A WEBGIS APPLICATION FOR VISUALIZATION AND DISSEMINATION OF ITALIAN SEISMICITY

The national seismic monitoring service is an advanced real-time analysis of seismic data managed by the Centro Nazionale Terremoti in Rome of the Istituto Nazionale di Geofisica e Vulcanologia (INGV). The service provides a first location within a few seconds of any Italian earthquake and a definite location within few minute

A new combined quasigeoid model in Tierra del Fuego

This work focuses on the development of a combined quasigeoid model for Tierra del Fuego province. The Equivalent Source Technique (EST) is applied together with the remove-compute-restore technique in order to combine gravity and GPS/levelling observations and to obtain a quasigeoid model. This model features an improved accuracy in relation to previous models. A discussion about the geodetic reference system is also presented. Geodetic coordinates of all stations used were transformed to TDF08 to be in accordance with the new geodetic reference frame of Argentina. After a cross validation procedure it is determined that a 5cm (r.m.s.) quasigeoid model has been achieved for the major part of the province, fulfilling the requirements for its practical use. New Global Geopotential Models (GGM) are introduced in the discussion, particularly the EGM2008 which is used for evaluation purposes. It shows a 9cm agreement after its evaluation on the levelling lines

Anomalous ocean load tide signal observed in lake-level variations in Tierra del Fuego

We demonstrate the application of a 100 km long lake as a sensor for studying the tidal effects on Tierra del Fuego main island. The lake-level variations observed in Lago Fagnano reflect both the direct response to the tidal potential and the indirect effect of the ocean tidal loading. Modeling both contributions explains the observed tidal signal in the lake to about 70%. Underestimated model load tide amplitudes are found to be probably responsible for the remaining difference. We interpret this discrepancy as a hint for regional elastic lithosphere properties differing substantially from those represented by currently available global models.Fil: Richter, Andreas Jorg. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Technische Universität Dresden; AlemaniaFil: Hormaechea, José Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Dietrich, R.. Technische Universität Dresden; AlemaniaFil: Perdomo, Raul Anibal. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Departamento de Astrometría; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Fritsche, M.. Technische Universität Dresden; AlemaniaFil: del Cogliano, Daniel Hector. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Departamento de Astrometría; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Liebsch, G.. Bundesamt fur Kartografie und Geodasie; AlemaniaFil: Mendoza, Luciano Pedro Oscar. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Departamento de Astrometría; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

The contribution of seismic data in microzonation studiesfor downtown L’Aquila

After the 2009 April 6th Mw 6.3 L’Aquila earthquake (Central Italy) the Italian Civil Defense Department promoted the microzoning study in the ten zones in the epicentral area that suffered major damage. In this paper we present the activities and the results concerning a temporary seismic network installed in the historical L’Aquila city center indicated as “macroarea 1” in the microzoning project. Seismic data were collected to investigate the amplification effects in the city and to support the microzoning activities in verifying both geological profiles and 1D numerical modeling of the seismic response of the city. The conventional spectral approaches using both microtremor and earthquake data allowed to determine the fundamental resonance frequencies and the amplification factors within the city respectively. The spatial variability of these quantities can be related to the geological and geomorphologic characteristics of the investigated area. A comparison between the network data and the data recorded by the two strong motion instruments installed in the city was also made. This allows verifying the relative response of the accelerometric stations that recorded in the city the major events of the sequence.Published741–7594.1. Metodologie sismologiche per l'ingegneria sismicaJCR Journalreserve

Seismic site response estimation in the near source region of the 2009 L'Aquila, Italy, Earthquake

To better estimate the seismic ground motion during the April 6th, 2009 earthquake in L'Aquila, we deployed temporary arrays in the near-source region. Several arrays have been successively set up in the Aterno valley's epicentral area and have recorded the aftershocks that followed the main shock, between April and September. The data has been processed in order to study the spectral ratios of the horizontal component of ground motion at the soil site and at a reference site, as well as the spectral ratio of the horizontal and the vertical movement at a single recording site. The results obtained confirm the presence of large amplification effects in both L'Aquila's historic centre and in the suburban areas. The resonance frequency has been found to be close to 0.6 Hz in downtown L'Aquila whereas the suburban areas show amplification at frequencies ranging from 2 Hz to 5 Hz.PublishedSkopje, Macedonia4.1. Metodologie sismologiche per l'ingegneria sismicaope

Seismic site response estimation in the near source region of the 2009 L'Aquila, Italy, Earthquake

To better estimate the seismic ground motion during the April 6th, 2009 earthquake in L'Aquila, we deployed temporary arrays in the near-source region. Several arrays have been successively set up in the Aterno valley's epicentral area and have recorded the aftershocks that followed the main shock, between April and September. The data has been processed in order to study the spectral ratios of the horizontal component of ground motion at the soil site and at a reference site, as well as the spectral ratio of the horizontal and the vertical movement at a single recording site. The results obtained confirm the presence of large amplification effects in both L'Aquila's historic centre and in the suburban areas. The resonance frequency has been found to be close to 0.6 Hz in downtown L'Aquila whereas the suburban areas show amplification at frequencies ranging from 2 Hz to 5 Hz

La Rete Integrata Nazionale GPS (RING) dell' INGV: una infrastruttura aperta per la ricerca scientifica

Since 2004, the Istituto Nazionale di Geofisica e Vulcanologia (INGV) is investing important energies for the creation of a continuous GPS network dislocated all over the Italian territory. Data transmission will occur in real time, integrating the experiences already existing in the different INGV institutes and developing a 3-yrs strategy for the new installations. The main targets of the network are represented by active tectonics studies, including also the seismological part as strain accumulation on faults. Within a 3-yrs funding project, it is expected, to realize for the scientific community an infrastructure which is comparable to those existing in countries where advanced crustal deformation studies are carried out. Thus, INGV have co-located the classical seismological instrumentation (broad band seismometers and accelerometers) with GPS receivers to observe and quantify the whole seismic cycle. In this short paper, we describe the CGPS network, the technological choices for the monumentation and the data transmission, the data and metadata management and, finally, the data policy and the deliverables.INGVUnpublishedreserve

Local variability of the ground shaking during the 2009 L’Aquila earthquake (April 6, 2009—Mw 6.3): the case study of Onna and Monticchio villages

The 2009 Mw 6.3 L’Aquila event caused extensive damage in the city of L’Aquila and in some small towns in its vicinity. The most severe damage was recognized SE of L’Aquila town along the Aterno river valley. Although building vulnerability and near-source effects are strongly responsible for the high level of destruction, site effects have been invoked to explain the damage heterogeneities and the similarities between the 2009 macroseismic field with the intensities of historical earthquakes. The small village of Onna is settled on quaternary alluvium and suffered during the L’Aquila event an extremely heavy damage in the masonry structures with intensity IX–X on the Mercalli-Cancani-Sieberg (MCS) scale. The village of Monticchio, far less than 1.3 km from Onna, is mostly situated on Meso- zoic limestone and suffered a smaller level of damaging (VI MCS). In the present paper, we analyze the aftershock recordings at seismic stations deployed in a small area of the middle-Aterno valley including Onna and Monticchio. The aim is to investigate local ampli-fication effects caused by the near-surface geology. Because the seismological stations are close together, vulnerability and near-source effects are assumed to be constant. The wave- form analysis shows that the ground motion at Onna is systematically characterized by large high-frequency content. The frequency resonance is varying from 2 to 3 Hz and it is related to alluvial sediments with a thickness of about 40 m that overlay a stiffer Pleistocene substrate. The ground motion recordings of Onna are well reproduced by the predictive equation for the Italian territory.Published783-8072T. Sorgente SismicaJCR Journalreserve

Acquisition, storage and distribution of data and metadata of the Italian CGPS network (RING)

In the framework of the development of the “Rete Integrata Nazionale GPS” of the Istituto Nazionale di Geofisica e Vulcanologia, we worked on the acquisition, storage and distribution of the data recorded by the network. We will show problems and solutions that we have faced, from the transmission stage to the final distribution of data and metadata of the recorded observations. In general, we have worked on software solutions to provide a quality check on the observation files that make use of java platform implemented with a front-end software for a rapid graphical time series restitution of common quality parameters as for multipath on L1 and L2, cycle slips and others, that can run easily on any operative system (namely “Clinic”). The observation files, and metadata of the network, are managed by a Knowledge Management infrastructure finalized to the web sharing management. The direct exposure on internet needs to interface all the modifying/querying processes of information contained in the database, by means of a software based on a framework of MVC type (Model View Controller), carried out on a J2EE platform (java2 Enterprise Edition). This system uses JSP (Java Server Page) and Servlet to allow, through HTTP protocol (Hyper Text Transfer Protocol), the management of devices in the field with dynamic HTML pages. A restricted access allows: creation and download of the CGPS log files, creation and download of the site monographic information, operations of files uploading and downloading from/to the central server, site status management and creation of time series plots. A web site, presently under construction but open within 2006, will access to the database and will be complemented with territorial and geographic data elaborated using a Geographical Information System (Ring WebGis). The WebGis is a user-friendly interface for reference territorial and cartographic data and for the development of the CGPS network. The HTML viewer allows the user to interact with geographical data using the common tools of a webgis (interrogation, selection etc.

Posiciones precisas de componentes de sistemas dobles y múltiples

El satélite HIPPARCOS necesita tener un catálogo de entrada con precisión mejor que 1". Los catálogos de dobles existentes tienen posiciones relativas precisas, pero muy malas posiciones absolutas. El consorcio INCA (INput CAtalog) solicitó nuestra colaboración para la obtención de posiciones precisas de componentes de sistemas dobles y múltiples a partir de placas astrométricas obtenidas en el ESO por astrónomos belgas. El primer lote consistió en 33 placas y en este informe de muestran los resultados.Asociación Argentina de Astronomí