Applications of a Low-Cost, Wireless, Self-Organising System (SOSEWIN) to Earthquake Early Warning and Structural Health Monitoring

The rapid characterization of ground motion during the initial stage of an earthquake is one of the most effective approaches for quantifying the hazard associated with its impact on populated or otherwise sensitive areas. Earthquake early warning (EEW) systems are based on this approach, and aim to mitigate earthquake hazard for a target area by the provision of timely warnings. In addition, during and soon after the occurrence of earthquakes, the necessity for information on the state of health of structures in real-time that permit timely warnings in case of damaging events requires structural health monitoring systems. The Self-Organising Seismic Early Warning Information Network (SOSEWIN) is a new concept in EEW and structural health monitoring (SHM) systems. SOSEWIN employs advances in various technologies to incorporate off-the-shelf sensor, processing and communications components into low-cost sensing units that are linked by advanced, robust and rapid communications routing and network organisational protocols that are appropriate for wireless mesh networks. Significant and innovative aspects of SOSEWIN are that each sensing unit performs on-site, independent analysis of the ground motion, and that the early warning is transmitted throughout the network by means of dedicated alarming processes. In this work, a description of the SOSEWIN philosophy, hardware, and software is provided, as well as an overview of its application within different contexts. In particular, we present the results of tests carried out with SOSEWIN in Istanbul, Turkey, where a first test-bed consisting of 20 instruments is installed, as well as a novel approach for EEW that exploits the SOSEWIN philosophy to obtain, in the event of an earthquake, a real-time structural response assessment following an interferometric approach (Fleming et al. 2009). Finally, the application of SOSEWIN for SHM purposes at a building in L’Aquila (Picozzi et al. 2009a), a suspension bridge in Istanbul (Picozzi et al. 2009b), and a historical arch bridge in Luxembourg City (Oth and Picozzi 2012) are presented.