GNGTS 2019 - Atti del 38° Convegno Nazionale

426 GNGTS 2019 S essione 2.2 The network. To form a network different solutions could be exploited: Internet connection, radio bridges, GSM, local area networks, or satellite transmission. The network topology chosen for the project is a star network where each host is connected to a central hub with a point-to- point connection (Fig. 1b). This network has been chosen because it complies with the main needs of our system: flexibility and reliability. From the hub can depart n linear connections, therefore further devices can be added or removed without disturbing the network. Moreover, two or more end-points can be merged in a sub-network and, similarly, two or more networks can be merged into a unique network simply connecting their hubs (Fig. 2). The hub manages and controls all functions of the network and is represented by the seismic room located in the headquarter of our hosting institution. Every monitoring station can be accessed remotely to fix Fig. 2 - Schemes for the sensors’ distribution into edifices: a) minimum necessary requirements for a regular multi- storey building, and b) ideal extensive installations for an irregular masonry building. eventual problem and to update the software. The set-up and the arrangement of the monitoring stations at the sites, and within the edifices, have been accurately planned. Considering the scheme of a generic multi-story building, the literature suggests to install sensors at every level and in correspondence with changes of stiffness (Boscato 2016). The sensors at the base of the building would also provide an almost unaltered record of the input motion. For the masonry buildings, the scheme of a regular multi-story building (Celebi 2000) can be directly reused taking account of the irregularities in height that often occurs in the historic buildings (Fig. 2). All the sensor where levelled on the horizontal plane and the horizontal components accurately oriented along the N-S and E-W directions in order to have a unique reference system for the signals in every station (Fig. 3). Conclusions and general remarks. These real-time networks are really pioneering projects and they will enable three main outcomes: i) real-time seismic monitoring and on-site early warning, ii) fast damage assessment of the urban area, and iii) structural health monitoring of the key infrastructures playing the major role during a crisis. In case of strong earthquake, the damages of the area covered by network are assessed through ground motion maps with the final objective to improve the effectiveness of the rescue operations. Such operations could then be carried out according to a logic of priority on the basis of the highest shaking measured by the seismic network. The automatic earthquake detection allows the rapid data elaboration to produce shake map to be provided to the centers for post-earthquake emergency management. Observed data and seismological knowledge to produce maps of peak ground motion (PGM). The shaking is represented through maps of peak ground acceleration (PGA), peak-ground velocity (PGV), response spectral acceleration (SA), Arias Intensity (AI), Houser Spectral Intensity (HSI), ground-motion shaking intensity, and any other seismological parameter useful to the evaluation of the potential of damage (Faenza 2010). Fig. 3 shows an example of a recorded local earthquake. Although the sensibility of the MEMS accelerometer is lower with respect the professional sensor, a local (16 km) 2.8 earthquake has been detected and the