1,721,148 research outputs found
High resolution microseismicity data constraining the activity of the Altotiberina low-angle normal fault, Northern Apennines (Central Italy).
No full textUnravelling the complexity of Apenninic extensional fault systems: A review of the 2009 L’Aquila earthquake (Central Apennines, Italy)
No full textThe 2009 L'Aquila sequence activated a normal fault system 50 km long in the Central Apennines, composed of two main NW-trending faults 12–16 km long: the main high angle L'Aquila segment and the Campotosto listric fault.
The MW 6.1 L'Aquila mainshock nucleated on the Paganica fault at a depth of ∼8.6 km and cut through the upper crust producing coseismic surface slip of up to 10 cm observed along a strike length of ∼13 km. Analysis of historical seismicity and data collected in paleo-seismological trenches suggest that this event filled a >500-year gap. In contrast, the blind Campotosto listric fault is composed of different fault segments displaying abrupt changes in dip at a depth where major events nucleate suggesting a rheological and geometrical control on stress concentration.
A foreshock sequence that started around 4 months before the L'Aquila mainshock activated the deepest portion of the Paganica fault and marked the onset of large variations in elastic properties of the crustal volume. The variations have been modelled in terms of dilatancy and diffusion processes, corroborating the hypothesis that fluids play a key role in the nucleation process of extensional faults in the crust.Published2-183.1. Fisica dei terremotiJCR Journalrestricte
Microseismic activity on a low angle normal fault (northern Apennines, Italy). European Geosciences Union.
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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
Foreshock sequence of The September 26th, 1997 Umbria-Marche earthquakes
No full textOn September 3 (22:07 UTC), 1997 a small earthquake with Mw=4.54 started the foreshocks sequence (1500
th
events with ML <3.1) of the September 26 seismic sequence. Two days after, three seismic stations of the
University of Camerino were installed around the macroseismic epicenter of the foreshock. We present in this
rd th
paper the location of foreshocks (with 2.1<ML<3.3) which occurred between September 3 and 26 . Foreshocks
location, with horizontal (ERH) and vertical (ERZ) error less than 1.5 km, de?ne an area4 km large. Foreshocks
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have been localized between the epicenters of the two major events of September 26 , which occurred at 00:33
UTC with Mw=5.6 and at 09:40 UTC with Mw=6.0 (Amato et al., 1998; Ekström et al., 1998). In a vertical cross-
section, hypocenters show a low angle (30) structure with SW dip-direction. Focal mechanisms for three of the
major events showdip-slip fault solutions with strike direction of aboutN130, in agreementwith the CMT solutions
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of September 3 and September 26 earthquakes (Ekström et al., 1998). Data recorded at two stations Popola
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(POP) e Capodacqua (CPQ) located on the rupture area of the September 26 faults, allowed us to calculate a mean
Vp/Vs ratio of 1.840.03 for the foreshock. This value is lower than the Vp/Vs ratio of 1.890.02 calculated for
the aftershock sequence occurred in the same area. Besides, the Vp/Vs ratio during the foreshocks sequence is not
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stable in time but it seems to increase approaching September 26 . After September 26 mainshocks, this value
tends to stabilize around a higher value of 1.89. Following the dilatancy model, we suggest that the relative low
Vp/Vs ratio before the main shocks could indicate the presence of ?uid in the focal volume. The presence of ?uids
could have increased the effective stress on the fault plane and could be responsible for the long foreshock activity
th
before the two main earthquakes of September 26 . Therefore, we suggest that this foreshock activity could have
th
also contributed to reduce the friction along the September 26 fault plane, breaking the active structure in two
smaller segments. In this hypothesis, foreshock activity could have drastically contributed to mitigate the seismic
potential of the Colfiorito’s active structure.Published387-3993.1. Fisica dei terremotiJCR Journalreserve
Foreshock sequence of The September 26th, 1997 Umbria-Marche earthquakes
No full textOn September 3 (22:07 UTC), 1997 a small earthquake with Mw=4.54 started the foreshocks sequence (1500
th
events with ML <3.1) of the September 26 seismic sequence. Two days after, three seismic stations of the
University of Camerino were installed around the macroseismic epicenter of the foreshock. We present in this
rd th
paper the location of foreshocks (with 2.1<ML<3.3) which occurred between September 3 and 26 . Foreshocks
location, with horizontal (ERH) and vertical (ERZ) error less than 1.5 km, de?ne an area4 km large. Foreshocks
th
have been localized between the epicenters of the two major events of September 26 , which occurred at 00:33
UTC with Mw=5.6 and at 09:40 UTC with Mw=6.0 (Amato et al., 1998; Ekström et al., 1998). In a vertical cross-
section, hypocenters show a low angle (30) structure with SW dip-direction. Focal mechanisms for three of the
major events showdip-slip fault solutions with strike direction of aboutN130, in agreementwith the CMT solutions
rd th
of September 3 and September 26 earthquakes (Ekström et al., 1998). Data recorded at two stations Popola
th
(POP) e Capodacqua (CPQ) located on the rupture area of the September 26 faults, allowed us to calculate a mean
Vp/Vs ratio of 1.840.03 for the foreshock. This value is lower than the Vp/Vs ratio of 1.890.02 calculated for
the aftershock sequence occurred in the same area. Besides, the Vp/Vs ratio during the foreshocks sequence is not
th th
stable in time but it seems to increase approaching September 26 . After September 26 mainshocks, this value
tends to stabilize around a higher value of 1.89. Following the dilatancy model, we suggest that the relative low
Vp/Vs ratio before the main shocks could indicate the presence of ?uid in the focal volume. The presence of ?uids
could have increased the effective stress on the fault plane and could be responsible for the long foreshock activity
th
before the two main earthquakes of September 26 . Therefore, we suggest that this foreshock activity could have
th
also contributed to reduce the friction along the September 26 fault plane, breaking the active structure in two
smaller segments. In this hypothesis, foreshock activity could have drastically contributed to mitigate the seismic
potential of the Colfiorito’s active structure.Published387-3993.1. Fisica dei terremotiJCR Journalreserve
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
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