1,720,959 research outputs found
Kinematics of the Sicily and Calabria Subduction System from Elastic Block Modeling of GPS Data
No full textWe use data from about 700 GPS stations in the EuroMediterranen region to investigate the present-day behavior of the the Calabrian subduction zone within the Mediterranean-scale plates kinematics and to perform local scale studies about the strain accumulation on active structures. We focus attenction on the Messina Straits and Crati Valley faults where GPS data show extentional velocity gradients of ∼3 mm/yr and ∼2 mm/yr, respectively. We use dislocation model and a non-linear constrained optimization algorithm to invert for fault geometric parameters and slip-rates and evaluate the associated uncertainties adopting a bootstrap approach. Our analysis suggest the presence of two partially locked normal faults. To investigate the impact of elastic strain contributes from other nearby active faults onto the observed velocity gradient we use a block modeling approach. Our models show that the inferred slip-rates on the two analyzed structures are strongly impacted by the assumed locking width of the Calabrian subduction thrust.
In order to frame the observed local deformation features within the present- day central Mediterranean kinematics we realyze a statistical analysis testing the indipendent motion (w.r.t. the African and Eurasias plates) of the Adriatic, Cal- abrian and Sicilian blocks. Our preferred model confirms a microplate like behaviour for all the investigated blocks. Within these kinematic boundary conditions we fur- ther investigate the Calabrian Slab interface geometry using a combined approach of block modeling and χ2ν statistic. Almost no information is obtained using only the horizontal GPS velocities that prove to be a not sufficient dataset for a multi-parametric inversion approach.
Trying to stronger constrain the slab geometry we estimate the predicted vertical velocities performing suites of forward models of elastic dislocations varying the fault locking depth. Comparison with the observed field suggest a maximum resolved locking depth of 25 km
Active strain-rate Across the Messina Straits and Kinematics of Sicily and Calabria From GPS Data
No full textThe Messina Straits is the locus of one of the strongest seismic event that ever hit Italy during historical times,
the 1908 Mw 7.1 earthquake, and the same region also suffered major damage from other strong earthquakes
in the last few centuries. However, despite the large amount of data and studies carried out, our knowledge of
the present-day deformation of this area is still debated. While a general consensus has been reached about the
kinematics of the 1908 causative fault, less is known about the rate and shape of interseismic loading across the
Straits, and debate continues also about the general kinematics and geodynamic framework of this region which
are strongly influenced by subduction and retreat of Ionian lithosphere. Thanks to the increasing number of GPS
Networks in the study region it is now possible to study both the regional kinematics and strain loading across
active faults. In this work we analyze all the observations collected over the Messina non-permanent GPS Network
for the 1994-2008 time span, and data from about 600 CGPS stations in the Euro-Mediterranean region, using the
GAMIT software.
The output of our analysis is a new and denser velocity field, which is used to study the plate kinematics and the
rate of interseismic strain building across the Straits. GPS velocities show a sudden change in their orientation
across the Straits moving to NNW-ward, in Estern Sicily, to NNE-ward in Western Calabria, depicting this area as
a primary boundary between two different tectonic domains.
The maximum strain-rates observed across the Straits are about 120 nanostrain/yr, with extension oriented about
normal to the coasts of Sicily according to the presence of a normal fault. The measured velocity gradient can
be used to model the creeping dislocation at depth, however, over the Messina Straits the interseismic elastic
strains accumulating across other nearby active faults can significantly affect the observed velocity gradient.For
this reason we investigate, using a regional elastic block-modeling approach, these effects. We use the block model
to test for different microplates configurations and to account for nearby active faults while inverting for optimal
fault geometry and intersismic slip-rates across the Straits.Publishedvienna, austria.1.9. Rete GPS nazionale3.2. Tettonica attivaope
Active strain-rate Across the Messina Straits and Kinematics of Sicily and Calabria From GPS Data
No full textThe Messina Straits is the locus of one of the strongest seismic event that ever hit Italy during historical times,
the 1908 Mw 7.1 earthquake, and the same region also suffered major damage from other strong earthquakes
in the last few centuries. However, despite the large amount of data and studies carried out, our knowledge of
the present-day deformation of this area is still debated. While a general consensus has been reached about the
kinematics of the 1908 causative fault, less is known about the rate and shape of interseismic loading across the
Straits, and debate continues also about the general kinematics and geodynamic framework of this region which
are strongly influenced by subduction and retreat of Ionian lithosphere. Thanks to the increasing number of GPS
Networks in the study region it is now possible to study both the regional kinematics and strain loading across
active faults. In this work we analyze all the observations collected over the Messina non-permanent GPS Network
for the 1994-2008 time span, and data from about 600 CGPS stations in the Euro-Mediterranean region, using the
GAMIT software.
The output of our analysis is a new and denser velocity field, which is used to study the plate kinematics and the
rate of interseismic strain building across the Straits. GPS velocities show a sudden change in their orientation
across the Straits moving to NNW-ward, in Estern Sicily, to NNE-ward in Western Calabria, depicting this area as
a primary boundary between two different tectonic domains.
The maximum strain-rates observed across the Straits are about 120 nanostrain/yr, with extension oriented about
normal to the coasts of Sicily according to the presence of a normal fault. The measured velocity gradient can
be used to model the creeping dislocation at depth, however, over the Messina Straits the interseismic elastic
strains accumulating across other nearby active faults can significantly affect the observed velocity gradient.For
this reason we investigate, using a regional elastic block-modeling approach, these effects. We use the block model
to test for different microplates configurations and to account for nearby active faults while inverting for optimal
fault geometry and intersismic slip-rates across the Straits.Publishedvienna, austria.1.9. Rete GPS nazionale3.2. Tettonica attivaope
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Microplate kinematics, strain accumulation and geodetic fault slip rates along the Sicily-Calabria segment (southern Italy) of the Nubia-Eurasia plate boundary from the analysis and modeling of dense GPS networks.
No full textMicroplate kinematics, strain accumulation and geodetic fault slip rates along the Sicily-Calabria segment (southern Italy) of the Nubia-Eurasia plate boundary from the analysis and modeling of dense GPS networks
Stima del tasso di deformazione attraverso lo Stratto di Messina dalla combinazione di reti di stazioni GPS permanenti e non-permanenti.
No full textIl campo di velocità GPS orizzontale è stato
utilizzato per calcolare il gradiente di
velocità interpolato su una griglia regolare
alla scala dello Stretto di Messina
- …
