bluuebunny/crossref_metadata_2025 huggingface dataset:
La constitución del niño preescolar a través de la enseñanza del saber matemático en el preescolar público bogotano (1980-1990)
Authors: Cárdenas-Forero Óscar Leonardo
Published: September 2021

El presente artículo de investigación, inscrito en una perspectiva cualitativa, enfoque arqueo-genealógico, analítica de la gubernamentalidad formulada por Michel Foucault, es una apuesta epistemológicamente situada en el marco de los estudios de los saberes y las disciplinas escolares, que pretende determinar el modo cómo se orientaron los comportamientos infantiles y se constituyó al niño de preescolar a través de la enseñanza del saber matemático (en las formas de la aritmética y las pre-matemáticas), durante la década de los 80 en el preescolar público bogotano, funcionando como una tecnología de poder que se empleó para alcanzar dichos propósitos. Aquí se describen las formas que asumió durante esta época el saber matemático en el preescolar y los contenidos de enseñanza que se introdujeron, así como, las actitudes, conductas, valores y patrones que se instalaron como verdades y que el niño de preescolar debió adoptar, adquirir y apropiar, como también, aquellos que debió corregir, para desenvolverse, actuar, ser reconocido, aceptado y legitimado en el escenario escolar y social. El ejercicio investigativo realizado permitió mostrar, en síntesis, el carácter fluctuante no solo de la subjetividad infantil preescolarizada sino de los saberes escolares, de su condición como tecnología de poder y de su incidencia como dispositivo de gobierno en la determinación de la complexión del niño en la escuela preescolar pública durante la década de los años 80.
El ciberacoso. Una aproximación a la opinión del alumnado de Educación Primaria
Authors: Amar Rodríguez Víctor
Published: September 2021

El ciberacaso preocupa y ocupa a un grupo de futuros maestros de primaria. A través de una investigación de corte documental atendemos a los comentarios vertidos en un foro de la asignatura de comunicación y tecnología de la información en educación (Universidad de Cádiz, España). Con diversas opiniones, a partir de hilos de conversación, se posicionan en la necesidad de atajar el ciberacoso. Sin embargo, suscriben que no es una responsabilidad exclusivamente de los docentes, sino de toda la comunidad educativa, además de los medios de comunicación. El poder de amplificación de la red del acoso puede llegar a tener consecuencias imprevisibles entre el alumnado que lo padece. Por ello, solicitan conocimientos tanto en su periodo de formación inicial como permanente; del mismo modo, irán a contar con el diálogo como adalid para la reflexión y la prevención.
La educación estadística a la luz de la educación matemática crítica
Authors: Fernández Hernández Felipe Jorge , Andrade Escobar Luisa
Published: September 2021

En una revisión de la investigación en educación estadística desde disertaciones recientes, se encuentra extensa indagación en torno a la alfabetización, cultura, razonamiento y pensamiento estadístico, así como evidencias de la tendencia de la comunidad internacional a incorporar la teoría crítica en la educación. En este artículo, se presenta una exploración acerca de posibles relaciones y convergencias entre principios de la educación matemática crítica y lineamientos de la educación estadística, que propicia la búsqueda de propuestas en conjunto y ofrece ideas promisorias tanto para la enseñanza-aprendizaje como para la investigación en estadística. Además, pretende la búsqueda de propuestas en conjunto para integrar las dimensiones sociales, culturales y políticas en las prácticas educativas de la estadística, y así contribuir a la formación de ciudadanos participativos de la sociedad.
Praxis educativa y trabajo-valor: problematizaciones críticas al modelo educativo por competencias desde Nuestra América
Authors: García-Ayala Natanael
Published: September 2021

Con el objetivo de evadir los “lugares comunes”, este artículo se enfoca en la necesidad de continuar con la problematización crítica del modelo educativo basado en competencias con el objetivo de clarificar los conceptos y categorías que articulan sus prácticas discursivas. Así, puede darse cuenta de las implicaciones de un modelo económico-seudopedagógico que promueve la deshistorización, desubjetivación y descontexturalización como principios reguladores de la praxis educativa. Si las competencias ─entendidas como la “nueva divisa del siglo XXI”─ se inscriben en una radicalización de los efectos negativos del sistema económico neoliberal, como se propone en este artículo, la teoría del trabajo-valor es un coadyuvante analítico-crítico para su desestructuración, es decir, al reconocer lo educativo fuera de los marcos de la “epistemología sin sujeto cognoscente” y la “antropología sin sujeto”.
La excelencia académica de mujeres con discapacidad visual en la Universidad: aportes de la teoría fundamentada
Authors: Yerga-Míguez María Dolores , Ramírez-Morera Marcela , Díaz-Jiménez Rosa María
Published: September 2021

En este artículo de investigación se realiza una aproximación a la vida académica de mujeres con discapacidad visual con el objetivo de analizar sus historias formativas y los factores que contribuyen a la excelencia académica. De esta forma, se presenta un estudio comparado de casos de dos mujeres con discapacidad visual matriculadas en universidades de Costa Rica y España, a partir de una hermenéutica cualitativa y una adaptación de la teoría fundamentada de diseño constructivista. Los datos se recolectaron con entrevistas semiestructuradas y se analizaron con el método comparativo constante con apoyo del software Atlas-ti v. 8. Las participantes fueron ocho, cuatro unidades de observación por cada caso y país: la mujer con discapacidad visual, un familiar, un docente y un compañero/a de clase. El marco de análisis incluyó cuatro dimensiones: personal, entorno familiar, académico y social. Como resultados destacan que los factores exógenos vinculados con la excelencia académica sitúan a la familia, el grupo de iguales (compañeros/as) y el equipo docente como apoyos permanentes a las mujeres con discapacidad visual en sus trayectorias académicas. Sin embargo, la familia influye de manera ambivalente, como apoyo y barrera, donde emerge un déficit de concienciación, especialmente entre profesorado y alumnado. Los factores endógenos que favorecen la excelencia académica se relacionan con el esfuerzo, desempeño y actitud individual, cuyo eje principal queda constituido por las características resilientes desarrolladas. Destaca como categoría emergente la violencia presente en el ámbito académico en diversas manifestaciones.
Değişen Tüketim Pratikleri Bağlamında Hızlı Moda
Authors: ÖZTAY Hilal
Published: September 2021

Örtünmenin, yerini giyinmeye bıraktığı dönemlerden yalnızca yüz yıl gibi yakın bir zamana kadar seçkinlerin tekelinde olan moda ve moda tüketimi, alt sınıflar ya da sıradan vatandaşlar için ulaşılması zor olan hatta çeşitli şekillerdeki yaptırımlarla kısıtlanan bir davranış kalıbı olmuştur. Ancak, üretim yapısındaki değişim ve bunun sonucunda tüketim pratiklerin de değişmeye başlamasıyla, moda ürünler de diğer tüketim nesneleri gibi nispeten ulaşılabilir bir hale gelmiş ve toplumdaki tüm kesimler tarafından kullanılmaya başlanmıştır. Süreç içerisinde modaya dair metalar, kavrama yüklenen anlamın da değişmesiyle birlikte en çok kullanılan ve en sık değiştirilen ürünler olarak karşımıza çıkmaktadır. Bu dramatik değişim, tüketimin genel yapısındaki farklılaşmadan ve içerisinde bulunduğu toplumsal değişim dinamiklerinden soyutlanarak anlaşılamaz. Bu çalışmanın amacı, tüketimi eleştirel bir bakış açısıyla ele almaktan öte, tarihsel perspektifte tüketim pratiklerinin değişimine ortam sağlayan gelişme ve olguların neden sonuç ilişkileri ile değerlendirilmesidir. Böylelikle günümüzdeki moda tüketiminin dinamikleri hakkında bakış açısı sunulmuş olacaktır.
Üniversite Öğrencilerinde Öznel İyi Oluş: Yaşamda Anlam, İyimserlik ve Umudun Rolü
Authors: DURSUN Pınar
Published: September 2021

Pozitif psikoloji ekolü ile öznel iyi oluş, anlamlı yaşam, umut ve iyimserlik gibi kavramlar en fazla araştırılan konular haline gelmiştir. Nitekim, pek çok araştırma, yaşamında anlam olduğunu belirten, iyimser ve umutlu bireylerin, fiziksel ve psikolojik açıdan daha sağlıklı olduklarını ortaya koymuştur. Bu araştırmada, yaşamda anlam algısı, iyimserlik ve umut düzeylerinin öznel iyi oluş kavramıyla olan ilişkisi incelenmiştir. Üniversite öğrencilerinden oluşan örnekleme, 984 (582 kadın, 402 erkek; Ortyaş = 21.26, SS = 1.69) Yaşamın Anlamı Anketi, Yaşam Yönelimi Testi, Umut Ölçeği, Olumlu-Olumsuz Duygu Ölçeği ve Yaşam Doyumu Ölçeği uygulanmıştır. Elde edilen veriler Yapısal Eşitlik Modeli (YEM) yoluyla incelenmiştir. Tüm değişkenlerin öznel iyi oluşu anlamlı olarak yordadığı görülmektedir, yani yaşamda anlama sahip olma, iyimserlik ve umut, öznel iyi oluş ile olumlu ve doğrudan ilişkidir ve diğer değişkenlere göre en güçlü yordayıcı iyimserliktir.
tets protocol v1
Authors: Test Test
Published: September 2021

this is a tets protocol
La participación ciudadana en el posconflicto: alcances y retos de la democratización territorial en Colombia
Authors: Buriticá Arango Esteban , Garzón Correa Camilo Andrés
Published: September 2021

En este artículo se analiza la naturaleza de los espacios de participación ciudadana creados por el Acuerdo Final para la Terminación del Conflicto y la Construcción de una Paz Estable y Duradera, suscrito entre el Gobierno Nacional y las FARC-EP, sus posibles contribuciones a la legitimación del ejercicio del poder político a nivel territorial y los retos que deben afrontar (y afrontan) en el posconflicto. En la primera parte, se analizan las principales características de los mecanismos, relacionadas con sus finalidades, funciones y estructura. En la segunda parte, se evalúa la importancia normativa y práctica de los mecanismos para alcanzar los objetivos básicos del acuerdo de paz. Finalmente, en la tercera parte, se describen los principales retos que afronta actualmente la implementación exitosa de los mecanismos en las zonas afectadas por el conflicto armado, el narcotráfico y la debilidad institucional.
La Constitución de 1991 y la contratación estatal. Visiones conflictivas y deficiencias en el diseño del Estado
Authors: Valencia Tello Diana Carolina
Published: September 2021

La Constitución de 1991 determinó la obligación al Congreso de la República de expedir un estatuto general de contratación pública, razón por la cual fue expedida la Ley 80 de 1993, la cual buscó otorgar mayor autonomía a las entidades estatales para contratar los bienes y servicios, mediante la formulación de principios generales, que evitaban regular el procedimiento contractual en detalle. Sin embargo, iniciando el siglo XXI, varios organismos internacionales (como la OCDE, Banco Mundial y Fondo Monetario Internacional), consideraron que debido al atraso de las infraestructuras en el mundo y, en particular, en América Latina, era necesario formular nuevas dinámicas contractuales. Desde entonces, los organismos internacionales han tenido una importante injerencia en la regulación del Sistema de Compras Públicas en Colombia (SCPC), mediante el desarrollo de diagnósticos que luego son utilizados en documentos Conpes, directivas presidenciales, decretos y resoluciones, modificando sustancialmente la Ley 80 de 1993, sin que hasta el momento se haya realizado un debate profundo al interior del Congreso sobre el estatuto general de contratación, conforme las modificaciones realizadas sobre el Sistema de Compras Públicas colombiano en las últimas décadas. El presente artículo tiene por objetivo reflexionar sobre las transformaciones que ha sufrido el SCPC y sus efectos en el diseño institucional inicialmente planteado por la Constitución de 1991.
¿Gobierno de los jueces o gobierno del pueblo? Consultas populares ambientales y activismo judicial regresivo en Colombia
Authors: Benavidez Vega César Augusto
Published: September 2021

En Colombia los conflictos socioambientales han escalado dentro de la expansión judicial en dos frentes (Feoli, 2015), vía judicialización de la política y vía activismo judicial. El primero, cuando los actores en pugna usan mecanismos jurídicos para resolver controversias ambientales (el control previo de constitucionalidad de consultas populares, la acción de tutela contra providencias judiciales, y la nulidad de sentencias de la Corte Constitucional, entre otros), en lugar de debatirlos en escenarios de participación democrática. Mientras que en el segundo la judicatura profiere providencias antiformalistas (López Medina, 2018). A partir de un estudio de caso sobre el régimen de competencias ambientales de las entidades territoriales en consultas populares ambientales, este escrito aborda si: I) ¿la Sentencia SU-095 de 2018 de la Corte Constitucional es activista? Y II) ¿Los cambios jurisprudenciales de esta sentencia obedecen a cambios de magistrados? Se concluye que esta sentencia de unificación sí es activista, y que representa un caso por excelencia del imperio del gobierno de los jueces que se opone al gobierno del pueblo, expresado en las consultas populares realizadas entre 2011-2019, y, por otro lado, que los cambios en la integración de la Corte sí incidieron en el viraje jurisprudencial sobre este tema.
Objective criteria for MRI evaluation of the effectiveness of treatment of bone metastases in patients with prostate cancer and breast cancer: systematic review and meta-analysis
Authors: Ripp Vladislav O. , Berezovskaya Tatyana P. , Ivanov Sergey A.
Published: September 2021

BACKGROUND: The possibility of a personalized approach to the treatment of metastatic prostate cancer and breast cancer requires objective methods for the evaluation of the response of foci treatment in the skeleton. The proven high efficiency of MRI in detecting bone metastases, in combination with the absence of ionizing radiation, has laid the groundwork for using this method in monitoring the treatment course based on objective criteria for evaluation of the therapeutic outcome.
AIM: To assess the possibilities of quantitative and semi-quantitative parameters of MRI-evaluation of treatment efficacy (radiation, chemotherapy, hormone therapy, and targeted therapy) of bone metastases that were used in prostate and breast cancer clinical trials.
MATERIALS AND METHODS: We searched the databases Embase, PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), eLibrary until April 1, 2021, using the following keywords: magnetic resonance imaging, MRI, DWI, treatment response, prostate or breast cancer, and bone metastasis. We only included studies related to the MRI-evaluation of treatment efficacy of any type of therapeutic intervention (with the exception of surgery) for metastatic skeletal lesions in this review.
RESULTS: We selected and analyzed 11 out of 312 sources found as a result of the search. It allowed us to identify four groups of objective MRI criteria for evaluating the therapeutic effect in metastatic bone lesions in patients with prostate and breast cancer, including the dynamics of sizes, signal intensity on DWI, ADC, and tumor total diffusion volume (tDV). Changes in these quantitative and semi-quantitative indicators, with only one exception, had the same direction, although they differed in numerical values. A random-effects model was used for analysis considering the presence of statistically significant heterogeneity (p 0,1 for 2 test; I2 40%),. The change in ADC as a result of treatment averaged +0.35 [+0.12; +0.49] 103 mm2/s, with average values of ADC before treatment ― 0.83 [0.71; 1.03] 103 mm2/s, after treatment ― 1.18 [0.83; 1.49] 103 mm2/s.
CONCLUSION: MRI is an informative technique for the objective evaluation of the response of bone metastases to therapy in patients with prostate cancer and breast cancer based on quantitative and semi-quantitative parameters. It has significant potential as a diagnostic test instrument for monitoring the effectiveness of treatment of metastatic skeletal lesions.
Cardiomyopathy in patients with type 1 tyrosinemia, and the effect of nitisinone treatment on cardiomyopathy
Authors: BİLGİNER GÜRBÜZ Berrak , AYKAN H. Hakan , ÇIKI Kısmet , KARAGÖZ Tevfik , SİVRİ Serap , DURSUN Ali , TOKATLI Ayşegül , COŞKUN Turgay
Published: September 2021

Purpose: This study aimed to retrospectively evaluate the frequency of cardiomyopathy and its response to routinely used nitisinone treatment in patients with tyrosinemia type 1.

Materials and Methods: Participants of this descriptive cross-sectional study were Tyrosinemia Type 1 patients who were under the care of a single metabolic unit. The primary outcome of the study was “presence of abnormal echocardiographic findings” at diagnosis and the impact of nitisinone treatment on the detected findings.

Results: Of the 54 patients enrolled in the study, 21 (38.9%) were female and 33 (61.1%) were male. 41 patients were evaluated using echocardiography at the time of diagnosis. 9 (21.9%) of them had hypertrophic cardiomyopathic alterations varying in severity. In the follow-up period, second echocardiographic examinations revealed improvements in cardiac alterations while on nitisinone treatment. Thirteen patients dropped out of follow-up. Of the remaining 41 patients, 10 (24.4%) patients died in the follow-up period, whereas 31 (75.6%) remained alive. Plasma aspartate aminotransferase (AST), total bilirubin, and direct bilirubin concentrations were significantly higher in patients witj normal cardiac evaluation.

Conclusion: Echocardiographic examination should be done in all tyrosinemia type 1 patients including those with an absence of cardiac manifestations. The presence of cardiomyopathy may indicate a poor prognosis. Nitisinone is found to have a positive impact on cardiomyopathy in patients with type 1 tyrosinemia.
Full Moment Tensor Solutions of U.S. Underground Nuclear Tests for Event Screening and Yield Estimation
Authors: Pasyanos Michael E. , Chiang Andrea
Published: September 2021

Moment tensor (MT) solutions are proving increasingly valuable in explosion monitoring, especially now that they are more routinely calculated for the unconstrained, full (six component) MT. In this study, we have calculated MTs for U.S. underground nuclear tests conducted at the Nevada National Security Site using seismic recordings primarily from the Livermore Nevada Network. We are able to determine them for 130 nuclear explosions from 1970 to 1996 for a range of yields and under a variety of material conditions, which we have supplemented with 10 additional chemical explosions at the test site. The result is an extensive database of MTs that can be used to assess the performance of important monitoring tasks such as event identification and yield determination. We test the explosion event screening on the fundamental lune of the MT eigensphere and find MT screening to be a robust discriminant between earthquakes and explosions. We then explore the estimation of moment-derived yield, in which we find that material properties are the largest contributor to differences in the estimated moment-to-yield ratio. Further research conducted on this dataset can be used to develop, test, and improve various explosion monitoring methodologies.
Earthquake sequences and b values in the southeast United States
Authors: Long Leland Timothy
Published: September 2021

abstract

Aftershock and foreshock activity within 12 hr of the July 13, 1971 earthquake near Seneca, South Carolina, indicates a b value of 0.9 at ML = 3.0. Approximately 40 events recorded in a 5-day aftershock survey near Seneca indicate a b value of 1.7 at ML = 0.5. A sequence of over 40 events occurring west of McCormick, South Carolina, indicates a b value of 1.3 at ML = 2.4. The McCormick sequence was active for 4 months. Unlike the Seneca region, the McCormick region has a history of earthquake activity. Examinations of other published southeastern b values suggest that southeastern United States earthquakes originate from conditions of ambient stress which vary with epicentral region or magnitude.
Geologic and seismologic aspects of the Managua, Nicaragua, earthquakes of December 23, 1972
Authors: Brown R. D. , Ward P. L. , Plafker George
Published: September 2021

abstract

The Managua, Nicaragua, earthquake of December 23, 1972 (body-wave magnitude of 5.6, surface-wave magnitude of 6.2), and its aftershocks strongly affected an area of about 27 km2 centered on Managua. Within this area, over 11,000 people were killed and 20,000 were injured. About 75 per cent of the city's housing units were destroyed or rendered uninhabitable leaving between 200,000 and 250,000 people homeless, and property damage exceeded half a billion dollars. As a consequence, the economy and government of the city, and to a large extent the entire country, were severely disrupted.

Surface geology shows that there are at least four subparallel strike-slip faults spaced 270 to 1,150 meters apart in the Managua area that slipped in a predominantly sinistral (left-lateral) sense during the earthquake. Aftershock studies show that at least one of these northeast-trending faults extends from the surface to a depth of 8 to 10 km over a maximum length of about 15 km. The faults are mappable on land for 1.6, 5.1, 5.9 and 2.7 km; aftershock data indicate that faulting extends at least 6 km northeast of the city beneath Lake Managua. Horizontal displacements vary, with the maximum aggregate sinistral slip ranging from 2.0 to 38.0 cm. There is also a local small down-to-the-southeast vertical component of slip on three of the four faults. The nature and distribution of the surface faulting are consistent with a tectonic origin for the earthquake.

The extensive destruction and loss of life in the Managua area were caused by a combination of the following factors: (1) occurrence of the earthquake on faults directly beneath the city, (2) poor behavior of structures, chiefly tarquezal (wood frame and adobe) and masonry, during strong seismic shaking, and (3) direct displacement of structures, streets, and utilities by faulting. The historic record of seismicity and geological evidence of active Holocene faulting and volcanism together show that Managua is an unusually high-risk area in terms of geological hazards and that these hazards should be a primary consideration in evaluating reconstruction of Managua.
Surface motion of a semi-elliptical alluvial valley for incident plane SH waves
Authors: Wong H. L. , Trifunac M. D.
Published: September 2021

By using the exact analytical solution for the two-dimensional SH-wave propagation in and around an elastic inclusion whose cross section corresponds to one half of an ellipse, we have examined those aspects of the resulting ground motion that are of special interest for earthquake engineering and strong-motion seismology. Computed amplitudes and phases of periodic ground motion display complicated wave-interference phenomena that lead to nearly-standing wave patterns, abrupt changes in the amplification of incident motions along the free surface of the alluvial valley and strong dependence of the overall motions on the incidence angle of SH waves. By comparing the amplification patterns derived from the exact model with the amplifications computed on the basis of an equivalent single-layer model excited by the vertically incident shear waves, we have demonstrated that this approximate representation may lead to meaningful results only if the wavelength of incident waves is longer than the characteristic dimension of the alluvial valley. Although simple, we expect that the model presented in this paper might explain qualitatively the vibrations of some alluvial valleys excited by SH components of strong ground motion.
A fall in P-wave velocity before the Gisborne, New Zealand, earthquake of 1966
Authors: Sutton D. J.
Published: September 2021

A fall in P-wave velocity before the Gisborne earthquake of March 4, 1966 is indicated by arrival-time residuals of P waves from distant earthquakes recorded at the Gisborne seismograph station. Residuals were averaged over 6-month intervals from 1964 to 1968 and showed an increase of about 0.5 sec, implying later arrival times. The change began about 480 days before the earthquake. This precursory time interval is about that expected for an earthquake of this magnitude (ML = 6.2), but unlike most other reported instances, there was no obvious delay between the return of the velocity to normal and the occurrence of the earthquake. Similar analyses were carried out over the same period for two other New Zealand seismograph stations; at Karapiro there was no significant variation in mean residuals, and at Wellington the scatter was too large for the results to be meaningful. The Gisborne earthquake had a focus in the lower crust, about 25 km deep and was deeper than other events for which such precursory drops in P-wave velocity have been reported.
Reflection and transmission of inhomogeneous waves with particular application to Rayleigh waves
Authors: Alsop L. E. , Goodman A. S. , Gregersen S.
Published: September 2021

abstract

The concept of inhomogeneous waves, which is quite common in the electromagnetic literature but not in the seismic, is reviewed. It is shown that the Rayleigh wave results from the constructive interference of a P inhomogeneous wave with an SV inhomogeneous wave. Of some interest is the fact that while the two inhomogeneous waves have prograde elliptical particle motions, they combine to yield the familiar retrograde motion near the surface. These two inhomogeneous waves are the only “allowed” inhomogeneous waves in a homogeneous elastic half-space. More can occur in a layered half-space but they are always discrete in number. However, “non-allowed” inhomogeneous waves often give a very good representation of the wave motion over a restricted area—a fact which is demonstrated for leaky modes and propagation of a Rayleigh wave on a three-quarter space. With this in mind, a formalism is developed for the transmission and reflection of the two allowed inhomogeneous waves making up the Rayleigh wave into nonallowed inhomogeneous waves. These are nonallowed in the sense that they do not fit the boundary conditions at a discrete number of points. Here the ray picture breaks down and diffractive effects occur. Our assumption is that for many interesting cases, these diffractive effects are small and can be ignored. The components of the resultant displacements and stresses from the nonallowed inhomogeneous waves on Rayleigh waves can be obtained by use of a relation due to Herrera, thus yielding the reflection and transmission coefficients. The agreement with previously published values is good. While only normal incidence is considered in this paper, the extension to non-normal incidence is straightforward. The required calculations are well within the capabilities of a small computer such as an IBM 1130.
Seismic event identification by negative evidence
Authors: Elvers Eva
Published: September 2021

abstract

A decision-theoretical model for seismic discrimination between earthquakes and underground nuclear explosions is developed. The influence of long- and short-period detection thresholds on the probabilities to identify explosions and to make false alarms is discussed. The model includes identification by negative evidence. This kind of identification is considered in the case when only short-period data are available and when the long-period signal amplitude is supposed to be less than or equal to the seismic noise amplitude. For one set of data—obtained from North American events at the Hagfors Observatory in Sweden—the applicability of the m(M)-method is increased about half a magnitude by including identification by negative evidence.
Soil-structure interaction during the San Fernando earthquake
Authors: Crouse Charles B. , Jennings Paul C.
Published: September 2021

abstract

Accelerograms obtained at two sites during the San Fernando earthquake of 1971 were analyzed to investigate the role of soil-structure interaction, using techniques developed by Bielak and others. Analysis of the data from the site of the Hollywood Storage Building, for which data from the Arvin-Tehachapi earthquake of 1952 are also available, showed evidence of soil-structure interaction in the way the transfer functions between parking lot and basement motion decayed with increasing frequency in the two lateral directions. It is concluded also that interaction probably had a small effect on the response near the EW fundamental frequency during the San Fernando earthquake. Although theoretical and experimentally determined transfer functions are broadly similar, they do not agree in detail. The lack of good agreement for reasonable choices of the parameters of the theoretical model indicates a need for some modifications of the theory or its application, and a need for more measurements at the site.

A similar analysis showed no clear evidence of soil-structure interaction for the Millikan Library and Athanaeum buildings on the campus of the California Institute of Technology. If soil-structure interaction caused the major differences measured in the base motions of these two buildings, it is of a more complex form than that considered by present theories.
The Delaware-New Jersey earthquake of February 28, 1973
Authors: Sbar Marc L. , Jordan Robert R. , Stephens Christopher D. , Pickett Thomas E. , Woodruff Kenneth D. , Sammis Charles G.
Published: September 2021

abstract

The largest earthquake to affect northern Delaware in 100 years occurred at 08:21 GMT on February 28, 1973. The event was perceptible over 15,000 km2 in New Jersey, Delaware, Pennsylvania, and Maryland with a maximum Modified Mercalli intensity of V-VI near the Fall Zone between Wilmington and Claymont, Delaware. The isoseismals are elongate in a northeast-southwest direction. The main shock had a magnitude of 3.8 and was located at 39°43.1′N, 75°26.4′W with a depth of 14.1 km as calculated by NOAA. The five aftershocks located in this study were centered within a few kilometers of the region of greatest intensity at about 39°47′N and 75°25′W with depths ranging from 5 to 8.4 km. The fault plane solution determined from the mainshock and aftershocks indicates dip-slip motion on a nearly vertical plane striking N28°E. The southeast side is down in agreement with geological observations of subsidence of the Coastal Plain and uplift of the Piedmont. The strike of this fault is similar to that of the border faults of a graben in the basement rocks about 30 km southwest along the strike from the epicenter suggesting that the seismic activity may be associated with such faults.
Attenuation of shear waves along the San Andreas fault zone in central California
Authors: Kurita Tuneto
Published: September 2021

abstract

Ground motions at distances of 20 to 30 km from two moderate earthquakes, which occurred along the San Andreas fault zone in central California on February 24, 1972 (M = 5.0) and on September 4, 1972 (M = 4.6), were well recorded at two stations on quite different crustal structures astride the fault. The similarity of the focal mechanisms and the observed spectra at each station, for both earthquakes, makes it possible to apply the spectral ratio method for evaluating Q for direct shear waves propagating along and adjacent to the fault zone. The resultant linear relations between the average values of Q of SH waves for the wave paths from both earthquakes to each station, together with a few reasonable assumptions, suggest the following properties of the variation of Q in the upper crust: In the fracture zone of Tertiary and Cretaceous sedimentary rocks along the fault to the northeast of the Gabilan range, the average Q in the upper 6 km is as low as 20. Although less certain, under the northeastern part of the Gabilan range composed of Mesozoic granites southwest of the fault, the average Q in the upper 6 km is about 100 or more and the intrinsic Q begins to decrease at a depth of several kilometers. This depth corresponds to the bottom of the well-defined zone of aftershock occurrence following moderate earthquakes.
Time-dependence of P residuals in Luzon
Authors: Wyss M.
Published: September 2021

abstract

During 1964 through 1970 changes of the average P residuals at Baguio show no clear anomaly that could be attributed to any of the recent large earthquakes in Luzon. The average P residuals at Manila show a strong anomaly which was evidently due to poor maintenance of this station rather than to a tectonic cause.
Historical seismicity of Iraq
Authors: Alsinawi Sahil , Ghalib Hafidh A. A.
Published: September 2021

abstract

Iraq has a rather long well-documented history of seismic activity, where 79 events of major and/or minor effect on the community are documented for the period 1260 B.C. through 1900 A.D. Fourteen of these events are listed and described for the first time from an Arabic manuscript.

The historical seismicity follows a well-defined pattern and fits with the boundaries of the major tectonic units of Iraq, as well as with the recent seismicity of the country.
The applicability of principal component analysis to the separation of multiple plane-wave signals
Authors: Der Z. A. , Flinn E. A.
Published: September 2021

abstract

It is shown that principal component analysis (eigenvector-eigenvalue decomposition of array spectral matrices) can be used for the approximate separation of superposed plane-wave signals only if at least one of the following conditions is satisfied:

Application of the method for such cases is demonstrated on composited long-period seismograms using recordings from the D ring and center element of ASA.
Evidence for afterslip on the San Fernando fault
Authors: Savage J. C. , Church J. P.
Published: September 2021

Postearthquake changes in elevation across the Tujunga segment of the San Fernando fault in the period March 1971 to 1973-1974 indicate deformation similar in distribution to, but on a much smaller scale than, the coseismic deformation (the maximum postearthquake uplift is about 60 mm compared to the 2 m of coseismic uplift). The postearthquake elevation change just east of the 1971 rupture is a nearly uniform increase in elevation to the north that reaches about 60 mm at the end of the profile. The postearthquake elevation change across the Sylmar segment of the San Fernando fault is more subdued and apparently in the opposite sense from the coseismic deformation; it may be due to local compaction. The horizontal deformation observed in the period August 1971 to March 1973 across a geodimeter network that spans the San Fernando fault is minor (displacement not more than 10 mm). If the explanation of the observed vertical deformation across the Tujunga segment of the fault is indeed afterslip, the deformation must have occurred chiefly in the period March to August 1971.
First motions from seismic sources in a semi-infinite homo-geneous medium overlain by an inhomogeneous layer
Authors: Sidhu R. S.
Published: September 2021

The problem of seismic radiation from buried sources situated at a depth H below the free surface of an inhomogeneous layer of thickness h(< H) overlying a semi-infinite homogeneous medium is considered. First-motion solutions have been obtained at the free surface. Three point sources—slip on a horizontal plane, strike slip on a vertical plane and dip slip on a plane dipping at 45°—are considered in detail. Numerical results are computed for a linear increase of P and S velocities in the layer. Amplitude variations and first-motion signs of P, SV and SH waves are shown graphically for homogeneous and inhomogeneous media.
Reconnaissance report of the Antigua, West Indies, earthquake of October 8, 1974
Authors: Tomblin J. F. , Aspinall W. P.
Published: September 2021

abstract

A major earthquake (mb = 6.6; Ms = 7.5, U.S. Geological Survey) occurred in the northern Lesser Antilles on October 8, 1974, causing damage of Modified Mercalli intensity VIII on the island of Antigua and lower intensities on the more distant islands.

The damage was confined mainly to larger and older buildings, to a petroleum refinery, and to a deep-water harbor. No earthquake-resistant building code exists in most of the Lesser Antilles, and in the majority of cases examined it was clear that structural damage had occurred because the building concerned could not have met the elementary requirements of a typical code.

A few people received minor injuries, but no fatality was reported.

The hypocenter of the main shock and many of the aftershocks lay about 30 km above the westward-dipping zone defined by activity over the last decade. The earthquake was tectonic in origin since the epicenter was 50 km from the nearest recent volcano.
Shear velocity from differential travel times of short-period ScS-P in New Hebrides, Fiji-Tonga, and Banda Sea regions
Authors: Choudhury Mansur A. , Poupinet Georges , Perrier Guy
Published: September 2021

abstract

Behavior of P, S and ScS residuals as well as those of differential travel times of ScS-P from the Jeffreys-Bullen tables are analyzed. The phases have been read from short-period records of the Antarctic station, Dumont d'Urville (DRV); the earthquakes originating in New Hebrides, Fiji-Tonga, and Banda Sea regions. P residuals from all regions show a mean value of about −1 sec. On the contrary, S and ScS residuals, well correlated among themselves, show important regional as well as focal-depth dependence. ScS-P residuals from shallow and intermediate shocks are largely positive for New Hebrides and largely negative for Banda Sea; those from intermediate shocks are moderately positive for Fiji-Tonga. The anomalies disappear at depths greater than about 200 km. Upper mantle shear velocity models are presented for the three regions. The models are discussed in relation to a sinking lithosphere.
Torsional response of structures for SH waves: The case of hemispherical foundations
Authors: Luco J. E.
Published: September 2021

abstract

A study is made of the harmonic torsional response of an elastic structure placed on a rigid hemispherical foundation which is supported on an elastic medium and is subjected to the action of obliquely incident plane SH waves. As a basic step in the solution of the torsion interaction problem, a closed-form solution is obtained for the torsional response of a rigid hemispherical foundation excited externally by a harmonic torque and through the soil by an obliquely incident plane SH wave. Comparisons between the results for a hemispherical foundation with those for a circular plate allow the estimation of the effects that the embedment of the foundation has on the torsional response of the superstructure.
The mechanics of locating earthquakes
Authors: Buland Ray
Published: September 2021

abstract

A complete reexamination of Geiger's method in the light of modern numerical analysis indicates that numerical stability can be insured by use of the QR algorithm and the convergence domain considerably enlarged by the introduction of step-length damping. In order to make the maximum use of all data, the method is developed assuming a priori estimates of the statistics of the random errors at each station. Numerical experiments indicate that the bulk of the joint probability density of the location parameters is in the linear region allowing simple estimates of the standard errors of the parameters. The location parameters are found to be distributed as one minus chi squared with m degrees of freedom, where m is the number of parameters, allowing the simple construction of confidence levels. The use of the chi-squared test with n-m degrees of freedom, where n is the number of data, is introduced as a means of qualitatively evaluating the correctness of the earth model.
Dynamics of an expanding circular fault
Authors: Madariaga Raul
Published: September 2021

abstract

We study a plane circular model of a frictional fault using numerical methods. The model is dynamic since we specify the effective stress at the fault. In one model we assume that the fault appears instantaneously in the medium; in another, that the rupture nucleates at the center and that rupture proceeds at constant subsonic velocity until it suddenly stops. The total source slip is larger at the center and the rise time is also longer at the center of the fault. The dynamic slip overshoots the static slip by 15 to 35 per cent. As a consequence, the stress drop is larger than the effective stress and the apparent stress is less than one half the effective stress.

The far-field radiation is discussed in detail. We distinguish three spectral regions. First, the usual constant low-frequency level. Second, an intermediate region controlled by the fault size and, finally, the high-frequency asymptote. The central region includes the corner frequency and is quite complicated. The corner frequency is shown to be inversely proportional to the width of the far-field displacement pulse which, in turn, is related to the time lag between the stopping phases. The average corner frequency of S waves v0s is related to the final source radius, a, by v0s = 0.21 β/α. The corner frequency of P waves is larger than v0s by an average factor of 1.5.
The Oroville earthquake sequence of August 1975
Authors: Morrison Paul W. , Stump Brian W. , Uhrhammer Robert
Published: September 2021

abstract

The characteristics of the Oroville, California earthquake sequence of 1975 are presented. Historically, the Oroville area is one of low seismicity; the largest earthquake in the region occurred with a magnitude (ML) 5.7 in 1940 some 50 km north of Oroville. The first foreshock of the sequence occurred on June 28, 1975. Twnety-one foreshocks (ML ≧ 1.6), the largest of magnitude 4.7, preceded the magnitude 5.7 main shock of August 1. All foreshocks and aftershocks of ML ≧ 3.0 were located using seismographs operated by the University of California at Berkeley, USGS, and the California Department of Water Resources. The aftershock region covers an area approximately 14 by 10 km southeast of the city of Oroville. The depth distribution of the earthquakes indicates a west dipping fault plane. The b value of 0.61 shows the sequence to be rich in larger magnitude aftershocks. Similar b values have been determined for other aftershock sequences in California, such as a sequence near Coalinga in August 1975. The aftershock occurrence rate follows an Omori relation with n(t∞t−0.70. Apparent variability in the earthquake mechanisms of the series makes interpretation of composite fault-plane solutions difficult, but the data indicate normal faulting striking NNW and a west dip of about 30°–40°, the Sierra Nevada moving up with respect to the Great Valley.
Focal depth determination from the signal character of long-period P waves
Authors: Herrmann Robert B.
Published: September 2021

abstract

The shape of long-period teleseismic P-wave signals is a function of many factors, among which are focal depth, focal mechanism, the source time function, and the earth structures at both the source and receiver. The effect of focal depth is quite pronounced, so much so, that focal depths should be able to be determined to within 10 km on the basis of the long-period P-wave character. This resolution capability is demonstrated for events occurring in continental and oceanic crust as observed by seismographs in the 30° to 80° epicentral distance range.
Body waves in a layered anelastic solid
Authors: Silva W.
Published: September 2021

abstract

A formulation extending the Haskell-Thompson matrix method to include the effects of anelastic attenuation is presented. The formulation is exact in that no low-loss approximations are made. Consideration is given to nonparallel propagation and attenuation directions with corresponding velocity anisotropy. Examples are presented for models representing soils, the crust, and the core-mantle boundary.
Short-period P-wave attenuation along various paths in North America as determined from P-wave spectra of the SALMON nuclear explosion
Authors: Der Zoltan A. , McElfresh Thomas W.
Published: September 2021

abstract

Average Q values were determined for ray paths to various LRSM stations from the SALMON nuclear explosion by taking ratios of observed P-wave spectra to the estimated source spectrum. Most Q values for P-wave paths throughout eastern North America are in the range 1600 to 2000 while those crossing over into the western United States are typically around 400 to 500. These differences in Q for intermediate distances can sufficiently explain the differences in the teleseismic event magnitudes observed, 0.3 to 0.4 magnitude units, in the western versus the eastern United States, if one assumes that the low Q layer under the western United States is located at depths less than 200 km.
Reflection and refraction of type-II S waves in elastic and anelastic media
Authors: Borcherdt Roger D.
Published: September 2021

abstract

The general theory of viscoelasticity, which accounts for elastic as well as anelastic linear behavior of materials, predicts that two types of S waves propagate in anelastic earth materials. The particle motion for an inhomogeneous plane S wave of type I is elliptical in the plane defined by the directions of propagation and attenuation, while the particle motion for an inhomogeneous plane S wave of type II is linear perpendicular to this plane. The general theory predicts that an S-wave incident upon a plane boundary perpendicular to the plane defined by the directions of propagation and attenuation generates S waves only of the same type. General characteristics of the type-II S waves reflected and refracted at plane anelastic boundaries are:

The general theory predicts these characteristics for the waves whenever a plane type-II S wave interacts with a plane anelastic boundary such as a soil-bedrock, crust-mantle, or core-mantle interface. None of these characteristics are predicted for the plane SH waves described by elasticity theory.
Discrete wave-number representation of seismic-source wave fields
Authors: Bouchon Michel , Aki Keiiti
Published: September 2021

A method based on a discrete horizontal wave-number representation of seismic-source wave fields is developed and applied to the study of the near-field of a seismic source embedded in a layered medium. The discretization results from a periodicity assumption in the description of the source. The problem is basically two-dimensional but its extension to three dimensions is sometimes feasible. The source is quite general and is represented through its body-force equivalents. Tests of the accuracy of the method are made against Garvin's (1956) analytical solution (a buried line source in a half-space) and against Niazy's (1973) results for a propagating fault in an infinite medium. In both cases, a remarkably good agreement is found. The method is applied to the modeling of the San Fernando earthquake, and to the computation of synthetic seismograms at short distance from a complex source in a layered medium. In particular, we show that the high acceleration-high frequency phase of the Pacoima Dam records is due to the Rayleigh wave from the point of ground breakage. Other high-acceleration phases, predicted by our model, are associated with the shear-wave arrival from the hypocenter or result from changes in the fault orientation.
Ground-motion amplification by topographic depressions for incident P wave under acoustic approximation
Authors: Singh Shri Krishna , Sabina Federico J.
Published: September 2021

Ground-motion amplification caused by a semi-spherical and a semi-cylindrical cavity in a half-space for an incident P wave is calculated from analytic solutions under acoustic approximation. We expect this approximation to be valid for materials with a Poisson's ratio near 0.5, e.g., saturated soils. The ground motion is zero at the edges of the cavity and is normal to the free surface. An amplification of about 2 to 3 occurs near the bottom of the cavity for large wavelengths. Detailed numerical results are given for vertical incidence.