DSpace Community: Affiliation

Matlab software for the analysis of seismic waves recorded by three-element arrays

Sat, 28 Jun 2008 22:58:59 GMT

Title: Matlab software for the analysis of seismic waves recorded by three-element arrays

Authors: Pignatelli, A.; Italian National Data Center, viale Pinturicchio 23/E, 00196 Roma, Italy; Giuntini, A.; Italian National Data Center, viale Pinturicchio 23/E, 00196 Roma, Italy; Console, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia

Abstract: We develop and implement an algorithm for inverting three-element array data on a Matlab platform. The algorithm allows reliable estimation of back azimuth and apparent velocity from seismic records under low signal-to-noise conditions. We start with a cubic spline interpolation of the waveforms and determine the differences between arrival times at pairs of array elements. The time differences are directly computed from cross-correlation functions. The advantages of this technique are (a) manual picking of the onset of each arrival is not necessary at each array element; (b) interpolation makes it possible to estimate time differences at a higher resolution than the sampling rate of the digital waveforms; (c) consistency among three independent determinations provides a reliability check; and (d) the value of apparent velocity indicates the nature of the recorded wavelet and physically checks the results. The algorithm was tested on data collected by a tri-partite array (with an aperture of 250 m) deployed in 1998 by the National Data Center of Israel, during a field experiment in southern Israel, 20km southwest of the Dead Sea. The data include shallow explosions and natural earthquakes under both high and low signal-to-noise conditions. The procedure developed in this study is considered suitable for searching of small aftershocks subsequent to an underground explosion, in the context of on-site inspections according to the Comprehensive Nuclear-Test-Ban Treaty (CTBT).

PLINIO: an interactive web interface for seismic monitoring of Neapolitan volcanoes

Mon, 29 Oct 2007 22:58:59 GMT

Title: PLINIO: an interactive web interface for seismic monitoring of Neapolitan volcanoes

Authors: D’Auria, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Curciotti, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Martini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Borriello, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; De Cesare, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Giudicepietro, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Ricciolino, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Scarpato, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia

Editors: Marzocchi, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Zollo, A.; Dipartimento di Scienze Fisiche, Università Federico II, Napoli, Italy

Abstract: Seismic monitoring of active volcanoes has different and sometimes contrasting requirements. The peculiar features of volcanic seismicity makes an interactive system more complex than required for typical seismic monitoring. Intense seismic swarms of small magnitude earthquakes need a rapid but consistent processing for tracking in real time the evolution of an ongoing volcanic unrest. At the same time a comparison with the past record for detecting patterns still observed or anomalous behaviours is needed. Furthermore a correlation between different parameters as event magnitude and depth, event occurrence rate and volcanic tremor amplitude may be required. Finally, a rapid exchange of information among scientists located worldwide can be important for drawing conclusions about the evolution of a crisis. The first task can be fullfilled by an automatic seismic processing system, followed by a manual revision from expert seismologists. The second and the third can be simply accomplished storing the results of the processing in relational databases, that very well suited for such applications. The last task can be simply achieved by making the dataset accessible on-line thour a web server, in a friendly and interactive way. On the basis of the experience matured on the automatic seismic monitoring system of Stromboli ([2]) the research team of Monitoring Centre of I.N.G.V. “Osservatorio Vesuviano” started developing a similar software infrastructure for the monitoring of Neapolitan volcanoes. The existing databases: GeoVes, with supervised analysis, and Web Based Seismological Monitoring (WBSM) system, with automatic location, have been joined into a single friendly graphical interface aimed at improving the data accesibility and efficiency of the monitoring system.

WiFi data transmission system for monitoring volcanic areas: an example application on Mt. Vesuvius

Sat, 12 Apr 2008 22:58:59 GMT

Title: WiFi data transmission system for monitoring volcanic areas: an example application on Mt. Vesuvius

Authors: Scarpato, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; De Cesare, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Peluso, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Orazi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Caputo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Capello, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Borriello, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Buonocunto, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Martini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia

Abstract: The Seismic Monitoring Network of Mt.Vesuvius, managed by Istituto Nazionale di Geofisica e Vulcanologia, sezione di Napoli, Osservatorio Vesuviano (INGV-OV), currently consists of 13 analog short period stations (9 single component and 4 triaxial), 2 digital broadband stations and a permanent seismic array (composed of 16 triaxial sensors). Moreover 2 dilatometers are installed in the area, that are integrated in the seismic monitoring system. The distance among the station and between each station and the data acquisition center varies from hundreds of meters to some kilometers. Part of the data is collected in local Data Acquisition Centers (CAD) and then centralized at theMonitoring Center of INGV-OV. In recent years, information technology has become fundamental in seismic networks and geophysical instrumentation, this includes also the data transmission systems. In this context, the new standards for wireless networks has proved to be a useful tool for the transmission of geophysical data. This is the reason why we have chosen to adopt the Wireless Fidelity transmission system, based on available frequencies typical of the IEEE 802.11h standard, which allows high capacity data traffic. We have realized different local area networks based on WiFi technology. They can offer a coverage to high density traffic with extensions varying from a few dozen of meters to kilometers. Each network can be connected through a concentrator device, called access points, and a base station, through a high-capacity system of geographic connectivity, which will be responsible for the liaison to the Monitoring Center of INGV-OV, where seismic data are centralized. There the data are acquired and analyzed by automated systems, that produces parametric information in real time. The architecture of local networks and the backbone for data transmission has been designed to allow a modular development that is well suited for the needs of continuous improvement of the network and the introduction of new systems for geophysical and geochemical volcano monitoring. Currently the infrastructure manages a total of 79 channels with a 24-bit at 100 cps sampling, but the network has a much greater potential. So the future transition of the seismic network from analog to a fully digital equipment will be supported by this data transmission system.

The monitoring seismic network of Mt. Vesuvius

Sat, 12 Apr 2008 22:58:59 GMT

Title: The monitoring seismic network of Mt. Vesuvius

Authors: Martini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Giudicepietro, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Orazi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Capello, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Borriello, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Buonocunto, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Caputo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Caputo, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; D’Auria, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; De Cesare, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Esposito, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Lo Bascio, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Ricciolino, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Peluso, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Scarpato, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia

Abstract: Mt. Vesuvius (South Italy) is one of the most hazardous volcanoes in the world. It has been very active from 1631, when a violent subplinian eruption occurred, until 1944, with the last, medium size, eruption. So far Mt. Vesuvius is quiescent and in the last 60 years the population of the surrounding areas strongly increased. Its activity is characterized by a fumarolic field inside the crater and a moderate seismicity, with hypocenters mainly clustered in a volume about 2-5 km beneath the crater zone. The monitoring network of Mt. Vesuvius is composed of 15 seismic stations (seven 3 component and 9 vertical) and two seismic arrays, one with just 3 stations and the other one with 48 channels. The remote instruments continuously transmit the data to the recording centre by using different technological solutions. The data are collected in the monitoring centre of the Vesuvius Observatory - INGV and automatically processed in order to obtain meaningful information in real time. This system allow to immediately retrieve the significance of the recorded phenomena and to early communicate the state of the volcano to Civil Authority.