86,924 research outputs found
On the preparatory processes of the M6.6 earthquake of June 17th, 2000, in Iceland
No full textA model is proposed to explain the spatial distribution of foreshocks of the June 17th 2000, Ms 6.6 earthquake in the South Iceland Seismic Zone (SISZ) and the high stress drop of the mainshock. Fluids of magmatic origin, ascending at near-lithostatic pressure through a low permeability layer perturb the regional stress field, inhibiting fluid flow laterally, where a high strength asperity is left. The asperity is modeled as elastic, embedded within a medium with low effective rigidity. Regional stresses due to tectonic motions are perturbed by the presence of the asperity, enhancing the production of hydrofractures and foreshocks in the NW and SE quadrants and increasing considerably the shear stress within the asperity, leading to the NS striking mainshock.
Citation: Bonafede, M., C. Ferrari, F. Maccaferri, and R. Stefansson (2007), On the preparatory processes of the M6.6 earthquake of June 17th, 2000, in Iceland, Geophys. Res. Lett., 34, LXXXXX, doi:10.1029/2007GL031391
How the differential load induced by normal fault scarps controls the distribution of monogenic volcanism
No full textUnderstanding shallow magma transfer and the related vent distribution is crucial for volcanic hazard. Here we investigate how the stress induced by topographic scarps linked to normal faults affects the distribution of monogenic volcanoes at divergent plate boundaries. Our numerical models of dyke propagation below a fault scarp show that the dykes tend to propagate toward and erupt on the footwall side. This effect, increasing with the scarp height, is stronger for dykes propagating underneath the hanging wall side and decreases with the distance from the scarp. A comparison to the East African Rift System, Afar and Iceland shows that (1) the inner rift structure, which shapes the topography, controls shallow dyke propagation; (2) differential loading due to mass redistribution affects magma propagation over a broad scale range (100-105-m). Our results find application to any volcanic field with tectonics- or erosion-induced topographic variations and should be considered in any volcanic hazard assessment
NOVEL SNP MARKERS FOR FINE MAPPING OF QSBM.UBO-2BS FOR RESISTANCE TO SOIL-BORNE CEREAL MOSAIC VIRUS (SBCMV)
No full textGenetic analysis of Soil-Borne Cereal Mosaic Virus (SBCMV) resistance in durum wheat was
carried out on two recombinant inbred line (RIL) mapping populations obtained from Meridiano
(resistant) x Claudio (susceptible) and Simeto (susceptible) x Levante (resistant) Italian elite
cultivars. The RILs were characterized for SBCMV response under severe infection conditions over
three consecutive years (2007-2009), as reported in Maccaferri et al. (2008 and 2011). Heritability
of the disease response was high, with h2 values always above 80%. Joined quantitative trait locus
(QTL) analysis pointed out the presence of a major quantitative trait locus (QSbm.ubo-2BS) in the
distal chromosome 2BS accounting for 60–90% of the phenotypic variation for symptom severity,
40–70% for virus concentration and 30-60% for grain yield. By means of meta-QTL analysis
QSbm.ubo-2BS was mapped as a unique QTL within a 2 cM-wide interval (LOD-2) close to the
DArT marker wPt-2106 and tagged by wmc661-gwm210-barc35. The addition of the Illumina 90K
SNPs array to the durum linkage maps allowed to map 36 gene-associated SNP markers flanking 1
cM on both sides the Mendelized QTL. The sequence of the wPt-2106 DArT clone was used to
obtain a diagnostic PCR-based assay based on both high resolution melting (HRM) analysis and
simple agarose gel electrophoresis (assay based on a 4 bp-indel) while the SNPs are being
transformed into fluorescent Kasp® marker assays. Up to now, seven functional Kasp® markers
have been obtained and re-mapped on the initial mapping populations. The distribution and
frequency of the resistant haplotype is being investigated in panels of elite durum wheat (Triticum
turgidum ssp. durum), cultivated emmer (Triticum dicoccum) and wild emmer wheat (Triticum
dicoccoides). Collectively, these results provide the basis for efficient marker-assisted selection of
resistance to SBCMV as well as the positional cloning of QSbm.ubo-2BS
Modeling the shape and velocity of magmatic intrusions, a new numerical approach
No full textNumerical code presented in the manuscript "Modeling the shape and velocity of magmatic intrusions, a new numerical approach" by S. Furst, F. Maccaferri and V. Pinel
Modeling the shape and velocity of magmatic intrusions, a new numerical approach
No full textNumerical code presented in the manuscript "Modeling the shape and velocity of magmatic intrusions, a new numerical approach" by S. Furst, F. Maccaferri and V. Pinel
Attività di promozione e comunicazione della ricerca ENEA ai diversi target interessati. Report 2024
No full textIl servizio REL-PROM (Promozione e comunicazione) dell’Unità Centrale Relazioni è così composto: Paola Giaquinto (Ricercatrice), Responsabile del Servizio Antonella Andreini (Collaboratore tecnico), Web designer Paola Carabotta (Collaboratore tecnico), Grafica Maurizio Giuliani (Collaboratore tecnico), Grafico Serena Lucibello (Funzionario di amministrazione), Web designer Flavia Maccaferri (Collaboratore tecnico), Grafica Flavio Miglietta (Collaboratore tecnico), Grafico Mirko Nobili (Funzionario di amministrazione), Video Editor Antonio Opromolla (Tecnologo) Massimo Palomba (Operatore tecnico), tipografo Stefano Restante (Collaboratore tecnico), informatico. Sulla base dell’esperienza maturata nel 2024, emergono alcune aree su cui concentrare l’attenzione per ottimizzare le future attività del Servizio REL-PROM (evidenziate con maggior chiarezza nelle Conclusioni del Rapporto): • la necessità di instaurare rapporti più efficaci con specifiche divisioni di alcuni Dipartimenti; • l’importanza di definire un piano strutturato di comunicazione e dissemination, con messaggi chiave e target ben delineati; • l’urgenza di implementare un sistema di monitoraggio per valutare gli impatti delle azioni di comunicazione intraprese. Il presente rapporto si articola in due sezioni principali: Macro-attività di ricerca ENEA: vengono illustrate le attività svolte, i messaggi chiave veicolati, i target raggiunti e le best practice emerse, sia a livello istituzionale che sui progetti di ricerca; Dettaglio dei servizi: sono analizzate le attività relative a fiere, grafica, editoria, video, stampa, web e fotografia, con una valutazione delle performance ottenute. Le conclusioni sintetizzano i punti di forza e le criticità del Servizio, individuando possibili strategie di miglioramento per il futuro
Rock-fluid interaction in the preparatory stage of earthquakes
No full textEffects of faulting on fluids permeating the crust have been documented in several
cases. The reverse effect of pressurized fluids in triggering seismicity was also observed
in connection with fluid re-injection experiments in deep wells. Since fluids
(e.g. H20,CO2 and Sulfur anhydrites) are continuously released by ascending
magma, we expect that they may influence significantly the seismic activity in volcanic
and geothermal regions. A model is devised for the upward migration of these
fluids from below the brittle-ductile transition within brittle crustal layers, subject to
high deviatoric stress imposed by tectonic motions. Fluids are thought to open their
way through small hydraulic fractures, within a medium endowed with low intrinsic
permeability: the appearance of fractures has no practical effect on fluid flow if the
intrinsic permeability K0 is relatively high (K0 > 1016 m2), but it alters the effective
permeability considerably if the intrinsic permeability is low (K0 < 10−17 m2). The
effective permeability Keff is found to be strongly pressure-dependent according to a
non-linear relationship: Keff may be order of magnitude higher than K0. As a result,
near lithostatic pore pressures are found to propagate from the brittle-ductile transition
through most of a low permeability layer, decreasing considerably the threshold
for failure, according to the modified Coulomb criterion. When the distribution of
hydrofractures crosses a discontinuity of elastic parameters, large stress changes are
induced along the stronger side of the discontinuity; these induced stresses enhance
fluid migration. Moreover, following the appearance of hydraulic fractures, the effective
elastic parameters of the rock change; this change might be observed from
seismic tomography studies (which are sensitive to the undrained elastic parameters)
but should be particularly important in long-term deformation processes (which are
sensitive to the drained elastic parameters). Several evidences are discussed which support the indications of the model
HIGH - THROUGHPUT PHENOTYPING OF A DURUM WHEAT ASSOCIATION PANEL REVEALS DIFFERENTIAL SELECTION FOR A ROOT ARCHITECTUR E QTL IN RESPONSE TO DIFFERENT WATER REGIMES
No full textIn this study we report the characterization of 183 elite durum wheat (
Triticum turgidum
ssp.
durum
Desf.) for root system architecture (RSA) and shoot developmental traits. Plants were grown
in controlled conditions up to the 7th leaf appearance
(late tillering) using the high throughput
phenotyping platform GROWSCREEN Rhizo, a rhizo
-
box
-
based system consisting of deep (90
cm) rhizo
-
boxes integrated with automatic root RGB imaging. The following RSA traits were
measured: seminal root length, noda
l root length, lateral root length, root system convex hull, root
system width and depth distribution (twice per week). Measurements of leaf area, leaf number and
tiller number were performed twice per week and SPAD measurements were collected twice during
the experiment. Root dry biomass and shoot fresh and dry biomass were collected at the end of the
experiment. The dynamic collection of the above mentioned traits allowed us to model root and
shoot growth and thus to disentangle the final point phenotypes
in simpler and integrative phenes. A
genome
-
wide association study (GWAS) based upon the Illumina Infinium 90K SNP assay
identified many QTLs for RSA and/or shoot growth traits (P < 0.0001). GWAS confirmed a highly
significant effect on adult plant root s
ystem width due to two major QTLs on chromosomes 6AL
and 7AC previously identified on seminal roots (Maccaferri et al. 2016). Notably, haplotype
frequency of the QTL cluster on chromosome 7AC was found to be significantly associated with
root depth, root s
ystem width, root specific weight and shoot/root ratio. Notably, shoot/root ratio
revealed a strong, contrasting selection pattern between the cultivars released by the rainfed and
irrigated breeding programs conducted at ICARDA and CIMMYT, respectively, suggesting an
indirect but major role of RSA features in durum wheat breeding and environmental adaptation.
These results provide valuable insights toward a better understanding and more effective
deployment of the RSA QTLome in durum wheat as related to di
fferent environmental conditions
Buoyancy versus local stress field control on the velocity of magma propagation: insight from analog and numerical modelling, Supporting Data
No full textExperimental data and numerical codes used in the manuscript "Buoyancy versus local stress field control on the velocity of magma propagation: insight from analog and numerical modelling" by V. Pinel, S. Furst, F. Maccaferri and D. Smittarello
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