THERMAL HISTORY OF THE CARNIC ALPS (NE ITALY-S. AUSTRIA) USING CAI ANALYSIS

Thermal patterns of an area which underwent a polyphase deformation history such as the Carnic Alps were analyzed using the Colour Alteration Index (CAI) of conodonts in order to constrain some aspects of the metamorphic history of this part of the Southern Alps. Hercynian and alpine tectonothermal events were distinguished using CAI analysis.  The Hercynian event developed temperatures up to low metamorphic conditions. Alpine tectonogenesis did not produce thermal levels in excess of the diagenetic zone. Moreover, CAI patterns allow recognition and evaluation of a hydrothermal metamorphic overprint of Permo-Triassic or Oligocene age that was superimposed on the pre-existing regional metamorphic zonation. 

Famennian (Late Devonian) conodonts from the Pizzul West section (Carnic Alps, Italy)

Conodonts from the Pizzul West section are presented. \u7f e section is located in the Cason di Lanza/Mt. Zermula area of the central Carnic Alps and it exposes about twenty-four metres of Upper Devonian limestone. \u7f e forty-one taxa documented allow the discrimination of seven biozones of Frasnian and Famennian: Upper rhenana, Upper crepida, Uppermost crepida, Lower rhomboidea, Upper rhomboidea, Lower marginifera and Lower expansa

New Concepts and Tools for Geological Mapping of Mars: Geological Mapping of Mars: A Workshop on New Concepts and Tools; Tuscany, Italy, 12–14 October 2009

Geological mapping is a key tool for understanding the evolution of any planetary surface. The availability of ever growing data sets (e.g., multispectral and hyperspectral imaging and subsurface radar sounding) requires increasing effort in analyzing, integrating, and exploiting them for mapping purposes.To discuss these issues, about 80 planetary geoscientists gathered in Italy at a workshop co‐organized by the Italian Space Agency (ASI), the International Research School of Planetary Sciences (IRSPS), and the U.S. Geological Survey (USGS). The workshop focused on both data and concepts and covered a range of scientific and technical topics

Terremoto in Emilia Romagna (2012): le attività del Centro Operativo Emergenza Sismica

Come definito negli accordi riportati nell’ambito della Convenzione1 esistente tra l’Istituto Nazionale di Geofisica e Vulcanologia (INGV) e il Dipartimento di Protezione Civile (DPC), a poche ore dal forte terremoto che nella notte del 20 maggio 2012 ha colpito una vasta area dell’Emilia [Moretti et al., 2012; 2013a], è stato attivato il Pronto Intervento Sismico dell’INGV [Govoni et al., 2008; Moretti e Govoni, 2011; Moretti et al., 2010c]. Durante la prima settimana dell’emergenza l’obiettivo principale della struttura emergenziale INGV ha riguardato il miglioramento del monitoraggio sismico; sono state quindi attivate le reti sismiche mobili [maggiori dettagli in Moretti et al., 2012; 2013a] con il fine di integrare le stazioni permanenti della Rete Sismica Nazionale [RSN, Amato e Mele, 2008; Delladio et al., 2011]. Solo in una secondo momento, dopo circa 10 giorni dall’inizio della sequenza sismica è stato ufficialmente attivato il Centro Operativo Emergenza Sismica [COES, Moretti et al., 2010a], a seguito del decreto del Capo del DPC, con il quale è stata costituita la Direzione di Comando e Controllo (Di.Coma.C.2) presso l’Agenzia della Protezione Civile Regionale dell’Emilia Romagna (AgDPC) in Bologna. L’allestimento e il coordinamento del COES sono stati realizzati grazie alla collaborazione tra il Centro Nazionale Terremoti (CNT), a cui afferisce la struttura, e la Sezione INGV di Bologna, sita nel capoluogo della regione colpita dall’emergenza. In questo lavoro saranno descritte le modalità, le tempistiche e l’impegno di personale che hanno permesso e garantito l'attivazione e il buon funzionamento del COES

Fluids mobilization in Arabia Terra, Mars: depth of pressurized reservoir from mounds self-similar clustering

Arabia Terra is a region of Mars where signs of past-water occurrence are recorded in several landforms. Broad and local scale geomorphological, compositional and hydrological analyses point towards pervasive fluid circulation through time. In this work we focus on mound fields located in the interior of three casters larger than 40 km (Firsoff, Kotido and unnamed crater 20 km to the east) and showing strong morphological and textural resemblance to terrestrial mud volcanoes and spring-related features. We infer that these landforms likely testify the presence of a pressurized fluid reservoir at depth and past fluid upwelling. We have performed morphometric analyses to characterize the mound morphologies and consequently retrieve an accurate automated mapping of the mounds within the craters for spatial distribution and fractal clustering analysis. The outcome of the fractal clustering yields information about the possible extent of the percolating fracture network at depth below the craters. We have been able to constrain the depth of the pressurized fluid reservoir between ~2.5 and 3.2 km of depth and hence, we propose that mounds and mounds alignments are most likely associated to the presence of fissure ridges and fluid outflow. Their process of formation is genetically linked to the formation of large intra-crater bulges previously interpreted as large scale spring deposits. The overburden removal caused by the impact crater formation is the inferred triggering mechanism for fluid pressurization and upwelling, that through time led to the formation of the intra-crater bulges and, after compaction and sealing, to the widespread mound fields in their surroundings

Standardization of Seismic Tomographic Models and Earthquake Focal Mechanisms Datasets Based on Web Technologies, Visualization with Keyhole Markup Language

We present two projects in seismology that have been ported to web technologies, which provide results in Keyhole Markup Language (KML) visualization layers. These use the Google Earth geo-browser as the flexible platform that can substitute specialized graphical tools to perform qualitative visual data analyses and comparisons. The Network of Research Infrastructures for European Seismology (NERIES) Tomographic Earth Model Repository contains datasets from over 20 models from the literature. A hierarchical structure of folders that represent the sets of depths for each model is implemented in KML, and this immediately results into an intuitive interface for users to navigate freely and to compare tomographic plots. The KML layer for the European-Mediterranean Regional Centroid-Moment Tensor Catalog displays the focal mechanism solutions or moderate magnitude Earthquakes from 1997 to the present. Our aim in both projects was to also propose standard representations of scientific datasets. Here, the general semantic approach of XML has an important impact that must be further explored, although we find the KML syntax to be more shifted towards detailed visualization aspects. We have thus used, and propose the use of, Javascript Object Notation (JSON), another semantic notation that stems from the web-development community that provides a compact, general-purpose, data-exchange format

Seismic Anisotropy beneath Northern Victoria Land from SKS Splitting Analysis

Abstract. Teleseismic data recorded by temporary and permanent stations located in the Northern Victoria Land region are analysed in order to identify the presence and location of seismic anisotropy. We work on data recorded by 24 temporary seismographic stations deployed between 1993 and 2000 in different zones of the Northern Victoria Land, and by the permanent very broad-band stations TNV located near the Italian Base M. Zucchelli. The temporary networks monitored an area extending from Terra Nova Bay towards the South beyond the David Glacier and up to the Indian Ocean northward. To better constrain our study, we also provide an analysis of data recorded by TNV in the same period of time and we take into account also SKS shear wave splitting measurements performed by Barruol and Hoffman (1999) on data recorded by DRV. This study, to be considered as preliminary, reveals the presence of seismic anisotropy below the study region, with a mainly NW-SE fast velocity direction below the Terra Nova Bay area and rather large delay times, that mean a deep rooted anisotropic layer

The Pre-Variscan sequence of the Carnic Alps

The Pre-Variscan sequence of the Carnic Alps includes rocks deposited between the Middle Ordovician and the early Late Carboniferous, and represents one of the most continuous sequence of the world in that time interval. In a relatively small area it is possible to distinguish rocks deposited at various latitudes and climate (from cold in the Ordovician to tropical in the Devonian), and in different sedimentary environments (from shallow water, including reef deposition, to basin). The lithostratigraphy of the sequence has been recently revised and formalised, and 36 formations have been discriminated

A New Semi-Continuous GPS Network and Temporary Seismic Experiment Across the Montello-Conegliano Fault System (NE-Italy)

The Montello–Conegliano Thrust is the most remarkable structure of the Southern Alpine fault belt in the Veneto-Friuli plain, as a result of the conspicuous morphological evidence of the Montello anticline, which is associated to uplifted and deformed river terraces, diversion of the course of the Piave River, as well as vertical relative motions registered by leveling lines (Galadini et al., 2005; Burrato et al., 2008). Many papers dealt with its geometry and evolution, and the presence of several orders of Middle and Upper Pleistocene warped river terraces (Benedetti et al., 2000) in the western sector strongly suggests that the Montello–Conegliano anticline is active and driven by the underlying thrust. However, in spite of the spectacular geomorphic and geologic evidence of activity of the Montello-Conegliano Thrust, there is only little evidence on how much contractional strain is released through discrete events (i.e. earthquakes) and how much goes aseismic. Benedetti et al. (2000) hypothesized that the western part of the thrust (Montello) may have slipped three times in the past 2000 years (during the Mw 5.8 778 A.D., Mw 5.4 1268 and Mw 5.0 1859 earthquakes), yielding a mean recurrence time of about 500 years, whereas, the eastern part of the thrust (Conegliano) would be silent. The Italian seismic catalogues have very poor-quality and incomplete data for these events associated with the Montello thrust, leaving room for different interpretations, as for example the possibility that these earthquakes were generated by nearby secondary structures. In this latter case, the whole Montello–Conegliano Thrust would represent a major “silent” structure, with a recurrence interval longer than 700 years, because none of the historical earthquakes reported in the Italian Catalogues of seismicity for the past seven centuries can be convincingly referred to the Montello Source. Given the uncertainties regarding the seismic potential of this segment of the Southern Alpine fault system, we designed and realized a new GPS network across the Montello region (Fig. 1), with the goal of detecting the present-day velocity gradient pattern and develop models of the inter-seismic deformation (i.e., geometry, kinematics and coupling of the seismogenic fault). In the 2009, we started realizing a new concept of GPS experiment, called “semi-continuous”. As the name suggests, the method involves moving a set of GPS receivers around a permanently installed network of monuments, such that each station is observed some fraction of the time. In practice, a set of GPS receivers can literally remain in the field for their entire life span, thus maximizing their usage. The monuments are designed with special mounts so that the GPS antenna is forced to the same physical location at each site. This has the advantage of mitigating errors (including possible blunders) in measuring the antenna height and in centering the antenna horizontally. This also has the advantage of reducing variation in multipath bias from one occupation session to another. The period of each “session” depends on the design of the operations. At one extreme, some stations might act essentially as permanent stations (though the equipment is still highly mobile), thus providing a level of reference frame stability, and some stations may only be occupied every year or two, in order to extend or increase the density of a network’s spatial coverage. In this work we will present the motivations and tools used to develop and implement the new GPS network. During the 2010 we will integrate the existing GPS network with 10 mobile seismic stations, belonging to the INGV mobile network, with the goal of illuminate local micro-seismicity patterns that would help constraining the locked fault geometry