PSI - Issue 44

Iolanda Nuzzo et al. / Procedia Structural Integrity 44 (2023) 1832–1839 Iolanda Nuzzo et al./ Structural Integrity Procedia 00 (2022) 000–000

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Introduction

In the last decade there are several information systems (IS) that have been developed to mitigate the impact of an earthquake on populations and their respective infrastructures (Picozzi et al., 2015). They can be classified according to their application time with respect to the duration of the earthquake as pre-seismic, co-seismic and post-seismic (Erdik et al., 2011). The pre-seismic IS involves methodologies for risk evaluation and hazard assessment. Whilst a co-seismic IS is able to forecast the intensity of an incoming earthquake just few seconds before it strikes, thus providing the possibility of launching alerts. The Earthquake Early Warning system (EEWs) classifies as a co-seismic tool, and it involves four stages, which are event detection, magnitude estimation, location estimation and warning decision (Cremen & Galasso, 2020). Hence, it can be used to alert the population to take shelter and the managerial organizations of critical infrastructures to order the change or cessation of activities. Post-seismic ISs, such as Rapid Response System (RRS) and Aftershock Warning System (AWS), mainly consist of computational tools able to process earthquake details to provide ground-shaking maps and estimate damage and losses distribution within the area hit by the earthquake (Gehl et al., 2022). There are several methodologies to perform rapid territorial loss estimation analysis (Pittore et al., 2014). Nevertheless, post-seismic ISs generally aim to generate damage distribution maps around high importance structures for the community (Tubaldi et al., 2022). In this case, the seismic risk mitigation is pursued lowering the downtime consequences through the optimizing of the resources available to counteract the earthquake effects. Some applied cases described as successful experiences of natural disaster management system were the WARED (Kangi, 2015), the PAGER and ShakeMap (Gallen et al., 2017). Cosentini & Bozzoni (2022) developed fragility models for obtaining seismic damage scenarios associated to a real earthquake occurred in Central Italy in 2016 (Fabozzi et al., 2018). Another solution that focused on the earthquake mitigation between border countries was that provided by e-Atlas tool. This tool was responsible for assessing the impact of an earthquake on the border area between Italy and Austria, so that both countries can take complementary actions for seismic risk mitigation (Grimaz et al., 2022). As widely reported in the literature, recently the IS that has been the main focus of research and development is EEW, since it represents the potentially most effective tool to achieve a significant seismic risk mitigation of strategical infrastructures with respect to an incoming earthquake. Nevertheless, many authors recognize several limits of this methodology. Among the others, there is the problem of the blind areas, concerning the geographical zones too close to the epicentre where the time lapse between the alert and the arrival of S waves is too tight (Y. Zhang et al., 2021). Y. Zhang et al. (2021) highlight the main limitations of conventional EEW in relation to its robustness, the inadequacy of few seconds time windows to capture the information of medium and large earthquakes, and the lack of differentiation of end users at the time of estimating potential losses. In this sense, Cremen & Galasso (2020) affirm that the warning decision stage of the EEW is still in an incipient development. In response to this issue, Cremen et al. (2022) proposed new approaches of EEW developing the so-called second generation EEW, i.e. EEW2.0, combining EEWs with neo-deterministic seismic hazard assessment (NDSHA). Furthermore, they integrated decision-support systems (DSS) to a Performance-Based Earthquake Early Warning (PBEEW). These authors implemented a 5-steps methodology of the latter option (mitigation actions, event identification, evaluation of consequences, translation of consequences and tuning of parameters) in the Gioia Tauro seaport, in the South of Italy. In this direction, The Italian railway network is developing an EEW for the high-speed rail line linking Rome and Naples, which consists of a loss-driven EEW and RRS to determine the condition of tunnels of the Italian high-speed railways network (Cremen et al., 2022). However, there is still a need for a cost-effective system that can be installed in specific structures with the ability to be scaled up, being also determinant a special development of the critical stage of conventional IS, such as the warning stage decision. In consequence of previously described issues, the main objective of this study is to establish a Railway Rapid Warning System (RRWS) for a portion of the viaduct connecting Quarto and Quarto-Centro stations of the railway network around Naples, Italy. Thus, the article describes the RRWS in Section 2 while RRWS implementation and main findings are provided in Section 3. Conclusions are summarized in Section 4. 2 Railway Rapid Warning System (RRWS)

The RRSW system proposed in this paper is a post-seismic IS that launches a warning protocol, organized as a set