The Irpinia Seismic Network (ISNet) is deployed in Southern Apennines along the active fault system responsible for the 1980, November 23, M S 6.9 Campania–Lucania earthquake.
It is set up by 28 stations and covers an area of about 100 × 70 km2. Each site is equipped with a 1-g full-scale accelerometer and a short-period velocimeter, furthermore, five sites are equipped with broad-band sensor. ISNet is organized in “sub-nets”, each of hem composed by a maximum of seven seismic stations and managed by a data concentrator (LCC, Local Control Center) Due to ts design characteristics, i.e., the wide dynamic range and the high density of stations, the ISNet network is mainly devoted to stimating in real-time the earthquake location and magnitude from low- to high- magnitude events, and to providing ground-motion arameters values so to get some insights about the ground shaking expected. Moreover, the availability of high-quality of data llows studying the source processes related to the seismogenetic structures in the area. The data analysis is managed by Earthworm oftware package that also provides the earthquake location while custom software has been developed for real-time computation of he source parameters and shaking maps. The development of the seismic network started in 2005 with the financial support of the ocal Government of the Campania Region
Map of the ISNet network
In the figure green squares indicate seismic stations. Yellow lines symbolize wireless radio links between each seismic station and its nearest Local Control Center (LCC, blue circles). Gray lines represent higher bandwidth, wireless connections among LCCs and the Network Control Center (red star). The latter transmission system is conceived as a redundant double ring.
The ISNet data management system is actually set to automatically detect the earthquakes with magnitude greater than 2 and to compute in near-real time the source parameters (location, local magnitude, seismic moment and focal mechanism...) and maps of the peak ground motion and intensity. Few minutes after the event occurrence, earthquake paramenters, along with their uncertainties, are published on a interactive web page, called ISNet Bulletin (a screen shot is displayed in the figure below). The automatic estimation of source parameters can be subject to a revision within 24-48 hours from the event occurrence.
ISNet Bulletin
The “ISNet Bulletin” interactive web page. Circles in the Google map on the upper half of the page represent events detected by the system. The events, with the associated parameters, are reported in the interactive table on the second half of the page. Additional information for each event is reported in the map or in a pop-up page by simply clicking on one or more parameters of the event. As an example, the instrumental intensity and the detailed information, including focal mechanism, for a ML = 2.8 event are displayed
Strong ground-shaking mapping soon after a moderate-to-large earthquake is crucial to recognize the areas that have suffered the largest damage and losses. These maps have a fundamental role for emergency services, loss estimation and planning of emergency actions by the Civil Protection Authorities. This is particularly important for areas with high seismic risk levels, such as the Campania-Lucania Region in southern Italy. Taking advantage of the Irpinia Seismic Network (ISNet), we have developed a procedure for rapid estimation of ground-shaking maps after moderate-to-large earthquakes (GRSmap). This uses an optimal data gridding scheme designed to account for bi-dimensional features of strong ground motion fields, such as directivity, radiation patterns and focal mechanisms, to which most damage can be correlated. The basis of the mapping technique is a triangulation procedure to locally correct predicted data at the triangle barycentres where their vertices correspond to seismic stations.
Rapid determination of ground shaking map
Simulated ground shaking maps of the 23 November 1980 (M 6.9) Irpinia earthquake obtained using synthetic data. In the three panels are shown: (a) map of PGA; (b) map of PGV; (c) map of Instrumental Intensit.
PRESTo is the acronym of PRobabilistic and Evolutionary early warning SysTem, a new software platform based on which the arthquake Early Warning System (EEWS) under development and testing in southern Italy is built. PRESTo is an integrated software tool that continuously processes the live streams of 3-component acceleration records from the seismic stations. As an energetic event is detected at a minimum number of two stations, the system promptly performs the first P-picking location. Peak ground displacement measurements (PD) in a narrow time windows after the observed P- and predicted S-signals are used to estimate the earthquake magnitude and predict a peak ground motion parameter at distant target sites. For earthquakes originating within the ISNet seismic network, a first alarm can be delivered within 4-6 seconds from the origin time and a stable, low error location and magnitude estimate is achieved within 10 seconds after the origin time.
PRESTo: a new stand-alone software tool for earthquake early warning
Application of PRESTo to synthetic seismograms of 1980, Ms = 6.9 Irpinia eq. Screenshot of PRESTo, processing the synthetic seismograms of the Irpinia earthquake Evolution with time of the magnitude estimate and of its uncertainty. The vertical red bar marks the estimated origin time (T0) of the earthquake. The interval (6 sec) elapsed from the origin time to the first magnitude estimate with a low uncertainty is highlighted by a yellow dashed.
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SeismNet Manager - A web application to manage hardware and data of a seismic network
