324,548 research outputs found
Correction to: Drill and Blast in Gypsum Quarries: Optimization of Technical, Economic, and Safety Aspects in “Monte Tondo” Mid-mountain Case Study (Mining, Metallurgy & Exploration, (2025), 42, 1, (99-113), 10.1007/s42461-024-01133-9)
No full textThe article Drill and Blast in Gypsum Quarries: Optimization of Technical, Economic, and Safety Aspects in “Monte Tondo” Mid mountain Case Study, written by Daniele Casertano, Francesco Tinti, Sara Kasmaeeyazdi, Vanessa Cellini, and Roberto Bruno was originally published under exclusive license to Society for Mining, Metallurgy & Exploration Inc. 2024 on 9 December 2024. As a result of the subsequent decision to publish the article under the open access model, the article’s copyright notice was changed on 29 December 2025 to © The Author(s) and the article is now distributed under a Creative Commons Attribution CC BY
Influence of topography on coseismic displacement induced by the Friuli 1976 and the Irpinia 1980 earthquakes (Italy) analyzed through a two-dimensional hybrid model
No full textWe investigate the perturbations introduced by the local topography on the coseismic displacement components induced by crustal seismic faults. The approach, proposed by Tinti and Armigliato [2002], is applicable to homogeneous two-dimensional domains with arbitrary topography of the free surface. It uses both analytical results, valid for homogeneous spaces and half-spaces bounded by a flat free surface (FFS), and a numerical code solving the equations of equilibrium of linear elasticity through a finite element (FE) scheme. A major characteristic of our "hybrid" method is that it allows for the correct representation of the displacement components in correspondence with the fault, which does not need to be explicitly introduced in the FE mesh. We show that, in the case of homogeneous domains, this makes our approach preferable to pure FE schemes. Our hybrid approach is here applied to two different disastrous events of the recent Italian seismic history, for which topography is expected to play an important role, namely the 6 May 1976 (MS = 6.5) Friuli and the 23 November 1980 (MS = 6.9) Irpinia-Basilicata earthquakes. For each event, we selected hypotheses for the parent fault proposed in the literature and compared the coseismic displacements computed through the widely used analytical models dealing with FFS and through our hybrid approach, accounting for the effect of realistic topographies. The most relevant effects are observed in the case of the Irpinia earthquake: depending on the profile chosen, the computed misfits can be as high as 19 and 13% for the horizontal and vertical displacements, respectively, with absolute differences up to 9 and 10 cm. Copyright 2003 by the American Geophysical Union
The estimation of b-value of the frequency-magnitude distribution and of its 1σ intervals from binned magnitude data
No full textThe estimation of the slope (b-value) of the frequency-magnitude distribution of earthquakes is based on a formula derived by Aki decades ago, assuming a continuous exponential distribution. However, as the magnitude is usually provided with a limited resolution, its distribution is not continuous but discrete. In the literature, this problem was initially solved by an empirical correction (due to Utsu) to the minimum magnitude, and later by providing an exact formula such as that by Tinti and Mulargia, based on the geometric distribution theory. A recent paper by van der Elst showed that the b-value can be estimated also by considering the magnitude differences (which are proven to follow an exponential discrete Laplace distribution) and that in this case the estimator is more resilient to the incompleteness of the magnitude data set. In this work, we provide the complete theoretical formulation including (i) the derivation of the means and standard deviations of the discrete exponential and Laplace distributions; (ii) the estimators of the decay parameter of the discrete exponential and trimmed Laplace distributions and (iii) the corresponding formulas for the parameter b. We deduce (iv) the standard 1 sigma intervals for the estimated b. Moreover, we are able (v) to quantify the error associated with the Utsu minimum-magnitude correction. Furthermore, we have discussed the formulas to produce statistically independent magnitude differences. We tested extensively the b-value estimators on simulated synthetic data sets including complete catalogues as well as catalogues affected by a strong incompleteness degree such as aftershock sequences where the incompleteness is made to vary from one event to the next. We have also analysed the real aftershock sequence of the 30/10/2016 Norcia (central Italy) to integrate the finding of the simulations. To judge the performance of the various estimators we have introduced an index p that can be seen as a non-parametric extension of the Student's t index. The main outcomes of this paper are that (1) the b-value estimators devised for continuous magnitude data are not adequate for binned magnitudes, (2) for complete data sets, estimators based on magnitudes and on magnitude differences provide substantially equivalent results, (3) for incomplete magnitude data sets, estimators based on magnitude differences provide better results and (4) for incomplete aftershock sequences there is no evidence that methods based on positive magnitude differences are superior than other methods using differences. This conclusion is further confirmed by our analysis of the above-mentioned Norcia seismic sequence. This last finding contrasts with the van der Elst's claim that the so called method is the most adequate to treat real aftershock sequences
Comment on "On the cause of the 1908 Messina tsunami, southern Italy" by Andrea Billi et al
No full textIntroduction: [1] The December 28th 1908 Messina Earthquake has been ranked as one of the most destructive events of the last centuries [Davison, 1936] The damages produced by ground shaking were aggravated by the effects of a remarkable tsunami, with up to 11 m of run-up height, that followed the earthquake [Omori, 1909; Baratta, 1910; Tinti et al., 2004]. The location of the causative fault is still a matter of debate [e.g., Argnani et al., 2009], the modelling of the associated tsunami [Tinti and Armigliato, 2003] allowing uncertainty. [2] Billi et al. [2008] have recently proposed that the tsunami that stroke the coast of the Strait in December 1908 originated from a large submarine landslide (20 km3) located offshore Giardini-Naxos. The hypothesis is based on the study of tsunami arrival times [Platania, 1909; Baratta, 1910] and is supported, according to Billi et al. [2008], by inspection of: a multibeam morphobathymetry [Marani et al., 2004] and of a crustal-scale seismic profile [Scrocca et al., 2004]. [3] The arguments of Billi et al. [2008], however, have weak points that cast doubt on their interpretation. But most importantly, data collected in the last few years by the authors of this comment (A. Argnani and F. Chiocci), and work on tsunami modelling (S. Tinti and his group) cast further doubt on the proposed hypothesis that a large submarine landslide that was caused by the 1908 earthquake is located offshore Giardini-Naxos. These issues will be discussed in the following
A new computational method based on the minimum lithostatic deviation (MLD) principle to analyse slope stability in the frame of the 2-D limit-equilibrium theory
No full textThe stability of a slope is studied by applying the principle of the minimum lithostatic deviation (MLD) to the limit-equilibrium method, that was introduced in a previous paper (Tinti and Manucci, 2006; hereafter quoted as TM2006). The principle states that the factor of safety <i>F</i> of a slope is the value that minimises the lithostatic deviation, that is defined as the ratio of the average inter-slice force to the average weight of the slice. In this paper we continue the work of TM2006 and propose a new computational method to solve the problem. The basic equations of equilibrium for a 2-D vertical cross section of the mass are deduced and then discretised, which results in cutting the cross section into vertical slices. The unknowns of the problem are functions (or vectors in the discrete system) associated with the internal forces acting on the slice, namely the horizontal force <i>E</i> and the vertical force <i>X</i>, with the internal torque <i>A</i> and with the pressure on the bottom surface of the slide <i>P</i>. All traditional limit-equilibrium methods make very constraining assumptions on the shape of <i>X</i> with the goal to find only one solution. In the light of the MLD, the strategy is wrong since it can be said that they find only one point in the searching space, which could provide a bad approximation to the MLD. The computational method we propose in the paper transforms the problem into a set of linear algebraic equations, that are in the form of a block matrix acting on a block vector, a form that is quite suitable to introduce constraints on the shape of <i>X</i>, but also alternatively on the shape of <i>E</i> or on the shape of <i>X</i>. We test the new formulation by applying it to the same cases treated in TM2006 where <i>X</i> was expanded in a three-term sine series. Further, we make different assumptions by taking a three-term cosine expansion corrected by the local weight for <i>X</i>, or for <i>E</i> or for <i>A</i>, and find the corresponding MLDs. In the illustrative applications given in this paper, we find that the safety factors associated with the MLD resulting from our computations may differ by some percent from the ones computed with the traditional limit-equilibrium methods
Contribution of tsunami data analysis to constrain the seismic source: The case of the 1693 Eastern Sicily earthquake
No full textThe January 11, 1693 eastern Sicily earthquake is comparable only with the December 28, 1908 Messina Straits event in the Italian seismic history as regards magnitude (ML ≅ 7), level of destruction and number of victims. The shock generated a strong tsunami, which hit the entire eastern coast of Sicily and particularly the town of Augusta. The problem of which fault was responsible for the earthquake is still open. Several hypotheses have been formulated in the literature on the basis of different kinds of geological, macroseismic and tectonic data, but a general agreement has not been reached yet. An important contribution to the discussion may come from the analysis of the tsunami data. In two previous papers (Piatanesi et al., 1996; Piatanesi and Tinti, 1998), the hydro-dynamical study of the tsunami based on finite-element (FE) numerical simulations was carried out taking into consideration mostly theoretical faults, i.e. faults selected for their significance in tsunami generation irrespective of the corresponding geological evidence. This paper has to be considered the continuation of the mentioned works. We have studied new sources proposed in the literature, consistent with macroseismic data and/or geological observations, and simulated the corresponding tsunamis. We also built a new FE grid introducing significant improvements in the coastline representation, and developed and applied a new algorithm in order to account for the effect of the sea-bottom topography on the tsunami initial condition. Some of the examined faults are located in the Scordia-Lentini (SL) graben region and intercept the coastline, others are placed in correspondence with the Hyblaean-Malta (HM) escarpment and run parallel or sub-parallel to the coast. The conclusion of our work is that none of these faults respects fully the available observations on tsunami, and that the faults exhibiting the best fit are those placed in the SL region. It is worth stressing that our results are important for the assessment of seismic and tsunami hazard/risk in eastern Sicily, keeping also in mind that the 1693 earthquake has been selected as the reference event for an earthquake-scenario study in Catania and in south-eastern Sicily, called 'Catania Project', funded by CNR/GNDT (Consiglio Nazionale delle Ricerche/Gruppo Nazionale Difesa dai Terremoti)
Optimization of the preselection algorithm for travel-time data inversion
No full textSeismic tomography based on body-wave travel-time inversion involves the solution of unstable problems in many applications, where the instabilities are chiefly due to the ill-conditioned mathematical operators that must be inverted in order to compute the wave-velocity fields. In problems where the region under study is discretized into cells with uniform velocity, an efficient way to mitigate the instabilities was proven to be an appropriate preselection of the seismic rays. In this paper an enhanced version of the preselection algorithm is given which essentially makes the selection procedure faster and more efficient
The Vajont landslide, 9th October 1963: Limit equilibrium model for slope stability analysis through the Minimum Lithostatic Deviation method
No full textFifty years ago the giant Vajont landslide slipped in the homonymous lake and caused a disaster. The purpose of this work is to apply classical limit-equilibrium methods as well as a the variant developed by Tinti & Manucci (2006, 2008) and called Minimum Lithostatic Deviation (MLD) method to analyse the stability of the Mt Toc flank from where the slide detached and to study the effect of the various factors influencing stability. The analysis was conducted on two profiles, one representing the west-side and one representing the east side of the slide, that were taken from the sliding surface as reconstructed by using pre-slide and post-slide topographic maps and by using suitable hypotheses from the literature on the shape of the hidden part of the surface (that is the surface that remained covered even after the slide occurrence). The analysis shows that the angle of friction is the most relevant parameter influencing the safety factor more than the material cohesion. The analysis shows further that the Vajont slide was close to instability. With data used in this paper, a drop of the basin level from 710 m a.s.l. down to 700 m a.s.l., in conditions of very high piezometric level (790 m a.s.l.) as can be produced by intense rainfall, may have the effect of drawing the safety factor below the critical line of 1 and give rise to instability
SERS characterization of self-assembling oligopeptides for tissue engineering
No full textEight alternating polar/non-polar peptides derived from the self-assembling peptide EAK-16 (Ac- AEAEAKAKAEAEAKAK-NH2) were examined in comparison with the EAK-16 parent form (peptide 1), both as-synthesized and after gamma-radiation treatment in oxidative environment (formation of ∙OH radical), to mimic the inflammation process occurring during the first phases of implantation. The peptides were studied for their possible use as biomimetic materials [1] due to their self-assembling properties and to the presence, in two of them, of the RGD sequence, an active modulator of cell adhesion. Previous investigations on titanium surfaces [2] demonstrated that some oligopeptides, i.e. EAK16 (peptide 1), peptide 3 (obtained by K→Orn substitution), peptide 5 (A→Abu substitution), peptide 7 (insertion at the N-terminus of the RGD sequence), and peptide 8 (RGD insertion and “scrambling” of the sequence) were not severely affected by the treatment and retained their prevalent structure. The other peptides, i.e. peptide 2 (obtained by E→D substitution), peptide 4 (E→D and K→Orn substitutions) and peptide 6 (A→Y substitution), underwent significant conformational changes (i.e. increase in the á-helix content). Interestingly, these same last 3 peptides were severely affected also by the radical attack induced by irradiation [3], changing their secondary structure and lateral chains interactions.
To better investigate the interaction between peptides and metallic surfaces, we carried out SERS experiments on silver nanoparticles. As regards the as-synthesized peptides, all of them interacted with the Ag colloid by the COO- lateral groups of aspartic or glutamic acid residues. Other observed interaction sites were:
- NH2/NH3+ of basic aminoacidic residues (lysine and/or ornithine) in peptides 3, 4 and 7;
- amide group in peptides 1, 2, 4 and 8;
- the aromatic ring of Tyr side chains in peptide 6.
As regards the peptides after irradiation, they still interact through the before-mentioned groups; however, those undergoing conformational changes showed differences in band intensities and positions (see Fig.1)
References
[1] A. Tinti, M. Di Foggia, P. Taddei, A. Torreggiani, M. Dettin, C. Fagnano, J. Raman Spetrosc. 39, 250 (2008)
[2] M. Di Foggia, P. Taddei, A. Torreggiani, M. Dettin, A. Tinti, J. Raman Spetrosc. 42, 276 (2011)
[3] M. Di Foggia, P. Taddei, A. Torreggiani, M. Dettin, A. Tinti, J. Raman Spetrosc. 44, 1446 (2013
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