bluuebunny/crossref_metadata_2025 huggingface dataset:
Las derivas del viajar: apuntes para un análisis itinerante de una barra del fútbol argentino
Authors: Cabrera Nicolás
Published: September 2021

Si de “barras bravas” argentinas se trata, hay una simplificación que siempre merodea la temática, me refiero al reduccionismo que las piensa como fósiles anclados en la tribuna. En posición, este trabajo se centra en las experiencias itinerantes de los miembros de la barra del Club Atlético Belgrano de Córdoba, Argentina, autodenominada Los Piratas. El articulo explora los distintos tipos de viajes que los miembros de tal grupo realizaron durante mi trabajo de campo etnográfico. En todos estos años he podido registrar cuatro modalidades de traslados organizados: a) barriales; b) provinciales c) de infiltrados; d) de anfitriones y huéspedes. A lo largo del trabajo iré analizando cada uno de ellos para luego, al final, proponer una sistematización que resume la importancia que el viajar condensa en el proceso de formación social de Los Piratas y el involucramiento de sus miembros. Veremos que los viajes se vinculan al imperativo que tiene todo grupo social de experimentar límites.
É possível falar de vocação quando se fala de ateísmo organizado? Reflexões sobre a iniciativa ateísta no Brasil
Authors: Testa Sabrina F.
Published: September 2021

Diversos agrupamentos ateístas emergiram no Brasil nos últimos anos. Trata-se de pequenas associações que surgem a partir de e são mantidas graças à iniciativa de atores individuais que investem uma quantidade considerável de tempo, esforço e, inclusive, dinheiro para sustentar uma causa que, nem se define facilmente além da negação da ideia de deus, nem oferece recompensas materiais ou simbólicas aparentes. Este artigo procura explorar os sentidos que estes líderes ateístas atribuem à atividade militante, a partir de uma discussão sobre a categoria weberiana de vocação. Argumenta-se que a articulação de um movimento de descrentes, tal como se configura no Brasil, constitui uma empreitada intrinsecamente ambígua, na medida em queresiste toda formalização e definição para além do mínimo necessário para existir como tal. Sob o risco constante de devir “religião” o ateísmo não seorganiza se não de forma embrionária, e dos seus articuladores exige um engajamento considerável que, no entanto, se evita definir em termos de  liderança. A abordagem, de corte interpretativo, tem por base empírica um trabalho de campo etnográfico levado adiante entre setembro de 2016 e  fevereiro de 2018 junto aos setores ateístas do Brasil.
Tres Marías y una canta. Migración rural y muertes de soledad en el campo de Boyacá (Colombia)
Authors: Cuéllar Gempeler Mónica
Published: September 2021

Este escrito gira en torno a una copla popular que lleva al menos un siglo prediciendo el fin de un mundo campesino y reflexiona sobre cómo esta resuena con una imagen recurrente en veredas de San Miguel de Sema y de Ráquira (Boyacá): la de un rancho con una última habitante de quien se sospecha que pudo haber muerto de tristeza o de soledad. En el espacio de esta resonancia, teniendo en cuenta una larga historia de migración rural, explora cómo se constituye un mundo que se siente a punto de terminar. Se pregunta, finalmente, cómo responder al canto que a la vez proclama y posterga su final.
Growth of mixed E. coli colonies v2
Authors: Moebius Wolfram
Published: September 2021

Growth of mixed E. coli colonies on agar plates and between an agar plate and an agar pad
Chlamydomonas reinhardtii nuclear transformation by electroporation. v3
Authors: Vitor Molino João
Published: September 2021

This protocols describe the steps required for nuclear transformation of Chlamydomonas reinhardtiiby electroporation. Here you can find a video following the protocol.
A method for the temperature-controlled extraction of DNA from ancient bones v1
Authors: Essel Elena , Meyer Matthias , Korlevic Petra
Published: September 2021

We here provide a protocol for the decontamination of ancient bones and teeth that is based on a temperature-controlled, sequential release of DNA. DNA can be extracted from all fractions generated with this method and the fraction with the highest proportion of endogenous DNA identified for further analysis. The protocol proceeds through repeated incubation of the sample powder in phosphate buffer at 37, 60 and 90 °C, followed by the complete lysis of the residual sample powder. As DNA is denatured at high temperature, subsequent DNA extraction and library preparation has to be performed using methods optimized for single-stranded DNA.
Step 2: RNA extraction and RT-qPCR v1
Authors: H L Krijger Peter , A Hoek Tim , Boersma Sanne , I P M Donders Lieke , M C Broeders Maaike , Pieterse Mark , W Toonen Pim , Logister Ive , M P Verhagen Bram , J A M Verstegen Marjon , W van Ravesteyn Thomas , J T M Roymans Rene , Mattiroli Francesca , Vandesompele Jo , Nijhuis Monique , Meijer Stefan , van Weert Anton , Dekker Edwin , J Dom Fred , Ruijtenbeek Rob , B J van der Velden Lieven , H B van de Bovenkamp Jeroen , Bosch Martijn , de Laat Wouter , E Tanenbaum Marvin
Published: September 2021

STRIP is a start-to-end streamlined and automated procedure for COVID-19 testing, centering on a single Tecan Fluent liquid-handling robot that can process over 14,000 samples per day. Key features of the customized Tecan Fluent robot are (1) on-board 1D and 2D barcode scanners, (2) an automated tube decapper, (3) two robotic arms for simultaneous processing of different procedural steps, (4) a newly-designed spin vessel to keep magnetic beads in solution and immediately transferable to 384-well plates, (5) a built-in magnetic deck and a 384-channel pipetting head for rapid RNA isolation, (6) a heating device for fast drying of RNA prior to elution, (7) a built-in plate sealer and (8) a plate storage system to allow processing of multiple sample plates in a single run (See Materials). Here we describe the RNA extraction and RT-qPCR protocol as currently applied in STRIP.
STRIP: Systematic Testing using Robotics and Innovation during Pandemics v1
Authors: H L Krijger Peter , A Hoek Tim , Boersma Sanne , I P M Donders Lieke , M C Broeders Maaike , Pieterse Mark , W Toonen Pim , Logister Ive , M P Verhagen Bram , J A M Verstegen Marjon , W van Ravesteyn Thomas , J T M Roymans Rene , Mattiroli Francesca , Vandesompele Jo , Nijhuis Monique , Meijer Stefan , van Weert Anton , Dekker Edwin , J Dom Fred , Ruijtenbeek Rob , B J van der Velden Lieven , H B van de Bovenkamp Jeroen , Bosch Martijn , de Laat Wouter , E Tanenbaum Marvin
Published: September 2021

STRIP is a start-to-end streamlined and automated procedure for COVID-19 testing, centering on a single Tecan Fluent liquid-handling robot that can process over 14,000 samples per day. The sensitivity, specificity, and practical implementation of STRIP have been validated in a clinical study on 1128 individuals, meeting the standards set by the Dutch National Institute for Public Health and the Environment (Dutch CDC). Automation throughout the testing procedure dramatically reduces the workload of diagnostic laboratory personnel and potentially allows the placement of multiple STRIP liquid-handling robots per testing facility, further increasing testing capacity. The entire test procedure also requires only 3 pipet tips per sample, as well as reduced testing reagents due to process miniaturization, which is important given scarcity of testing consumables during the COVID-19 pandemic. Furthermore, STRIP is compatible with reagents from any supplier, and thus less sensitive to supply chain bottlenecks. Finally, the system is open and modular, facilitating adaptation of future developments in diagnostics. Overall, the system enabled substantial savings in personnel and reagents requirements compared with conventional diagnostic testing; when STRIP runs at full capacity, it is possible to rapidly recoup the initial outlay in the liquid-handling system from savings in personnel costs, reagents and materials.
Local hemostasis disorders underlying endometric pathology
Authors: Iupatov E. Iu. , Mustafin I. G. , Kurmanbaev T. E. , Nabiullina R. M. , Atayants K. M. , Shmidt A. A. , Frederiks E. V.
Published: September 2021

Introduction. Hemostasis is an equilibrium system that performs 2 bidirectional tasks: on the one hand, it prevents bleeding development, whereas on the other hand, it counters thrombogenesis. Shifting the balance leads to development of various complications, and also serves as a key link in the pathogenesis of a number of diseases. Currently, the issue of changing the state of local endometrial hemostasis in various pathologies is of high priority. Unfortunately, publications available on this problem are limited.

Aim: to conduct a literature search and systematize the data analysis to expand understanding regarding a role of local hemostasis disorders in formation of endometrial pathology.

Materials and Methods. There has been performed a systematic analysis of full-text scientific reviews and original articles published in English and Russian in the modern literature. The review includes the 1995-2020 data published in the international abstract and bibliographic databases eLibrary, Google Scholar, Web of Science, Scopus and PubMed/MEDLINE.

Results. Hemostatic changes in the endometrium that occur under the influence of estrogens and progesterone, and create a local hemostatic environment, which disturbance contributes to emergence of various endometrial pathologies, are described. It was found that for the physiological course of pregnancy, complex changes in the local hemostasis are necessary, which are aimed at facilitating the processes of chorionic invasion and maintaining metabolic processes in the mother-fetus interface, whereas alteration of the aforementioned processes contributes to development of abnormal chorionic invasion as the basis for development of insufficient placental function, preeclampsia (PE), and pregnancy termination. Moreover, there have been summarized the data on key changes in the state of local endometrial hemostasis that play a role in the pathogenesis of endometriosis, as well as underlying abnormal uterine bleeding (AUB).

Conclusion. Current research publications provide sparse evidence that the state of the local hemostasis in the endometrium is an important aspect of the physiological course of the menstrual cycle, as well as formation of endometrial pathology. In this review, it is shown that local hemostasis is inextricably linked with the state of the systemic hemostasis, but at the same time, its functioning depends on the level of hormones estrogens and progesterone. Impaired function of local endometrial hemostasis is an important aspect of the pathogenesis of miscarriage, as well as conditions such as PE, endometriosis, AUB.
Lateralized influence of stereotaxic destruction of amygdaloid nucleus and forel fields on the dynamics of memorizing functions in epileptics
Authors: Vasserman L. I. , Lassan L. P. , Yashuk S. L.
Published: September 2021

Observation of 68 patients of 1245 years of age with partial and generalized epilepsy allowed to make a conclusion that left stereotaxic destruction of amyg daloid nucleus and Forel fields more often and more, distinctly increase preoperative disturbance of memory and attention volume at the early postoperative period. During the follow-up period more complete regression of disturbances of the early postoperative period and improvement of quotient in comparison with preoperative state were also more often observed after destruction of subcortical malformations of the left cerebral hemisphere.
Correlation between quality of life indicators, peculiarities of diet and clinical manifestations of multiple sclerosis
Authors: Tatarinova M. Yu. , Smirnova N. F. , Boyko A. N.
Published: September 2021

Multiple sclerosis is one of the most important problems of neurology. Onset age of disease is young, and young people, which are able to work often become invalids. That is why multiple sclerosis is medical and social problem. Questions of epidemiology and quality of life of our patients with multiple sclerosis are modern questions of multiple sclerosis problem. Our scientific work is devoted to relation between indicators of quality of life and dietary factors, clinical peculiarities of disease. We received interesting results. We found, that among males most important for quality of life are physical functions and common condition of health. And emotial problems, reduction of social functions, reduction of vitality are most important for quality of life among females.
The untrustworthiness of personal impressions of direction of vibrations in earthquakes
Authors: Branner John Casper
Published: September 2021

Resum矯f Conclusions

1. There is no clear or uniform idea of what is meant by the direction of vibration as determined by non-instrumental observations; some persons regard it as the direction of transmission of a wave-like movement along the surface of the earth; others regard it as a to-and-fro movement like the gentle balancing of a rocking-chair.

2. The sensation at the time of an earthquake is commonly a confused tremulous one produced by jar rather than by wave-like motion having direction recognizable through personal sensations alone.

3. The overthrow of objects shows that the disturbance of equilibrium has very little regularity, and that it bears no definite relation to the direction of movement as indicated by instrumental obsrvation and by other evidences.

4. In many cases where the epicenter is known and the individuals over the area affected have stated their impressions of direction, these impressions are found to be quite useless for purposes of locating the epicenter or for any other purpose, so far as I can see at present.

5. Instrumental records show that the directions are many and the movements complex. Out of such entangled movements it seems quite impossible for our uncertain impressions to gather trustworthy conclusions regarding the location of epicenters.
Application of a vertical strain seismograph to the enhancement of P waves
Authors: Shopland Robert C. , Kirklin Richard H.
Published: September 2021

abstract

Enhancement of P waves is obtained by the suppression of microseisms with a combination of vertical linear strain seismograph and vertical inertial seismograph outputs. Significant suppression is observed at sites where the predominant microseisms consist of essentially single-mode Rayleigh waves in contrast to that observed at a site where the microseismic noise is compositionally more complex. A description is given of the vertical linear strain seismograph used in these investigations. Consideration is given to the use of a vertical transverse strain seismograph at sites where the microseismic noise field is complex.
A note on fast computation of Rayleigh wave dispersion in the multilayered elastic half-space
Authors: Watson T. H.
Published: September 2021

abstract

Matrix formulas for modal solutions in the layered, elastic half-space are modified to give faster machine computation. Accuracy at high frequencies is also included. Computing time is reduced by 30 per cent from the fastest program previously reported.
The intermediate earthquake source near Bucaramanga, Colombia
Authors: Tryggvason Eysteinn , Lawson James Edwards
Published: September 2021

abstract

An intensive source of intermediate depth earthquakes has been located in northern Colombia. The activity of this source increased significantly between 1956 and 1966, but appears to be decreasing after 1966. The frequency-magnitude relation of the Bucaramanga earthquakes is anomalous, with fewer large earthquakes than expected. The distribution of determined hypocenters is the same as would be observed if all earthquakes originated in the same point source. Therefore it is concluded that the Bucaramanga seismic source consists of a volume, less than 10 km in radius, centered at 6.8°N, 73.1°W., and 150 km depth.
A note on an azimuthal correction for dT/dΔ for a single dipping plane interface
Authors: Zengeni Teddy G.
Published: September 2021

abstract

A relation is derived for correcting dT/dΔ for a single dipping interface under a seismic array: ( d T d Δ ) = ( δ T δ Δ ) ′ sin ⁡ ( Ω − ω ′ ) sin ⁡ ( Ω − ω ) . The formula depends only on the azimuth angles: ω is the computed azimuth, ω′ is the observed azimuth, Ω is the azimuth of the normal to the tilted interface, and (δT/δΔ)′ is the observed quantity. The relation is explicitly independent of the dip and the velocities of the media on either side of the interface.
Inversion of the spherical layer-matrix
Authors: Teng Ta-liang
Published: September 2021

In their formulation of wave problems in a spherically layered medium, Phinney and Alexander have arrived at a layer-matrix M which forms the fundamental building block of their solution. In actual application of the theory, the inversion of M is needed for each assumed spherical shell. Since numerical inversion of the matrix M may introduce undesired accumulation of errors, an analytical inverse matrix M−1 is obtained. Using Wronskians and recurrence relations of the spherical Bessel functions, it is shown that the inverse matrix M−1 can be simplified enough to insure an improvement in economy and accuracy in machine computations. Some useful properties of the inverse matrix M−1 are discussed which reduce the amount of machine time even further.
Surface waves in layered media
Authors: Sun C. T.
Published: September 2021

abstract

A continuum model with micro-structures is introduced to replace the layered media which consist of alternating laminae of two materials in the analysis of their mechanical behaviors. The continuum theory is employed to study surface-wave propagations in layered media. Dispersion equations according to the continuum theory are obtained and dispersion curves are computed. For a relatively simple laminated medium, exact dispersion curves are also worked out for comparison. It is found that the continuum theory reduces substantially the computational work and yields good agreement with the exact analysis. Rayleigh-wave dispersion on a laminated half-space for which exact dispersion equation cannot be obtained is also discussed by employing the continuum theory.
Analysis of the Station No. 2 seismoscope record—1966, Parkfield, California, earthquake
Authors: Trifunac M. D. , Hudson D. E.
Published: September 2021

During the 1966 Parkfield, California, earthquake a strong motion accelerograph and an adjacent seismoscope were located essentially at the causative fault. The accelerograph component parallel to the fault malfunctioned and left no recorded trace. The seismoscope record and the component of the ground motion perpendicular to the fault are used to reconstruct the acceleration component in the direction parallel to the fault. The details of the derived acceleration parallel to the fault differ from the past recorded strong ground motions in that higher frequency components are present. The peak ground accelerations transverse and along the fault are found to be of the same order of magnitude.
A note on the steady-state response of an elastic half-space
Authors: Tsai N. C.
Published: September 2021

With reference to the influence of local geology on earthquake ground motions, a more complete analytical formulation is made of the well-known problem of a horizontally stratified, linearly-elastic half-space subjected to vertically traveling, sinusoidal, plane waves. A more general interpretation of a result of Kanai is given, and a recursion formula is derived for computing amplification spectra. Some special properties of the system are pointed out and numerical examples are given.
A two-dimensional source function for a dynamic brittle bilateral tensile crack
Authors: Hanson Merle E. , Sanford Allan R.
Published: September 2021

abstract

A numerical technic is used to simulate the two-dimensional elastic dynamic characteristics of a bilateral tensile fracture that accelerates, propagates and stops in an elastic continuum. The fracture-velocity function is specified for the calculation. Particle motion in the near field about the final fracture geometry is the result. Motion parallel to the fracture amounts to as much as 50 per cent of the perpendicular motion near the crack. The relaxation begins to occur after the fracture stops and the dynamic elastic radiation from both tips crosses the material.
A wide-band digital seismograph system
Authors: Burke M. D. , Kanasewich E. R. , Malinsky J. D. , Montalbetti J. F.
Published: September 2021

A three-component, broad-band seismic system which records directly onto seven-track digital tape is described. A novel approach of synthesizing a desired response by a differential filtering and summing technic using low-noise operational amplifiers is demonstrated. As an example, the usable velocity sensitivity of a Willmore Mark II seismometer having a natural period of 1.5 sec is extended out to about 40 sec under normal operating conditions. Seismic energy over a wide spectrum may thus be recorded.
The effect of focal depth on the spectra of P waves II. Observational studies
Authors: Guha Shyamal K. , Stauder William
Published: September 2021

Using the theoretical development of Part I, properties of transfer functions (radiation patterns) for P waves are investigated for different point sources as functions of depth of burial and orientation of the source in a layered crust. The calculated transfer functions, in general, exhibit two or more minima. These minima shift to longer periods as the source depth increases. The position and relative development of the minima are also functions of depth, of azimuth about the source, and of orientation of the source. In order to investigate whether the predicted effect of focal depth is identifiable in the amplitude spectra of recorded P waves, seismograms of four earthquakes are analyzed. It is found that some of the minima of the observed spectra are due to focal depth, and that for foci in the middle or lower crust, it is possible to determine the depth of focus of an earthquake from the positions of the minima in the spectra.
Surfa ce-wave dispersion computations: Knopoff's method
Authors: Schwab Fred
Published: September 2021

The optimization of Knopoff's method computer computation of surface-wave dispersion, and the comparison of this method with the Thomson-Haskell technic and its extensions are studied. Of the various versions of the Thomson-Haskell formulation for Rayleigh-wave dispersion computations, the reduced-δ-matrix extension is the most powerful, i.e., the fastest which contains the feature controlling the loss-of-precision problem occasionally encountered by the original formulation. It is shown that the results of the δ-matrix extensions are actually contained in Knopoff's work, which appeared earlier than these extensions, and that these results are obtainable directly from his formulation without recourse to δ-matrix theory. The flexibility of Knopoff's method is used to devise a new representation of the Rayleigh-wave dispersion function which is more powerful than the most powerful of the Thomson-Haskell versions, i.e., it contains the loss-of-precision control feature and is about 38 per cent faster than the reduced-δ-matrix extension; in fact, it is about 12 per cent faster than the fastest of the Thomson-Haskell versions. Explicit forms of the new representation are given for the layered-half-space analogs of continental and oceanic models of the Earth, which can be terminated by a homogeneous half-space beginning in the mantle, a liquid outer core, or a solid inner core. The representations for symmetric and antisymmetric modes of the symmetric-plate analog of the Earth are also given. The Rayleigh-wave dispersion functions for the product form of the original Thomson-Haskell formulation, the δ-matrix and reduced-δ-matrix extensions of this formulation, and the representations developed from Knopoff's method, are identical when written out fully. The various technics differ only in their matrix representations of the dispersion function, which, of course, govern the speeds of computation of the various methods.

The Knopoff and Thomson-Haskell technics for computing Love-wave dispersion are compared. Although the matrix representations of the dispersion function differ for the two technics, the functions are identical, except for a possible sign reversal, when written out fully. The speeds of computation are also identical. The representations derived from Knopoff's method are given for the two possible flat-layer analogs of the Earth, which are applicable to Love-wave propagation.
A portable inexpensive seismic system for crustal studies
Authors: Mereu Robert F. , Kovach Ronald J.
Published: September 2021

A portable seismic system designed for use in crustal experiments is discussed in this paper. The main features of the system which make it attractive are (1) a 7-lb commercial stereo tape recorder, (2) a simple chronometer, (3) a capability to be monitored in the field with a speaker rather than with a paper recorder, (4) a timer for self-operation, and (5) low overall power requirements.

The seismic signal from the seismometer is amplified and fed to one channel of the recorder via a voltage-to-frequency converter so that very low-frequency signals can be recorded. Three additional signals made up of a WWVB radio time signal, a 100-Hz oscillator signal (to be used for compensation) and a 10-sec mark from a chronometer are fed into the second channel of the stereo recorder. The total weight of the instrumentation including the seismometer and carrying case is only 51 lb. This system will operate for over 120 hr with 27 lb of 6-volt batteries. This is more than sufficient for most crustal experiments. Because of its lightness and self-operating features, the system can easily be transported to remote areas by light aircraft at a minimum of expense and trouble.
Calculation of surface motions of a layered half-space
Authors: Tsai N. C. , Housner G. W.
Published: September 2021

A new method is presented for computing the transient response of a set of horizontally stratified, linearly elastic layers overlying a uniform half-space and excited by vertically incident, transient plane waves. In addition, a simple approximate method of satisfactory accuracy is developed that reduces the computing time required. Calculated responses are compared with motions recorded under Union Bay in Seattle to evaluate the agreement between recorded and calculated motions.
A high-sensitivity strain/inertial seismograph installation
Authors: Fix James E. , Sherwin John R.
Published: September 2021

A seismograph complex consisting of short-period (SP), long-period (LP), and extended long-period (XLP) inertial and strain seismographs has been installed. Recordings are made on magnetic tape and photographic film. Routine magnifications on the 20-trace, 16-mm film recorders for all three components are: SP inertial, 500 K; LP inertial, 100 K. The noise levels permit equivalent magnifications on the strain seismographs. The complex provides seismic wave discrimination by directional response, which is independent of period, and by detection of differences in phase velocities between P, S, Love, or Rayleigh arrivals. The strain seismographs use 40-m-long rods and moving coil transducers with generator constants of 32,000 v/m/sec. They sense waves of 5 × 10-13 strain at 30 sec and reject the 2 × 10-8 earth-tide strain. A low-noise preamplifier drives a filter assembly which provides SP, LP, and XLP strain outputs. The complex is installed in an abandoned mine 50 km southeast of Phoenix, Arizona. Environmental control is provided by burial at a depth of about 110 m in a quartz diorite, by sealing the mine, and by insulating the seismometers.
Variation of rayleigh-wave amplitude with distance
Authors: Evernden J. F.
Published: September 2021

abstract

Amplitudes of surface waves of both explosions and earthquakes are investigated as a function of distance (0-4000 km). Disagreements with the generally accepted law of amplitude versus distance are noted and discussed.
Soil behavior and related effects in the Peru earthquake of May 31, 1970
Authors: Enkeboll William
Published: September 2021

abstract

Soil and water conditions had an effect on the degree of damage to structures. Most structures were located on alluvium with a high water table. Settlements occurred in dike and causeway fill in Chimbote harbor. Severe problems to communication occurred in some areas through embankment failures and road slides.
Performance of school buildings in the Peru earthquake of May 31, 1970
Authors: Meehan John F.
Published: September 2021

abstract

The paper reports a field investigation of school buildings in the devastated area of this earthquake. Most school buildings did not collapse. Portions of one in Casma and Huaraz collapsed and many were damaged. Had the earthquake occurred in school hours, injury and death would have been high. Specific structural recommendations are made.
Seismic energy transmission to deep-founded structures
Authors: Brown Colin B.
Published: September 2021

abstract

The predominant seismic energy input into structures is from Rayleigh waves. These attenuate rapidly with distance from the surface and are partially reflected and partially transmitted by a hole in the ground. A structure founded in such a hole may anticipate a smaller seismic input than a surface-founded structure. Estimates of such a reduction are given which indicate that only short buildings and material with low shear-wave velocities will provide the proper conditions for this beneficial effect.
On teleseismic beam formation by very large arrays
Authors: Steinberg Bernard D.
Published: September 2021

abstract

A theory of seismic beam formation at large distances (30° to 100°) is presented. The three cross-sectional dimensions are derived for a spherically symmetrical earth in terms of travel-time functions and their derivatives.
Detection capabilities of the Yellowknife seismic array and regional seismicity
Authors: Anglin F. M.
Published: September 2021

abstract

Detection statistics from a search of 99 days of Yellowknife Array data have been obtained. The mean 50 and 90 per cent cumulative detection levels are found to be m 3.9 and m 4.2 for the third zone from Yellowknife. Regional variations in the detection levels have been found. The 50 per cent cumulative detection level ranges from m 3.8 for Asia to m 4.3 for the Aleutians. Regional values of the slopes of the recurrence curves for log N versus magnitude have been obtained, the mean slope for the third zone from Yellowknife being −0.99.
Magnitude-frequency relation and deep-focus earthquakes
Authors: Acharya H.
Published: September 2021

abstract

Investigation of the magnitude-frequency realtion for earthquakes in island arcs has revealed lower values of the slope for deep earthquakes in New Hebrides, Solomon Islands and Japan as compared to the values of the slope for shallow and intermediate earthquakes. A very low value of the slope is revealed for the deep Andean earthquakes. The slope is the same for Tonga-Fiji for all depth ranges.
The displacement fields of inclined faults
Authors: Mansinha L. , Smylie D. E.
Published: September 2021

abstract

Closed analytical expressions for the displacement fields of inclined, finite strike-slip and dip-slip faults are given. They may be readily used in the numerical computation of displacements, and, by differentiation, strain and stress fields may be derived. The expressions are valid both at the surface and at depth.
The 1970 Gediz earthquake in Western Anatolia, Turkey
Authors: Taşdemiroifelg˘lu Mehmet
Published: September 2021

abstract

The Gediz earthquake of March 28, 1970 in western Anatolia, Turkey, killed 1,086 people and heavily damaged 12,234 houses. Faults of 61-km length were produced in the Gediz area; in general, they strike north or east and are left-lateral normal faults. Vertical displacement reached 2 m in crystalline rock. Rockfalls and landslides were common, and thermal springs were initiated in some areas. Historic records indicate that the maximum previous intensity in this area was VIII, but the local intensity of this earthquake was about IX. The basement rocks of the area are crystalline schists, but the severest damage occurred in areas of Neogene outcrop.
Motion of a rigid disc in an elastic solid
Authors: Mal A. K.
Published: September 2021

abstract

A rigid circular disc embedded in an infinite, isotropic elastic solid is assumed to be excited by a normally-incident plane, harmonic compressional wave. The disc is assumed to be either in perfectly welded or perfectly smooth contact with the surrounding solid. In each case, the problem is reduced to the solution of Fredholm integral equations of the second kind. For the case of the welded contact, exact numeral solutions valid at any given frequency are given. Approximate solutions valid at low and high frequencies are obtained for both cases and are compared with the exact solution. The displacement and compliance of the disc as well as other quantities of interest are presented graphically as functions of frequency.
A Venus seismic experiment for the late 1970's
Authors: Derr John S.
Published: September 2021

abstract

NASA is planning a series of small-payload Venus missions, with launches beginning in 1976, some of which may be suited to small active and passive seismic experiments. Because the Earth and Venus are nearly the same size, one may theorize many parallels in seismic and tectonic activity, and any differences will provide information about the development of the Earth, as well as of Venus. A combined passive and active experiment with two separated short-period, three-component seismometers and one explosive charge may be carried as 3 entry vehicles on one spacecraft. The weight of explosive, however, is limited to about 20 kg. This limits the charge-seismometer separation to 1 or 2 km. Acoustic and radio ranging devices measure the positions of the 3 probes on the surface. Seismic velocities would be obtained for any layering down to about 500-m depth. A velocity transducer peaked at 20 Hz is desired for the active experiment, and would give some indication of the presence of microquakes on Venus, although a 1-sec period would be better for a passive experiment. An average science data rate of 30 bps would be adequate if the record from the active experiment is recorded for slower playback. A lifetime of 24 hr appears feasible. A dual launch of identical payloads landed in widely-separated areas would give a vastly greater return for the passive experiment. Although not unambiguous, the data should provide some information on seismic velocities, density, and anelasticity. Science and engineering data returned would determine desirability and feasibility of subsequent long-lived passive experiments with long-period, high-temperature instruments.
The earthquake sequence near Danville, California, 1970
Authors: Lee W. H. K. , Eaton M. S. , Brabb E. E.
Published: September 2021

abstract

Several thousand small earthquakes, with magnitudes ranging up to 4, occurred near Danville, California, during May, June, and July 1970. Seven temporary seismographs were installed near the epicentral region to augment an existing telemetered network within 1 day after the first felt earthquake. The dense concentration of 10 seismographs within 12 km of the seismic activity and the existence of a reversed seismic-refraction profile through the region permitted a very detailed study of this earthquake sequence. Over 400 events with magnitude greater than 0.5 were located with an average accuracy of ±1 km. The main earthquake region was approximately spherical: 1 km in radius, 6 km deep, and centered about 5 km southeast of Danville, 40 km east of San Francisco. Fault-plane solutions indicate that faulting associated with the earthquakes was of the right-lateral strike-slip type, with a strike of N 35°W.

The earthquakes cannot readily be related to any previously identified geological structure or fault. They suggest that active right-lateral faulting is not restricted to the mapped fault trace of the Calaveras fault. This result implies that not all of the sources of future earthquakes in the San Francisco Bay region can be indentified by surface mapping alone. The use of small earthquakes to map active faulting at depth may help to identify areas of potential earthquake hazards.
Anomalous microtilt preceding a local earthquake
Authors: Wood M. D. , Allen R. V.
Published: September 2021

abstract

The three largest earthquakes to occur within 50 km of San Francisco during 1970 were centered near the community of Danville, California, and spanned a time interval of 50 sec starting on June 12, at 0330 hr GMT. These earthquakes were greater than magnitude 4.0 and were part of a shallow, tightly-clustered earthquake swarm that persisted for approximately 2 months starting in mid-May 1970. During the same period of time, continuous tilt at tidal sensitivity (10−8 radian) was being recorded in two vaults at distances of 25 and 45 km west of the epicentral area. Two types of anomalous tilting preceded the principal events: (1) a long-term (1-month) constant tilt rate of 8 × 10−10 radian/hr that was recorded by both tilt stations and (2) a short-term (1-day) accelerated micro-tilt change which occurred just prior to the events and was most pronounced on the station closest to the epicentral area. Neither type of anomaly was recognized in the post-Danville record. The lack of a strong correlation with meteorological phenomena to account for the long-term coherency between two tilt stations of 25-km separation and the apparent azimuthal correlation of the Berkeley residual tilt vector with the earthquake epicenters suggests that the anomalous tilt preceding the Danville events were tectonic.
The Broach earthquake of March 23, 1970
Authors: Gupta Harsh K. , Mohan Indra , Narain Hari
Published: September 2021

The recent seismicity of the Broach region has been studied and correlated with the regional geological structure. The macroseismic effects are briefly described. Analysis of the first motion of P-wave data indicates the plane striking N 92°E to be the fault plane as supported by field observations also. The present seismic activity is found to be similar to the recent Godavari Valley earthquake sequence of April 1970 and different from the earthquakes in the Koyna region on the basis of b values, foreshock-aftershock pattern, and the ratio of the largest aftershock to the main shock magnitude.
Structural response results during July 29, 1970 earthquake in Burma-India border region
Authors: Agrawal P. N.
Published: September 2021

The data from the Structural Response Recorder installations during the July 29, 1970 earthquake in the Burma-India border region have been interpreted in terms of structural response results. These results suggest the possibility of dependence of the nature of the response spectrum curves on the azimuth of recording.

The strike of the fault plane, determined on the basis of the directions of the maximum recorded amplitudes, coincides with the local structural trend and is in conformity with the fault-plane solutions for some previous earthquakes in the region.
Array detection and location of core shadow events
Authors: Datt Ram , Varghese T. G.
Published: September 2021

The spectral features and slowness vector of the PKIKP and PP signals recorded clearly at the Gauribidanur Seismic Array (GBA) from four underground explosions (mb = 5.6, 5.9, 6.2 and 6.6) at the Nevada Test Site (NTS) were studied in detail. From the spectral similarity which characterizes their phase-summed signals, in the band 0.5 cps to 1.5 cps, it has been possible to synthesize reference signals, corresponding to these phases. By “chirping” these signals against the appropriately-phased array beams, the onset of these phases were identified for such events down to mb = 5.3.

Application of techniques of velocity and frequency filtering to the GBA records corresponding to 16 well-recorded NTS events (Δ ∼ 127.7° and the San Fernando earthquake of February 9, 1971 Δ ∼ 129.9°) has failed to reveal any precursor to the principal PKP phase which corresponds to the DF branch (PKIKP) of the Bolt (1968) curve. It is found that only the PP phase shows significant spectral differences between the earthquake and the set of explosions investigated.
Characteristic periods of fundamental and overtone oscillations of the earth following a deep-focus earthquake
Authors: Nowroozi A. A.
Published: September 2021

The deep-focus earthquake of July 31, 1970, (1.5°S, 72.6°W, h = 651 km, Mb = 7.1) excited a set of fundamental and overtone free oscillations. From analysis of seismograms recorded at Berkeley, California, at an ocean-bottom station in the Pacific, and at Ogdensburg, New Jersey, the fundamental spheroidal oscillations, l = 10-98, and a number of overtones with n = 1, 2, and 3, fundamental torsional oscillations, l = 3-70, and overtones with n = 1, 2, 3, and 4, are identified. The majority of resolved spectral peaks are above the 95 per cent confidence level. For some modes with periods less than 300 sec, the observed period at each station differs by up to 2 sec. This path-dependency of the period may thus suggest the existence of lateral heterogeneity in the upper mantle. The observed periods are compared to calculated periods for Haddon-Bullen's model HB1 and Derr's model DI-11; for fundamental modes the agreements are good, while differences up to 2 sec exist for some overtone modes. A relationship between order of oscillations, l, the frequency, nωl, and the ray parameter dt/dθ is derived, which is equivalent to the Jean's equation for phase velocity. The relationship implies that each mode with period nTl will travel with phase velocity dΔ/dt along its own ray with parameter dt/dθ. Other models will travel along the same ray if they have the same ray parameter.
The effect of a dipping layer on P-wave transmission
Authors: Rogers Albert M. , Kisslinger Carl
Published: September 2021

A ray-theory development of the effect of dip on P-wave transmission through a single layer over a half-space permits an assessment of errors due to dip in estimates of crustal thickness from observed P-wave spectral properties using transmission coefficients for a nondipping interface. The possibility of simultaneously deriving depth and dip from such observation is also shown. The theory has been tested by experiments in a two-dimensional laboratory model and applied to observations of deep South American earthquakes at small epicentral distances.

Theory and laboratory results show that errors in depth reflecting dip are less than 5 per cent for dips up to 25°. Dip can be estimated by matching observed and theoretical curves, once a velocity contrast has been fixed independently. A curve-matching technique for objectively selecting the best match has been developed.

A variation of parameter study shows that changes in velocity contrast do not change the shape of the crustal transfer function, but peak-to-trough differences increase with increasing velocity contrast. A change in depth of a dipping layer produces no change in the crustal transfer function plotted in dimensionless frequency. The transfer function changes with dip more rapidly for waves incident downdip. If the data window is long enough to include P and PPP (three P legs in the layer), the depth determination is not sensitive to window length, but dip determination is not possible for short windows.

The data for Antofagasta permit one of two solutions, a crust either 46.1 or 56.7 km thick, with the M discontinuity dipping 5° east, with the 46.1 km thickness preferred. This result agrees well with refraction results of others. A less firm result for Naña is a crust 74.7 km thick, with dip 15° to the southeast.
Array studies of seismic waves arriving between P and PP in the distance range 90° to 115°
Authors: Wright C.
Published: September 2021

Arrival times, slownesses and azimuths for coherent signals arriving between P and 60 secafter PP have been measured for 12 earthquakes recorded at the Yellowknife array at distances between 90° and 115°. The slowness (dT/dΔ) and azimuth values for P indicate that corrections to dT/dΔ for local structure beneath the array are small and can be neglected. A statistical study of arrivals from 10 events at distances less than 103° did not demonstrate conclusively the existence of PdP waves, and revealed a pattern of slowness values for precursors to PP similar to that observed by Wright and Muirhead (1969) at a distance of 106.0°. Further, a more detailed examination of three events at distances of 93.1°, 105.5° and 114.5° showed the presence of precursors with slowness values of about 10 sec/deg. These results required the development of an asymmetric reflection hypothesis in which the large amplitudes of these waves are produced by cusps in the travel-time curve near 20° and lateral variations in the uppermost regions of the Earth.
A note on correction of strong-motion accelerograms for instrument response
Authors: Trifunac M. D.
Published: September 2021

Two methods for accelerometer instrument correction are described: (1) a direct numerical differentiation of recorded accelerograms from which high-frequency digitization errors have been filtered out and (2) an ideal “mathematical accelerometer” with a natural frequency significantly higher than the natural frequency of the recording instrument. Although both methods give good results, the first one is recommended for standard use.
Lateral structure-foundation interaction of structures with base masses
Authors: Scavuzzo R. J. , Raftopoulos D. D. , Bailey J. L.
Published: September 2021

abstract

The interaction of lateral inertia forces of an N-mass structure with a base mass and lateral seismic motion of the foundation is formulated as an integral equation of the Volterra type. Flexibility of the foundation is based on the transient solution of a two-dimensional elastic half-space. Interaction effects are evaluated by comparing the response spectra of the free-field motion to that of the foundation motion. Results show that changes in the response spectra are significant for heavy, stiff structures such as a reactor-containment vessel.
Elastodynamic near-field of a finite, propagating tensile fault
Authors: Haskell N. A. , Thomson K. C.
Published: September 2021

Displacement, particle velocity, and acceleration wave forms in the near-field of a finite, propagating tensile fault have been computed by numerical integration of the Green's function integrals for an infinite medium. The displacement discontinuity (dislocation) on the fault plane is assumed to have the form of a unilaterally propagating, finite ramp function in time. Computer generated wave-form plots are presented for a variety of close-in locations with respect to the fault plane and for two different fault lengths.
Precision of different varieties of magnitude
Authors: Howell B. F.
Published: September 2021

The standard deviations of the body-wave magnitude, surface-wave magnitude and frequency-band magnitude of four shallow (H < 60 km) earthquakes are compared. For three out of four of these earthquakes, surface-wave magnitude exhibited lower standard deviations than either body-wave or frequency-band magnitude. In three out of the four cases, lower standard deviations were obtained by calculating surface-wave magnitude from the largest surface-wave amplitude than from time-correlated surface-wave phases.
A borehole tiltmeter for measurements at tidal sensitivity
Authors: Allen Rex V.
Published: September 2021

A tiltmeter suitable for operation at tidal sensitivities in a shallow borehole has been designed. Construction is of stress-relieved aluminum and the design is so simple it can be fabricated in most machine shops. The electronic system is built around available modular circuits, both integrated and hybrid. The meter is sensitive, stable and inexpensive. Representative samples of record presented include a 200-hr period in which the instrument was operated adjacent to a 5-meter baselength liquid-level tiltmeter. Drift during this period amounts to no more than a few parts in 108.