr). Both sequences consist of six events. There is a plausible physical explanation for the periodicity observed at Parkfield; such an explanation for the Bishop-Mammoth Lakes sequence is lacking.
The Meckering earthquake of 14 October 1968: A possible downward propagating rupture
Authors: Vogfjörd Kristín S. , Langston Charles A. 
Published: July 2021

AbstractAverage source parameters of the 1968 Meckering, Australia earthquake are obtained by the inversion of body waves. The objectives of the inversion are the elements of the moment tensor and the source-time history. An optimum source depth of 3 km is determined, but because of source complexity the point source assumption fails and the moment tensor obtained at that depth has a large nondouble-couple term, compensated linear vector dipole = 34 per cent. The source parameters of the major double-couple are: strike = 341°; dip = 37°; rake = 61°; and seismic moment = 8.2 ×1025 dyne-cm. The source-time function is of approximately 4 sec duration, with a long rise time and a sharp fall-off. The fault length is constrained on the surface by the observed surface break, and results from vertical displacement modeling suggest a width of approximately 10 km in the middle, assuming a dip of 37°. That restricts the entire faulted area to lie above 6 km depth. Two finite fault models for the earthquake are presented, with rupture initiating at a point (1) near the top of the fault and (2) at the bottom of the fault. Both models produce similar long-period synthetics, but based on the short-period waveforms, model 1 is favored. It is argued that such a rupture process is the most reasonable in this cold shield region.
Aftershocks and surface faulting associated with the intraplate Guinea, West Africa, earthquake of 22 December 1983
Authors: Langer C. J. , Bonilla M. G. , Bollinger G. A. 
Published: July 2021

Abstract
This study reports on the results of geological and seismological field studies conducted following the rare occurrence of a moderate-sized West African earthquake (mb = 6.4) with associated ground breakage. The epicentral area of the northwestern Guinea earthquake of 22 December 1983 is a coastal margin, intraplate locale with a very low level of historical seismicity. The principal results include the observation that seismic faulting occurred on a preexisting fault system and that there is good agreement among the surface faulting, the spatial distribution of the aftershock hypocenters, and the composite focal mechanism solutions. We are not able, however, to shed any light on the reason(s) for the unexpected occurrence of this intraplate earthquake. Thus, the significance of this study is its contribution to the observational datum for such earthquakes and for the seismicity of West Africa.
The main shock was associated with at least 9 km of surface fault-rupture. Trending east-southeast to east-west, measured fault displacements up to ∼13 cm were predominantly right-lateral strike slip and were accompanied by an additional component (5 to 7 cm) of vertical movement, southwest side down. The surface faulting occurred on a preexisting fault whose field characteristics suggest a low slip rate with very infrequent earthquakes. There were extensive rockfalls and minor liquefaction effects at distances less than 10 km from the surface faulting and main shock epicenter. Main shock focal mechanism solutions derived from teleseismic data by other workers show a strong component of normal faulting motion that was not observed in the ground ruptures.
A 15-day period of aftershock monitoring, commencing 22 days after the main shock, was conducted. Eleven portable, analog short-period vertical seismographs were deployed in a network with an aperture of 25 km and an average station spacing of 7 km. Ninety-five aftershocks were located from the more than 200 recorded events with duration magnitudes of about 1.5 or greater. Analysis of a selected subset (91) of those events define a tabular aftershock volume (26 km long by 14 km wide by 4 km thick) trending east-southeast and dipping steeply (∼60°) to the south-southwest. Composite focal mechanisms for groups of events, distributed throughout the aftershock volume, exhibit right-lateral, strike-slip motion on subvertical planes that strike almost due east. Although the general agreement between the field geologic and seismologic results is good, our preferred interpretation is for three en-echelon faults striking almost due east-west.
Response of an oceanic wave guide to an explosive point source using leaking modes
Authors: Haddon R. A. W. 
Published: July 2021

AbstractA new method for computing transient wave fields in a stack of liquid layers overlying a solid elastic layered half-space is presented. By taking the frequency, ω, and wavenumber, k, simultaneously as complex variables and choosing appropriate paths of integration in the ω-plane, the integration with respect to k in the well-known integrals representing the exact solution is performed exactly using Cauchy residue theory. The remaining integration (with respect to ω) is then performed approximately by use of the Fast Fourier transform and by other numerical integration methods. The theoretical results derived show that the complete wave field, including all possible body waves, can be represented simply as a superposition of modes. The method is easy to apply and computationally efficient, and is valid for both near- and far-field solutions. The same method is also applicable to axisymmetric borehole problems. The application of the method is illustrated in detail with a numerical example.
P-wave deflection or off-azimuth arrivals in the Charlevoix Seismic Zone
Authors: Buchbinder Goetz G. R. 
Published: July 2021

Abstract
During the months of August 1984 and October 1985, experiments were undertaken in the Charlevoix Seismic Zone to record high-frequency body waves from earthquakes. The seismograms were recorded by digital three-component seismographs. The experiments were conducted on the north shore of the St. Lawrence River only and covered nine sites. All but the two most northeasterly recording sites exhibited P-wave arrivals that arrived from azimuths that differed from the theoretical azimuth based on the computed hypocenter-station relationship. These differences amounted to several tens of degrees. Neither the errors in hypocenter location nor in the orientation of the horizontal seismometers are believed to be the cause of this difference.
Theoretical computations based on a two-dimensional model with strong lateral velocity gradients or a discontinuity in velocity produce deviations of the direction of arrival of the P wave in a horizontal plane normal to the anomaly that can amount to several tens of degrees. Both the lateral gradient and discontinuity models satisfy the observed deviation of azimuth versus azimuth deflection. However, only the discontinuity satisfies the deflection versus hypocentral distance distribution, at least for distances to 20 km.
Comparing the observed data with the theoretical values suggests that the anomaly in velocity occurs in a near-vertical plane striking parallel to the St. Lawrence River. This is also the direction of ancient extension faults in the region. Other structures were introduced 350 m.y. ago when the Charlevoix impact structure was formed. A number of anorthosite bodies with very high seismic velocities also outcrop in the region. Because of the high frequencies involved, the scale of the anomaly may well be only a few hundred meters, and the anomaly may most likely be located very close to, even directly beneath, the station.
Radiation characteristics of elastodynamic line sources buried in layered media with periodic interfaces. II.P- andSV-wave analysis
Authors: Varadan Vijay K. , Lakhtakia Akhlesh , Varadan Vasundara V. , Langston Charles A. 
Published: July 2021

AbstractA method for determining for determining the elastodynamic (P and SV waves) radiation characteristics of finite-size sources buried in horizontally layered media, having periodically corrugated interfaces, is described. In particular, the example problem chosen to illustrate the procedure is as follows: a solid plate lies on top of a solid half-space; the solid-solid interface has been taken to be planar, but traction-free conditions prevail on the other boundary of the elastic plate, which surface is also periodically corrugated; and the source has been taken to be an isotropic, P-wave line source located inside the elastic plate. The technique presented utilizes the plane wave spectral decomposition of the relevant fields within the framework of the extended boundary condition method or the T matrix method. Since the T-matrix method is a matrix approach, it is very attractive computationally and is certainly more tractable than a method based on the direct solution of the integral equations involved in the scattering problem. Numerical results are given to delineate the various features of the field diffracted into the elastic half-space, as well as the displacement field induced on the traction-free boundary of the elastic plate. The specific example examined is directly related to regional wave propagation in a continental crustal wave guide.
Rola ubezpieczeń w koncepcjach zarządzania ryzykiem współczesnych przedsiębiorstw
Authors: Bednarczyk Teresa H. , Szymańska Anna 
Published: July 2021

Cel artykułu/hipoteza: Koncepcje zarządzania ryzykiem w przedsiębiorstwie ewoluują w czasie pod wpływem gwałtownych zmian, zachodzących zarówno w otoczeniu zewnętrznym, jak i wewnętrznym. Tradycyjne podejście do zarządzania ryzykiem w przedsiębiorstwie ustępuje miejsca filozofii holistycznego zarządzania ryzykiem. Celem opracowania jest analiza tych dwóch koncepcji pod kątem ustalenia aktualnej roli i praktycznego znaczenia metody ubezpieczeniowej. W opracowaniu zweryfikowano hipotezę badawczą w brzmieniu: Pomimo zmieniających się teoretycznych koncepcji zarządzania ryzykiem, a także relatywnego wzrostu znaczenia ryzyka nie nadającego się do ubezpieczenia, w praktyce biznesowej ubezpieczenia nadal zajmują ważne miejsce zwłaszcza w procesie zarządzania ryzykiem dużych i średnich przedsiębiorstw.
Metodyka: Opracowanie ma charakter teoretyczno-analityczny. Obok przeglądu dostępnej literatury krajowej i zagranicznej, przeanalizowano również wyniki badań empirycznych oraz wybrane raporty instytucji doradczych i konsultingowych, w tym najnowszy raport AON Polska 2019 na temat zarządzania ryzykiem w przedsiębiorstwach.
Wyniki: W większości krajowych przedsiębiorstw realizowany jest silosowy model zarządzania ryzykiem, a ubezpieczenie jako metoda finansowania skutków urzeczywistnienia się ryzyka wciąż nie traci na znaczeniu. Chociaż względne znaczenie ubezpieczeń maleje z powodu wzrostu znaczenia ryzyka nie nadającego się do ubezpieczenia jak np. ryzyko niestabilności ekonomicznej i geopolitycznej, spowolnienia gospodarczego, wzrastającej konkurencji, czy braku profesjonalnych kadr, to jednak ubezpieczenia nie utraciły kluczowej roli w praktyce, zwłaszcza dużych i średnich przedsiębiorstw.
Developing a heutagogy approach to promoting teacher competencies in Indonesia
Authors: Handayani Silvia Mariah , Yeigh Tony , Jacka Lisa , Peddell Lewes 
Published: July 2021

This study aims to establish a Heutagogy approach for teacher professional education in Indonesia as an attempt to improve teacher competencies. This study will identify key elements of a Heutagogy approach derived from previous Heutagogy practices. The methods to collect data for developing the Heutagogy approach in this study employs a literature review of previous research and findings related to Heutagogy practice. In this regard, this study's established elements are Learner-determined learning, Metacognitive reflection, Collaboration, and Capability development. These elements are analysed and then incorporated into the TPE model with support from online learning tools. Capability development is the goal of experiencing each of the elements of Heutagogy in this approach. Each of these key elements will contribute to developing participants capability as professional teachers. The Heutagogy approach in this study is expected to be significant for improving teacher competencies in Indonesia.

Keywords: teacher professional education, heutagogy
The effectiveness of advance organiser learning model assisted by Zoom Meeting application
Authors: Syaharuddina Syaharuddina , Husain Husriani , Herianto Herianto , Jusmiana Andi 
Published: July 2021

The COVID-19 pandemic caused the education system to suddenly move from offline to online learning, so it takes a variety of effective learning design trials. This research aims to find out the effectiveness of the advance organiser learning model assisted by the Zoom Meeting application. This research was conducted at State Junior High School 3 Binamu, Jeneponto Regency. The research sample was 20 people. The research was conducted with an embedded design model of mixed methods. The findings show that the online advance organiser learning model uses an effective Zoom Meeting application for use, where 1) the application of advance organiser learning has a positive relationship with student learning outcomes; 2) the implementation of learning takes place in the category of â€˜goodâ€™; 3) studentsâ€™ positive activities increase in each meeting and 4) students respond well to the implementation of the advance organiser learning model/ using the Zoom Meeting application. The implementation of advance organiser online learning using the Zoom Meeting application, however, is no more effective when compared to the implementation of learning conducted offline or under normal conditions.

Keywords: Advance organiser, distance learning, pandemic COVID-19, Zoom meeting.
The effect of indirect feedback on students’ writing performance across different learning strategies
Authors: Aridah Aridah , Iswari Weningtyas Parama 
Published: July 2021

This paper aims at knowing how indirect feedback affects the writing performance of students who have different language learning strategies. The study used pre-experimental design with pretest and posttest design. Twenty-one students participated in the treatment which lasted for one semester. The treatment applied a process writing approach in which feedback provision was one of the steps in the process. The students were required to write five essays on different topics and the teacher gave indirect feedback on each essay draft. During the revision session, the students revised and rewrote their essays following the feedback provided by the teacher. The last version of each essay was scored. The results showed the students’ writing performance significantly improved from the first essay to the succeeding essays, regardless of their learning strategies. However, a significant difference in writing performance across different learning strategies was not found. They both performed equally well.

Keywords: Direct Strategies, Indirect Strategies, Indirect Feedback, Process Approach, Writing Performance
Admission test analysis of pre-service math-science teacher based on its related factors
Authors: Qadar Riskan , Mahdiannur Muhamad Arif , Sulaeman Nurul Fitriyah 
Published: July 2021

The admission test of pre-service teachers uses a knowledge test that has not explored the non-cognitive factors. This study is focused on considering the basic abilities, logical thinking abilities, gender, level of cognitive development and the type of pre-service teacher programme. Moreover, other factors, such as motivation, role of life experiences and verification of logical thinking test result (TOLT), were also contemplated. This study applied TOLT to 281 pre-service math–science teachers from four different programmes. This study also developed a multiple mini interview modification with expert screening methods that have validity, reliability and homogeneity parameters based on Aiken's criteria. Our study provides an alternative to reformulate the selection test that combines paper-based tests with interviews as an admission test for pre-service teacher candidates. Our results also illustrate how gender and cognitive development affect the basic abilities based on their programme. Furthermore, admission tests should have balanced cognitive and non-cognitive factors.

Keywords: admission test; content-knowledge ability; level of cognitive development; logical thinking (TOLT); multiple-mini interview (MMI); teacher education.
Diseño de sanitario urbano inteligente para suplir necesidades fisiológicas de personas en condición de calle en Costa Rica
Authors: Rojas-Jiménez Andrea M. , Jurburg-Chaves Katherina 
Published: July 2021

En la capital de Costa Rica, se concentra el mayor porcentaje de personas en condición de calle. Este sector de la población es marginado por la sociedad y presenta deficiencias para suplir sus necesidades básicas. Por lo cual, durante el proyecto, se estudian estas carencias para determinar cuál puede solucionarse a través del diseño de un producto inteligente que mejore su calidad de vida.Debido a lo anterior, se realiza una etnografía digital para obtener información sobre el usuario final y se investigan sus necesidades de mayor importancia. Una vez identificadas dichas necesidades, se decide desarrollar un producto para el manejo de los desechos sanitarios de esta población; este cubre necesidades biológicas, de seguridad y de pertenencia. Para el desarrollo del producto, se lleva a cabo una conceptualización que contempla la definición y validación de requisitos, según la necesidad planteada, un estudio de mercado y un análisis de lo existente.
Una vez planteados estos aspectos, se definen sus funciones, tanto prácticas como inteligentes, componentes, perceptualidad, ergonomía, topología, interacción, ensamble, instalación, materiales y manufactura. Esto da como resultado a SU, un sanitario urbano inteligente desarrollado mediante modelado 3D y renderizado de alta calidad. En este diseño, se limita el contacto con el usuario y se plantea una desinfección automática periódica con ayuda de sensores y luz. Además, este es un producto modular de acero inoxidable, lo que facilita su fabricación y montaje de varios sanitarios. Este producto aporta social e individualmente, ya que su implementación reduce de manera indirecta los desechos sanitarios en las zonas públicas y beneficia directamente a los habitantes de la calle.