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Stabile, T. A.
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- PublicationOpen AccessDevelopment of a multi-phase dynamic ray-tracing code(2007)
; ; ; ;Stabile, T. A.; Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II (RISSC-Lab), Napoli, Italy ;De Matteis, R.; Dipartimento di Studi Geologici ed Ambientali, Università degli Studi del Sannio, Benevento, Italy ;Zollo, A.; Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II (RISSC-Lab), Napoli, Italy; ; We here propose a method for rapid, high-frequency seismogram generation that makes use of an algorithm to automatically generate an exhau- stive set of seismic phases that produce an appreciable amplitude on the sei- smogram. The method uses a hierarchical order of rays and seismic phases generation, taking into account some existence constraints for a ray-path and some physical constraints. To compute synthetic seismograms, the COMRAD code (from the Italian: “COdice Multifase per il RAy-tracing Dinamico”) uses as its core a dynamic ray-tracing code. To validate the code, we have computed in a layered medium synthetic seismograms using both COMRAD and a code which computes the complete wavefield by the discrete wavenumber method. The seismograms are compared according to a time-frequency misfit criteria based on the continuous wavelet transform of the signals. The comparison shows that the ray-theory seismogram is enough complete and moreover, the time for the computing of the synthetics using the COMRAD code (truncating the ray series at the 10th generation) is 3-4-fold less than that needed for the Axitra code (to a frequency of 25 Hz).204 239 - PublicationRestrictedLong-term seafloor experiment with the CUMAS module: performance, noise analysis of geophysical signals, and hints towards the design of a permanent network(2010)
; ; ; ; ; ; ; ;Iannaccone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Vassallo, M.; AMRA Scarl, Via Nuova Agnano, 11 - 80125 Napoli, Italy ;Elia, L.; AMRA Scarl, Via Nuova Agnano, 11 - 80125 Napoli, Italy ;Guardato, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Stabile, T. A.; Dipartimento di Scienze Fisiche, Università di Napoli “Federico II”, Napoli, Italy ;Satriano, C.; AMRA Scarl, Via Nuova Agnano, 11 - 80125 Napoli, Italy ;Beranzoli, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; ; The Campi Flegrei caldera (southern Italy) is one of the most hazardous areas in the World as several hundred thousand people live there and where important socio-economic activities have developed. The caldera includes the western-most part of the city of Naples and extends into the Gulf of Pozzuoli (eastern Tyrrhenian basin; Fig. 1). The main feature of the present volcanic activity of the caldera is the episodic slow and high-amplitude soil movement (bradyseism) accompanied by intense and shallow seismic activity that only occurs during the uplift phase.494 44 - PublicationOpen AccessUnderwater acoustic channel properties in the Gulf of Naples and their effects on digital data transmission(2007-06)
; ; ; ; ;Stabile, T. A.; Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II, Napoli, Italy ;Zollo, A.; Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II, Napoli, Italy ;Vassallo, M.; Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II, Napoli, Italy ;Iannaccone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; In this paper we studied the physical properties of the Gulf of Naples (Southern Italy) for its use as a communication channel for the acoustic transmission of digital data acquired by seismic instruments on the seafloor to a moored buoy. The acoustic link will be assured by high frequency acoustic modems operating with a central frequency of 100 kHz and a band pass of 10 kHz. Since the maximum depth of the sea is about 300 m and the planned horizontal distance between the seismic instruments and the buoy is 2 km, the acoustic data transmission shall be near horizontal. In this study the signal-to-noise ratio is plotted against depth and distance from the source, thus defining the limit after which the transmitted information becomes unreliable. Using ray-theory, we compute the amplitudes of a transmitted signal at a grid of 21×12 receivers to calculate the transmission loss at each receiver. The signal-to-noise ratio is finally computed for each receiver knowing also the transmitter source level and the acoustic noise level in the Gulf of Naples. The results show that the multipath effects predominate over the effects produced by the sound velocity gradient in the sea in the summer period. In the case of omnidirectional transmitters with a Source Level (SL) of 165 dB and a bit rate of 2.4 kbit/s, the results also show that distances of 1400-1600 m can be reached throughout the year for transmitter-receiver connections below 50 m depth in the underwater acoustic channel.172 807 - PublicationOpen AccessA prototype system for earthquake early warning and alert management in southern Italy(2010)
; ; ; ; ; ; ; ; ; ; ; ; ;Iannaccone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Zollo, A.; Università di Napoli ;Elia, L.; AMRA Scarl ;Convertito, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Satriano, C.; AMRA Scarl ;Martino, C.; AMRA Scarl ;Festa, G.; Università di Napoli ;Lancieri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Bobbio, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Stabile, T. A.; AMRA Scarl ;Vassallo, M.; AMRA Scarl ;Emolo, A.; Università di Napoli; ; ; ; ; ; ; ; ; ; ; The Irpinia Seismic Network (ISNet) is deployed in Southern Apennines along the active fault system responsible for the 1980, November 23, MS 6.9 Campania-Lucania earthquake. It is comprised of 28 stations and covers an area of about 100x70 km2. Each site is equipped with a 1-g full-scale accelerometer and a short-period velocimeter. Thanks to its design characteristics, i.e. the wide dynamic recording range and the high density of stations, the ISNet network is mainly devoted to estimating in real-time the earthquake location and magnitude from low- to high- magnitude events, and to providing ground-motion parameters to get some insights about the ground shaking expected. Moreover, the availability of high-quality data allows studying the source processes related to the seismogenetic structures in the area. The network layout, the data communication system and protocols and the main instrumental features are described in the paper. Most of the data analysis is performed through the Earthworm software package, that also provides the automatic earthquake locations, while custom software has been developed for real-time computation of the source parameters and shaking maps. Technical details about these procedures are given in the article. The data collected at the ISNet stations are available upon request.496 1469 - PublicationOpen AccessCUMAS: a seafloor multi-sensor module for volcanic hazard monitoring - First long-term experiment and performance assessment(2009)
; ; ; ; ; ; ;Iannaccone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Guardato, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Vassallo, M.; AMRA, Analisi e Monitoraggio dei Rischi Ambientali ;Stabile, T. A.; AMRA, Analisi e Monitoraggio dei Rischi Ambientali ;Elia, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Beranzoli, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; ; ;EOS; AGUA seafloor multi-sensor module with real-time data transmission, named CUMAS (Cabled Underwater Module for Acquisition of Seismological data), has been deployed in January 2008 in the Gulf of Pozzuoli, in the Campi Flegrei caldera (southern Italy), which is one of the most active volcanic areas in the world. The sensors installed in CUMAS were selected to monitor a set of signals related to the local seismicity as well as the ground uplift and subsidence of the seafloor that are related to the bradyseismic phenomenon. In particular, together with a broad-band three-component seismometer and a low-frequency hydrophone, a seafloor water-pressure sensor is used to assess the feasibility of measurements of the slow vertical movement of the seafloor (bradyseism). Further sensors are acquired by two embedded Linux computers, namely tilt and heading sensors for the measure of the actual module orientation on the seafloor, and status sensors that monitor the state of health of the vessel (e.g., internal temperature, power absorption, water intrusion). The underwater acquisition systems are linked to a support infrastructure, a floating buoy (elastic beacon), through an electro-mechanical cable with an Ethernet line. The buoy provides the needed power supply thanks to batteries charged by solar panels and a wind- generator. A Wi-Fi antenna on the buoy is used to transmit the seafloor data from the sea surface to the land acquisition centre in the city of Naples. A meteorological station is also mounted on the buoy, to allow the correlation of the air and seafloor data. CUMAS, although based on commercial sensors, relies on an original system for the centralized management of a wide set of geophysical and physical oceanographic sensors, that handles the continuous data acquisition and real-time data transmission. After the installation in the Gulf of Pozzuoli at about 100 m w.d., and after a test period, CUMAS uninterruptedly operated from May 2008 to June 2009, thus providing continuous geophysical data to the Monitoring Center of the Campi Flegrei volcanic areas, managed by the Istituto Nazionale di Geofisica e Vulcanologia. The long-term operational performance of CUMAS is presented here, together with the first results from the analysis of the geophysical long time-series acquired. Examples of the acquired signals, especially geophysical data, will be presented to point out the high quality in term of signal-to-noise ratio. In particular, earthquake recordings obtained from the hydrophone resulted of comparable quality to the seismic data acquired on land by the permanent network, thus demonstrating the suitability of hydrophones to monitor the seismic activity of the caldera.184 130 - PublicationRestrictedA comprehensive approach for evaluating network performance in surface and borehole seismic monitoring(2012)
; ; ; ; ; ; ; ;Stabile, T.; Istituto di Metodologie per l’Analisi Ambientale, CNR-IMAA ;Iannaccone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Zollo, A.; Dipartimento di Scienze Fisiche, Università di Napoli Federico II, Naples ;Lomax, A.; ALomax Scientific, Mouans-Sartoux, France ;Ferulano, F.; ENI S.p.A. - E&P Division, San Donato Milanese (MI), Italy ;Vetri, L.; ENI S.p.A. - E&P Division, San Donato Milanese (MI), Italy ;Barzaghi, L.; ENI S.p.A. - E&P Division, San Donato Milanese (MI), Italy; ; ; ;; ; The accurate determination of locations and magnitudes of seismic events in a monitored region is important for many scientific, industrial and military studies and applications; for these purposes a wide variety of seismic networks are deployed throughout the world. It is crucial to know the performance of these networks not only in detecting and locating seismic events of different sizes throughout a specified source region, but also by evaluating their location errors as a function of the magnitude and source location. In this framework, we have developed a method for evaluating network performance in surface and borehole seismic monitoring. For a specified network geometry, station characteristics and a target monitoring volume, the method determines the lowest magnitude of events that the seismic network is able to detect (Mw detect), and locate (Mw loc) and estimates the expected location and origin time errors for a specified magnitude. Many of the features related to the seismic signal recorded at a single station are considered in this methodology, including characteristics of the seismic source, the instrument response, the ambient noise level, wave propagation in a layered, anelastic medium and uncertainties on waveform measures and the velocity model. We applied this method to two different network typologies: a local earthquake monitoring network, Irpinia Seismic Network (ISNet), installed along the Campania-Lucania Apennine chain in Southern Italy, and a hypothetic borehole network for monitoring microfractures induced during the hydrocarbon extraction process in an oil field. The method we present may be used to aid in enhancing existing networks and/or understanding their capabilities, such as for the ISNet case study, or to optimally design the network geometry in specific target regions, as for the borehole network example.165 32 - PublicationRestrictedOverview of the earthquake earlywarning system development in Southern Italy(Doppiavoce, 2010)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Iannaccone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Zollo, A.; Dipartimento di Scienze Fisiche Università degli Studi di Napoli Federico II Napoli, Italy ;Bobbio, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Cantore, L.; Dipartimento di Scienze Fisiche Università degli Studi di Napoli Federico II Napoli, Italy ;Convertito, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Corciulo, M.; Dipartimento di Scienze Fisiche Università degli Studi di Napoli Federico II Napoli, Italy ;Di Crosta, M.; Univesità di Napoli, Federico II, Dip. Scienze Fisiche ;Elia, L.; Univesità di Napoli, Federico II, Dip. Scienze Fisiche ;Emolo, A.; Univesità di Napoli, Federico II, Dip. Scienze Fisiche ;Festa, G.; Univesità di Napoli, Federico II, Dip. Scienze Fisiche ;Iervolino, L.; Dip. Ingegneria Strutturale, Univesità di Napoli, Federico II ;Lancieri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Martino, C.; Univesità di Napoli, Federico II, Dip. Scienze Fisiche ;Satriano, C.; Univesità di Napoli, Federico II, Dip. Scienze Fisiche ;Sorrentino, S.; Univesità di Napoli, Federico II, Dip. Scienze Fisiche ;Stabile, T. A.; Univesità di Napoli, Federico II, Dip. Scienze Fisiche ;Vassallo, M.; Univesità di Napoli, Federico II, Dip. Scienze Fisiche ;Weber, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Iannaccone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Zollo, A.; Università di Napoli, Federico II, Dip. Scienze Fisiche; XXXX231 26