Analysis of strong ground motions to evaluate regional attenuation relationships

Italian attenuation relationships at regional scale have been refined using a data set of 322 horizontal components of strong ground motions recorded mainly during the 1997-1998 Umbria-Marche, Central Italy, earthquake sequence. The data set includes records generated by events with local magnitude (M L ) ranging between 4.5 and 5.9, recorded at rock or soil sites and epicentral distance smaller than 100 km. Through a multiple step regression analysis, we calculated empirical equations for the peak ground acceleration and velocity, the Arias Intensity and for the horizontal components of the 5% damped velocity pseudo response spectra, corresponding to 14 frequencies ranging from 0.25 to 25 Hz. We compared our results with well known predictive equations, widely used on the national territory for Probabilistic Seismic Hazard Analysis. The results obtained in this study show smaller values for all the analyzed ground motion indicators compared to other predictive equations

Analysis of strong ground motions to evaluate regional attenuation relationships

Italian attenuation relationships at regional scale have been refined using a data set of 322 horizontal components of strong ground motions recorded mainly during the 1997-1998 Umbria-Marche, Central Italy, earthquake sequence. The data set includes records generated by events with local magnitude (M L ) ranging between 4.5 and 5.9, recorded at rock or soil sites and epicentral distance smaller than 100 km. Through a multiple step regression analysis, we calculated empirical equations for the peak ground acceleration and velocity, the Arias Intensity and for the horizontal components of the 5% damped velocity pseudo response spectra, corresponding to 14 frequencies ranging from 0.25 to 25 Hz. We compared our results with well known predictive equations, widely used on the national territory for Probabilistic Seismic Hazard Analysis. The results obtained in this study show smaller values for all the analyzed ground motion indicators compared to other predictive equations

Genotyping-by-sequencing of a melon (Cucumis melo L.) germplasm collection from a secondary center of diversity highlights patterns of genetic variation and genomic features of different gene pool.

Melon (Cucumis melo L.) is one of the most important horticultural species, which includes several taxonomic groups. With the advent of next-generation sequencing, single nucleotide polymorphism (SNP) markers are widely used in the study of genetic diversity and genomics. Results: We report the first successful application of genotyping-by-sequencing (GBS) technology in melon. We detected 25,422 SNPs by the analysis of 72 accessions collected in Apulia, a secondary centre of diversity in Southern Italy. Analyses of genetic structure, principal components, and hierarchical clustering support the identification of three distinct subpopulations. One of them includes accessions known with the folk name of 'carosello', referable to the chate taxonomic group. This is one of the oldest domesticated forms of C. melo, once widespread in Europe and now exposed to the risk of genetic erosion. The second subpopulation contains landraces of 'barattiere', a regional vegetable production that was never characterized at the DNA level and we show was erroneously considered another form of chate melon. The third subpopulation includes genotypes of winter melon (C. melo var. inodorus). Genetic analysis within each subpopulation revealed patterns of diversity associated with fruit phenotype and geographical origin. We used SNP data to describe, for each subpopulation, the average linkage disequilibrium (LD) decay, and to highlight genomic regions possibly resulting from directional selection and associated with phenotypic variation. Conclusions: We used GBS to characterize patterns of genetic diversity and genomic features within C. melo. We provide useful information to preserve endangered gene pools and to guide the use of germplasm in breeding. Finally, our findings lay a foundation for molecular breeding approaches and the identification of genes underlying phenotypic traits

Nuova formulazione delle procedure per la stima dell’intensità macrosismica da dati epicentrali o da risentimenti in zone vicine

Vengono presentate nuove relazioni empiriche, definite per il territorio italiano, per la stima dell’intensità in un dato sito a partire da informazioni epicentrali o relative a località vicine. Queste relazioni, espresse in forma probabilistica e quindi direttamente utilizzabili per la stima della pericolosità sismica, condividono la stessa formalizzazione e la medesima base informativa. In particolare, sono state seguite tre diverse strategie: le prime due hanno portato alla definizione di una relazione di attenuazione per la stima dell’intensità al sito da dati epicentrali utilizzando una forma parametrica rispettivamente Gaussiana e Binomiale; la terza analisi è stata invece mirata a definire le modalità di “correzione” del valore locale di intensità, dedotto dalle informazioni epicentrali, con dati di risentimenti osservati in località vicine al sito in esame

Valutazioni di pericolosità sismica in termini di intensità macrosismica utilizzando metodi di sito

Vengono presentate le stime di pericolosità sismica, in termini di intensità macrosismica, ottenute mediante l’approccio probabilistico proposto da Albarello e Mucciarelli (2002), basato sull’impiego dei dati documentari relativi agli effetti locali prodotti dai terremoti passati (storie sismiche di sito). I risultati forniti da questa procedura (approccio “di sito”), in termini di minimo valore di intensità caratterizzato da una probabilità di eccedenza inferiore al 10% in 50 anni (Iref), sono confrontati con quelli ottenuti sul territorio italiano tramite la metodologia “standard” di Cornell-McGuire. Per meglio comprendere i motivi delle differenze osservate tra le due stime e il ruolo di differenti basi informative, sono state prodotte diverse mappe di pericolosità. Stime di pericolosità a scala locale sono state inoltre effettuate nell’area dell’Etna dove, grazie a numerosi studi macrosismici di dettaglio, sono disponibili storie sismiche di sito particolarmente ricche

The momentum and photon energy dependence of the circular dichroic photoemission in the bulk Rashba semiconductors BiTeX (X = I, Br, Cl)

Bulk Rashba systems BiTeX (X = I, Br, Cl) are emerging as important candidates for developing spintronics devices, because of the coexistence of spin-split bulk and surface states, along with the ambipolar character of the surface charge carriers. The need of studying the spin texture of strongly spin-orbit coupled materials has recently promoted circular dichroic Angular Resolved Photoelectron Spectroscopy (cd-ARPES) as an indirect tool to measure the spin and the angular degrees of freedom. Here we report a detailed photon energy dependent study of the cd-ARPES spectra in BiTeX (X = I, Br and Cl). Our work reveals a large variation of the magnitude and sign of the dichroism. Interestingly, we find that the dichroic signal modulates differently for the three compounds and for the different spin-split states. These findings show a momentum and photon energy dependence for the cd-ARPES signals in the bulk Rashba semiconductor BiTeX (X = I, Br, Cl). Finally, the outcome of our experiment indicates the important relation between the modulation of the dichroism and the phase differences between the wave-functions involved in the photoemission process. This phase difference can be due to initial or final state effects. In the former case the phase difference results in possible interference effects among the photo-electrons emitted from different atomic layers and characterized by entangled spin-orbital polarized bands. In the latter case the phase difference results from the relative phases of the expansion of the final state in different outgoing partial waves.Comment: 6 pages, 4 figure

DETERMINISTIC SCENARIOS AS INPUT MOTION FOR LOSS ASSESSMENT

A predominantly deterministic viewpoint has been adopted for computing seismic ground motion both for urban areas (SP10) and infrastructures loss modeling (SP11) at three selected areas: the cities of Lisbon (Portugal) and Thessaloniki (Greece), and the metropolis of Istanbul (Turkey). The generation of earthquake ground motion scenarios involves both the particular choice of earthquake sources with associated fault rupture parameters, and the ensuing ground motion field calculated by an appropriate numerical tool, or empirically estimated, at a set of selected points within the urban area of interest. Ground shaking values are predicted for rock conditions and for two distinct frequency bands, i.e. the high frequency range (from 1.0 Hz to 4-5 Hz) in the case of damage evaluation for the vast majority of ordinary building, and the low frequency (≤ 2 Hz) more appropriate for lifeline system damage assessment. The advanced simulation techniques allowed to properly consider the finite fault effects and directivity, which imply extreme expected values, and they are capable of quantifying the spatial variability of the ground motion near the extended fault

Simulating earthquake scenarios in the European Project LESSLOSS: the case of the metropolitan area of Lisbon (MAL)

In the framework of the ongoing European project “LESSLOSS – Risk Mitigation for Earthquakes and Landslides” two sub-projects are devoted to earthquake disaster scenario predictions and loss modeling for urban areas and infrastructures. This paper is dealing with the sub-project 10, SP10, Task Programme “Scenario earthquake definitions for three cities”. Finite-fault seismological models are proposed to compute the earthquake scenarios for three urban areas – Istanbul (Turkey), Lisbon (Portugal) and Thessaloniki (Greece). For each case study, ground motion scenarios are developed for the most probable two events with different return periods, locations and magnitudes derived from historical and geological data. In this study, we simulate the accelerometric time series and response spectra for high frequency ground motion in the city of Lisbon and surrounding counties (Metropolitan Area of Lisbon), using two possible earthquake models: the inland source area of Lower Tagus Valley, M 5.7 (4.7) and a hypothesis of the offshore source area of the 1755 Lisbon, M 7.6. The non-stationary stochastic method RSSIM (Carvalho et al. 2004) and a new hybrid stochastic-deterministic approach, DSM (Pacor et al., 2005) are used in order to evaluate the ground shaking and to characterize its spatial variability. Then the site effects are evaluated by means of an equivalent stochastic non-linear one-dimensional ground response analysis of stratified soil profile units properly designed. Results are here presented in terms of PGA maps, for offshore and inland scenarios. The mean and worst shaking scenarios for the Metropolitan Area of Lisbon have been delineated at the bedrock. Local effects amplify the synthetic PGA values by approximately a factor of 2. This means that PGA values computed for bedrock in Lisbon city can increase from 0.12g up to 0.25g and up to 0.5g in surroundings, for the inland scenario, and from 0.045g up to 0.090g for a M7.6 offshore scenario

Task 5 - Potenza - Deliverable D17: Bedrock shaking scenarios

The main goal of this report is the computation of the bedrock seismic scenarios in the Potenza city (Southern Italy) to be used for evaluating damage scenarios (described in PS3-Deliverables D18-D19-D24). This area represents one of the prediction case studies, planned in the framework of Project S3 which aim is the production of ground shaking scenarios for high and moderate magnitude earthquakes. The area around Potenza was affected by several destructive earthquakes in historical time (Table 2.1.1) and a number of individual sources representing the causative faults of single seismic events with magnitude up to 7 were identified. Deeper and smaller faults are present very close to the Potenza city, generating events with M up to 5.7 (1990 Potenza earthquake). Due to the involved source-to-site distances (about 25 km) and to the computation resolution of the simulation techniques, the site is represented by a single point. In total 9 faults were identified and the deterministic shaking scenarios are computed for each of them. The following strategy is adopted to provide ground motions. We compute shaking scenarios at level 1, using a simplified simulation technique (DSM, Pacor et al.; 2005) for all the faults. By these simulations we identify the three faults (F3, F7. and F8) producing the maximum expected shaking at the Potenza city, in terms of peak ground acceleration, peak ground velocity and Housner intensity. Based on these results, simulations at level 2, using the broad band technique HIC (Gallovic and Brokeshova, 2007) have been performed at Potenza for F3, F7 and F8 sources. For the Potenza city, we decided to predict the shaking scenarios at level 2, in order to provide suitable estimates of the low frequency ground motion (e.g. velocity time series) and engineering parameters (e.g. Arias intensity) strictly related to the duration of the signals. For each source, we generated hundreds of rupture models varying slip distribution, nucleation points and rupture velocity, and for each model we simulated the acceleration time series by HIC. Then we computed the probability density functions (PDF) of the ground motion parameters (PGA, PGV, PGD, Arias and Housner intensities) and estimated several statistical quantities in order to select families of accelerograms to be used for damage analysis: mean and associated standard deviation, median, 75% percentile, 84% percentile, mode, minimum and maximum. Finally we provided to the engineering Research Unit 6 of this project three sets of 7 accelerograms, having ground motion parameters equal to the statistical requirements computed by the synthetic distributions. The first set includes 7 accelerograms (three components), each of them having PGA equal to the mean, median, mode, 75-percentile, 84-percentile, minimum and maximum values of the PGA distribution. The second set and third sets include 7 accelerograms (horizontal components only), having PGA and Housener Intensity in the neighborhood of the median values of the corresponding distributions. A further comparison of adopted procedure for the predicted ground motion at Potenza was performed with respect to stochastic ground motions generated with EXSIM method (Motazedian and Atkinson; 2005). Even if the scenarios modelling was carried out varying different kinematic parameters, the statistical parameter were quite similar. Finally to provide shaking scenarios in term of macroseismic intensity, we applied a probabilistic empirical approach, developed in Progetto DPC-INGV S1.Progetto INGV-DPC S3 “Scenari di scuotimento in aree di interesse prioritario e/o strategico”Published4.2. TTC - Scenari e mappe di pericolosità sismicaope

Simulating earthquake scenarios in the European Project LESSLOSS: the case of the metropolitan area of Lisbon (MAL)

In the framework of the ongoing European project “LESSLOSS – Risk Mitigation for Earthquakes and Landslides” two sub-projects are devoted to earthquake disaster scenario predictions and loss modeling for urban areas and infrastructures. This paper is dealing with the sub-project 10, SP10, Task Programme “Scenario earthquake definitions for three cities”. Finite-fault seismological models are proposed to compute the earthquake scenarios for three urban areas – Istanbul (Turkey), Lisbon (Portugal) and Thessaloniki (Greece). For each case study, ground motion scenarios are developed for the most probable two events with different return periods, locations and magnitudes derived from historical and geological data. In this study, we simulate the accelerometric time series and response spectra for high frequency ground motion in the city of Lisbon and surrounding counties (Metropolitan Area of Lisbon), using two possible earthquake models: the inland source area of Lower Tagus Valley, M 5.7 (4.7) and a hypothesis of the offshore source area of the 1755 Lisbon, M 7.6. The non-stationary stochastic method RSSIM (Carvalho et al. 2004) and a new hybrid stochastic-deterministic approach, DSM (Pacor et al., 2005) are used in order to evaluate the ground shaking and to characterize its spatial variability. Then the site effects are evaluated by means of an equivalent stochastic non-linear one-dimensional ground response analysis of stratified soil profile units properly designed. Results are here presented in terms of PGA maps, for offshore and inland scenarios. The mean and worst shaking scenarios for the Metropolitan Area of Lisbon have been delineated at the bedrock. Local effects amplify the synthetic PGA values by approximately a factor of 2. This means that PGA values computed for bedrock in Lisbon city can increase from 0.12g up to 0.25g and up to 0.5g in surroundings, for the inland scenario, and from 0.045g up to 0.090g for a M7.6 offshore scenario