bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial variation of ground motion determined from accelerograms recorded on a highway bridge
Authors: Wilson John C. , Jennings Paul C. 
Published: July 2021

AbstractA set of time-synchronized strong-motion accelerograms, obtained on the San Juan Bautista 156/101 Separation Bridge in California during the 6 August 1979 Coyote Lake earthquake (ML = 5.9), are used to study the spatial variation of ground motion at the bridge site, including traveling wave effects and the influence of multiple-support excitation. Analysis of the ground motion recorded at the base of two of the bridge supports (32.6 m apart) revealed the presence of a differential support excitation having a period of ≈ 3 sec, much longer than any structural periods of the bridge. This signal also appeared as a noticeable long-period component in the superstructure displacements. Analysis of the vertical and radial components of the 3-sec ground motion indicated that ground displacements were retrograde for the duration of strong shaking, with several cycles exhibiting elliptical particle motions. These findings suggest that long-period differential support motions were induced by phase delays in a Rayleigh wave traveling across the bridge site. Further support to this premise is given by the location of the bridge site near a maxima of the Rayleigh wave radiation pattern for the Coyote Lake earthquake (based on published focal mechanism data). Traveling wave effects were also detected for compressional body waves by a correlation analysis which indicated a time delay of ≈ 7 msec between P-wave arrivals at two of the bridge supports.
Deformation due to a rectangular tension crack in an elastic half-space
Authors: Yang Xue-Min , Davis Paul M. 
Published: July 2021

AbstractClosed, analytic expressions are given for the displacement fields, their derivatives, and stresses from a rectangular crack in an elastic half-space having Burger's vector normal to its surface. Displacements are found by integration of Volterra's formula over the crack area using Mindlin's (1936) point force solutions for the elastic half-space. Differentiation of the displacement fields yields expressions for calculating stress and strain throughout the medium. Contours of stresses and displacements are given for selected geometries. The expressions for displacements give identical values to those calculated using angular dislocations (Comninou and Dundurs, 1975). All solutions are presented as a FORTRAN subroutine to facilitate practical implementation.
Periodic energy release in the New Madrid seismic zone
Authors: Mento Dean J. , Patrick Ervin C. , McGinnis L. D. 
Published: July 2021

AbstractThe annual release of strain energy by earthquakes in the New Madrid seismic zone, as represented by the strain factor, is calculated and cumulated. When the main annual energy release, in the form of a linear regression, is subtracted from the data, the residual curve suggests that the energy release rate is cyclical with a period of 30 to 35 yr for earthquakes of magnitude 5.5 or less. Furthermore, the current rate is well below normal and may be expected to significantly increase in the near future. Although the increase may be in the form of several small earthquakes, the historical pattern suggests that at least one earthquake of body-wave magnitude 5.0 to 5.2 may be anticipated.
A fourth-order accurate finite-difference scheme for the computation of elastic waves
Authors: Bayliss A. , Jordan K. E. , LeMesurier B. J. , Turkel E. 
Published: July 2021

AbstractA finite-difference model for elastic waves is introduced. The model is based on the first-order system of equations for the velocities and stresses. The differencing is fourth-order accurate on the spatial derivatives and second-order accurate in time. The model is tested on a series of examples including the Lamb problem, scattering from a plane interfaces and scattering from a fluid-elastic interface. The scheme is shown to be effective for these problems. The accuracy and stability is insensitive to the Poisson ratio. For the class of problems considered here, we find that the fourth-order scheme requires from two-thirds to one-half the resolution of a typical second-order scheme to give comparable accuracy.
Inferences about the local stress field from focal mechanisms: Applications to earthquakes in the southern Great Basin of Nevada
Authors: Harmsen S. C. , Rogers A. M. 
Published: July 2021

AbstractFocal mechanisms determined from regional-network earthquake data or aftershock field investigation often contain members ranging from strike slip to normal slip in extensional tectonic environments or from strike slip to thrust slip in compressional environments. Although the coexistence of normal and strike-slip faulting has suggested to some investigators that the maximum and intermediate principal stresses are of approximately equal magnitude, several have asserted that the directions of principle stresses can or must interchange to accommodate both types of mechanisms (Zoback and Zoback 1980b; Vetter and Ryall, 1983). A Coulomb-Navier criterion of slip is invoked to demonstrate that both types of mechanisms, as well as oblique members having preferred nodal-plane dips intermediate between those of the strike-slip and normal mechanisms, may be observed in a region where the stress field, resolved into principal components, is axially symmetric. The proximate coexistence of earthquakes having diverse focal mechanisms could be interpreted as evidence for an approximately axially symmetric stress field in a region where optimally oriented planes of weakness are known to exist in the host rock.
Rupture process of the 1983 Japan Sea (Akita-Oki) earthquake using a waveform inversion method
Authors: Fukuyama Eiichi , Irikura Kojiro 
Published: July 2021

AbstractThe rupture process of the 1983 Japan Sea earthquake (MJMA = 7.7) is determined by applying waveform inversion of displacement-type, strong motion records based on the Bayesian method. The synthesis of the seismic motions from the main shock is made using the records from the two aftershocks (MJMA = 7.1 and MJMA = 6.1) as empirical Green's functions. The main shock fault consists of two subfaults. The aftershock (M = 6.1) occurring south of the main shock fault is used for the southern subfault empirical Green's function and the aftershock (M = 7.1) occurring north of the main shock fault is used for the northern subfault. In this synthesis, it is not necessary to calculate propagation path and local site effects. Therefore, the information about the source process can be extracted from the comparison between observed seismic motions and the synthetic ones without detailed information on the velocity structure along the whole path from the source to each station. The inversion for the rupture process is attempted for both a line source model and an area source model. In both models, the main shock fault surface is divided into several elements whose sizes are determined from the scaling relations between the main shock and its aftershocks. The slip displacement and the rupture starting time on each element are estimated as model parameters in the inversion. A good convergence is obtained after about 10 iteration steps for the line source case and after 5 iteration steps for the area source case. The results are summarized: (1) the average rupture velocity is approximately 2.5 km/sec for the southern subfault and 2.0 km/sec for the northern subfault, and (2) there is a large slip displacement near the rupture initiation point and the north edge of the fault. Thus, there is considerable heterogeneity in rupture propagation and slip distribution over the fault plane.
Long-period surface waves of four western United States earthquakes recorded by the Pasadena strainmeter
Authors: Doser Diane I. , Kanamori Hiroo 
Published: July 2021

AbstractLong-period surface waves recorded on the north-south Pasadena strainmeter are used to determine the seismic moments and fault parameters of the 19 May 1940 Imperial Valley, California, the 16 December 1954 Dixie Valley and Fairview Peak, Nevada, and the 18 August 1959 Hebgen Lake, Montana, earthquakes. Synthetic strain seismograms are matched with the observed strainmeter seismograms. Source parameters from the strainmeter modeling are more consistent with source parameters estimated from geodetic and geologic information than parameters estimated from short-period (&lt;15 sec) body wave data. Long-period surface wave moment estimates agree well with geodetic estimates of moment, but are 1.5 to 5 times greater than moments obtained from modeling of teleseismic body waves or geologic information. The Imperial Valley earthquake is best modeled as consisting of 5 point sources along a fault 87.5 km in length with a strike, rake, and dip of 326°, 180°, and 90°. The moment for the earthquake was 4.8 × 1019 N-m. The synthetic seismogram that best models the Fairview Peak and Dixie Valley earthquakes assumes that the Fairview Peak earthquake was twice the size of the Dixie Valley event. Moments of 5.9 to 13 × 1019 and 3 to 6.5 × 1019 N-m are obtained for these events. A moment of 1.5 × 1020 N-m is obtained for the Hebgen Lake earthquake. Love waves of this earthquake are best modeled by a fault striking 102°, although surface faulting produced during the earthquake strikes 130°.
An automatic phase picker for local and teleseismic events
Authors: Baer M. , Kradolfer U. 
Published: July 2021

AbstractAn automatic detection algorithm has been developed which is capable of time P-phase arrivals of both local and teleseismic earthquakes, but rejects noise bursts and transient events. For each signal trace, the envelope function is calculated and passed through a nonlinear amplifier. The resulting signal is then subjected to a statistical analysis to yield arrival time, first motion, and a measure of reliability to be placed on the P-arrival pick. An incorporated dynamic threshold lets the algorithm become very sensitive; thus, even weak signals are timed precisely. During an extended performance evaluation on a data set comprising 789 P phases of local events and 1857 P phases of teleseismic events picked by an analyst, the automatic picker selected 66 per cent of the local phases and 90 per cent of the teleseismic phases. The accuracy of the automatic picks was “ideal” (i.e., could not be improved by the analyst) for 60 per cent of the local events and 63 per cent of the teleseismic events.
Source parameters of the 1949 magnitude 7.1 south Puget Sound, Washington, earthquake as determined from long-period body waves and strong ground motions
Authors: Baker Glenn Eli , Langston Charles A. 
Published: July 2021

AbstractTeleseismic P, SH, and SV first motions and SH to SV amplitude ratios recorded at eight teleseismic receivers from the 1949 magnitude 7.1 Olympia, Washington, earthquake in combination with data from three stations at regional distances were utilized in a grid testing routine to constrain focal mechanism. Identification of the pP phase places the event at 54 km depth. Distinct pulses, assumed to be source effects, are observed in the far-field waveforms. Analysis of these pulses for directivity made possible discrimination between the fault and auxiliary planes. The plane taken to represent the fault surface strikes east-west ± 15°, dips 45° ± 15° to the north, and has nearly pure left-lateral slip. The preferred source model has an eastward propagation of 40 km. Surface reflections of successive source pulses suggest an upward component of propagation of 5 km. Bounds on the earthquake location and rupture of the 13 April event were determined using depth and source mechanism constraints from the teleseismic study and characteristics of local strong ground motion recordings. The 9-sec S-instrument trigger time seen in the Seattle acceleration recordings places the event at least 60 km from Seattle. Strong motion velocity at the Olympia Highway Test Laboratory is characterized by an impulsive and rectilinear S wave. The low amplitude of the vertical component of initial S motion suggests that either the epicenter is within 5 km of the Olympia Highway Test Laboratory for a pure incident SV wave or located along an azimuth of N159° if the wave is SH. The combined constraint of minimum distance from Seattle and the S polarization angle implied by the teleseismic data focal mechanism places the initiation of rupture 5 to 10 km north to north-northwest of the Olympia Highway Test Laboratory at 47.13°N, 122.95°W. This is approximately 20 km west of previously determined epicenters. The T axis, gently dipping to the southeast, supports other evidence that the Juan de Fuca plate dips to the southeast in a zone between segments of the plate north and south of the event's location. The fault plane's slip is taken to indicate that subduction is still active beneath Washington and that motion of the two segments is probably independent.
Instrumental group delay for high-frequency and teleseismicPwaves
Authors: Buchbinder Goetz G. R. 
Published: July 2021

AbstractThe instrumental group delay dθ/dω is considered here. First, these delays were calculated for three different recording systems that were used in a precise travel-time monitoring experiment where the delays varied between 10 and 40 msec for the high frequencies of the seismograms involved. A technique is demonstrated by which these delays may be readily accounted for and by which instrumental malfunctions can be readily detected.Second, two of these systems are also currently used for the recording of short-period teleseisms; at the 1-sec period, the group delays are from 0.3 to 0.4 sec, which is significant and must be accounted for. This is particularly important when these systems are used in connection with data from other systems that have different delays, such as the World-Wide Seismograph Station Network and Canadian Seismograph Network stations. Neglecting these delays will create serious problems in seismological tomography and earthquake catalogs.Third, for long-period phases recorded by the SRO-type instruments, the delays for the 10- to 20-sec periods are 6 to 12 sec; again, these are significant and must be accounted for.
Women’s Experience of Vulnerability in Flood in the context of Northern Region of Bangladesh
Authors: Masud Marjina , Chowdhury Md. Mahabub , Kamal Farhana 
Published: July 2021

Flood is one of the most common and devastating disasters in the northern region of Bangladesh. The objective of this research is to investigate how and to what extent flood has been affecting people’s livelihood and how men and women are taking steps to mitigate the impact and cope up with the situation. The research work was conducted based on a qualitative point of view and the lens of feminist research methodology. This study has revealed that flood-induced vulnerability affects men and women differently. Women experience the severity of the flood and household food insecurity much more than men as women are responsible for maintaining the household, taking care of everyone, and playing the role of buffer and absorber the impact. To mitigate the impact and cope up with the devastating effects of floods, men and women employ different strategies. While men go to nearer or far towns or cities for alternative livelihoods, women remain within the household and try to mitigate the impact. This study is conducted through qualitative research techniques such as semi-structured interview, focus group discussion, case study, and conversational exchange method and aims at contributing to a broader understanding of women’s experience of flood-induced vulnerability in the context of the northern region of Bangladesh.
A construção da paternidade ao nascimento do filho à termo e de risco habitual
Authors: Santos Suzanne Da Silva , Morais Rita de Cássia Melão , Silveira Aline Oliveira , Medeiros Camila Camargo , Franzoi Mariana Andre Honorato 
Published: July 2021

Este estudo teve por objetivo descrever a percepção de homens, que vivenciaram o nascimento do filho à termo e de risco habitual, sobre o processo de construção da paternidade. Estudo descritivo com abordagem qualitativa realizado no Alojamento Conjunto de uma maternidade de um hospital público de Brasília. Os participantes do estudo foram 18 pais. A coleta de dados se deu pela entrevista semiestruturada a análise foi temática e emergiu as seguintes unidades temáticas: Planejando ter um filho; Sentimentos aflorados com a paternidade; A paternidade acarreta maturidade e novas responsabilidades; O cuidado do pai ao binômio. Conclui-se que ocorreu a descentralização dos cuidados maternos e a inserção ativa dos homens nos cuidados do seu filho. No entanto, as práticas da enfermagem ainda se mostram centradas nos processos biológicos com pouco alcance das necessidades dos pais/família em constituição. A enfermagem deve exercer o papel de promotora da paternidade positiva.
Overcoming obstacles in implementing 2013 curriculum policy
Authors: Warman Warman , Suryaningsi Suryaningsi , Mulawarman Widyatmike Gede 
Published: July 2021

Teachers as curriculum implementers face various obstacles in its implementation. This study reports on teachers' views on the implementation of curriculum policies 2013 (K-13), the obstacles encountered, and efforts to overcoming and managing obstacles. The number of participants is ten teachers who have implemented K-13. Data were collected through the group, individual interviews and questionnaires. Data were analysed using a percentage model, Likert scale measurement. The study results: the teacher's view of the implementation of the K-13 policy was classified as bad. Most of the teachers have difficulty implementing K-13. The obstacles faced are that the teacher has difficulty determining learning media, applying project-based learning methods, lack of infrastructure, and learning assessment difficulties. Recommendations for future improvements: need continuous training, adequate infrastructure, activate subject teacher deliberations, monitoring and evaluation.

Keywords: 2013 curriculum policy, implementation 2013 curriculum policy, manage obstacles, teachers' opinions.
The impact of COVID-19 and lockdown on families of students with special education needs
Authors: Sakarneh Mohammad Abed 
Published: July 2021

The Covid-19 pandemic has been one of the most significant events affecting the largest number of countries at the same time around the globe. Governments instituted the closure of schools and lockdown of cities and other areas to prevent the spread of the virus. Students had to learn through online platforms meant to enhance continued learning. The current study aimed to explore the extent to which Covid-19 pandemic and the lockdown impact families of students with special education needs. Qualitative approach was used; semi-structured interviews were undertaken using online communication tools via Google Meet platform and for data analysis Atlas.ti program was used for coding and categorizing. The findings revolved around main themes in the study include; behavior problems in the children, psychological distress for the parents, and difficulty of delivering the rigid content and schedules. Implications for school and social support are discussed for policymakers in Jordan.

Keywords: COVID 19, families, lockdown, students with special education needs.
Evaluation of the social studies course on Education Information Network (EBA) in accordance with the opinions of pre-service teachers
Authors: Karagozoglu Nazike 
Published: July 2021

The Fatih Project has been one of the big steps in the field of education in Turkey, which aims to reflect the developments in technology and communication to education. The Education Information Network (EBA), which was created in 2011 within the scope of the project, was put into service as an online platform for integrating technology with education. With the introduction of distance education in line with health and safety measures during the COVID -19 outbreak, the usage area and importance of the EBA has increased. Various courses and teaching materials suitable for all education levels was provided through this platform. The aim of the current study is to reveal the opinions of pre-service teachers about the social studies course delivered on the EBA during the pandemic process. Case study, one of the qualitative research models, was used in the current study. 25 pre-service social studies teachers who voluntarily participated in the study watched a total of 75 lessons delivered from July to October for 5th, 6th, 7th grade students and evaluated those lessons in terms of attention-drawing, motivation, teaching methods and techniques, teaching materials, evaluation and communication elements. "Course Evaluation Form" was used as data collection tool. Content analysis was carried out on the evaluations made by the teachers. According to the pre-service teachers, the attention-drawing phase of the social studies lessons delivered through the EBA was neglected in most of the lessons, and the teaching method was limited to the method of lecture, question-answer, and case method. In addition, it was determined that while the evaluation phase of the courses was insufficient, the use of teaching materials was sufficient. Some characteristics of the teachers who teach the lessons such as the tone of voice and body language were generally found to be sufficient.

Keywords: Education Information Network, social studies, teachers’ opinions
Impacts of inquiry learning model on students’ cognitive and critical thinking ability
Authors: Adnan Gunawan , Zulfikar Teuku , Armia Muhammad Siddiq , Gade Syahbuddin , Walidin Warul 
Published: July 2021

This article describes the effects of inquiry learning model on college students’ cognitive and critical thinking skills. The research aims at understanding the extent inquiry learning model improves the college students’ cognitive and critical thinking skills in the lessons of educational philosophy and exploring students’ responses to the model. This is a pre-experimental research design, using the one group pretest-posttest design. The samples of the study were an intact class, the experimental group and no control group is needed. The data was analysed using independent test samples t-test and Normalized Gain test. The Research found that the inquiry model is effective in improving college students’ cognitive and critical thinking ability in an educational philosophy class. Overall, the N-Gain indicator of cognitive ability increased by an average of 0.66, and the N-Gain indicator of critical thinking skills increased by an average of 0.63.

Keywords: Congnitive skill, Critical thinking, Inquiry learning, Educational Philosophy, College Student