bluuebunny/crossref_metadata_2025 huggingface dataset:
New Economy, E-Commerce Businesses, and E-Businesses
Authors: Yaşlıoğlu Duygu Toplu
Published: June 2021

Electronic commerce and electronic business concepts are highly researched in recent management literature. Network economy has revealed e-commerce, a new trade route that is carried out over the interlinked computers and mobile devices. E-commerce is a method used by almost all businesses that are physically processing. Therefore, there should be a significant distinction between e-business and e-commerce. With the development of e-commerce, new ways of doing business have emerged. Thus, many e-commerce companies have emerged, traditional businesses have started trading in electronic networks, and new business models have begun to be created in digital environments. In order to understand how e-businesses make money, many business models have been studied. For this reason, the concept of business model in the new economy and the transformation of business models into e-business models are examined. In line with this, it is aimed in this chapter to examine e-businesses, to clarify e-business models, and to explain e-commerce types and e-business model types in detail, with examples.
Strategies to Predict E-Commerce Inventory and Order Planning
Authors: Rahman Mohammad Anwar , Casanovas Laura
Published: June 2021

This study examines the characteristics of a prediction model for businesses in the online marketplace by considering the market trend, prior sales and decision maker's preference on potential demand estimate. With the rapid growth of the electronic market, the main challenge for online sellers is the ability to analyze customer expectation, market data, and sales information to make the accurate procurement decision. The proposed model integrates a mathematical structure for a target season sale comprising upcoming demand projection by seller's internal team, data from past sales and the overall trend of seller's e-brand to determine the online customer demand. The study proposed a newsvendor model as a tool for sellers to make the instantaneous decision of ordering merchandise from the supplier when the quick response to the customer order is a priority for electronic market. Results of the study provide insights into the procurement dynamics and implications of the e-commerce inventory plan.
Analysing Critical Success Factors for Supporting Online Shopping
Authors: Varela Maria Leonilde R. , Putnik Goran D. , Carvalho Maria do Sameiro , Ferreira Luís , Cruz-Cunha Maria Manuela , Manupati V. K. , Manoj K.
Published: June 2021

Online shopping is nowadays is a highly frequent action but there are several critical factors that have to be considered for enabling websites and platforms to be able to offer all necessary requisites for guaranteeing user friendly, secure and also enjoyable shopping experiences to clients, offering them exactly what they expect to buy, and quickly find, among a huge offer available online. In this paper, a set of considered critical success factors are analysed on a set of top ranked websites, about luxurious furniture, to understand to what extent these critical factors are satisfied. The results can be taken into consideration for implementing a successful business through e-commerce from herein analysed perspectives.
The Online Reviews' Effects on Internet Consumer Behavior
Authors: Zhang Mingli , Ding Suyun , Bian Yuanwei
Published: June 2021

Consumer behaviors have always been the hot spot of the study. With the arrival of the network age and the popularity of e-commerce, the consumption pattern of shopping online is beginning. Until December of 2014, there were 649 million Internet users in China, and it's increasing. In the year of 2014, the number of most mainstream online shoppers has increased by 23.7% and shopping online has become an irresistible trend. New consumption mode can produce a new research subject, the study of Internet consumer behaviors becomes very important. This article used LocoySpider, a data mining software, to mine Taobao online reviews. Through the analysis of online reviews, we can study the effect of online reviews on consumer behaviors. During the study, we set the risk perception as intermediary variable. By the study, we can help the electronic commercial enterprises to attract customers, retain customers and reduce the information search cost.
An Exploration of the Impact of Virtual Reality Interfaces on Online Shopping
Authors: Hsu Wen-Chin , Chen Po-Han , Chen Chung-Yang
Published: June 2021

Virtual reality presents exciting new opportunities for e-commerce with regard to the development of innovative shopping services. This article reports on an experimental investigation into the coordinated use of two human-computer interfaces (HCIs) for online shopping: virtual reality (VR) and webpages. We adopted the uses and gratification theory and technology acceptance model to determine how these HCIs affect online shopping intentions. Data from 98 participants revealed that entertainment value, informativeness, perceived ease-of-use, and perceived usefulness are the primary factors influencing the intention to use the VR HCI for online shopping (p < 0.05). Informativeness, perceived ease-of-use, and perceived usefulness are the main factors influencing the intention to use the webpage HCI for online shopping (p < 0.05). This study provides insights for businesses how to develop innovative shopping services using VR.
Relationships Among Dimensions of Online Second-Hand Shopping, Satisfaction, and Repurchase Intention
Authors: Swapana Murali , Padmavathy Chandrasekaran
Published: June 2021

The purpose of this study is to examine the relationships among dimensions of online second-hand shopping, customer satisfaction, and repurchase intention. Responses obtained from 608 Indian online second-hand shoppers show that the dimensions of online second-hand shopping such as price, website quality, nostalgia, and brand image influence customer satisfaction. In addition, customer satisfaction positively affects repurchase intention. Findings of the present study provide intuitive guidelines for online second-hand marketers in approaching emerging markets through effective online shopping strategies.
Examination of Effects of Competitive Strategies on the E-Commerce Companies in Terms of Achieving Sustainable Competitive Advantage
Authors: Adiguzel Zafer
Published: June 2021

E-commerce brings companies and customers together in an exchange market environment, beyond any physical, cultural, and legal boundaries, and on an unimaginable scale, which was considered to be technically impossible before. The companies' online facilities have been improved and become accessible to everyone through smart phones, tablets, etc. as the web pages and social networks started to direct individuals towards e-commerce. E-commerce not only raises economic concerns related to competition and pricing, but also reveals new social and environmental threats that can be quite widespread and viral. Several studies have been conducted to examine the transformation of traditional business models into e-businesses, the impact of e-commerce businesses on traditional business activities, or opportunities brought by technological innovations. For this reason, the effects of the competitive strategies will be explained in terms of ensuring sustainable competitive advantage within e-commerce companies.
Influence of Perceived Benefits on Consumers' Online Purchase Behaviour
Authors: Katta Rama Mohana Rao , Patro Chandra Sekhar
Published: June 2021

This article describes how e-retailing has become one of the most important uses of technology relating to the internet. The activity of online shopping is considered to be one of the important features of e-retailing. The enormous advantages offered by online shopping stimulate corporate managers, marketing departments and retailers to offer their products through the websites to attract the largest number of shoppers, not only to local markets but also global markets. The change in consumer behavior along with the availability of cheaper and reliable technology for secure transactions has led to a significant growth in online sales around the world. The present article focuses on identifying the key factors influencing the consumers' perceived benefits while shopping online. The article further focuses on the influence of demographic factors on consumers' perceived benefits. The findings of the article would help e-retailers to have a better understanding and to develop strategies for making the online shopping experience more effective and trustworthy to the target consumers.
The Perceived Risks Affecting Online Shopping Adoption in Jordan
Authors: Alnsour Muhammed , Ismael Nadar , Nsoor Zaid , Feidi Midhat
Published: June 2021

This article studies online shopping and e‐commerce adoption in Jordan due to the significant growth of this industry in Jordan particularly and the rest of the world generally, which is receiving attention globally and has proven to largely contribute to the growth of nations' economies. This article specifically studies the risk that online users perceive from online shopping and how they affect the growth of this industry. This study adopts a quantitative research approach, with a total of 355 questionnaires distributed by the researchers, to determine whether perceived risks of online shopping have an effect on a number of user adoptions. The article studies the two main risks of online shopping, payment risk, and product risk. Payment risks are defined as the financial loss which included risks associated with using credit cards and identity theft. Product risk is described as the loss incurred when a product does not perform as expected or does not match what was shown and described online. The study concludes that perceived payment risk and product risk affect online shopping negatively and has negatively impacted the number of users adopting this phenomenon.
Sustainable Logistics Systems
Authors: Yu Zhang
Published: June 2021

Green logistics has much value for our societal development. The essential task is helping build a sustainable economy. Due to environmental impact economic activities bring and sustainable development and the requirement for logistics activities, the green logistics system must include green supply, green warehousing or distribution, green packaging, green transportation, the greening of sales logistics, remanufacturing of used products, and waste recycling. It is necessary to take corresponding countermeasures to build a scientific system for the development of green logistics, which is a necessity for modern logistics.
A Monte-Carlo Analysis of Monetary Impact of Mega Data Breaches
Authors: Canan Mustafa , Poyraz Omer Ilker , Akil Anthony
Published: June 2021

The monetary impact of mega data breaches has been a significant concern for enterprises. The study of data breach risk assessment is a necessity for organizations to have effective cybersecurity risk management. Due to the lack of available data, it is not easy to obtain a comprehensive understanding of the interactions among factors that affect the cost of mega data breaches. The Monte Carlo analysis results were used to explicate the interactions among independent variables and emerging patterns in the variation of the total data breach cost. The findings of this study are as follows: The total data breach cost varies significantly with personally identifiable information (PII) and sensitive personally identifiable information (SPII) with unique patterns. Second, SPII must be a separate independent variable. Third, the multilevel factorial interactions between SPII and the other independent variables elucidate subtle patterns in the total data breach cost variation. Fourth, class action lawsuit (CAL) categorical variables regulate the variation in the total data breach cost.
The Forms of Education
Authors: Chiusaroli Diletta
Published: June 2021

A key figure as an interpreter of the spirit of the time, the educator needs continuous training. This is an essential requirement for carrying out what is one of the main aspects of his work: facilitating inclusion, limiting any type of marginality and social exclusion. The role of the educator, based primarily on humanistic and social knowledge, is also rich in ethical values. Two valuable allies that the educator cannot help but resort to are observation and active listening; in fact, while observation allows us to collect the necessary information, by listening we welcome the other, with his strengths and weaknesses. To educate is also to communicate, to be close to the student, to communicate also with looks and gestures. In his action, the effective educator must also follow the path of dialogue, reciprocity, and communicative integration. This chapter explores these forms of education.
Engaging Students Through Escape Games and a Play Environment During Recess
Authors: Seifert Tami , Gez Yoav
Published: June 2021

The article describes projects that combined experiential learning and gamification with teachers and pupils in junior high school science classes. The pupils planned and designed projects and critiqued the quality of the final products. A field report study model was employed using principles from the world of play in order to better understand the production of a high-quality project. An “Octalysis” model was constructed to identify and analyze the factors that enhance human motivation, and principles for the creation of experiential learning and play. One of the significant characteristics that enabled the production of many varied products was the teachers' ability to find time and physical space in which to create the learning environments. Provision of experiential learning and play environments is demanding for the teacher, but rewarding since they involve pupils and deepen learning quality throughout the process. As a result of this experimentation and reflection, insights were gained concerning the creation of experiential learning and play environments.
Historical earthquake investigation and research in China
Authors: J. Wang
Published: June 2021

China is one of the countries with the longest tradition of culture and has suffered many earthquake disasters, so many earthquake documents have therefore been conserved. In this paper we try to outline some basic information of historical earthquake investigation and research in China, such as collection of historical earthquake data from archives, historical earthquake catalogues, seismic intensity scales. We introduce briefly the huge accomplishments of historical research and discuss some problems encountered. Through examples, we illustrate the solutions to some typical problems. There are some suggestions on further work.
Finite element analysis of ground deformation due to dike intrusion with applications to Mt. Etna volcano
Authors: A. Occhipinti Amato  , M. Elia  , A. Bonaccorso  , G. La Rosa
Published: June 2021

A 2D finite elements study was carried out to analyse the effects caused by dike intrusion inside a heterogeneous medium and with a realistic topography of Mt. Etna volcano. Firstly, the method (dimension domain, elements type) was calibrated using plane strain models in elastic half-spaces; the results were compared with those obtained from analytical dislocation models. Then the effects caused both by the topographic variations and the presence of multi-layered medium on the surface, were studied. In particular, an application was then considered to Mt. Etna by taking into account the real topography and the stratification deduced from seismic tomography. In these conditions, the effects expected by the dike, employed to model the 2001 eruption under simple elastic half-space medium conditions, were computed, showing that topography is extremely important, at least in the near field.
Results from the temporary installation of a small aperture seismic arrayin the Central Apenninesand its merits for local event detectionand location capabilities
Authors: T. Braun  , J. Schweitzer  , R. M. Azzara  , D. Piccinini  , M. Cocco  , E. Boschi
Published: June 2021

In order to evaluate the detection and localisation improvement of a small aperture array in the Northern Apennines, we installed an irregularly spaced test configuration in the vicinity of Città di Castello (CDC) for a period of two weeks. The experimental array consisted of nine 3-component stations with inter-station distances between 150 m and 2200 m. Seismic data were digitised at 125 Hz and telemetered to a mobile acquisition, processing and storage centre. The data could only be recorded in trigger mode. The peculiarity of the test array installation was the exclusive use of 3-component sensors at all array sites, which also allowed beamforming for S-phases on the horizontal components. Since the altitudes of the single array sites differed considerably among each other, for f-k analysis and beamforming an elevation correction was included. During the two weeks of operation about 20 local earthquakes with magnitudes ML<2.6, 1 regional, and several teleseismic events were recorded. In addition to these events, the array occasionally triggered on coherent noise-signals generated by local industrial activity. The data analysis was performed by means of f-k analysis and beamforming, providing wavenumber characteristics of the incident plane wave. Typical apparent velocities were determined to be 4.8 km/s and 6 km/s for Pg-phases and ~10 km/s for Pn-phases. We observed local seismic events, which occurred just beneath the array. In these cases wavefronts with unusual high apparent velocities, similar to those found for the Pn-phase, were observed. Since no continuously recorded array data were available, we extrapolated the lower detection magnitude threshold as a result of the SNR improvement due to array beamforming. Compared to the actual detection threshold of MT ~1.6 reached by the national seismic network in this area, a nine element array would improve this value up to MT ~ 0.8.
Tectonomagnetic modeling based on the piezomagnetism: a review
Authors: Y. Sasai
Published: June 2021

Development of tectonomagnetic modeling on the basis of the piezomagnetic effect is reviewed for the period since the early 1990's. First, the basic theory is briefly summarized, in which the representation theorem or the surface integral representation for the piezomagnetic potential and the Green's function method are presented. In the 1990's, several field observations in earthquakes and volcanoes were interpreted with the aid of analytic solutions based on the Green's function method. A general formula was developed for an inclined rectangular fault with strike-slip, dip-slip and tensile faulting. The surface integral method has been applied to 2D and 3D models, as well as to fault models in the inhomogeneously magnetized crust. When the magnetic field is measured within a bore hole, the effect of magnetic poles around the hole should be taken into account. As a result, tectonomagnetic signals are much enhanced in a bore hole compared with on the ground surface. Finally, piezomagnetic field changes associated with the Parkfield fault model are introduced and the new aspect of the model is discussed.
Could ionospheric variations be precursors of a seismic event? A short discussion
Authors: S. S. Kouris  , P. Spalla  , B. Zolesi
Published: June 2021

A short review of published papers on the perturbations in the ionosphere due to seismogenic effects is reported. The method to correlate different classes of phenomena as ionospheric variations and subsequent seismic events is discussed. Even if the theoretical attempts to understand or to explain the electromagnetic phenomena in the ionosphere, as precursors of earthquakes are not satisfactory, the reported results encourage further investigations.
Source parameters of the Izmit-Bolu 1999 (Turkey) earthquake sequences from teleseismic data
Authors: A. Kiratzi  , E. Louvari
Published: June 2021

Body waveform modelling and far-field displacement spectral analyses were used to study the source parameters of five of the largest earthquakes of the (Izmit-Bolu) Turkey 1999 sequence. The derived source parameters for the August 17, 1999 M W 7.4 event are: strike = 267°, dip = 85°, rake =  175°, h = 10 km, M 0 = 1.31×10 20 Nm. The length of the fault was found equal to 76 km, the average displacement 6.4 m and the static stress drop 90 bars. The Bolu November 12, 1999 M W 7.1 event has a focal mechanism with strike = 262°, dip = 53°, rake = 177°, h = 12 km, M 0 = 4.71×10 19 Nm, fault length of 56 km, average displacement 2.1 m and average static stress drop 29 bars. The focal mechanisms of three other aftershocks of the Izmit sequence indicate right lateral strike slip motion, as well. The slip vectors of the events studied are in accordance with the GPS velocity vectors, have a mean azimuth of 269° and reveal the extrusion of the Anatolian plate towards the Aegean.
The global paleogeographical reconstruction of the Triassic in the earth dilatation framework and the paleoposition of india .
Authors: G. Scalera
Published: June 2021

Following the production of a series of three and Jurassic (Scalers, assistance of paleogeographical reconstructions for the Paleocene, Cretaceous 1995, 1998), a further reconstruction has been made here for the Triassic period, with the paleomagnetic data. The data provided by mutual fragment positions and paleomagnetic vectors, are best reconciled if the data are treated in an expanding Earth framework, and give credence to the view that this represents the real evolution of the Earth. ln particular a new solution of the case of indian paleoposition is given which could constitute the key to a reinterpretation of the Eurasia paleogeography throughout geological time. The main conclusion of this work is that the unambiguous choice between constant radius and increasing radius geodynamic frameworks (dr/dt = 15 mm/yr on average in this work) can be made on the basis of the possibility to define the paleoposition and kinematics of india from the Triassic to the Paleocene.
Short-term prediction of ionospheric parameters based on auto-correlation analysis
Authors: I. Kutiev  , P. Muhtarov  , L. R. Cander  , M. F. Levy
Published: June 2021

A prediction method based on a simple auto-regressive model has been developed for short-term prediction of ionospheric characteristics. The method determines the auto-correlation function for the hourly values of the parameter of interest, using the time series from the previous 25 days. The resulting weighting coefficients can then be used to forecast future values of the parameter. The method has been applied to predict f0F2 up to 24 h ahead for stations Uppsala, Slough, Poitiers and Sofia. Error statistics are presented
Measurements of vector magnetic anomalies on board the icebreaker Shirase and the magnetization of the ship
Authors: Y. Nogi  , K. Kaminuma
Published: June 2021

Vector measurements of the geomagnetic field have been made in the South Indian Ocean since 1988 when a Shipboard Three Component Magnetometer (STCM) was installed on board the icebreaker Shirase by the 30th Japanese Antarctic Research Expedition (JARE-30). Twelve constants related to the ship's induced and permanent magnetic field were determined by the data obtained from the JARE-30 to the JARE-35. The constants related to the ship's magnetic susceptibility distribution are almost stable throughout the cruise and mostly depend on the ship's shape. On the other hand, the constants related to the ship's permanent magnetization are variable. However, absolute values of total intensity geomagnetic field calculated from vector geomagnetic field is possible to use, if the constraints from total intensity geomagnetic field measured by the proton magnetometer and/or satellite derived magnetic anomalies are applied.
The Osservatorio Geofisico Sperimentale marine magnetic surveys in the Antarctic Seas
Authors: E. Lodolo  , F. Coren  , C. Zanolla
Published: June 2021

About 40 000 km of marine magnetic and gradiometric data have been collected during eight geophysical surveys conducted since the Austral summer 1987/1988 in the circum-antarctic seas, by the research vessel OGS-Explora. For the most surveyed areas (Ross Sea, Southwestern Pacific Ocean, and Southern Scotia Sea), the analysis of the acquired data have contributed to clarify important aspects of their geological structure and tectonic evolution. The main scientific results, obtained combining other available geophysical data (multichannel seismic profiles and satellite-derived data), will be briefly illustrated.
Development of an improved geomagnetic reference field of Antarctica
Authors: A. De Santis  , M. Chiappini  , J. M. Torta  , R. R. B. von Frese
Published: June 2021

The properties of the Earth's core magnetic field and its secular variation are poorly known for the Antarctic. The increasing availability of magnetic observations from airborne and satellite surveys, as well as the existence of several magnetic observatories and repeat stations in this region, offer the promise of greatly improving our understanding of the Antarctic core field. We investigate the possible development of a Laplacian reference model of the core field from these observations using spherical cap harmonic analysis. Possible uses and advantages of this approach relative to the implementations of the standard global reference field are also considered.
The shape of Vesuvius before the 79 A.D. eruption according to a new finding from a Pompei fresco and Vesuvius central cone history in the last 2000 years
Authors: A. Nazzaro
Published: June 2021

The history of Vesuvius and its central cone or Great Cone (Gran Cono) is important because it enables us to improve our understanding of the structural evolution of Somma-Vesuvius. Apart from geological and stratigraphic studies, investigations of the literary and artistic testimonies can also help to clarify some unresolved problems. Recently a detailed study of the consequences of the 1631 eruption on the volcano morphology as well as that of the following volcanic activity has shown that the present central cone was formed in the last few centuries after that eruption. With regard to the history of the central cone prior to the 1631 eruption, rare writings and iconographic records help clarify this question. In this short communication we announce the discovery of a new image representing Vesuvius before the 79 A.D. eruption identified in a fresco from Pompei excavations. This fresco could confirm the interpretation of a well-known Strabo quotation according to which there already existed a large caldera prior to the 79 A.D. eruption.
On the validity of the regional time and magnitude predictable model in China
Authors: C. Qin  , E. E. Papadimitriou  , B. C. Papazachos  , G. F. Karakaisis
Published: June 2021

A simplified form of the "regional time and magnitude predictable model" gives the time interval, T, between two successive mainshocks in a region and the magnitude, Mf, of the following mainshock by the relations: logT=cMP+a; Mf=CMp+A, where Mp is the magnitude of the preceding mainshock, a, A are constants which depend on the minimum considered mainshock and on the region's tectonic loading (moment rate). The physical meaning of the model is that the larger the magnitude of the preceding main shock, Mp, the longer the time, T, will be till the occurrence of the next one and the smaller its magnitude, Mf. This means that parameters c and C are positive and negative, respectively, when the model has been found valid for a certain area. In order to examine if the above model is appropriate to describe the seismicity behavior in the area of China, a detailed inspection was carried out aiming to show if the estimated values of parameters c and C favor the model. The results show that c tends to the global value 0.33, obtained by Papazachos and Papadimitriou (1997), and that C tends to be within the range [-0.30, -0.23]. The results, which favored the model, greatly outnumber those that do not follow it, the latter being concentrated around the boundaries of the seismically active regions. It is concluded that the results, which favor the model, obviously dominate the whole territory of China.
An integrated study of physical precursors of failure in relation to earthquake prediction, using large scale rock blocks
Authors: K. Baddari  , G. A. Sobolev  , A. D. Frolov  , A. V. Ponomarev
Published: June 2021

This paper is multi-analysis approach to rock failure using metric size rock samples. The use of large-scale models permits simulation of the seismic process (including internal rupture on several scales) and utilization of a dense network for observation of the spatial variations of several physical parameters. The experiments were performed both on solid rock blocks and on concrete blocks with artificial defects, which enabled simulation of internal shear fracture. The number of various precursors appears to rise up to failure, all of them clearly manifest at the stage of a rapid drop in the applied stress (unstable deformation). The experiment suggests that rocks under strain and prior to failure must be characterized by a heterogeneous field of strains. This means that the strain is distributed mosaically, dilatancy does not generate uniformly and areas where it occurs are likely to be structurally mosaic themselves. To reinforce the prediction of micro- and macrofailure, we have realized simultaneous processing of the obtained data, using sophisticated multidimensional orthogonal functions to represent the different precursors. The possibility to identify the early stages of microfailures and to predict the macrofailure by means of statistical complex parameters derived from data on local deformations, acoustic emissions, elastic waves velocities, electric resistivity and self electric potentials is shown. Despite a considerable dissimilarity in mechanical properties of granite basalt and concrete, the complex parameter proves morphologically identical. Parameter S1 reveals exponential rise up to failure in all cases, and parameter S2 is bay-shaped in form, which makes it more promising in terms of prognosis.
Upper crustal structure in the Potenza area (Southern Apennines, Italy) using Sp converted wave
Authors: D. Demanet  , L. Margheriti  , G. Selvaggi  , D. Jongmans
Published: June 2021

In this paper we analyse the records of the two Potenza seismic sequences (Southern Apennines, Italy) which occurred in 1990 and 1991, in order to obtain information on the upper crustal structure in this area. The hypocentral depths are mainly concentrated below 10 km which is the supposed upper limit of the crystalline basement. The seismograms recorded at temporary arrays deployed during the two sequences clearly show on the vertical component, an intermediary phase between the P and S waves. For the investigated epicentral distances (less than 30 km) the delay between this secondary phase and the direct S wave arrival is almost constant at each station, suggesting that the observed intermediary phase might be an S to P conversion at a discontinuity shallower than the hypocentral depth. This interpretation has been supported by polarisation analysis and numerical modelling results. Considering the regional geological structure, these latter have also shown that the interface generating strong converted waves could be the top of the Apulian carbonate platform overlaid with recent clay deposits and flysch sediments. 1D inversion of the travel-time data was performed in order to evaluate a local vertical upper crustal profile.
The supposed Egyptian earthquakes of 184 and 95 B.C. Critical review and some lines of research in historical seismology using Greek papyri from Egypt
Authors: R. Mazza
Published: June 2021

In the context of a project to update the data collected in the catalogue of Guidoboni et al.(1994), we noticed that two Egyptian earthquakes of 184 and 95 B.C. mentioned in the catalogue of Ambraseys et al. (1994, p. 20) were not included. A search to verify whether these two events should be added to the list of seismic events in the ancient Mediterranean area led to the conclusion that the two Egyptian earthquakes of 184 and 95 B.C. never occurred. The texts cited by the authors (a papyrus and an inscription) seem to deal with other events; in fact the word seismós, which has among others the meaning of 'earthquake', in these sources means 'blackmail' or 'extortion'. This conclusion leads to further discussion of relationships between ancient history and historical seismology and in particular of the use of Greek papyri from Egypt to study ancient earthquakes. A research project on Greek papyri, which will also consider other kinds of evidence such as Coptic literary and documentary texts, has been initiated by a group of researchers belonging to the SGA, in order to continue investigation of ancient earthquakes in the Mediterranean area.
The set valued unified model of dispersion and attenuation for wave propagation in dielectric (and anelastic) media
Authors: M. Caputo
Published: June 2021

Since the dispersion and attenuation properties of dielectric and anelastic media, in the frequency domain, are expressed by similar formulae, as shown experimentally by Cole and Cole (1941) and Bagley and Torvik (1983, 1986) respectively, we note that the same properties may be represented in the time domain by means of an equation of the same form; this is obtained by introducing derivatives of fractional order into the system functions of the media. The Laplace Transforms (LT) of such system functions contain fractional powers of the imaginary frequency and are, therefore, multivalued functions defined in the Riemann Sheets (RS) of the function. We determine the response of the medium (dielectric o anelastic) to a generic signal summing the time domain representation due to the branches of the solutions in the RSs of the LT. It is found that, if the initial conditions are equal in all the RSs, the solution is a sum of two exponentials with complex exponents, if the initial conditions are different in some of the RSs, then a transient for each of those RSs is added to the exponentials. In all cases a monochromatic wave is split into a set of waves with the same frequency and slightly different wavelengths which interfere and disperse. As a consequence a monochromatic electromagnetic wave with frequency around 1 MHz in water has a relevant dispersion and beats generating a tunnel effect. In the atmosphere of the Earth the dispersion of a monochromatic wave with frequency around 1 GHz, like those used in tracking artificial satellites, has a negligible effect on the accuracy of the determination of the position of the satellites and the positioning of the bench marks on the Earth. We also find the split eigenfunctions of the free modes of infinite plates and shells made of dielectric and anelastic media.
International activities in HF sky-wave field-strength estimation (period 1956-1991)
Authors: P. A. Bradley
Published: June 2021

Methods for the determination of the strengths of radio signals reflected from the ionosphere and propagated to distant locations are required for service planning and circuit operation. Efforts are described following World War II to arrive at agreed procedures and some of the features of the various empirical prediction methods that have been formulated over the years are discussed. The problems are highlighted of determining a "best" method from among those available. Measurement data collected for this purpose are reviewed and attention is drawn to their limitations of accuracy and coverage. Even comparison of predicted and measured values is not straightforward, and the techniques that have been developed to do this are considered.
Spatial distribution of scalar seismic moment release in Italy (1983-1996): seismotectonic implications for the Apennines
Authors: G. Selvaggi  , B. Castello  , R. Azzara
Published: June 2021

We analyzed the distribution of seismic moment in Italy, computed from instrumental seismicity recorded by the Italian National Seismic Network in the past 14 years, to map the areas where seismic deformation processes have been active in this time interval. Seismic moment is the most suitable parameter to quantify earthquake size. It is related to the geometric characteristics of faults, to seismic energy and it is a quantity that can be summed and represented in its cumulative value. The maps of seismic moment distribution display more information than epicentral maps, better showing actively deforming regions. They provide further and original evidence for the existence, within the Apenninic belt, of two regions (north and south) characterized by different seismic energy release. The seismic moment is almost continuously and homogeneously distributed all along the belt in the Northern Apennines, whereas in the Southern Apennines it is concentrated in the zones recently activated by mainshock-aftershock seismic sequences. Seismic deformation takes place in a 30 km narrow belt along the Apennines, while in the transition zone between the Northern and Southern Apennines this belt is about 100 km wide. Comparing instrumental seismic moment release with the areas struck by the largest historical earthquakes which have occurred in the past six centuries, we qualitatively extended back to the past the information on where the seismic deformation occurs. In the Southern Apennines background energy release from instrumental seismicity is very low in the several areas hit by large historical earthquakes, suggesting that these seismogenic zones are currently quiescent.
Investigation of the single layer model of GPS ionospheric data processing using IRI-90 and the attached diffusive equilibrium model of plasmaspheric electron density
Authors: L. Bànyai
Published: June 2021

The single layer model of GPS ionospheric data processing is compared with the International Reference Ionosphere í 1990 and the attached Diffusive Equilibrium model of Plasmasphere (IRI-90+DEP) which proved to be a good supplement to GPS data processing. These models can be used to estimate the single layer height and to improve the mapping function in day-time. The code delays estimated from IRI-90+DEP models are compared with GPS measurements carried out by TurboRogue receiver. These models can be used to estimate the preliminary receiver biases especially in the case of cross-correlation tracking mode. The practical drawback of the IRI-90 model is the sharp discontinuity of the ion components during sunset and sunrise at an elevation of 1000 km, because it also causes a sharp discontinuity in the TEC values computed from the DEP model. The GPS data may be a good source to improve the topside region of the IRI model estimating smooth TEC transition before and after sunrise in the plasmasphere.
Structural model of the Northern Latium volcanic area constrained by MT, gravity and aeromagnetic data
Authors: P. Capuano  , G. Florio  , P. Gasparini
Published: June 2021

The results of about 120 magnetotelluric soundings carried out in the Vulsini, Vico and Sabatini volcanic areas were modeled along with Bouguer and aeromagnetic anomalies to reconstruct a model of the structure of the shallow (less than 5 km of depth) crust. The interpretations were constrained by the information gathered from the deep boreholes drilled for geothermal exploration. MT and aeromagnetic anomalies allow the depth to the top of the sedimentary basement and the thickness of the volcanic layer to be inferred. Gravity anomalies are strongly affected by the variations of morphology of the top of the sedimentary basement, consisting of a Tertiary flysch, and of the interface with the underlying Mesozoic carbonates. Gravity data have also been used to extrapolate the thickness of the neogenic unit indicated by some boreholes. There is no evidence for other important density and susceptibility heterogeneities and deeper sources of magnetic and/or gravity anomalies in all the surveyed area.
On dynamics of seismicity simulated by the models of blocks-and-faults systems
Authors: A. I. Gorshkov  , V. I. Keilis-Borok  , I. M. Rotwain  , A. A. Soloviev  , I. A. Vorobieva
Published: June 2021

The major results obtained by numerical simulation of block structure dynamics are juxtaposed and analysed: the possibilities to reconstruct tectonic driving forces from territorial distribution of seismicity, clustering of earthquakes in the model, and dependence of the occurrence of strong earthquakes on fragmentation of the media, and on rotation of blocks. These results show that modelling of block structure dynamics is a useful tool to study relations between the geometry of faults and block movements and earthquake flow, including premonitory seismicity patterns, to test the existing earthquake prediction algorithms, and to develop new ones.
Noncausality of numerical models of dynamic fracture growth
Authors: L. Knopoff
Published: June 2021

Discretization of the wave operator for purposes of solving problems in the dynamics of crack growth numerically, introduces noncausality associated with the nonlinearity of the fracture criterion at the edge of the crack, i.e. with an imperfect formulation of the fracture criterion in the discretized case. The noncausality can be attributed to jumps from one inertial coordinate system to another as successive particles at the edge of a digitized crack are triggered into motion. It is shown that there is an equivalent explanation in terms of the incompatibility of the short-range edge conditions and the long-range correlations of slip on the crack in the discretized case. The noncausal effects can lead to supersonic crack growth, and in some cases to infinite crack growth velocities. A proposal for amelioration of the problem is offered.
A revisitation of the triangular prism surface area method for estimating the fractal dimension of fractal surfaces
Authors: A. De Santis  , M. Fedi  , T. Quarta
Published: June 2021

Fractal dimension is widely used to give a measure of variability and roughness of curves, signals, objects, sta- tistical distributions, and so on, We found that an often used method, the so-called triangular prism surface- area method, for estimating the tractal dimension of fractal surfaces possesses some intrinsic mistake., in appli- cation. This note describes the misintel"pretation and suggests the proper application, that we calI Revised Tri- angular Prism Method (RTPM). To show its feasibility we apply RTPM to some synthetic Euclidean and frac- tal surfaces of known dimension.
Neogene-Quaternary magmatic activity and its geodynamic implications in the Central Mediterranean region
Authors: G. Serri
Published: June 2021

The petrogenesis and time/space distribution of the magmatism associated with the formation of the Northern and Southern Tyrrhenian basins, together with the directions and ages of lithospheric extension and/or spreading north and south of the 410N discontinuity, show that the two arc/back-arc systems have undergone a different structural evolution at least since the middle Miocene (Langhian). The geochemical components involved in the genesis of the heterogeneities of the mantle sources of this magmatism require two separate, compositionally different slabs: 1) an old oceanic (Ionian) lithosphere still seismically active below the Calabrian arc and the Southern Tyrrhenian region; 2) an almost seismically inactive continental (Adriatic) lithosphere which carried large amounts of upper crustal materials within the upper mantle under the NW Roman Province/Tuscan/Northern Tyrrhenian region. The proposed geodynamic models require: 1) for the Northern Tyrrhenian/Northern Apenninic arc/back-arc system, the delamination and foundering of the Adriatic continental lithosphere as a consequence of the continental collision between the Corsica block and the Adriatic continental margin. This delamination process, which is still ongoing, probably started in the early-middle Miocene, but earlier than 15-14 Ma, as indicated by the age and petrogenesis of the first documented magmatic episode (the Sisco lamproite) of the Northern Apennine orogenesis; 2) for the Southern Tyrrhenian/Southern Apenninic-Calabrian arc/back-arc system, the roll-back subduction and back-arc extension driven by gravitational sinking of the Ionian oceanic subducted lithosphere. This process started after the end of the arc volcanism of Sardinia (about 13 Ma) but earlier than the first recorded episode of major rifting (about 9 Ma) in the Southern Tyrrhenian back-arc basin.
Seismic anisotropy: an original tool to understand the geodynamic evolution of the Italian peninsula
Authors: L. Margheriti  , C. Nostro  , A. Amato  , M. Cocco
Published: June 2021

Anisotropy is a common property of the Earth's crust and the upper mantle; it is related to the strain field of the medium and therefore to geodynamics. In this paper we describe the different possible origins of anisotropic behavior of the seismic waves and the seismological techniques used to define anisotropic bodies. In general it is found that the fast polarization direction is parallel to the absolute plate motion in cratonic areas, to the spreading direction near rifts or extensional zones, and to the main structural features in transpressive regimes. The delay times between fast and slow waves reflect the relative strength and penetration at depth of the deformation field. The correspondence between surface structural trends and anisotropy in the upper mantle, found in many regions of the world, strongly suggest that orogenic processes involve not only the shallow crust but the entire lithosphere. Recently in Italy both shear wave splitting analysis and Pn inversion were applied to define the trend of seismic anisotropy. Along the Northern Appeninic arc fast directions follow the strike of the arc (i.e., parallel to the strike of the Miocene-Pleistocene compressional features), whereas in the Tyrrhenian zone fast directions are about E-W SW-NE; parallel to the post-Miocene extension that is thought to have reoriented the mantle minerals fabric in the astenosphere.
Magnetotelluric monitoring of geodynamic processes
Authors: B. S. Svetov  , S. D. Karinskij  , Y. I. Kuksa  , V. I. Odintsov
Published: June 2021

Electromagnetic (EM) monitoring of geodynamic processes can be based on the two different seismo-electrical phenomena: a change in resistivity of some geological cross-sections and a generation of EM fields of internal (geodynamic) origin. Continuous observation of the natural magnetotelluric (MT) field simultaneously provides information on both such phenomena. The transfer functions between components of the MT field reflect geoelectrical section and the residual field includes the EM field of internal origin. Their variations in time give independent information on geodynamic processes. The transfer functions and the residual field can be determined by known deterministic methods, although it appears more convenient to apply the methods of adaptive data processing. They elicit information on both phenomena in real time. Continuous MT observations were carried out at the Bishkek geodynamic testing ground (Kirgizia) during 1993. Their results show how informative MT monitoring is.