|Observatories and Research Facilities for EUropean Seismology|
|Volume 2, no 3||December 2000||Orfeus Newsletter|
The educational broadband seismic network at Naples (Southern Italy)Antonella Bobbio1,2 and Aldo Zollo 2
During 1996-1998 two broadband seismic stations were installed in Naples, at the Museum of Science and at the Department of Physical Sciences in the University campus. The museum seismograph is deployed in an exposition room dedicated to the volcanoes and to the themes of seismic monitoring in volcanic and tectonic areas. The seismometer in the Museum responds to different purposes: it records the earthquakes on the whole Planet and functions as an interactive hands-on exhibit through which the visitors (most of all are students) observe live the seismograms produced by their own movement.
PEPP) (lead by Prof. G.Nolet and Prof. R. Phinney) a similar initiative was launched in Europe since 1997, called the Educational Seismology project (EduSeis, Virieux et al., 1999; Virieux, 2000), by the Nice (France) and Naples University groups with the creation of an educational broad-band seismic network to be installed in schools and museums.
The fundamental aim of the EduSeis European Network is to confront school students with the current practice of scientific data acquisition and management. Recent networking developments make data and tools, previously only accessible in research laboratories, now also available in the classroom. The basic idea behind the project is that seismological observations can be a vehicle to train the active use of modern technologies, learn about the dynamics and evolution of the Earth and create public awareness about the seismic activity and hazard. These objectives are accomplished by operating and maintaining a high-tech, but low-cost seismic station (sensor, data acquisition board and data acquisition software and processing) to be installed in schools, science centres/museums and other places open to schools and the general public. All components of the seismic station are especially designed for educational purposes and can be operated independently by the students and teachersi themselves.
Presently, in southern Italy four additional EduSeis stations are operated in three high schools ("Copernico" ,downtown Naples; "Ettore Majorana", Isernia, 100 km north of Naples and IPSIA, Pozzuoli, 15 km west of Naples) and in a 100m deep borehole drilled on the slope of Mt. Vesuvius volcano, 25 km east of the town of Naples (Figure 1). In particular the borehole station is part of a cooperative scientific and educational project between Osservatorio Vesuviano, University of L'Aquila and the University of Naples.
Figure 1. Map of the educational broadband seismic network at Naples and Isernia.
The server controls the station and performs the following tasks:
After retrieving the earthquake location and origin time through the Internet from National and global earthquake agencies, the relevant seismic records are recovered via modem through a daily call to every station of the network. The retrieved seismic waveforms are preliminary processed (filtering, windowing, glitch removal, ..) and transformed to the standard SAC format suitable for educational software applications. A seismic data archive is created and updated on the server and made accessible to schools and the broader public through the WEB using a rather simple data-base architecture (see EduSeis). Software for data formatting and archiving have been developed by the group in Naples.
The seismic waveforms can be either downloaded for local applications or remotely displayed by the Internet browser through a tcl/tk graphic tool developed by André Herrero in Naples. This allows for a seismogram quick view, zooming, arrival time picking and main phase identification based on the IASPEI91 travel time tables (Figure 2).
Figure 2. Example of seismogram quick-view and phase detection through the web using the tcl/tk applet.
A nearly real-time display of the ground motion recording at the station NAPI, located in the caves of the Department of Physical Sciences, is also available on the WEB through a Java-based tool developed by Luca D'Auria in Naples (Figure 3). Based on an amplitude threshold criterion, an automatic alert procedure is active, which sends an e-mail to the web manager in case a relevant regional or large global earthquake occurs.
Figure 3. Near real time recording at station NAPI of the event occurred on November 16, 2000, at New Ireland (M=8.0)
Agecodagis srl in France (J.Virieux, 2000). Since about two years we started to investigate and test tri-axial seismic sensors available on the market, which may be suitable for educational purposes (low-cost, broad-band frequency response and wide dynamic range). The seismic stations operating in southern Italy are equipped with different sensor types. This enable us to make a quantitative comparison of instrument responses and characteristics. Figure 4 displays the horizontal components of ground velocity for an earthquake that occurred on the Sakhalin Islands (Russia) August 4, 2000 as recorded at stations ISMI and NAPI. Both stations are equipped with a broadband sensor (PMD Scientific, 20s-20Hz). VESI is equiped with a short-period sensor (Mark Product, 1-25 Hz) and BENI with an accelerometer (EPISENSOR-Kinemetrics, 10s-100Hz). The traces have been 0.05-0.5Hz band-pass filtered. In France the EduSeis stations are equipped with PMD and Guralp products.
Figure 4. Band-pass filtered recordings at stations of the EduSeis network of the EW component of the ground motion velocity for the Ms=7.1 Sakhalin Island earthquake occurred on August 4, 2000.
The EduSeis project has recently received financial support from the Italian Ministry of Civil Protection (through the National Group for Earthquake Defense) to use the educational seismograph as a tool for training and awareness on the seismic risk. This project is coordinated by the Scientific Museum "Città della Scienza di Napoli" with the participation of the Institute GeoAzur at the University of Nice, the Department of Physical Sciences at the University of Naples and the high school "Liceo Scientifico Copernico" in Naples. The educational activity is organized at different levels for teachers, students and the broader public. A small group of high school teachers participate in practises at university laboratories during which they use the seismic station, analyze and interpret seismic data under the scientific assistance of researchers. For these practises we design and prepare didactic modules dedicated to the seismological practice and to seismic risk evaluation. These modules are used and verified in schools and musea by students and visitors, who provide feedback for adaption and inclusion in the italian scholar curricula.