bluuebunny/crossref_metadata_2025 huggingface dataset:
Orotraqueal intubation training in the coronavirus pandemic: application of the rapid cycle deliberate practice
Authors: André Rodrigo Pereira Diaz , Oliveira Hudson Carmo de , Gouvêa Glauber , Fernandes Fátima Carneiro , Jerônimo Ingrid Régia Lopes , Campos Juliana Faria
Published: July 2021

Abstract: Introduction: the coronavirus pandemic disclosed the need for safe orotracheal intubation not only for the patient, but also for the professionals involved in the procedure. Therefore, training and technique reviews became necessary. Objective: this article aims to propose the application of the Rapid Cycle Deliberate Practice (RCDP) strategy for the training of anesthesiologists in orotracheal intubation in people with confirmed or suspected COVID-19 and to present a guide for the application of this strategy in this situation. Method: This is a methodological study presenting the theoretical and operational aspects for the Rapid Cycle Deliberate Practice application and a guide constructed from the search for evidence published in journals and official recommendations published by the institutions linked to the Brazilian and international health area. Results: the main theoretical aspects reported are related to the three principles on which Rapid Cycle Deliberate Practice is based: maximizing time in deliberate practice, targeted feedback, and explicit psychological security. As for the operational aspects, it is highlighted that the training must be carried out with a maximum of six people. An error must be interrupted, prescriptive feedback must be given, and the task must be performed again until the participant reaches mastery. As for the procedure technical specificity, a guide to the application of the rapid cycle deliberate practice is presented with the sequence for the adequate airway management of hypoxemic patients with suspected or confirmed COVID-19 infection. Conclusion: it is concluded that the assessed instructional strategy showed to be promising for the training with mastery learning in all professionals who will perform the procedure of orotracheal intubation while facing the severe forms of COVID-19, minimizing the risk of contamination.
Experiência de mentoria na residência médica: desafios e vivências
Authors: Lopes Filho Fernando Lima , Azevedo Francisco Vileimar Andrade de , Augusto Kristopherson Lustosa , Silveira Hyvinna Suellen de Oliveira , Costa Fabrício André Martins da , Alves Karine Paschoal Botelho
Published: July 2021

Abstract: Introduction: Medical residency represents a challenging moment, with a high level of demand and the need to develop several personal and professional skills. Therefore, in April 2019, the unprecedented mentoring program for thirty internal medicine residents was implemented, seeking to offer personal support and encourage professional development. Experience Report: A mentoring program was structured in April 2019, lasting 11 months, consisting of 30 internal medicine residents and 6 mentors with experience in clinical preceptorship, covering topics that are not usually discussed in the training of these specialists, such as professionalism, empathy, burnout and quality of life, time management, conflict management and role-model. The meetings took place monthly, in a location defined by the group. After the end of the activity, an opinion poll was conducted using a standardized questionnaire with answers arranged on a Likert scale to assess the relevance of the discussed topics and the impact on the medical residents’ practice. A 90% response rate was obtained, highlighting the relevance of the topic Burnout and quality of life and empathy. A total of 96.3% of residents stated that the program changed their mind about their professional behavior. They declared that mentoring “opened their mind about the diversity of opinions, allowing personal and professional growth” and that “to manage time, conflicts, burnout are present in our daily lives and are also part of the medicine we practice”. However, there were complaints about some difficulties among the group members to define the time and day when the meetings should be held. In summary, the activity had a positive evaluation from the mentees. Discussion: There is a positive impact of the mentoring program on the training of a resident doctor, improving self-confidence and having a positive impact on the professional career despite the faced difficulties. Mentoring also serves as a psychosocial support, creating free access between the resident and the preceptor, culminating, based on our evaluation, in an excellent relationship between mentors and mentees. Conclusion: In Ceará, the mentoring program for internal medicine residents was unprecedented. There is a positive effect, in which important topics were discussed in more depth, with greater personal and professional growth. We suggest that mentoring be maintained and included as an essential activity in the curriculum of Medical Residency Programs.
Mentoring experience in medical residency: challenges and experiences
Authors: Lopes Filho Fernando Lima , Azevedo Francisco Vileimar Andrade de , Augusto Kristopherson Lustosa , Silveira Hyvinna Suellen de Oliveira , Costa Fabrício André Martins da , Alves Karine Paschoal Botelho
Published: July 2021

Abstract: Introduction: Medical residency represents a challenging moment, with a high level of demand and the need to develop several personal and professional skills. Therefore, in April 2019, the unprecedented mentoring program for thirty internal medicine residents was implemented, seeking to offer personal support and encourage professional development. Experience Report: A mentoring program was structured in April 2019, lasting 11 months, consisting of 30 internal medicine residents and 6 mentors with experience in clinical preceptorship, covering topics that are not usually discussed in the training of these specialists, such as professionalism, empathy, burnout and quality of life, time management, conflict management and role-model. The meetings took place monthly, in a location defined by the group. After the end of the activity, an opinion poll was conducted using a standardized questionnaire with answers arranged on a Likert scale to assess the relevance of the discussed topics and the impact on the medical residents’ practice. A 90% response rate was obtained, highlighting the relevance of the topic Burnout and quality of life and empathy. A total of 96.3% of residents stated that the program changed their mind about their professional behavior. They declared that mentoring “opened their mind about the diversity of opinions, allowing personal and professional growth” and that “to manage time, conflicts, burnout are present in our daily lives and are also part of the medicine we practice”. However, there were complaints about some difficulties among the group members to define the time and day when the meetings should be held. In summary, the activity had a positive evaluation from the mentees. Discussion: There is a positive impact of the mentoring program on the training of a resident doctor, improving self-confidence and having a positive impact on the professional career despite the faced difficulties. Mentoring also serves as a psychosocial support, creating free access between the resident and the preceptor, culminating, based on our evaluation, in an excellent relationship between mentors and mentees. Conclusion: In Ceará, the mentoring program for internal medicine residents was unprecedented. There is a positive effect, in which important topics were discussed in more depth, with greater personal and professional growth. We suggest that mentoring be maintained and included as an essential activity in the curriculum of Medical Residency Programs.
Incorporating inherent uncertainties in seismic liquefaction assessments
Authors: Williams Holly
Published: July 2021

Liquefaction assessments for tailings facilities have significant uncertainty, yet their results are typically presented as single-value deterministic factors of safety (FoSs) to compare against standard practice guidance. Some of the uncertainty is due to inherent material variability or measurement error associated with in situ testing techniques. There is also a considerable – and often ignored – contribution from the transformation models used to convert in situ measurements to design parameters. For seismic liquefaction assessments, the key sources of transformation model uncertainty are from the empirical relationships relating standard penetration testing or cone penetration testing (CPT) results to cyclic resistance and residual undrained strength. While the uncertainties associated with the material variability and measurement error will vary by site and can usually be reduced through additional investigation, the model uncertainties are constant and irreducible without further work. This paper shows how the transformation model uncertainties associated with CPT-based liquefaction assessments can be incorporated into design practice to estimate probabilities of failure and lead to very different outcomes than simply considering FoS alone.
Application of technology readiness level assessment model in realization of innovative scientific and technological projects
Authors: Goncharova N. P. , Gorlacheva E. N.
Published: July 2021

At present, innovative activity is becoming more and more significant, and is a vital factor of maintaining economic growth of the country. When realizing innovative scientific and technological projects it is possible to make well-grounded managerial decisions basing on the performance indicators within the technology readiness level (TRL) assessment model. The authors study the TRL assessment model and present a set of performance indicators of similar Russian TRL model. On the example of monitoring of suggested performance indicators of the eighth technology readiness level the authors reveal the factor producing the most serious impact on one of the factors (profitability of production) and present an option for solving the problem, and a neuron network has been trained to control the indicator. The results obtained have revealed the possibility of adapting the TRL scale for the needs of high technology businesses which implement technological development programs. The results can be used in realization of innovative scientific and technological projects to reduce the costs at different life cycle stages and to increase the efficiency of the managerial decisions taken.
Adherence to a standard operating procedure for patients with acute cervical spine dislocations: review of a tertiary, referral, academic hospital in South Africa
Authors: Ayik Goud DD , Mukabeta Takura DM , Nyandoro George , Osborne Charles , Kruger Nicholas A
Published: July 2021

ABSTRACT BACKGROUND: To analyse the impact that the adoption of our institutional standard operating procedure (SOP) for cervical spine dislocations had on the timing of closed reduction at our hospital METHODS: The study was a retrospective review of patients who presented to our institution with cervical dislocation injuries and who were managed with closed reduction. The patient records of acute cervical spine dislocations from 2015 to 2018, data from the Acute Spinal Cord Injury database along with patient's demographic information were gathered and compared. Participants within the study time frame were diagnosed with a cervical facet dislocation based on clinical examination findings and radiological confirmation. Patients who had reduction performed at other referring hospitals were excluded from the study. RESULTS: The practice within all tertiary hospitals in the Western Cape is to perform closed reduction of cervical fracture dislocations as soon as possible after injury. In this study the time between injury and closed reduction before introducing the SOP was 13 h 13 min and after introducing the SOP, the time increased to an average of 14 h 28 min. The main cause of delay was the transfer time from the site of injury to the emergency ward. Other reasons for the delay include missed diagnosis, orthopaedic registrar unavailability and incomplete reduction bed CONCLUSION: This study found that the time taken for orthopaedic management of cervical dislocations increased by an hour after introduction of the SOP. Additionally, the overall time to reduction also increased. This was due to delays in transfer to the emergency ward and referral to Orthopaedics. We recommend that, in our setting, reduction could be initiated within an hour of patient arrival, if emergency ward doctors rapidly identified the problem and commenced cervical traction when the orthopaedic team was not immediately available. Our impression was that there was poor adherence to the new SOP guidelines on time management by the trauma team, and possibly transport delays prior to hospital admission. A further study to investigate the bottlenecks of the referral system is advisable Level of evidence: Level 4 Keywords: acute outcomes, cervical spine, dislocation injuries
Implementation of the adaptive quantization method in digitally controlled measuring generators
Authors:   Novosibirsk State Technical University, Russian Federation, Babichev Mikhail
Published: July 2021

Measuring generators with digital control, in particular power calibrators, used to calibrate electricity meters, contain a digital-to-analog converter (DAC) that converts codes of the generated signal into voltage. Signal codes are stored in the generator memory. A truncation discreteness error (quantization noise) arises caused by sampling (quantization) in time and by the level of signal samples in the DAC. A relative value of the quantization noise depends on the amplitude of the generated signal (relative to the reference voltage of the DAC): the larger the amplitude, the more significant bits of the DAC are involved in the conversion process, and the less the relative value of the noise. In generators, where the amplitude of the output signal changes over a wide range (high dynamic range) by changing the digital samples of the signal, the quantization noise at low signal amplitudes can become unacceptably large. This situation occurs in power calibrators where the output current changes hundreds of times since the error of the verified electricity meter is normalized in a wide range of current flowing through it. A new algorithm for generating samples of a sinusoidal signal in measuring generators with digital control called adaptive quantization is proposed. Adaptive quantization can significantly improve one of the selected signal parameters (the so-called optimality criterion), for example, reduce the error in reproduction of the first harmonic, or reduce the value of higher harmonic components. In addition, the proposed algorithm reduces the dependence of the selected parameter on the sampling frequency and on the number of DAC bits used, which makes it possible to expand the dynamic range of the generator (in the current channel) without using additional amplifiers with programmable gain (PGA). Studies carried out using computer simulation have confirmed the efficiency of the adaptive quantization algorithm.
Algunas precisiones sobre la idea de la igualdad de armas en el proceso penal
Authors: Guzmán Díaz Carlos Andrés
Published: July 2021

En el presente artículo se propone establecer el alcance del concepto comúnmente enunciado como “igualdad de armas” y su trascendencia en el proceso penal colombiano. Se analizan las facultades de las partes y la participación de otros intervinientes en ese modelo.
Teaching History to Petersburg Gymnasium Students in the First Half of the 19th Century
Authors: Pashkova Tatiana
Published: July 2021

This article explores the practices of teaching history in men’s gymnasiums of the first half of the 19th century in Petersburg, analyzing the curricula, the content of textbooks, and examinations as well as theoretical developments and methodological techniques in the design of textbooks on world and Russian history. At the infancy stage of gymnasium education development, the focus was on teaching world history. Meanwhile, even schools in Petersburg had great difficulty in selecting the textbooks. Handbooks written by foreign authors and, later, Petersburg instructors, represented bulky volumes with no illustrative material or teaching methodology.
Inequality of Educational Opportunity in Soviet and Post-Soviet Russia: An Empirical Analysis
Authors: Ibragimova Zulfiya , Frants Marina
Published: July 2021

This study seeks to assess inequality of educational opportunity in Soviet and post-Soviet Russia and measure the impact of specific circumstances. Inequality of opportunity suggests that outcomes significant for everyone or nearly everyone, such as income level, educational attainment or health status, are determined by factors or variables that are beyond individuals’ responsibility (so-called circumstances) and by factors for which individuals are deemed responsible (so-called efforts). Inequalities arising from efforts are considered ethically acceptable, while those that are due to circumstances are considered offensive and therefore must be eliminated. The study uses data from two waves (2006 and 2011) of the Russia Longitudinal Monitoring Survey administered by Higher School of Economics (RLMS-HSE). Research methodology is based on the ex-ante approach to equality of opportunity. Three levels of educational attainment are analyzed: secondary school, vocational school, and college. Inequality of opportunity was lower during the Soviet period than in post-Soviet Russia at all levels of educational attainment, being the lowest at the level of at least secondary school and the highest at the level of at least vocational school. Parental education is the most powerful circumstance in both Soviet and post-Soviet periods, while ethnicity makes no significant contribution to inequality of opportunity. The roles of gender and place of birth are quite important in both periods and vary greatly as a function of educational attainment.
Psychologically Traumatic Situation as a Formal Element of an Offence under Article 106 of the Criminal Code of the Russian Federation (Murder by a Mother of Her Newborn Child)
Authors: Safuanov F.S. , Sarycheva Y.A.
Published: July 2021

The study is aimed at finding general grounds of criminal responsibility for neonaticide (murder by a mother of her own newborn child). The formal crime signs listed in article 106 of CCRF have been analysed. The theoretical analysis is supplemented with a study of 40 criminal cases. It was concluded that the common ground for inclusion of the three formal elements of the crime (differing in a number of criteria) is the mother's limited capability to consciously and arbitrarily control her behavior while murdering her newborn child. In the first case, the main factor limiting this legally significant capability is a legislator-presumed specific psychophysical condition of the parturient woman, in the second case it is a specific emotional state caused by a psychologically traumatic event associated with pregnancy and childbirth. The third case is a mental disorder not excluding sanity. A remark about the baby-murdering mother's special emotional condition limiting her capability to be aware of her actions (and control them) has been suggested for inclusion in the text of the article. The advisability of obligatory prescription for a comprehensive forensic psychological and psychiatric examination has been substantiated when the offence is categorized under article 106 of CCRF.
Urgency of Axiological Problems in Legal Psychology
Authors: Ilyina V.A.
Published: July 2021

The article substantiates the necessity to research the axiological problems of legal psychology and shows the results of a theoretical study of the value-related aspect of legal psychology. These results advocate the idea of using a systemic approach in values analysis. It is maintained that in order to resolve the axiological problems of legal psychology by way of systematization of its values what's needed is a return to the philosophical foundations of cognition, ontology, dialectics, logic, the material basis of psyche. At the same time, it is believed that not every systemic approach can cope with value systematization in legal psychology. As a doctrinal alternative, philosophy and psychology develop and offer an ontological system of ethical categories to be the cornerstone of natural and positive law. This system relies on the ontological criteria and is a matrix (grid) of fundamental knowledge at the categorial level. The ontological matrix of axiological categories of ethics (the foundations of law) must manifest itself in psychological concepts and must represent value orientations for legal psychology, making it possible for one to develop within the framework of scientific cognition, without losing touch with the fundamentals of law and ethics.
Effect of organophosphorus compounds on the external respiratory functionin rats during intratracheal andintraperitonealadministration
Authors: Kryazhevskikh Anastasiya A. , Kryazhevskikh Aleksey A. , Subbotina Svetlana N. , Sklyarova Nataliya A.
Published: July 2021

Due to the increasing influence of chemical factors on the human body, the experiment has been conducted using organophosphorus compounds (OPC) to stimulate poisoning cases in the production facilities. Given that the development of respiratory failureis a specific organophosphate poisoningsymptom, a comparative analysis of external respiratory function (ERF)in rats with intratracheal and intraperitoneal administration of diisopropyl fluorophosphates (DFP) has been carried out. During the research, the average lethal doses of the toxic chemicals have been established, the conditions of DFP intoxication have been modeled.Thus, LD16 was 0.284 mg/kg by intratracheal administration, 1.6 mg/kg byintraperitoneal administration. Experimental data have shown that the intratracheal intake of OPC causes the development of respiratory failure in the first minutes after poisoning.The return of the ERF indicators to the background values was noted a day after poisoning. With the intraperitoneal administration of the toxic chemical, the rate of development of ERF disorders was lower, toxic effects persisted for two days. The data obtained can be used to make appropriate recommendations for the prevention of accidents and non-emergency cases in a production facility.
Test ban treaty verification with regional data—A review
Authors: Pomeroy Paul W. , Best William J. , McEvilly Thomas V.
Published: July 2021

abstract

This paper summarizes the use of regional (Δ ≦ 30°) seismic data in a test ban context for detecting, locating, identifying, and determining the yield of underground nuclear explosions. In many areas of the world (Eastern North America, Africa, Eastern USSR), Lg is the largest amplitude wave recorded on standard seismograph systems and thus is the most appropriate phase for monitoring small magnitude events. Excellent location capability for near-regional events has been demonstrated at the Norwegian small aperture array (NORESS) using Lg and P waves. Lg and other regional phases may contain information on source depth, but such information has not been exploited to date. Fifteen classes of regional discriminants have been identified including

Each of these proposed discriminants has, with differing degrees of success, separated some explosions from some earthquakes. However, most have been tested only on limited data, usually from one geographic region and only one or two recording stations. No systematic analyses have been done to determine the best individual discriminant or combination of them.

Preliminary evaluation of the use of Lg for yield determination suggests that regional waves hold promise in this application. Theoretical studies have contributed significantly to the understanding of propagation characteristics of regional waves but further studies are required emphasizing modeling for realistic anisotropic sources.

The major conclusion of this study is that a systematic and comparative evaluation of all the proposed regional discriminants is now required, utilizing a common data base derived from all present-day test sites. This evaluation would suggest the optimal discrimination procedure using regional waves, and would also define areas of needed research. Without such an integrated evaluation, it is still possible to speculate, using existing results, on the most promising regional discriminants.
High-frequency approximation to the nongeometricalS* arrival
Authors: Daley P. F. , Hron F.
Published: July 2021

abstract

When an explosive point source is buried less than one wavelength from the free surface in a perfectly elastic, homogeneous, isotropic half-space, a very strong non-geometric arrival, tentatively denoted as S* by Hron and Mikhailenko (1981), exists in the reflected shear wave field. It has all basic characteristics of an ordinary shear body wave (linear polarization, transverse particle motion, and shear wave velocity) and, as such, it can be also reflected or transmitted upon incidence at an interface according to the rules governing ordinary body waves. Because of its very strong amplitude which at most epicentral distances exceeds even the amplitude of a direct P wave, the S* arrival is undoubtedly responsible for a large part of the shear wave energy content seen in the seismic records in oil exploration, which deals almost exclusively with shallow explosive sources. In our paper, we develop a high-frequency approximation to the S* arrival applying a saddle-point method to the integral representing a shear wave reflected from the free surface due to the incidence of a spherical longitudinal wave radiated by the shallow point source. Numerical results presented in the paper show that our high-frequency approximation preserves all basic features of the S* arrival, thereby making it suitable for easy incorporation into any synthetic seismogram computation based on the ray approach.
The horizontal propagation of P waves through scattering media: Analog model studies relevant to long-range Pn propagation
Authors: Menke William , Richards Paul G.
Published: July 2021

abstract

We compare seismograms produced through the use of analog models of scattering and nonscattering Earth structure to access the effect of lateral heterogeneities on the horizontal propagation of P waves. Our results are applicable to propagation out to 16° and to periods as short as 5 sec. We find that layers of scatterers within the mantle near the turning points of P waves can cause these phases to have long coda similar in certain respects to the coda observed in long-range Pn. The overall appearance of this coda is similar to that produced in laterally homogeneous models that include low-velocity crustal material near their surfaces. Scatterers at shallower depths in the mantle or crust have a different effect. Those in very uppermost mantle seem to suppress the horizontal propagation of P waves while those in the crust have very little overall effect, at least at the perod range we studied. We also find that the scatterers have an amplifying effect on the horizontal propagation of the very longest periods (>20 sec), an effect that may be related to the scattering-controlled boundary waves discovered by Biot (1968).
Large earthquakes, mean sea level, and tsunamis along the Pacific Coast of Mexico and Central America
Authors: Cruz Gonzalo , Wyss Max
Published: July 2021

abstract

Along the Pacific Coast of Mexico and Central America, 26 local tsunamis have been reported during the period 1732 to 1973. Nine of these were caused by earthquakes with teleseismic hypocenters, all of which were located well inland. If these epicenters were correct, these earthquakes could not have generated tsunamis. Under the assumption that the true epicenters must have been located at the coast or off shore, it was estimated that teleseismic hypocenters in this area are mislocated by about 75 km toward the northeast, and 20 km toward greater depth. We propose that most teleseismic locations in this area are afflicted by this same error. The most likely cause for the mislocations are shorter than expected travel times for rays in the down-dip direction of the subducted lithospheric slab. These rays travel to North American stations which contribute strongly to hypocenter locations in Middle America.

The annual mean sea level of 13 tide gauge stations along the Pacific coast of Mexico and Central America were examined for evidence of vertical crustal deformation changes that could have been associated with earthquakes along this coast. Only one coseismic change could be identified in the annual mean sea level data. It occurred at Acapulco, Mexico, during the 11 May (Ms = 7.0) and 19 May (Ms = 7.2) 1962 earthquakes. The crustal uplift was about 22 cm, estimated from the difference of the 10-yr sea level means before and after the events. By comparing annual mean with daily mean sea level data, it appears that about 23 per cent of the permanent uplift observed at Acapulco was due to aseismic slip or aftershocks in this area. If tide gauge data in this area are kept current, long-term precursory crustal movements might be detectable if they exceed several centimeters.
Evidence of tectonic release from underground nuclear explosions in long-periodPwaves
Authors: Wallace Terry C. , Helmberger Donald V. , Engen Gladys R.
Published: July 2021

abstract

In this paper, we study the long-period body waves at regional and upper mantle distances from large underground nuclear explosions at Pahute Mesa, Nevada Test Site. A comparison of the seismic records from neighboring explosions shows that the more recent events have much simpler waveforms than those of the earlier events. In fact, many of the early events produced waveforms which are very similar to those produced by shallow, moderate-size, strike-slip earthquakes; the phase sP is particularly obvious. The waveforms of these explosions can be modeled by assuming that the explosion is accompanied by tectonic release represented by a double couple. A clear example of this phenomenon is provided by a comparison of GREELEY (1966) and KASSERI (1975). These events are of similar yields and were detonated within 2 km of each other. The GREELEY records can be matched by simply adding synthetic waveforms appropriate for a shallow strike-slip earthquake to the KASSERI observations. The tectonic release for GREELEY has a moment of 5 ՠ1024 dyne-cm and is striking approximately 340°. The identification of the sP phase at upper mantle distances indicates that the source depth is 4 km or less. The tectonic release time function has a short duration (less than 1 sec). A comparison of these results with well-studied strike-slip earthquakes on the west coast and eastern Nevada indicate that, if tectonic release is triggered fault motion, then the tectonic release is relatively high stress drop, on the order of several hundred bars. It is possible to reduce these stress drops by a factor of 2 if the tectonic release is a driven fault; i.e., rupturing with the P velocity. The region in which the stress is released for a megaton event has a radius of about 4 km. Pahute Mesa events which are detonated within this radius of a previous explosion have a substantially reduced tectonic release.
Ground failure along the New River caused by the October 1979 Imperial Valley earthquake sequence
Authors: Heaton Thomas H. , Anderson John G. , German Peter T.
Published: July 2021

abstract

We recognized a number of ground failures along the south bank of the New River north of Brawley, California, following the 15 October 1979 Imperial Valley, California, earthquake sequence. The zone includes a large pond and numerous sand boils, apparently caused by liquefaction, near the Del Rio Country Club. These ground failures, together with failures at the New River bridge west of Brawley and at Wiest Lake, form a discontinuous zone 10 km long. While this zone appears to coincide with the aftershocks following the 16 October 1979, ML 5.8, Brawley earthquake (the largest aftershock of the Imperial Valley earthquake), a cause and effect relationship cannot be demonstrated. No evidence of tectonic surface faulting could be found.
Geodetic measurements of postseismic crustal deformation following the 1979 Imperial Valley earthquake, California
Authors: Langbein J. , McGarr A. , Johnston M. J. S. , Harsh P. W.
Published: July 2021

abstract

A geodetic trilateration network comprising 54 baselines was established around the northern part of the Imperial fault beginning 12 days after the Imperial Valley earthquake of 15 October 1979, and the line lengths were repeatedly observed during the following 110 days. During the observational period, there was an average of about 10 cm of dextral postseismic fault slip. Geodetic data in conjunction with alignment-array measurements indicate that the postseismic slip U at time t following the main shock is well described by U (t) = (10.96 ± 0.12) cm log(t/1.75 day + 1), a result that implies that it will be approximately 9 to 10 yr before the rate of postseismic displacement diminishes to the ambient rate of creep of 0.5 cm/a. The postseismic strain changes are localized to the east side of the Imperial fault in the southern part of the Mesquite Lake basin, where significant north-south extension occurred at an average rate of 2.7 ± 0.3 × 10−5/a during the observational period. These changes are compatible with dextral fault slip within the top 5 km of the fault.
Determination of rupture duration and stress drop for earthquakes in southern California
Authors: Frankel Arthur , Kanamori Hiroo
Published: July 2021

A simple technique is developed for determining the rupture duration and stress drop of earthquakes between magnitudes 3.5 and 4.0 using the time between the P-wave onset and the first zero crossing (τ1/2) on seismograms from local seismic networks. This method is applied to 10 main shocks in southern California to investigate regional variations in stress drop. The initial pulse widths of 65 foreshocks or aftershocks of these events were measured. Values of τ1/2 for small earthquakes below about magnitude 2.2 are generally observed to remain constant with decreasing magnitude in four sequences studied. The relative pulse width of a particular main shock (M ≧ 3.5) at a given station is found to be correlated with the relative pulse width of its aftershocks recorded at that station. These observations are interpreted to signify that the waveforms of these small events (M ≦ 2.2) are essentially the impulse response of the path between the source and receiver. Values of τ1/2 determined from small foreshocks and aftershocks are, therefore, subtracted (in effect deconvolved) from those of each main shock to obtain an estimate of the rupture duration of the main shock which is corrected for path effects.

Significant variations in rupture duration and stress drop are observed for the main shocks studied. Aftershock locations and azimuthal variations in τ1/2 both indicate that the rupture zone of one earthquake expanded unilaterally. A factor of 10 variation in stress drop is calculated for two adjacent events of similar seismic moments occurring 1 hr apart on the San Jacinto fault system. The first event in this pair had the highest stress drop of the events studied (860 bars) and was followed within 8 months by a magnitude 5.5 earthquake 2 km away.
Spatial-temporal variation of seismicity and spectrum of the 1980 earthquake swarm near the Izu Peninsula, Japan
Authors: Ishida Mizuho
Published: July 2021

The spatial-temporal variation of seismicity of the 1980 earthquake swarm off the east coast of the Izu Peninsula, Japan, was investigated. Hypocentral distribution, focal mechanism, wave forms, and spectra of seismic waves were studied. The hypocenters were relocated by using the master event method. The forerunning earthquakes which started about one week before the largest shock (main shock), the 1980 Izu-Hanto-Toho-Oki earthquake (M = 6.7), occurred within the quiescent area of the earthquake activity for the preceding one year. The swarm area migrated toward the south with time and triggered the main shock in June 1980. The fault dimension and geometry were estimated from the aftershock area: the fault length and width are 14 km and 8 km; the strike and dip angles of the fault are N15°W and 65° to N75°E.

Locations of the events in an earlier earthquake swarm (1978) were also examined by using difference in the S-P time at five selected stations distributed around the epicentral area. The 1978 swarm events were found to have clustered within a very small area of 8 ×1 km2 located about 2 km to the west of the 1980 swarm area.

The earthquakes which occurred after the main shock of the 1980 swarm were classified into two groups, aftershocks and swarm events, according to the location of epicenters, wave forms, and spectra of S waves. The peak frequencies of spectra were distributed around 5 to 8 Hz for the aftershocks and around 10 to 15 Hz for the swarm events. Most of the aftershocks, characterized by low-frequency content, occurred to the south of the main shock within 2 weeks after the main shock. The number of aftershocks decayed following the modified Omori's formula with p = 1.5 ± 0.3. The swarm activity, on the other hand, continued intermittently for about 1 month after the main shock. The 1980 seismic activity is interpreted as a complex of a foreshock-main shock-aftershock sequence and swarm activity.

The direction of the longer axis of the swarm area coincided with the direction of the maximum pressure axis of the main shock. The trend of the aftershock zone coincided with the strike of the fault planes of the main shock and aftershocks. This feature strongly suggests that tension cracks trending in the maximum stress direction opened prior to the occurrence of the main shock. The opening of cracks may be accounted for by increasing of interstitial pore pressure associated with increase in regional stress.
A new analytic procedure to determine hypocentral parameters of local seismic events
Authors: Caccamo D. , Neri G.
Published: July 2021

A new procedure for locating local earthquakes is proposed.

Essentially, this procedure consists in solving—by means of least-squares technique—a system of equations which is formally analogous to that of Geiger (Ax = b) but different from his in the values of the matrix A and vector b elements. This difference makes our procedure more reliable than Geiger's because it significantly reduces the cases of both iterative process divergence and low precision. Among the factors contributing to this progress the lesser possibility that the matrix A contains columns proportional (or nearly proportional) one to another is considered of particular influence.

More than 20,000 hypocentral calculations have been performed on simulated shocks: significant differences in the number of good locations were revealed between our procedure and the classical method of Geiger (1910). Ours is more precise, particularly when few stations were used or networks with an unsatisfactory geometry. The earth model also influences the observed differences as it contributes to generating those analytical conditions which make the calculation convergence more problematic when applying Geiger's method.

Further applications are currently carried out in order to verify the procedure features for velocity laws and station configuration different from those used in this study.
Elastic wave calculations by the Fourier method
Authors: Kosloff Dan , Reshef Moshe , Loewenthal Dan
Published: July 2021

We introduce a two-dimensional forward modeling algorithim based on a Fourier method. In order to be able to handle the free surface boundary condition with the Fourier method, a new set of wave equations are derived which contain the stresses as unknowns instead of the displacements. The solution algorithm includes a discretization in both space and time. Spatial derivatives are approximated with the use of the Fast Fourier Transform, whereas temporal derivatives are calculated with second order differencing. The numerical method is tested against the analytic solution for Lamb's problem in two dimensions.
First noise and teleseismic recordings on a new ocean bottom seismometer capsule
Authors: Prothero William A. , Schaecher William
Published: July 2021

An ocean bottom seismometer capsule designed specifically for the long-term monitoring of teleseisms has been designed and tested. An efficient triggering algorithm consisting of multiple high-pass filters effectively discriminates between locally generated earthquakes and noise, and teleseisms. During a 1-month deep ocean deployment west of the Santa Barbara Channel, a magnitude 5.9 earthquake at a distance of 76° was recorded, in addition to a number of regional events in the 300- to 450-km range. Noise levels were monitored by automatically recording data at intervals. Vertical noise levels were approximately 20 times greater than those recorded at quiet land sites, and horizontal noise levels were about 5 times greater than that. The instrument consists of a microprocessor-controlled data logging system in three parallel pressure tubes, joined by a common baseplate. Wires between the three tubes are contained within the baseplate. There are no external connectors which are exposed to sea water, allowing the deployment time to extend to 1 yr. Data are recorded on two Braemar cassette recorders with a capacity of 15 Mbits each, for a continuous recording time of approximately 43 hr. This is adequate for the expected data acquisition rate, given the robustness of the triggering algorithm. The sensors are Mark Products L4-C 1-Hz seismometers with useful extended low-frequency response to about 30-sec periods for earthquake signals. The three components are leveled with a mechanical gimbal arrangement. The instrument has been successfully deployed 3 times in the Santa Barbara Channel and deep ocean, and should prove extremely useful for extending teleseismic studies into the ocean.
Theoretical investigation of scattering phenomena inside wedge caused by incidence of Rayleigh wave
Authors: Takeuchi Shozaburo , Fujii Kazunari , Nakano Masayoshi
Published: July 2021

A theoretical analysis is performed on the behaviors of the internal scattered wave in the case where a two-dimensional plane Rayleigh wave is incident to an acute- or obtuse-angled wedge. By using the theory in our preceding research (1984), the distributions of energy densities and lines of constant phase of scattered wave are obtained inside the wedge when its angle of corner ranges from 71° to 109°. Momoi's conception (1980) of generation process of reflected and transmitted Rayleigh waves is applied to the above numerically calculated results, by which the complicated variations of reflection and transmission coefficients with wedge angle could be explained to some extent.
Average body-wave radiation coefficients
Authors: Boore David M. , Boatwright John
Published: July 2021

Averages of P- and S-wave radiation patterns over all azimuths and various ranges of takeoff angles (corresponding to observations at teleseismic, regional, and near distances) have been computed for use in seismological applications requiring average radiation coefficients. Various fault orientations and averages of the squared, absolute, and logarithmic radiation patterns have been considered. Effective radiation patterns combining high-frequency direct and surfacere-flected waves from shallow faults have also been derived and used in the computation of average radiation coefficients at teleseismic distances.

In most cases, the radiation coefficients are within a factor of 1.6 of the commonly used values of 0.52 and 0.63 for the rms of P- and S-wave radiation patterns, respectively, averaged over the whole focal sphere. The main exceptions to this conclusion are the coefficients for P waves at teleseismic distances from vertical strike-slip faults, which are at least a factor of 2.8 smaller than the commonly used value.
A note on the use of random vibration theory to predict peak amplitudes of transient signals
Authors: Boore David M. , Joyner William B.
Published: July 2021

Random vibration theory offers an elegant and efficient way of predicting peak motions from a knowledge of the spectra of radiated energy. One limitation to applications in seismology is the assumption of stationarity used in the derivation of standard random vibration theory. This note provides a scheme that allows the standard theory to be applied to the transient signals common in seismology. This scheme is particularly necessary for predictions of peak response of long-period oscillators driven by short-duration ground motions.
Tomographic reconstruction of velocity anomalies
Authors: Fawcett John A. , Clayton Robert W.
Published: July 2021

An approximate inversion formula is proposed for the reconstruction of slowness anomalies in a known depth varying background field. The data are observed travel-time perturbations for reflections from a known planar reflector. The limitations of the formula are discussed and numerical examples are given.
Aftershocks of anM= 4.2 earthquake in Hawaii and comparison with long-term studies of the same volume
Authors: Savage Martha Kane , Meyer Robert P.
Published: July 2021

Study of the aftershocks recorded in a 3-hr period after a 4.2 magnitude event on the East Rift Zone of Kilauea volcano, Hawaii, on 12 April 1982 shows that the aftershocks occurred on different planes than the main shock, probably as a result of stress redistribution; the aftershock locations are probably controlled by preexisting structures. This study also suggests that these relatively small aftershocks occurred in the same seismicity patterns as larger events recorded in the same volume over a period of 10 yr. Slips on most of the aftershocks and the main shock are in the same direction, perpendicular to the East Rift Zone, as has been found in studies of other, larger earthquakes. However, fault-plane solutions varied more, as did the tensional axes, and several of the smaller events showed movement in the opposite direction from the main shock and the rest of the aftershocks, suggesting some rebound was occurring near the edges of the aftershock zone. Because ten times as much energy was released in the aftershocks in a narrow linear region as elsewhere, and since the main shock epicenter was oceanward of all the aftershocks, we suggest that rupture began at the main shock hypocenter and propagated landward, implying an almost “one-dimensional” fault.

For the aftershocks, the relationship between moment and magnitude was: log M0 = (1.18 ± 0.17) ML + (17.3 ± 0.17). Differences in amplification lead to site differences of up to 0.8 units in local magnitude and 1.5 orders of magnitude in energy release. These correlated somewhat with station time corrections in that the stations with the longest delay times also had greatest amplification.
Orientação espacial no pré-escolar: lateralidade e posição relativa
Authors: Nunes Ana , Mamede Ema
Published: July 2021

Neste artigo explora-se a orientação espacial, particularmente a lateralidade e posição relativa, em crianças da Educação Pré-escolar dos 3 aos 5 anos. A investigação centrou-se em três questões principais: a) Que conhecimentos têm as crianças sobre a sua posição relativa? b) De que forma as crianças descrevem o meio? c) Como se posiciona a criança em relação ao meio? Realizou-se uma intervenção pedagógica de 8 sessões, com 25 crianças duma sala de pré-escolar de ensino público. As tarefas de caráter individual e grande grupo centraram-se na orientação espacial, envolvendo noções de lateralidade (ao lado; esquerda/direita) e posição relativa (em cima/baixo; à frente/atrás; dentro/fora). Os resultados sugerem mudanças na capacidade de descrição da localização de objetos e pessoas, utilizando termos específicos adequados com mais frequência e maior facilidade, levando à melhoria da comunicação matemática. Ademais, as crianças demostraram serem capazes de perceber a sua posição no espaço e a dos objetos nele inseridos.