bluuebunny/crossref_metadata_2025 huggingface dataset:
Sufi Shrine as Space of Hegemonic Struggle in Pakistan
Authors: Zahra Seemab , Bilal Muhammad , Azam Shafia
Published: September 2021

In the post-9/11 period, while the rise of the Taliban and their alliance with Al-Qaeda accelerated radicalism in Pakistan, Sufism and Sufi shrines have been awarded the status of an antidote to counter the extremist propensities of orthodox Islam typically associated with mosques and madrasas. Nevertheless, contrary to popular belief, sectarian schism, loathing and violence have also been witnessed at several Sufi shrines across Pakistan. The article explores the dynamics of power struggle at the shrine of Bari Imam in Islamabad, Pakistan, while examining the role of sectarian conflicts and violence in achieving the desire for social and economic hegemony. Ethnographic research design was employed, involving participant observation while partaking in different activities of the shrine. Also, respondents including members of the Auqaf Department, pilgrims, caretaker(s) of the Bari Imam shrine and inhabitants of the area were interviewed. The respondents include both males and females of diverse age groups belonging to various socio-economic statuses, sectarian affiliation and educational backgrounds. The findings propose that regardless of the spiritual character of the Bari Imam shrine, it has become a pivot of economic and political power struggle, eventually engendering and escalating sectarian discord, violence and detestation.
To the anniversary of Nikolay Vaganov
Authors: Editorial Article
Published: September 2021

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Using microbial metalo-aminopeptidases as targets in human infectious diseases
Authors: González-Bacerio Jorge , Izquierdo Maikel , Aguado Mirtha Elisa , Varela Ana C. , González-Matos Maikel , del Rivero Maday Alonso
Published: September 2021

Several microbial metalo-aminopeptidases are emerging as novel targets for the treatment of human infectious diseases. Some of them are well validated as targets and some are not; some are essential enzymes and others are important for virulence and pathogenesis. For another group, it is not clear if their enzymatic activity is involved in the critical functions that they mediate. But one aspect has been established: they display relevant roles in bacteria and protozoa that could be targeted for therapeutic purposes. This work aims to describe these biological functions for several microbial metalo-aminopeptidases.
Eş Seçiminde Aranan Özelliklerden Güven, Fiziksel Çekicilik ve Sosyal Statünün Yordayıcısı Olarak Evlilik İnançları
Authors: KELDAL Gökay , KARADAŞ Cemal
Published: September 2021

Bu çalışmanın amacı beliren yetişkinlerin eş adaylarında önem verdikleri güven, fiziksel çekicilik ve sosyal statüyle evliliğe verilen önem ve evliliğin zamanlamasına yönelik inançlar arasındaki ilişkinin incelenmesidir. Araştırmanın çalışma grubunu 609 (435 kadın, 174 erkek) bekâr beliren yetişkin oluşturmuştur. Verilerin analizinde hiyerarşik regresyon analizi tekniği kullanılmıştır. Çalışmanın bulgularına göre evliliğin önemine ve evliliğin zamanlamasına ilişkin inançlar güvenin anlamlı bir yordayıcısı değildir. Evliliğin önemine ilişkin inanç fiziksel çekicilik ve sosyal statünün pozitif yönlü anlamlı bir yordayıcısı olduğu evliliğin zamanlamasına ilişkin inancın ise fiziksel çekicilik ve sosyal statünün anlamlı bir yordayıcısı olmadığı belirlenmiştir. Bu sonuçlara göre beliren yetişkinlerin evliliğin önemine ilişkin daha fazla inanca sahip olması eş seçiminde fiziksel çekicilik ve sosyal statüye daha fazla önem vermeleriyle ilişkilidir.
Validity of Rational Addiction Model for Cinema Demand in Turkey
Authors: KAYMAZ Volkan
Published: September 2021

This study examines the demand for cinema in Turkey using economic and other explanatory variables. The study includes annual data for the period 2009-2017 on 26 sub-regions of Turkey and a dynamic panel data analysis was performed. Furthermore, the validity of the rational addiction model developed by Becker and Murphy (1988) has been investigated for the Turkish cinema market and the role of addiction in cinema demand has been discussed. Estimation results from the dynamic panel data model show that the number of screen and the share of domestic films in total films are an important component in explaining cinema demand. Furthermore, the results showed that the demand for cinema is compatible with the rational addiction model.
BAŞ-BOYUN KANSERİ YOĞUNLUK AYARLI RADYOTERAPİSİNDE PAROTİS BEZİ HACMİ VE HEDEF HACİM İLİŞKİLERİNİN PAROTİS BEZİ DOZUNA ETKİSİ
Authors: ÖZSEVEN Alper , KAYMAK Zümrüt Arda , ÖZKAN Emine Elif , ÇOBANBAŞ İbrahim
Published: September 2021

Amaç

Baş-boyun kanseri radyoterapisinde, parotis ve hedef

hacim ilişkilerinin, parotisin alacağı radyasyon dozu

üzerine etkisini araştırmaktır.

Gereç ve Yöntem

Baş-boyun bölgesi kanserleri tanısı ile küratif, definitif

veya postoperatif adjuvan radyoterapi uygulanmış

hastalardan rastgele 50 hasta seçildi. Konturlama

sonrası her hastanın sağ ve sol parotislerinin ayrı ayrı

kraniyo-kaudal uzunluğu (KKU), parotis hacmi (Vparotis),

parotis ile kesişen planlanan hedef hacim (PTV)

dozu, sağ ve sol parotisin ayrı ayrı PTV70 hedefi ile

örtüşen KKU, parotis seviyesinde olan fakat parotis ile

kesişmeyen maksimum PTV dozu ve parotisin PTV

ile kesişen hacminin toplam parotis hacmine oranı

kaydedildi. Ayrıca, parotis seviyesindeki kesitlerde

PTV70 hacminin olup-olmadığı; var ise yerleşiminin

tek taraflı mı veya bilateral olup-olmadığı kaydedildi.

Yoğunluk ayarlı radyoterapi planlaması sonrası,

doz-hacim histogramları kullanılarak ortalama parotis

dozu (Dmean), 20 Gy ve üstü doz alan parotis hacmi

oranı (V20) ve 30 Gy ve üstü doz alan parotis hacmi

oranı (V30) değerleri ölçüldü. Ortalama parotis dozunun

26 Gy üstünde olmasına etki edebilecek faktörler

lojistik regresyon analizi ile incelendi. Sınır değer

belirleme amacıyla Receiver operating characteristics

(ROC) eğrisi analizi kullanıldı.

Bulgular

Tüm parotislerin ortanca Dmean, V20 ve V30 değerleri

sırasıyla, 26,55 Gy (14,74-66,78), %50,91 (26,53-

100) ve %32,21 (7,12-100) idi. Dmean>26Gy olan

grupta, parotis hacmi istatistiksel olarak anlamlı yüksek

bulundu (p=0,027). Dmean>26Gy olan grupta,

parotisin PTV ile kesişen hacminin tüm parotise oranı

belirgin yüksekti (%1,25 karşın %7,06, p
Estratificación municipal y efectividad de la misma frente a otros instrumentos de identificación de población vulnerable existentes en Latinoamérica
Authors: Bernal Berrio Luisa Fernanda
Published: September 2021

Este escrito aborda la estructuración tarifaria de los servicios públicos domiciliarios en Colombia, los cuales al no tener competencia están expuestos a distintas fallas de mercado como lo son precios excesivamente altos, suministro ineficiente, entre otros; por lo tanto, estos aspectos y específicamente el precio se controlan mediante instrumentos regulatorios como la estratificación a través de la cual se realiza un cobro diferencial en la tarifa de servicios públicos con el fin de asignar subsidios a los sectores marginados. Por lo que, en primer lugar, se analizará la intervención regulatoria del Estado, sus límites y cuáles son las distorsiones del mercado que se corrigen a través de esta, para continuar con una caracterización de la estratificación y un análisis comparativo por medio del cual se busca determinar si hay evidencia de alternativas regulatorias más costo-efectivas para la selección de beneficiarios de subsidios, en términos de equidad y eficiencia, la primera, se evaluará con respecto a los errores que se puedan cometer en la selección y la segunda, a través del resultado de comparar los costos de oportunidad que enfrentan los actores al momento de aplicar estas metodologías, para concluir con una propuesta de esquema de asignación de subsidios.
HISTORIA DE LA ARTROPLASTIA TOTAL DE CADERA
Authors: Alvarez Eduardo , Villanueva Guerra Eduardo
Published: September 2021

La patología articular u osteoartrosis es una enfermedad altamente prevalente por la naturaleza de la evolución humana. Desde la primera mitad del siglo XIX, se entendió la necesidad de tratamiento para la patología debido a la alta morbilidad que esta conlleva. Todos los tratamientos diseñados desde ese tiempo han sido en búsqueda de devolver la funcionalidad al paciente y minimizar su dolor. Al inicio se utilizaron tratamientos rudimentarios como la extirpación articular de Henry Park, sin embargo, la evolución científica nos ha llevado al desarrollo de técnicas menos invasivas, que buscan mejorar la condición física del paciente. La artroplastia total de cadera es un avance de grandes dimensiones dentro de la ortopedia moderna representando la idea básica de reemplazar una articulación destruida. Este procedimiento tan utilizado en la actualidad ha sufrido grandes cambios desde sus inicios en 1962 cuando John Charnley la describió. Incluso hoy en día, existen diferentes materiales que cambian los resultados de una artroplastia y por ello se desarrollaron indicaciones para cada uno de estos. Los pares de fricción han evolucionado en búsqueda de aquel que sea resistente, biomecánicamente funcional y con la menor tasa de complicaciones posible.
INFLUENCIA DE LA TEMPERATURA Y LA ATMOSFERA EN LA SINTERIZACIÓN DE LA HIDROXIAPATITA
Authors: Gonzalez Juan Manuel , Vasquez Andres felipe , Gonzalez David , Rivera Camilo , Ruden Alexander , Trujillo Juan Pablo , Alvarado Juan Manuel
Published: September 2021

En el siguiente trabajo se presenta el efecto de la temperatura y atmósfera de sinterización de polvos comerciales de Hidroxiapatita (HA) comercial en su bioactividad y viabilidad celular. Se sinterizaron muestras compactadas de HA de 12 mm de diámetro y 0.35g de peso a un rango de temperaturas de 900 – 1200°C, con incrementos de 100°C, en atmosferas de aire y argón. Los análisis de XRD y FTIR indicaron la descomposición de la HA en -TCP desde 1100°C para la sinterizada en atmósfera reductora y a 1200°C para la densificada en aire, además de un mayor grado de deshidroxilación de las muestras en argón. La HA sinterizada a 900 y 1000°C en atmósfera de aire y a 900°C en argón presentaron mayor bioactividad, estimada por la apatita precipitada sobre su superficie. Lo anterior se vio reflejado en la densidad celular de las mismas, la cual fue mayor para las muestras anteriores. Se obtuvieron porcentajes de citotoxicidad negativos para todas las muestras, salvo las sinterizadas a 1200°C, para las cuales se evidenció la presencia de fases de descomposición.
DIGITALIZACION EN LA MEDICINA: IMPLICACIONES PARA EL DISEÑO, INNOVACION Y LA INGENIERIA
Authors: Munguia Javier
Published: September 2021

La aplicación de las tecnologías de diseño computacional, manufactura digital, así como el uso de técnicas de visualización aumentada se encuentra en aumento en los sistemas hospitalarios. Mientras que los hospitales universitarios cuentan con la ventaja de fácil acceso a instalaciones de disciplinas como ingeniería, materiales, diseño o mecatrónica, los hospitales tanto públicos, como privados se enfrentan al reto de tener acceso a nuevas tecnologías que se abren camino en el entorno médico: diseño computarizado, acceso a técnicas de fabricación, software y digitalización de información de radiodiagnóstico. Este artículo recopila experiencias recientes de varias unidades médicas del sistema hospitalario de Newcastle upon Tyne, perteneciente al sistema nacional de salud del Reino Unido (NHS). Los recientes resultados muestran una creciente tendencia hacia la digitalización que tiende a modificar los flujos de trabajo y en general la forma en la que se desarrollan distintos dispositivos médicos dentro del sistema de salud en cuestión.
PROFESSIONAL MOBILITY AS A FACTOR OF BORDER GUARDS READINESS FOR PROFESSIONAL ACTIVITY: UKRAINIAN AND EUROPEAN EXPERIENCE
Authors: Islamova O.
Published: September 2021

The article presents an analysis and generalization of approaches to the nature and content of professional mobility. It is concluded that professional mobility is directly interrelated with readiness to work in the specialty, since these two concepts have common elements in the structure, in particular professional knowledge, abilities, skills and professionally important qualities. Taking into account the results of the analysis of research related to the problem of professional mobility, it was found out that this concept can be defined as readiness and ability to work in the context of transformation of professional (production, service) tasks, development of new specialties or changing them. Professional mobility covers the ability to successfully switch to another activity or change types of activities, effectively use the system of generalized professional techniques to perform any tasks in the professional sphere, and it is relatively easy to move from one type of activity to another.
For professional mobility, it is important to have a high level of generalized professional knowledge, experience in improving them and obtaining them independently. The results of the review of publications on the research topic suggest that there are two types of mobility – horizontal and vertical. Horizontal mobility involves the transition of an individual or social object from one social position to another, which is at the same level, as well as a change of place of residence. As for vertical mobility, it involves the transition of an individual or social object from one social position to another. It was found out that mobility is an integrative property that is formed and developed during practical, educational, social, socio-cultural activities of a person and provides him with the opportunity to realize his inclinations, abilities, opportunities. It was found that in the context of training of border guard agencies' personnel in the EU, professional mobility of border guards is ensured by their high level of interoperability, which is a necessary condition for effective organization of protection of EU external borders by representatives of various European border guard agencies. The most common form of ensuring the professional mobility of European border guards is working within the Permanent Corps of the European Border and Coast Guard Agency Frontex. The training of Ukrainian Border Guard Agency's staff in the context of European integration requires the study of the experience of border agencies in EU countries to provide conditions for the development of professional mobility of border guards, which requires further thorough study of the outlined topic.
TRAINING OF FUTURE OFFICERS OF THE ARMED FORCES OF UKRAINE FOR PROFESSIONAL ACTIVITY IN MILITARY LYCEUMS AS A PEDAGOGICAL PROBLEM
Authors: Bondarenko О.
Published: September 2021

In the scientific article the training of future officers for professional activity in military lyceums is considered as not only theoretical but also practical component, because without the theoretical component in combination with practice it is impossible to orient properly in the educational process of higher military educational institutions and military training units of higher educational institutions during the training of tactical level officers and the assessment of training final results. The training of future officer of the Armed Forces of Ukraine for professional activity in military lyceum is considered and scientifically substantiated both as a purpose and as a result of professional training. Since the main purpose of any higher military educational institution is to prepare the graduates for professional activity, the main guideline and basis for solving the problems of training of future officers for professional activity should undoubtedly be the essence of this activity, which reflects the set of its deep connections, relations and internal laws. The detailed analysis of the scientific works provided grounds to substantiate the author's determination of training of future officers of the Armed Forces for professional activity in military lyceum, which provides the formation of a holistic personal education as a result of special professional and psychological-pedagogical professional training, which ensures the transition to a qualitatively new form of activity for the cadet as a future officer of the Armed Forces and it is a set of interdependent and interconnected components: motivational-value, cognitive and reflexive. The criterias of readiness for professional activity of an officer of the Armed Forces of Ukraine as an important and defining feature that characterizes various qualitative aspects, essences and specifics of professional activity of a serviceman are evaluated. The professional activity of an officer of the Armed Forces of Ukraine in a military lyceum is characterized by a high degree of social responsibility, conservatism of values and clear regulation of the conditions for its implementation. In the professional environment of the military lyceum, the role of socially conditioned characteristics and conditions of activity of both faculty that includes officers of the Armed Forces, and pupils (lyceum students) is significantly increasing. It follows that mastering the profession of an officer of the Armed Forces is not only the ability to effectively perform duties, but also the adoption of the appropriate lifestyle, way of thinking, system of norms and values by a future officer.
SOCIAL SCIENCES’ TRANSFORMATION IN LIGHT OF COVID-19
Authors: Ahrens Andreas , Zascerinska Jelena
Published: September 2021

Transformations in social sciences accelerated by the COVID-19 pandemic remain under-explored. The aim of the article is to analyse scientific literature on social sciences’ transformation in light of COVID-19 underpinning the elaboration of implications for teaching a Research Methodology course to the higher education students. The present research work made use of theoretical and empirical methods. The exploratory study was of qualitative nature. The study carried out in April 2021 was based on the analysis of scientific publications selected from the Web of Science and google search by indicating the key words “COVID-19” and “Social sciences’ transformation”. The conclusion is drawn that social sciences’ transformation to the remote conduct is “a new normal” in the conditions of uncertainty. Virtual fieldwork is proposed to be a new qualitative method in social sciences’ research as some populations live mostly in digital environments. Another conclusion is that there is a need for a balance, when composing the empirical study’s sample, between respondents in the digitally divided populations, namely inclusions of both groups’ - digital and non-digital - respondents. Implications for teaching a Research Methodology course to the higher education students are presented. Research limitations are identified. Directions of further research are proposed.
ELEMENTS OF ESCAPE GAMES IN LATVIAN HISTORY LESSONS IN PRIMARY SCHOOL CLASSES
Authors: Brīvere Inese , Levinska Līvija
Published: September 2021

The paper “Elements of Escape Games in Latvian History Lessons in Primary School Classes” reflects escape games as an application of the interactive teaching method in history lessons. Explores  the game as a learning technique, as well as the history and characteristics of the escape game, summarizes the students' opinion on the application of the breakout game in lessons of Latvian history, methodological material for the use of escape game elements in history lessons in primary school classes is developed.
CAREER GUIDANCE FOR REMIGRANTS
Authors: Gruznova Oksana , Strods Gunārs
Published: September 2021

People have always looked for the best opportunities for life and for a variety of reasons there has been migration from country to country. The aim of the study is to find out, through questionnaires and interviews, the reasons for people leaving and the creation of support that would encourage returns. 23 respondents were surveyed, who answered 87 questions. Emigrants were interviewed using email lists to find out what people expected from their country, what differences they see in their home country and in their country of origin. The reasons for leaving are mentioned is credit, debt, marriage with foreigner and many other reasons. Career guidance for remigrants have the task to help them to find a job that is consistent with their abilities and interests and helping to build a successful career.
Gain-ranging analog or digital seismic system
Authors: Kanasewich E. R. , Siewert W. P. , Burke M. D. , McCloughan C. H. , Ramsdell L.
Published: September 2021

abstract

A wide-band, gain-ranging amplifier is described that may be used for recording data with a dynamic range of 60 db in each of three different levels, 12 db apart, so that we achieve an “effective” dynamic ±160-v analog or 84-db digital, within a normal ±10-v analog system. As described, the ranging circuit reduces the gain of the amplifier by a factor of either 4 or 16 whenever the output signal approaches the maximum for the system. The wide-band response is achieved with low-noise operational amplifiers and second-order active filters. Signals with periods greater than 30 sec are amplified by 100 db and those with periods shorter than 1 sec are amplified by 70 db. The system works well in extending the useful output range of a Willmore Mark II seismometer with a natural period of 1.5 sec to over 40 sec under normal field operating conditions. When analog recording, the gain-range switching occurs when the input signal reaches ±8.1-v; when digital recording, the level is ±9.375 v. The period in a divide-by-4- or 16-state is preset by the experimentalist. The gain level is recorded on an extra channel which is also used to record absolute time.
Effect of boundaries on wave propagation in media with microstructure: II. Surface waves in a half-space
Authors: Farshad M. , Ahmadi G.
Published: September 2021

abstract

The surface-wave propagation in a half-space according to couple-stress theory is studied herein. Dispersion curves as well as displacement variations with the depth coordinate are obtained for a range of material parameters. Comparison is made with the classical elasticity predictions upon which certain conclusions are reached.
Coda suppression capabilities of the beam and mixed-signal processor
Authors: Cohen T. J.
Published: September 2021

abstract

Using data recorded on 7- and 19-element subarrays at TFO, we compare the relative abilities of the beam and a mixed-signal processor to attenuate P-wave codas. The P-wave signals from various earthquakes are time-shifted to simulate arrivals from different azimuths and 60° distance. These signals are assumed to mask an explosion detonated at Semipalatinsk, about 96° distant from TFO. The analysis consists of determining how much of signal 1 (the earthquake) leaks into our estimate of signal 2 (the event being masked). Because the beam and mixed-signal processor are linear processors, signal 2 need not actually be present; we need only determine how much of signal 1 is present in our estimate of signal 2. The coda attenuation capability of the mixed-signal processor is found to exceed that of the beam. Up to 14-db improvement over the beam is obtained, although improvement is generally on the order of 3 to 5 db for both subarrays. A nominal value of 18 db is representative of the maximum coda attenuation obtained using the mixed-signal processor and the 19-element subarray; for the 7-element subarray, maximum attenuation is roughly 14 db. Coda attenuation obtained using the 7-element subarray and the mixed-signal processor is comparable to that obtained using the 19-element subarray and the beam. Preliminary results suggest that when the difference in the ray parameter vectors is small, a large-aperture array and the mixed-signal processor are required for significant (∼9 db) coda attenuation.
Some numerical solutions for Lamb's problem
Authors: Mooney Harold M.
Published: September 2021

abstract

We consider a version of Lamb's Problem in which a vertical time-dependent point force acts on the surface of a uniform half-space. The resulting surface disturbance is computed as vertical and horizontal components of displacement, particle velocity, acceleration, and strain. The goal is to provide numerical solutions appropriate to a comparison with observed wave forms produced by impacts onto granite and onto soil.

Solutions for step- and delta-function sources are not physically realistic but represent limiting cases. They show a clear P arrival (larger on horizontal than vertical components) and an obscure S arrival. The Rayleigh pulse includes a singularity at the theoretical arrival time. All of the energy buildup appears on the vertical components and all of the energy decay, on the horizontal components.

The effects of Poisson's ratio upon vertical displacements for a step-function source are shown. For fixed shear velocity, an increase of Poisson's ratio produces a P pulse which is larger, faster, and more gradually emergent, an S pulse with more clear-cut beginning, and a much narrower Rayleigh pulse.

For a source-time function given by cos2(πt/T), −T/2 ≦ T/2, a × 10 reduction in pulse width at fixed pulse height yields an increase in P and Rayleigh-wave amplitudes by factors of 1, 10, and 100 for displacement, velocity and strain, and acceleration, respectively. The observed wave forms appear somewhat oscillatory, with widths proportional to the source pulse width. The Rayleigh pulse appears as emergent positive on vertical components and as sharp negative on horizontal components.

We show a theoretical seismic profile for granite, with source pulse width of 10 µsec and detectors at 10, 20, 30, 40, and 50 cm. Pulse amplitude decays as r−1 for P wave and r−12 for Rayleigh wave. Pulse width broadens slightly with distance but the wave form character remains essentially unchanged.
P-wave anomalies from CANNIKIN at the Indian stations
Authors: Srivastava H. N. , Chaudhury H. M.
Published: September 2021

abstract

P-wave travel-time anomalies due to the U.S. nuclear explosion, CANNIKIN in the Amchitka Islands, recorded at 25 stations in India, were studied with reference to the Jeffrey-Bullen (1952) and Herrin et al. (1968) travel-time tables. The results indicated better agreement with the latter tables for this source.
High-frequency attenuation by a thin high-velocity layer
Authors: Mellman George R. , Helmberger Donald V.
Published: September 2021

The Cagniard-de Hoop method is used to investigate elastic-wave tunneling through a thin high-velocity layer. The results indicate high-frequency attenuation in the geometric shadow zone. Attenuation is roughly proportional to layer thickness. Comparison of results obtained by omitting the high-velocity layer but using an average Q operator shows that effects of the high-velocity layer are similar to Q effects, with the equivalent Q for a given layer thickness varying as a function of source-receiver distance. These attenuation effects are explained in terms of deformation of the de Hoop contour.
Variations of strong earthquake ground shaking in the Los Angeles area
Authors: Trifunac M. D. , Udwadia F. E.
Published: September 2021

Accelerograms recorded at six stations in the metropolitan Los Angeles area during the Borrego Mountain, 1968, the Lytle Creek, 1970, and the San Fernando, 1971, earthquakes in southern California have been studied. In comparing the ground motions recorded during different earthquakes at each of the six stations and in correlations of these motions recorded at different stations during the same earthquake, those aspects of the analysis which emerge from this study and are relevant for seismic zoning have been emphasized.

It has been found that the patterns of strong ground shaking in this area depend predominantly on the mechanism and the distance of an earthquake source from a recording station and that the local soil conditions played only a minor role in modifying the ground motion at this particular area. It has been shown that gross spectral characteristics of ground motion recorded at various stations can be approximately related by the seismic moment at the low-frequency end and by the stress drop at the high-frequency end.
Near-field observations and source parameters of central California earthquakes
Authors: Johnson Lane R. , McEvilly Thomas V.
Published: September 2021

abstract

This is a study of source characteristics of 13 earthquakes with magnitudes between 2.4 and 5.1 located near the San Andreas fault in central California. On the basis of hypocentral locations and fault-plane solutions the earthquakes separate into two source groups, one group clearly related to the throughgoing northwest-trending San Andreas fault zone and the other apparently associated with generally north-trending bifurcations such as the Calaveras fault. The basic data consist of broad-band recordings (0.03 to 10 Hz) of these earthquakes at two sites of the San Andreas Geophysical Observatory (SAGO). Epicentral distances range between 2 and 40 km, and maximum ground displacements from 4 to 4000 microns were recorded. The whole-record spectra computed from the seismograms lend themselves to source parameter studies in that they can be interpreted in terms of low-frequency level, corner frequency, and high-frequency slope. Synthetic seismograms have also been used to estimate source parameters in both the time domain and frequency domain, and the results compare favorably with those estimated directly from the spectra. The influences of tilts and nonlinear response of the seismometer were considered in the interpretation of the low frequencies. Seismic source moments estimated from the low-frequency levels of the spectra show a linear dependence on magnitude with a slope slightly greater than 1. The geology at the recording site can contribute an uncertainty factor of at least 3 to the estimated moments. Observed corner frequencies are only weakly dependent on magnitude. Interpreted in terms of source dimension, these corner frequencies imply values of 1 to 2 km for the earthquakes of this study. The corner frequencies may also be interpreted in terms of the rise time source function, yielding values in the range 0.5 to 1.0 sec. The data indicate that the earthquakes of this study are all surprisingly similar in their fundamental source parameters, with only the seismic moment showing a strong dependence on magnitude.
P-wave amplitudes and magnitudes between 10° and 35°
Authors: McMechan George A. , Workman Warren G.
Published: September 2021

abstract

The observed behavior of P-wave relative amplitudes, as a function of epicentral distance, between 10° and 35°, is controlled primarily by the velocity-depth structure of the upper mantle. P-wave synthetic seismograms calculated by the new quantized ray theory technique are used to determine theoretical log (A/T) versus log Δ curves from a number of upper mantle models. Maximum amplitude arrivals show less model dependence than the first arrivals in the same wave trains, and hence are more consistent magnitude indicators for regions where the upper mantle structure is poorly known. Log (A/T) versus log Δ curves vary considerably, but predictably, from model to model. This model-dependent variation can account for a major part of the large standard deviations usually associated with the calculation of magnitudes from body waves.
Seismotectonic maps of southwest Asia region comprising Eastern Turkey, Caucasus, Persian Plateau, Afghanistan and Hindukush
Authors: Kaila K. L. , Madhava Rao N. , Narain Hari
Published: September 2021

abstract

Three seismic activity maps, the A-value map, the b-value map and the returnperiod map for earthquakes with magnitude 6 and above, have been prepared for the southwest Asia region using the Kaila and Narain (1971) method, and the same are compared with regional tectonics. For the preparation of these maps, a modified relation A = 6.36b - 1.00 has been used instead of the earlier relation where A and b are constants in the cumulative regression curve represented by log N = A − bM. The A-value seismicity map reveals that the Southwest Asia region consists of a number of seismic high zones such as the Caucasus-Abul Samsar high, the Zagros high, the Shahrud-Doruneh high and the Hindukush-West Pakistan high. The Caucasus-Abul Samsar seismic high shows two superimposed trends, one NW-SE which is consistent with the Caucasus tectonic trend and the other NE-SW which is parallel to the Abul Samsar fracture zone. The Zagros seismic high runs in the NW-SE direction almost parallel to the Zagros thrust zone with diversions to the northeast at the two ends. High seismic activity is revealed in the Zagros foothills area rather than the thrust-zone. The Shahrud-Doruneh high shows a NW-SE trend parallel to Kopet Dagh, and, toward the west, it bends down aligning itself almost parallel to the Elburz mountains, thus indicating the possibility of a connection between this high and the Zagros high. The Hindukush-West Pakistan high runs in the NNE-SSW direction consistent with the tectonic trends in this area, indicating the highest seismic activity near the Yasman fracture zone. The b-value seismicity map also reveals the same seismic features as brought out by the A-value map. The b-values obtained by this new method over various regions of southwest Asia agree fairly well with those reported by other workers obtained from earthquake regression curves. The return-period map further brings out the zones of high and low seismic activity which are quite consistent with the A-and the b-value maps, and the regional tectonics.
A simplification in the calculation of motions near a propagating dislocation
Authors: Boatwright John , Boore David M.
Published: September 2021

abstract

From Haskell's (1969) integral representations for the near-field displacements due to a propagating strike-slip and dip-slip dislocation, a solution is obtained for a dislocation “line source” by an analytic integration in the direction of the fault propagation. This reduces the numerical integration from a surface integral required for the usual evaluation of the near-field motion, to a one-dimensional integration over the fault width. Since the dislocation function modeled here is a Heaviside step function, these results may be extended to any arbitrary source time-function by convolving these displacements with the time derivative of the desired source function.
Seismic source summary for U.S. underground nuclear explosions, 1971-1973
Authors: Springer Donald L. , Kinnaman Ross L.
Published: September 2021

abstract

A summary of information is presented for all announced U.S. underground nuclear explosions detonated during the 1971-1973 time period. The data include detonation times, locations, and depths of burial, as well as information about shot media and surface collapse (subsidence) phenomena. This summary is an addendum to a previous publication which covered the period 1961-1970, and includes some additions and corrections to that work.
Source dimensions of two deep earthquakes estimated from aftershocks and spectra
Authors: Wyss M. , Shamey L. J.
Published: September 2021

abstract

The relation the spectral corner frequency and the source dimensions, r(P, S) = c(P, S)β/ƒ0 is tested for two deep earthquakes under the assumption that aftershocks approximately outline the rupture area. It was found that c = 0.37 as proposed by Brune (1970) leads to radii estimates within ±20 per cent of the radii outlined by the aftershocks.
Surface-wave magnitudes of Eurasian earthquakes and explosions
Authors: Nuttli Otto W. , Kim So Gu
Published: September 2021

abstract

Body-wave magnitudes, mb, and surface-wave magnitudes, MS, were determined for approximately 100 Eurasian events which occurred during the interval August through December 1971. Body-wave magnitudes were determined from 1-sec P waves recorded by WWSSN short-period, vertical-component seismographs at epicentral distances greater than 25°. Surface-wave magnitudes were determined from 20-sec Rayleigh waves recorded by long-period, vertical-component WWSSN and VLPE seismographs. The earthquakes had mb values ranging from 3.6 to 5.7.

Of 96 presumed earthquakes studied, 6 lie in or near the explosion portion of an mb:MS plot. The explosion mb:MS curve was obtained from seven Eurasian events which had mb values ranging from 5.0 to 6.2 and MS values from 3.2 to 5.1. All six anomalous earthquakes were located in the interior of Asia, in Tibet, and in Szechwan and Sinkiang provinces of China. In general, oceanmargin earthquakes were found to have more earthquake-like mb:MS values than those occurring in the continental interior. Neither focal depth nor focal mechanism can explain the anomalous events.
Dependence on the elastic constants of surface deformation due to faulting
Authors: Converse Glenn , Comninou Maria
Published: September 2021

In general, the explicit expressions for surface displacements calculated from dislocation models of faulting in a half-space are restricted to the case λ = μ, where λ and μ are the Lamé elastic constants (e.g., Maruyama, 1964; Press, 1965; Mansinha and Smylie, 1971). It is obviously of some interest to know how the surface fields might be modified by other choices of the elastic constants. In this paper it is shown that the surface displacements depend upon the elastic constants only as linear functions of the Poisson ratio v. The intercepts and slopes of the linear functions, of course, vary with position on the free surface. The surface tilts and strains are also simple functions of the Poisson ratio.
Analysis of seismic response in the city of Las Vegas, Nevada: A preliminary microzonation
Authors: Murphy J. R. , Hewlett R. A.
Published: September 2021

abstract

Ground motion data recorded at 26 different locations in Las Vegas from six underground nuclear tests have been used to perform a preliminary microzonation of the city. The microzonation results are presented in the form of contour maps of the average observed seismic response throughout the city in 12 different frequency bands covering the period range from 0.16 to 6.0 sec. These data indicate that variations in long-period seismic response of as much as an order of magnitude can be expected at sites only a few kilometers apart in the city. Simple models of surface-wave propagation in the surface layer of alluvium of variable thickness can account for much of the observed variability. However, it appears that surface waves reflected back from the valley boundaries at the base of the surrounding mountain ranges also have a significant effect on the measured response.
On the estimation of seismic detection thresholds
Authors: Ringdal F.
Published: September 2021

abstract

The incremental detection capability of a seismic station, i.e., the probability of detection as a function of event magnitude, is usually estimated either by using the exponential magnitude-frequency relationship of earthquakes (the recurrence method) or by comparing the station detections to an independent reference system (the direct method). The recurrence method usually yields significantly lower 90 per cent thresholds than the direct method, while a hypothetical “true” threshold would lie between these values. This is explained theoretically as resulting from the global variance of observed signal amplitudes for a given seismic event. A maximum likelihood estimation procedure is developed for the direct method, and approximate confidence limits on the estimated detection thresholds are derived. The two estimation techniques are applied to determine the event detection capability of the NORSAR array for the Japan-Kuriles-Kamchatka region, and the results are related to previously published estimates.
Surface motions due to fault slip in the vertical mode with friction
Authors: Brock L. M.
Published: September 2021

abstract

Approximations to the wave motions generated on the surface of an elastic half-space by slip in the vertical mode with friction on a fault plane of arbitrary dip are analyzed. The half-space is initially motionless under uniformly distributed tectonic stresses and hydrostatic stresses due to the weight of the material. The resistance to slip obeys the Coulomb model for static and kinetic friction. Slip is triggered along a line parallel to the fault surface trace. The moving edge of the slip zone extends toward the surface with a constant velocity. Homogeneous function techniques are used to derive the stresses and displacements for a general class of related problems as single integrals of analytic functions. The results are easily specialized to obtain approximate expressions for the wave-induced surface displacement and particle velocity components. For various values of the time, dip angle, coefficient of kinetic friction and rate of extension of the slip-zone edge, curves for the surface particle-velocity components are given. This paper will serve as a basis for future work.
A comprehensive study of long-period (20 to 200 seconds) earth noise at the high-gain worldwide seismograph stations
Authors: Murphy Andrew J. , Savino John M.
Published: September 2021

abstract

The characteristics of long-period (20 to 200 sec) earth noise have been investigated at the 11 high-gain, long-period (HGLP) seismograph stations using as many as 3 years of analog seismograms and digital data from these stations. A major contribution of this study is the significant increase in the number of long-period earth-noise spectra that are available from areas of vastly differing geological and tectonic settings outside the contiguous United States. This information is important to the study of the long-period portion of the spectra of earthquakes and to the discrimination of earthquakes and underground explosions.

A significant feature of earth-noise spectra based on data from all the HGLP stations is a minimum between about 25 and 45 sec. This minimum spectra level is most pronounced at sites with more than 200 m of overburden. The level of earth noise generally recorded by vertical-component seismographs at both the shallow and deep stations is independent of local meteorological conditions if the seismographs are located on competent bedrock and are subject to rigid environmental controls.

The level of earth noise recorded by horizontal component seismographs at HGLP stations, however, is dependent on local meteorological conditions. This dependency decreases with increasing depth of overburden. The decay rate with depth of this horizontal earth noise is such that approximately 150 m of competent overbuiden is usually sufficient to attenuate about 90 per cent of the earth noise caused by local atmospheric conditions.
On viscosity and the inelastic nature of waves in geological media
Authors: Blake Thomas R. , Dienes John K.
Published: September 2021

abstract

An asymptotic solution for spherical wave propagation in linear viscoelastic solids is compared with particle velocity measurements from underground explosive tests in tuff; the magnitudes of these experimental data are of the order of 5 ×102 cm/sec. The qualitative nature of the theoretical solution is similar to that of the measured velocity time histories. When material and kinematic parameters in the model are specified, good quantitative agreement is obtained with respect to radial attenuation of the magnitudes and radial growth of the wavelengths. Both the phenomenological character of the viscoelastic model and limitations on its applicability are discussed.
Source properties of a Blue MT. Lake earthquake
Authors: Anderson John G. , Fletcher Jon B.
Published: September 2021

abstract

An accelerogram obtained at Blue Mt. Lake, New York is remarkable for the simplicity of its S-wave pulse. This results from (1) a nearly complete absence of scattering and reflections as second arrivals on the accelerogram, and (2) a very elementary earthquake source. The earthquake identified with this accelerogram had a magnitude mb = 2.2 and a hypocentral distance of about 1 km from the accelerometer. Spectral analysis of the S wave indicates the earthquake had a moment of 8 × 1018 dyne-cm, and a source radius of 20 to 40 m. When the accelerogram is integrated to obtain displacement, there is a step offset of about 5μ associated with a near-field component of the S-wave pulse. The S-wave, including the step offset, can be matched in remarkable detail by a dislocation model with a moment of 8.4 × 1018 dyne-cm.
P-wave spectra of nevada test site events at near and very near distances: Implications for a near-regional body wave-surface wave discriminant
Authors: Peppin William A.
Published: September 2021

abstract

Some 140 P-wave spectra of explosions, earthquakes, and explosion-induced aftershocks, all within the Nevada Test Site, have been computed from wide-band seismic data at close-in (< 30 km) and near-regional (200 to 300 km) distances. Observed near-regional corner frequencies indicate that source corner frequencies of explosions differ little from those of earthquakes of similar magnitude for 3 < ML < 5. Plots of 0.8 to 1.0 Hz Pg spectral amplitude versus 12-sec Rayleigh-wave amplitude show a linear trend with unit slope over three orders of magnitude for explosions; earthquakes fail to be distinguished from explosions on such a plot. These spectra also indicate similar source spectra for explosions in different media (tuff, alluvium, rhyolite) which corroborates Cherry et al. (1973). Close-in spectra of three large explosions indicate that: (1) source corner frequencies of explosions scale with yield in a way significantly different from previously published scaling laws; (2) explosion source spectra in tuff are flat from 0.2 to 1.0 Hz (no overshoot); (3) the far-field source spectrum decays at least as fast as frequency cubed. Taken together, these data indicate that the following factors are not responsible for Peppin and McEvilly's (1974) near-regional discriminant: (a) source dimension, (b) source rise time, or (c) shape of the source spectrum.
Automatic seismic array and network detection
Authors: Wirth M. H. , Blandford R. R. , Shumway R. H.
Published: September 2021

abstract

The theory of automatic detection at a seismic array by means of an F-statistic is extended to a network of such arrays. The results are generally valid for detection using other statistics. The arrays may have equal or different expected signal-to-noise ratios. Two techniques are discussed: (1) the voting detector in which K out of M arrays must detect; K is determined to be optimum; (2) an incoherent detector which detects on the sum of the subarray detection outputs. For small variation of signal and noise amplitudes between arrays, the detectors are found to be nearly equal in detection capability.

If the standard deviation of log10 (signal/noise) is 0.3, the incoherent detector becomes substantially superior to the voting detector and approaches the capability of a perfect beam of well-correlated signals. This result is in agreement with the few available empirical data.
The Canadian seismic array monitor processing system (cansam)
Authors: Weichert D. H. , Henger M.
Published: September 2021

abstract

An on-line digital beamforming and detection system has been operating at the Canadian short-period array near Yellowknife since early 1974. The installation followed the renewed recognition of the important contribution this array can make to worldwide detection and location of small seismic events. System design is based on earlier Canadian experience. Daily event detection logs are available in Ottawa via dialed telephone line. Nonlinear beamforming is used to lower the false alarm rate at given detection level, and it is shown to perform as predicted. During the 6 winter and spring months, the detection threshold is mb 4.0 to 4.1 at 50 per cent false alarm rate. During summer and fall, organized surface-wave noise originating on Great Slave Lake raises this level to mb 4.6 to 4.7.