bluuebunny/crossref_metadata_2025 huggingface dataset:
Green Synthesis of Silver Nanoparticles using Eranthemum Pulchellum (Blue Sage) Aqueous Leaves Extract
Authors: Prakash Jai , Shekhar Himanshu , Yadav Shyam Raj , Dwivedy Abhishek Kumar , Patel Vijay Kumar , Tiwari Shikha , Vishwakarma Niraj Kumar
Published: June 2021

Background:

Nanoparticles modulate several physiochemical and biological properties. In this regard, silver nanoparticles (AgNPs) have shown remarkable applications. The present research work comprises green synthesis of AgNPs using aqueous leaves extract of Eranthemum pulchellum and evaluation of its efficacy as antifungal and antioxidant agents.

Methods:

Synthesized AgNPs have been characterized by Fourier Transforms Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and ultraviolet-visible spectrophotometry. Qualitative phytochemical analysis of aqueous leaves extract of E. pulchellum and FTIR spectrum of the synthesized AgNPs suggest about the presence of different phytochemicals and functional groups, respectively, which are responsible for reducing silver ions as well as capping and stabilizing synthesized nanoparticles.

Results:

The wavelength of maximum absorbance of AgNPs solution near to 439 nm indicates the spherical morphology. XRD infers about average crystalline size of the synthesized AgNPs to be ~12 nm. Selected area electron diffraction pattern of the synthesized AgNPs shows four visible diffraction rings corresponding to (111), (200), (220), and (311) set of planes which are attributed to face centered cubic metallic silver. The size and spherical shape of the synthesized AgNPs have been further determined by TEM. The synthesized AgNPs have shown a significant antifungal activity against Aspergillus flavus (AF-LHP-NS7) strain with minimum inhibitory concentration value of 200 μg/mL. The synthesized AgNPs have also shown strong antioxidant efficacy through Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid assay with IC50 value of 462.56 μg/mL.

Conclusions:

The present study shows a green and facile synthesis of AgNPs. Leaves extract of E. pulchellum has been first time utilized as efficient reductant for the AgNPs synthesis. These AgNPs have shown potent antifungal and antioxidant activity.
Gender Difference in Health-Related Quality of Life of Adolescent Idiopathic Scoliosis Patients between the 2nd and 5th Year of Bracing Treatment using Scoliosis Research Society-22 Questionnaire
Authors: Chau Wai-Wang , Hung Alec Lik-Hang , Ng Bobby Kin-Wah
Published: June 2021

Background:

Offering brace for moderately suffering adolescent idiopathic scoliosis (AIS) patients is a recognized intervention to control further curve progression, and the treatment period varies from each patient. Some AIS patients required to wear longer than expected with different clinical reasons. Health-related quality of life (HRQOL) of AIS patients who have undergone bracing from the 2nd year to 5th year has not been discussed. The aim of this study is to evaluate the HRQOL of patients who have undergone bracing between their 2nd to 5th year of treatment using Scoliosis Research Society-22 (SRS-22) questionnaire.

Materials and Methods:

One hundred and twenty-six AIS patients who were under brace treatment completed SRS-22 questionnaire at their 2nd, 3rd, 4th, and 5th year on brace. Five SRS-22 domain scores (function, pain, self-image, mental health, and satisfaction with management) collected longitudinally were compared among the 4-time points. Gender-specific analysis was performed to look for any difference between boys and girls.

Results:

Mean numbers of months among visits were 8.99 (between 2nd and 3rd), 8.42 (between 3rd and 4th), and 7.89 (between 4th and 5th). Function, pain, and satisfaction with management scores were significantly decreased in the 3rd year during bracing and increased steadily afterward. Gender-specific analysis showed female patients experienced similar changes in function, pain and satisfaction at the 3rd year.

Conclusions:

Function, pain, and satisfaction scores were much affected at the 3rd year and recovered afterward. Gender difference was found and the same significant changes were found in female patients but not in male patients.
A Novel Technique of Stabilization of Supracondylar Femoral Dome Osteotomy with Proximal Humeral Locking Plate for Surgical Management of Genu Valgum Deformity
Authors: Mohindra Mukul , Gautam V. K. , Meena Amit , Gupta Navdeep , Desai Jagannath , Saikia Sumon Singphow
Published: June 2021

Background:

Genu valgum is a common deformity in the developing world. When the patient presents after a second growth spurt, corrective surgery remains the only treatment option. Different types of osteotomies and fixation methods have been described in the literature, but the choice of the method remains debatable. We evaluated the outcome of the proximal humeral locking plate used for stabilization of supracondylar femoral dome osteotomy (DO).

Methods:

In this prospective study, we performed 39 osteotomies for genu valgum deformity on 24 patients who satisfied inclusion criteria (15 bilateral and 9 unilateral) between May 2015 and May 2017. The mean age was 13 years (11–20), 16 were male and 8 were female patients. All patients underwent supracondylar femoral DO and stabilization with the proximal humeral locking plate. Informed consent was obtained from all patients. All patients were evaluated preoperatively and postoperatively by using the Bostman knee score, intermalleolar distance (IMD), tibiofemoral angle (TFA), and lateral distal-femoral angle (LDFA). Patients with a minimum follow-up of 2 years were included in the study.

Results:

The preoperative LDFA was 73.4 ± 2.1 which improved to 87.2 ± 0.6 postoperatively while clinical and radiological TFA improved from 19.7 ± 21 and 21.4 ± 2.1 to 7.3 ± 0.8 and 8.6 ± 0.8, respectively. The mean Bostman score improved significantly. Two patients (2 limbs) had a good score (20–27), while the rest had an excellent score (28–30). IMD, TFA, and LDFA also improved statistically significantly (P < 0.001). All the patients were satisfied with the cosmetic correction. There were no implant failures, re-operations, and any loss of correction.

Conclusion:

This novel technique of stabilizing supracondylar femoral DO with the proximal humeral locking plate is cost-effective and has encouraging early results.
Recurrent Complex Regional Pain Syndrome after Minor Hip Surgery
Authors: Kaplan Hüseyin , Güler Emel , Kirnap Mehmet
Published: June 2021

Complex regional pain syndrome (CRPS) Type I, a chronic pain disorder, occurs in the sequel of certain predisposing conditions. Recurrence may be observed in 4%–10% of cases in the same or another limb. There are no specific parameters to prevent CRPS after surgery or trauma. However, some authors have reported several recommendations about surgical techniques and Vitamin C supplementation. We report a case who had CRPS Type I history before and developed recurrent CRPS Type I in the lower limb due to surgery for osteonecrosis of the hip. We observed significant improvement with physical therapy and medication.
California earthquake history
Authors: T. Toppozada  , D. Branum
Published: June 2021

This paper presents an overview of the advancement in our knowledge of California's earthquake history since ~ 1800, and especially during the last 30 years. We first review the basic statewide research on earthquake occurrences that was published from 1928 through 2002, to show how the current catalogs and their levels of completeness have evolved with time. Then we review some of the significant new results in specific regions of California, and some of what remains to be done. Since 1850, 167 potentially damaging earthquakes of M ~ 6 or larger have been identified in California and its border regions, indicating an average rate of 1.1 such events per year. Table I lists the earthquakes of M ~ 6 to 6.5 that were also destructive since 1812 in California and its border regions, indicating an average rate of one such event every ~ 5 years. Many of these occurred before 1932 when epicenters and magnitudes started to be determined routinely using seismographs in California. The number of these early earthquakes is probably incomplete in sparsely populated remote parts of California before ~ 1870. For example, 6 of the 7 pre-1873 events in table I are of M = 7, suggesting that other earthquakes of M 6.5 to 6.9 occurred but were not properly identified, or were not destructive. The epicenters and magnitudes (M) of the pre-instrumental earthquakes were determined from isoseismal maps that were based on the Modified Mercalli Intensity of shaking (MMI) at the communities that reported feeling the earthquakes. The epicenters were estimated to be in the regions of most intense shaking, and values of M were estimated from the extent of the areas shaken at various MMI levels. MMI VII or greater shaking is the threshold of damage to weak buildings. Certain areas in the regions of Los Angeles, San Francisco, and Eureka were each shaken repeatedly at MMI VII or greater at least six times since ~ 1812, as depicted by Toppozada and Branum (2002, fig. 19).
The history of historical earthquake research in Germany
Authors: G. Grünthal
Published: June 2021

The paper summarizes the history of collecting and evaluating information on earthquakes in Germany. A rich literature mentioning historical and contemporary earthquakes has existed since the 16th century. Early earthquake catalogues began to appear in the middle of the 16th century, some of which report earthquakes in Germany dating back to the 9th century. Modern seismological views were introduced in connection with intense philosophical analysis of the 1755 Lisbon earthquake, which was largely observed in Central Europe. The 19th century was characterized by a tremendous increase in detailed earthquake studies as well as earthquake compilations in the form of catalogues. The most comprehensive non-parametric catalogues were created in the middle of the 20th century, while the first digital parametric catalogues were published in the 1980s. This was also the time when critical studies on the re-interpretation of historical earthquakes began. Only in the 1990s was such analysis made in a systematic manner resulting in numerous publications and the current development of a modern earthquake catalogue.
Earthquakes in India and the Himalaya: tectonics, geodesy and history
Authors: R. Bilham
Published: June 2021

The record of earthquakes in India is patchy prior to 1800 and its improvement is much impeded by its dispersal in a dozen local languages, and several colonial archives. Although geological studies will necessarily complement the historical record, only two earthquakes of the dozens of known historical events have resulted in surface ruptures, and it is likely that geological data in the form of liquefaction features will be needed to extend the historical record beyond the most recent few centuries. Damage from large Himalayan earthquakes recorded in Tibet and in Northern India suggests that earthquakes may attain M = 8.2. Seismic gaps along two-thirds of the Himalaya that have developed in the past five centuries, when combined with geodetic convergence rates of approximately 1.8 m/cy, suggests that one or more M = 8 earthquakes may be overdue. The mechanisms of recent earthquakes in Peninsular India are consistent with stresses induced in the Indian plate flexed by its collision with Tibet. A region of abnormally high seismicity in western India appears to be caused by local convergence across the Rann of Kachchh and possibly other rift zones of India. Since the plate itself deforms little, this deformation may be related to incipient plate fragmentation in Sindh or over a larger region of NW India.
Self-potential chenges associated with volcanic activity: Short-term signals associated with March 9, 1998 eruption on La Fournaise volcano (Reunion Island)
Authors: J. Zlotnicki  , J. L. Le mouel  , Y. Sasai  , P. Yvetot  , M. H. Ardisson
Published: June 2021

After six years of quietness La Fournaise volcano entered into activity on March 9, 1998. Fissures opened gradually downwards on the northern flank of the cone. Two cones, Kapor and Krafft built, from which lava poured until September 1998. Several other vents opened during this eruption. Mappings, surveys, and continuous recordings of the Self-Potential have been performed on the volcano for twenty years. SP mappings disclose the variability of large scale SP anomalies due to the modification of the hydrothermal system over some ten years. Most of the eruptions take place along a Main Fracture Zone (MFZ) in which ground water flows prevail. SP measurements have also regularly been made on the northern flank of the cone, on a west-east profile crossing the MFZ. Between 1981 and 1992 an enlargement and a shift of the MFZ to the east are evidenced. In particular, the eastern fissural axis trending N35°E could be related to the possible collapse of the east flank of the volcano. After a decrease between 1992 and 1997, the SP anomaly was enhanced again by the 1998 eruption. Short scale, about 250 m wide, 750 mV amplitude anomalies were superimposed on a large scale one, 2500 m wide, and about 250 mV in amplitude. For several years, continuous stations have been measuring the electric field along two directions, with a 20 s sampling, in order to record the genesis of SP signals associated with the volcanic activity. Oscillations belonging to the ULF band were evidenced several days before the 1988 eruption, some of them at 9 km from the summit. Their amplitude reached several tens mV/km. These oscillations sometimes present a phase lag from one station to another; they progressively shift towards the location of the future effusive vents. The polarisation of the oscillations is similar to the polarisation of longer SP variations (1 h period or more) and are correlated with the structural anisotropy. Finally, during the last hours preceding the effusive activity, huge SP signals, up to a few Volts/km, appeared at the stations located on the MFZ, and especially on the branch where the magma migrated. We interpret these SP signals as due to electrokinetic effects generated by fluid flow in cracks opened by the stress field changes.
The impact of a and b value uncertainty on loss estimation in the reinsurance industry
Authors: D. Liechti  , E. Ruettener  , S. Eugster  , R. Streit
Published: June 2021

In the reinsurance industry different probabilistic models are currently used for seismic risk analysis. A credible loss estimation of the insured values depends on seismic hazard analysis and on the vulnerability functions of the given structures. Besides attenuation and local soil amplification, the earthquake occurrence model (often represented by the Gutenberg and Richter relation) is a key element in the analysis. However, earthquake catalogues are usually incomplete, the time of observation is too short and the data themselves contain errors. Therefore, a and b values can only be estimated with uncertainties. The knowledge of their variation provides a valuable input for earthquake risk analysis, because they allow the probability distribution of expected losses (expressed by Average Annual Loss (AAL)) to be modelled. The variations of a and b have a direct effect on the estimated exceeding probability and consequently on the calculated loss level. This effect is best illustrated by exceeding probability versus loss level and AAL versus magnitude graphs. The sensitivity of average annual losses due to different a to b ratios and magnitudes is obvious. The estimation of the variation of a and b and the quantification of the sensitivity of calculated losses are fundamental for optimal earthquake risk management. Ignoring these uncertainties means that risk management decisions neglect possible variations of the earthquake loss estimations.
Algorithms for the inversion of lidar signals: Rayleigh-Mie measurements in the stratosphere
Authors: F. Masci
Published: June 2021

We report the features and the performances of the algorithms, developed at the Lidar Station of L'Aquila, for retrieving atmospheric parameters and constituents from elastic lidar signals. The algorithm for ozone retrieving is discussed in detail and checked with model lidar signals to take into account the numerical distortion on the profile. The performances of the aerosol backscattering ratio algorithm that includes the transmission loss due to the aerosol extinction are evaluated. A new algorithm developed to retrieve atmospheric temperature profiles from elastic lidar returns in the altitude range 30-90 km is also examined in detail.
Improved compilationof Antarctic Peninsula magnetic data by new interactive grid suturing and blending methods
Authors: A. Johnson  , S. Cheeseman  , J. Ferris
Published: June 2021

The utility of aeromagnetic and other geoscientific compilations on a range of scales, is well established for a wide variety of geological investigations. Aeromagnetic compilations, currently underway for the Antarctic continent are vital to take full advantage of existing aeromagnetic surveys and for planning new surveys of this relatively unknown continent. Grid compilation is often a time-consuming and subjective task, which requires considerable effort from the geoscientist involved. A new interactive grid compilation tool, GridKnit, is presented, which enables the operator to rapidly combine gridded data sets with high quality results. The system offers two methods: a conventional blending method and a new suturing method. The blending method distributes the errors between grids over the area of overlap, effectively 'feathering' one grid into the other. The suturing method uses an analysis of the wavelengths of the data mismatches to correct each grid by an amount proportional to that wavelength. Each method has been applied to data sets from the Bellingshausen Sea-Alexander Island area of Antarctica to produce the first coherent magnetic map of this remote region.
Observations of volcanic earthquakes and tremor at Deception Island - Antarctica
Authors: G. Alguacil  , J. C. Almendros  , E. Del Pezzo  , A. Garcia  , J. M. Ibañez  , M. La Rocca  , J. Morales  , R. Ortiz
Published: June 2021

Deception Island - South Shetlands, Antarctica is site of active volcanism. Since 1988 field surveys have been carried out with the aim of seismic monitoring, and in 1994 a seismic array was set up near the site of the Spanish summer base in order to better constrain the source location and spectral properties of the seismic events related to the volcanic activity. The array was maintained during the Antarctic summer of 1995 and the last field survey was carried out in 1996. Data show the existence of three different groups (or families) of seismic events: 1) long period events, with a quasi-monochromatic spectral content (1-3 Hz peak frequency) and a duration of more than 50 s, often occurring in small swarms lasting from several minutes to some day; 2) volcanic tremor, with a spectral shape similar to the long period events but with a duration of several minutes (2-10); 3) hybrid events, with a waveform characterised by the presence of a high frequency initial phase, followed by a low frequency phase with characteristics similar to those of the long period events. The high frequency phase of the hybrid events was analysed using polarisation techniques, showing the presence of P waves. This phase is presumably located at short epicentral distances and shallow source depth. All the analysed seismic events show back-azimuths between 120 and 330 degrees from north (corresponding to zones of volcanic activity) showing no seismic activity in the middle of the caldera. Particle motion, Fourier spectral and spectrogram analysis show that the low frequency part of the three groups of the seismic signals have similar patterns. Moreover careful observations show that the high frequency phase which characterises the hybrid events is present in the long period and in the tremor events, even with lower signal to noise ratios. This evidence suggests that long period events are events in which the high frequency part is simply difficult to observe, due to a very shallow source and/or hypocentral distance higher than that of hybrids, while the tremor is composed of rapidly occurring hybrid events. We propose a possible interpretation for the three groups of seismic events. These may be generated by multiple pressure-steps due to the rapid phase change from liquid to vapour in a shallow aquifer which comes in contact with hot materials. The pressure change can put a crack in resonance or excite the generation of multiple surface waves modes in the shallow layered structure.
Seismic hazard assessment in the Ibero-Maghreb region
Authors: M. J. Jiménez  , M. García-Fernández
Published: June 2021

The contribution of the Ibero-Maghreb region to the global GSHAP map has been the result of a fruitful cooperation among the participants in the established Working Group including representatives from Algeria, Morocco, Portugal, Spain and Tunisia and coordinated by ICTJA-CSIC, Spain. For the first time, a map of regional seismic source zones is presented, and agreement on a common procedure for hazard computation in the region has been achieved. The computed Ibero-Maghreb seismic hazard map constitutes the first step towards a uniform hazard assessment for the region. Further joint regional efforts are still needed for earthquake hazard studies based on a homogeneous regional earthquake catalogue. Ongoing initiatives in relation to seismic hazard assessment in the Mediterranean should profit both from these results and the established cooperation among different groups in the region as well as contribute to future regional studies.
Seismic hazard assessment for the Caucasus test area
Authors: S. Balassanian  , T. Ashirov  , T. Chelidze  , A. Gassanov  , N. Kondorskaya  , G. Molchan  , B. Pustovitenko  , V. Trifonov  , V. Ulomov  , D. Giardini
Published: June 2021

The GSHAP CAUCAS test area was established under the INTAS Ct.94-1644 (Test Area for sismic Hazard Assessment in the Caucasus) and NATO ARW Ct.95-1521 (Historical and Prehistorical Earthquakes in the Caucasus), with the initial support of IASPEI, UNESCO and ILP. The high tectonic interest and seismicity rate of the whole area, the availability of abundant multi-disciplinary data and the long established tradition in hazard assessment provide a unique opportunity to test different methodologies in a common test area and attempt to establish some consensus in the scientific community. Starting from the same input data (historical and instrumental seismic catalogue, lineament and homogeneous seismic source models) six independent approaches to seismic hazard assessment have been used, ranging from pure historical deterministic to seismotectonic probabilistic and areal assessment methodologies. The results are here compared.
Global Seismic Hazard Assessment Program (GSHAP) in continental Asia
Authors: P. Zhang  , Z. X. Yang  , H. K. Gupta  , S. C. Bhatia  , K. M. Shedlock
Published: June 2021

The regional hazard mapping for the whole Eastern Asia was coordinated by the SSB Regional Centre in Beijing, originating from the expansion of the test area initially established in the border region of China-India-Nepal-Myanmar- Bangla Dash, in coordination with the other Regional Centres (JIPE, Moscow, and AGSO, Canberra) and with the direct assistance of the USGS. All Eastern Asian countries have participated directly in this regional effort, with the addition of Japan, for which an existing national hazard map was incorporated. The regional hazard depicts the expected peak ground acceleration with 10% exceedance probability in 50 years.
The Global Seismic Hazard Assessment Program (GSHAP) - 1992/1999
Authors: D. Giardini
Published: June 2021

The United Nations, recognizing natural disasters as a major threat to human life and development, designed the 1990-1999 period as the International Decade for Natural Disaster Reduction (UN/IDNDR; UN Res. 42/169/ 1987). Among the IDNDR Demonstration Projects is the Global Seismic Hazard Assessment Program (GSHAP), launched in 1992 by the International Lithosphere Program (ILP) and implemented in the 1992-1999 period. In order to mitigate the risk associated to the recurrence of earthquakes, the GSHAP promoted a regionally coordinated, homogeneous approach to seismic hazard evaluation. To achieve a global dimension, the GSHAP established initially a mosaic of regions and multinational test areas, then expanded to cover whole continents and finally the globe. The GSHAP Global Map of Seismic Hazard integrates the results obtained in the regional areas and depicts Peak-Ground-Acceleration (PGA) with 10% chance of exceedance in 50 years, corresponding to a return period of 475 years. All regional results and the Global Map of Seismic Hazard are published in 1999 and available on the GSHAP homepage on http://seismo.ethz.ch/GSHAP/.
The Al Hoceima earthquake of May 26, 1994 and its aftershocks: a seismotectonic study
Authors: S. O. El Alami  , B. A. Tadili  , T. E. Cherkaoui  , F. Medina  , M. Ramdani  , L. A. Brahim  , M. Harnafi
Published: June 2021

The present paper focuses on the moderate earthquake that occurred on May, 26, 1994, at 8 h 27 min, which caused great damage and two deaths. The epicentre of the main shock was located at 35.280N, 3.990W. The focal depth was 13 km, and the magnitude (Md) attained 5.6. A field survey of the earthquake effects showed that the maximal intensity (VIII-IX EMS) follows an elongated corridor trending NNE-SSW, where 80% of the constructions were destroyed. During the 14-day survey carried out with the help of the temporary network established in the area, 512 shocks were located. The best constrained epicentres (68) are shallow and are largely distributed over a NNE-SSW trending cluster along an almost-vertical plane. Focal mechanisms determined for the main shock and for the 7 largest aftershocks, correspond to strike-slip faulting with a reverse (main shock and one aftershock) or normal component (6 events). The P axes have a NNW-SSE trend, with variable plunge, whereas the T axes are ENE-WSW with a slight plunge. The state of stress determined with the help of these mechanisms corresponds to a strike-slip regime with s1 oriented NNW-SSE and s3 ENE-WSW, which is in conformity with previous studies. The present study also shows that the Nekor fault remained inactive during the seismic crisis of 1994, as during the previous surveys, and this casts some doubt on the present-day role of this major fault. Instead, as proposed by some authors, a seismic zone trending NNE-SSW may be related to the faults of the same trend that appear to cross the Al Hoceima area towards the Alboran Sea.
Evolution of the ionosonde
Authors: K. Bibl
Published: June 2021

Almost 60 years development of ionosondes and their data processing capabilities are described with emphasis on the authors contributions from the early beginnings of ionospheric studies to the latest digital equipment to be used for the exploration of the magnetosphere.
Ionospheric drift measurements with ionosondes
Authors: B. W. Reinisch  , J. L. Scali  , D. L. Haines
Published: June 2021

In the last forty years many attempts have been made to measure ionospheric plasma motions with HF radio sounders, generally specialized ionosondes. Starting in the 1950's, the so-called similar fading and the correlation methods were applied to estimate the velocities in the ionosphere. More recently, the interferometric Doppler technique was introduced which successfully measured ionospheric drifts that were verified by incoherent scatter radar measurements. The latter technique is discussed in some detail in this paper.
Fault plane solutions of the 1993 and 1995 Gulf of Aqaba earthquakes and their tectonic implications
Authors: A. K. Abdel-Fattah  , H. M. Hussein  , E. M. Ibrahim  , A. S. Abu El Atta
Published: June 2021

The stereographic projection of P-wave first motions for the 3 August 1993 Gulf of Aqaba earthquake, its largest aftershock (16 h 33 min), and for the 22 November 1995 earthquake were constructed using the polarity readings of regional and teleseismic stations. The focal mechanism solutions of the 3 August 1993 mainshock and its largest aftershock represent a normal faulting mechanism with some left lateral strike slip component. The nodal planes selected as the fault imply high similarity in strike and dip. They are related to a local fault striking NW-SE and dipping to the SW. The selected fault planes are in good agreement with the aftershock distribution. For the main shock of the 22 November 1995, the fault plane solution displays the same mechanism (normal faulting with left lateral strike slip component) with a plane striking N-S and dipping to the west. The fault plane is greatly conformable with the direction of the regional tectonics and also with the aftershock distribution. The main trend of the extension stress pattern is in a NE-SW direction, corresponding to the rifting direction of the Gulf of Suez and may be related to the paleostress along the Gulf of Suez and Aqaba during the Middle to Late Miocene.
Correlation between macroseismic intensities and seismic ground motion parameters
Authors: G. F. Panza  , R. Cazzaro  , F. Vaccari
Published: June 2021

We propose correlation relations between the macrosesimic intensity felt in Italy and displacement, velocity, acceleration, design ground acceleration obtained from synthetic seismograms modelling the ground motion generated by past seismicity. The results are in good agreement with empirical relations given by other authors and compare quite well with the few observations available in the Italian territory.
Quaternary tectonic activity of the Murge area (Apulian foreland -Southern Italy)
Authors: P. Pieri  , V. Festa  , M. Moretti  , M. Tropeano
Published: June 2021

Integration of structural, stratigraphical, and sedimentological data and instrumental records of some recent low-energy seismic events in the Murge area allow us to suggest a new seismotectonic picture of this region, generally considered an aseismic and stable sector of the Apulian foreland.
Generation of electric field in an earthquake preparation zone
Authors: R. Teisseyre
Published: June 2021

Different attempts have been made to explain the generation of the electric currents before an earthquake that take place in an earthquake preparation zone; in some of them the coseismic effects are also included. In this paper we discuss the possibility to construct a model of displacement current generation in an earthquake source zone which combines polarization processes and motion of charged dislocations. Such a process is associated with the transition from isotropic to stress-induced anisotropic properties in an earthquake source zone. Concurrently, we consider the conduction currents related to a high velocity motion of charged dislocations. Another approach related to an electrokinetic model of current generation is also briefly discussed.
Geoelectrical study of archaeological structures in the Himera plane (North-western Sicily)
Authors: P. Cosentino  , D. Luzio  , E. Rotigliano
Published: June 2021

This paper presents the results obtained from a geoelectrical study carried out on the Himera plane for archaeological research. Both the tripotential method and the dipole-dipole profile method have been used on a 40 m ´ 40 m investigation area in order to obtain several resistivity maps. The latter show different geoelectrical anomalies, the shape of which allows us to interpret simple archaeological structures, consistent with current knowledge of ancient Himera sites. Furthermore, the study of the whole set of data in the resistivity domain has allowed us to infer some other characteristics from the subsequent geological process of alluvial covering of the site.
On the use of earthquake multiplets to study fractures and the temporal evolution of an active volcano
Authors: G. Poupinet  , A. Ratdomopurbo  , O. Coutant
Published: June 2021

Multiplets, i.e. events with similar waveforms, are common features on active volcanoes. The seismograms of multiplets are analyzed by cross-spectrum techniques: this procedure improves by a factor of about 10 the precision of differential P-arrival times and therefore the accuracy of the relative location of earthquakes. Long period events which cannot be located because of the impossibility to pick up P-waves on individual seismograms can be located with a precision of about 10 m. Such a precision permits fault planes to be mapped inside a volcanic edifice and the azimuth and strike of fractures to be defined. Seismograms of the two events (of a doublet) that occur on different dates are analyzed by the Cross Spectrum Moving Window technique (CSMW) for measuring the time delay between waves in the coda. The pattern of the delays in the coda is a function of the temporal changes of seismic velocity that occurred inside the volcano during the time interval that separates the two events of a doublet. We illustrate the potential of the doublet technique for detecting temporal changes inside a volcano by performing computations of synthetic seismograms. The case of a dyke injected inside the volcano is considered as well as that of the replenishment of a superficial magma chamber and of a general increase in velocity in the summit of the volcano. Data from Merapi volcano (Indonesia)illustrate a possible temporal velocity change inside the volcano several months before the 1992 eruption.
The seismicity of the British Isles
Authors: R. M. W. Musson
Published: June 2021

A new and homogeneous catalogue of earthquakes in the British Isles has been produced, including events of magnitude 4 ML and greater to 1700 and events of 3 ML and greater thereafter. The distribution of seismicity is uneven, with some areas (e.g Ireland) almost aseismic. Magnitude/frequency analysis shows that a double-tl.uncated exponential distribution gives a better fit than a classic Gutenberg-Richter linear fit. Thecacnlated b value for the linear part of the exponential distribution is 0.94 with a maximum magnitude of 6.2 ML.
Mid-point electron density profiles from oblique ionograms
Authors: X. Huang  , B. W. Reinisch  , W. S. Kuklinski
Published: June 2021

A computationally efficient technique for the inversion of oblique ionograms into mid-point electron density profiles is described. The profile is given as the sum of quasi-parabolic functions suitable for ray tracing. The CPU time for a 486 desk top computer is 30 s.
Compatible analysis of vertical and oblique ionospheric sounding data
Authors: I. V. Krasheninnikov  , J. C. Jodogne  , L. F. Alberca
Published: June 2021

Examples are presented of the ray-tracing synthesis of multifrequency Oblique Sounding (OS) data on the Dourbes (Belgium) í Roquetes (Spain) path using electron density height profiles derived from Vertical Sounding (VS) measurements at both terminals. Comparison with the measured OS ionograms provides a means of assessing the accuracy of the VS true-height procedure POLAN. Particular attention was paid to a consideration of the E-F1 valley, that as concluded is often less deep than currently supposed, when derived using both ordinary and extraordinary components of the VS ionograms. Also, it was found that the peak of the F1 -layer should be expressed more distinctly (sometimes with a small valley between the F1 and F2 layers) though the corresponding VS ionograms may have no discontinuity in the region.
Historical cities and earthquakes: Florence during the last nine centuries and evaluations of seismic hazard
Authors: E. Guidoboni  , G. Ferrari
Published: June 2021

The authors' aim in the following study is to contribute to the assessment of the seismic hazard of historical cities. From this preliminary analysis the general characteristics of the seismicity affecting Florence and the evaluation of its seismic hazard may be deduced. Florence is a <> city of world tourism, and its extraordinary artistic value and its ability to be utilized constitute a great economic resource. From this perspective, the authors have tackled some aspects of its urban features (demography and main building types, successive phases in the growth of the city, etc.), aimed at the pooling of information as a basis for further, more specific analyses of seismic risk. The study is based on a review of 131 seismic events of potential interest for the site of Florence from the 12th century. In the case of each of these earthquakes, it was possible to verify the real seismic effects sustained, and thus to assess the seismic intensity on the site. This also enabled the limits in the application of the standard attenuation laws of to be checked. Of all the earthquakes analyzed. those which caused the greatest effects on the urban area have also been identified: namely, the earthquake of 28 September 1453. and those of 18 May and 6 June 1895, both with Io=VIII MCS. From their overall analysis the authors have further extrapolated the necessary data to statistically evaluate the probabilities of any future earthquake occurring, according to intensity classes.
A hypothesis on earthquakes and political power in Minoan Crete
Authors: V. La Rosa
Published: June 2021

The seismic destruction of the first Minoan palace at Phaistos is preliminarily confirmed. The hypothesis is then proposed that a change in the relationships a~nongth e powers in the Messarh plain was also produced by the different capacity of the Phaistos centre to react to the 1700 B.C. seismic effects, as compared to that of Knossos. This trend is thought to have continued after the second earthquake of the middle(?) of the XVII century B.C., indirectly confirming Knossian leadership in the island's entire central region during the age of the second palaces.
Collapses and seismic collapses in archaeology: proposal for a thematic atlas
Authors: E. Guidoboni  , S. Santoro Bianchi
Published: June 2021

The problem of how to recognise seismic collapse lies at the basis of the possibility of using archaeological sources in the rield of historical seismology. Hitherto this problem has been approached in an arbitraiy and subjectile manner, because there exists no systematic collection of data which permits access to a specific series of case histories in the field of archaeological collapse, distinguishing their numerous causes. The problein is also posed because archaeological techniques are by nature ~destructivena, nd important seismic traces may disappear and no longer be utilizable in the scientific sphere. The authors point our this documentary lacuna, and propose the compilation oT a thematic atlas on seismic collapses in archaeology: a new disciplinary tool. which may also prove useful for those concerned with the protection and conservation of archaeological areas
The Southeastern Sicily GPS network
Authors: V. Achilli  , M. Anzidei  , P. Baldi  , F. Broccio  , R. Velardita
Published: June 2021

The area located between Catania and Syracuse (Southeastern Sicily), characterised by the presence of the Simeto-Scordia-Lentini graben, was affected in the past by a strong seismicity as proved by the occurrence of seismic events strong enough to reach the XI degree of the MCS scale. In particular the January 11 th, 1693 (l = XI MCS) earthquake with a magnitude over 7.5 (estimated), caused huge damage and a great loss of human lives. Following the last seismic event which occurred on December 13th, 1990 (Ml = 5.4) which caused heavy damage and many victims in the Catania-Syracuse area, a geodetic Global Positioning System network (GPS) was set up with the aim of monitoring ground movements in one of the Italian areas subjected to high seismic risk, This "pace geodesy technique supplies high precision measurements and represent, a powerful new tool for investigating both regional stress fields and the evolution of local tectonic areas. The GPS network will allow the detection of ground movements with a centimetric accuracy through repeated surveys in time. The results obtained in two surveys carried out il1 1991 al1d 1993, are described in this paper.
Sporadi-E layer and metereological activity
Authors: C. Scotto
Published: June 2021

Obscrvations of Es laycr performed at the ionospheric observatory of Rome from 1982 to 1989 have been used to investigate a possible correlation with cold front passages. Such a correlation may exist because of the AGW excited by tropospheric activity at cold front passages. A relationship with thunderclouds electrostatic field is also marginally considered. The treatment of data shows that the distributions of the frequencies of renection at cold front passages present only small differences compared to normal days, both for the f and for the I type; therefore, a correlation between Es layer anù meteorological activity cannot be affirmed.
The 1990.0 magnetic repeat station survey and normal reference fields for Italy
Authors: A. Meloni  , O. Battelli  , A. De Santis  , G. Dominici
Published: June 2021

A survey of 116 repeat stations of the Italian Magnetic Network was carried out between 1989 and 1992. We describe the characteristics of the selected network repeat station sites, the characteristics of the measuring equipment, the data reduction procedure and the analysis in terms of normal field, data mapping and secular variation. Together with the values from our previous campaigns, we also determined, for all elements, the normal fields of secular variation. The new repeat station data are listed. Results, maps and normal fields are discussed with respect to previous work and future survey plans.
Seismogenic structure behaviour revealed by spatial clustering of seismicity in the Umbria-Marche Region (Central Italy)
Authors: P. Tosi
Published: June 2021

Time variations in the spatial distribution of earthquake epicentres are analyzed by application of the fractal correlation dimension method. The zone under investigation is located in Central Italy, bounded in longitude by 12.0 and 14.4 degrees east and in latitude by 42.0 and 43.6 degrees north. From 1st January 1978 to 5th October 1997, 2028 events with a magnitude above Ml= 2.5 constitute the database.Evolution of the spatial fractal dimension Ds permits the identification of seismic cycles that are connected to the occurrence of main earthquakes.In particular, it is possible to recognize a division within each cycle, between a period of random background seismicity and a spatial clustering of events where shocks of magnitude Ml ³occur. Moreover, the decrease in Ds prior to such events, evidences a structural relationship between foreshocks and the occurrence of a main shock, even if not in close territorial proximity.This feature indicates a new, more extensive definition of seismogenic structure which can includes several interconnected structures within a large area.
Boundaries of magnetic anomaly sources in the Tyrrhenian region
Authors: F. Cella  , M. Fedi  , G. Florio  , A. Rapolla
Published: June 2021

Analysis of the analytic signal of the aeromagnetic field in the Tyrrhenian region allowed the systematic location of the boundaries of magnetic shallow sources. This method was chosen because of its independence from the magnetization and inducing field direction, and the results were similar to those of the boundary analysis of the horizontal gradient of the pseudogravity transformed field. The analytic signal was computed by a stable algorithm based on the second order horizontal derivatives of the field and Laplace equation. The complexity of the investigated area is well reflected in the aeromagnetic field and an objective and systematic study, such as boundary analysis, provided a rather complete description of the main regional structures. Significant trends indicated the existence of structures, whose nature was still unknown or uncertain. These included structures located between the Vavilov and De Marchi seamounts, NW of Stromboli Island, south of Ponza Island, a buried horst immediately south of the Cilento coastline, a body located northwest of the Cassinis seamount and other small magnetized structures located south of the Tuscanian archipelago. In many cases, a better definition of several structures previously recognized was obtained as in the case of some tectonic alignments (e.g., the Elba ridge, the Romolo and Selli lines, etc.), a large number of igneous seamounts (e.g., Magnaghi, Marsili, Vavilov, Anchise, Quirra, Enarete, Eolo and Sisifo seamounts) and several crystalline outcrops (e.g., Ichnusa, Vercelli, M. della Rondine, Tiberino, Cassinis, Traiano, Glauco and Augusto seamounts).
GDS (Geomagnetic Depth Sounding) in Italy: applications and perspectives
Authors: D. Di Mauro  , E. Armadillo  , E. Bozzo  , V. Cerv  , A. De Santis  , M. Gambetta  , A. Meloni
Published: June 2021

The analysis of geomagnetic field variations is a useful tool to detect electrical conductivity contrasts within the Earth. Lateral resolution of outlined patterns depends on the array dimensions and density of measurement sites over the investigated area. The inspection depth is constrained by the period of geomagnetic variations considered in data processing. Regions with significant geological features such as boundaries of continental plates, marginal areas of contact between tectonic units or other geodynamical processes, are of primary interest for the application of the MagnetoVariational (MV) method. In the last ten years, in the frame of the ElectroMagnetic (EM) sounding techniques in applied geophysics, this method has been applied in Italy by researchers of the Istituto Nazionale di Geofisica, Rome, the Dipartimento di Scienze della Terra, Universitá di Genova and the Czech Science Academy of Prague. The Ivrea body in the Northwestern Alps and their junction with the Apennine chain, the micro-plate of the Sardinian-Corsican system and, recently, the central part of the peninsula along Tyrrhenian-Adriatic lithospheric transects were investigated. Studies in time and frequency-domain used in the first investigations, have been followed by more refined analysis involving tests on the induced EM field dimension, computations of single site Transfer Functions (TFs) through Parkinson arrows' and Fourier maps in the Hypothetical Event technique (HE). It was possible to describe the electrical conductivity distribution in the inner part of the SW Alpine arc and to confirm the presence of lithospheric and asthenospheric anomalies obtained by other geophysical methods. For the Sardinia-Corsica system, 2D and 3D inversion models highlighted the existence of two major conducting bodies, one north of Corsica, and the other south of Sardinia. In Central Italy, the regional electrical conductivity distribution pointed out a deep conductive structure beneath the Apennines and a very resistive root for this part of the mountain chain.
FEMSA: a finite element simulation tool for quasi-static seismic deformation modeling
Authors: M. Volpe  , D. Melini  , A. Piersanti
Published: June 2021

We set up a computational tool to numerically model static and quasi-static deformation generated by faulting sources embedded in plane or spherical domains. We use a Finite Element (FE) approach to automatically implement arbitrary faulting sources and calculate displacement and stress fields induced by slip on the fault. The package makes use of the capabilities of CalculiX, a non commercial FE software designed to solve field problems (see  for details), and is freely distributed by request.