1,721,082 research outputs found
An attempt of real-time structural response assessment by an interferometric approach: A tailor-made earthquake early warning for buildings
No full textMobile mashup: A pervasive and flexible paradigm for data access [Mobile mashup: Un paradigma pervasivo e flessibile per l'accesso ai dati]
No full textStructural Health Monitoring Using Wireless Technologies: An Ambient Vibration Test on the Adolphe Bridge, Luxembourg City
Full text linkMajor threats to bridges primarily consist of the aging of the structural elements, earthquake-induced shaking and standing waves generated by windstorms. The necessity of information on the state of health of structures in real-time, allowing for timely warnings in the case of damaging events, requires structural health monitoring (SHM) systems that allow the risks of these threats to be mitigated. Here we present the results of a short-duration experiment carried out with low-cost wireless instruments for monitoring the vibration characteristics and dynamic properties of a strategic civil infrastructure, the Adolphe Bridge in Luxembourg City. The Adolphe Bridge is a masonry arch construction dating from 1903 and will undergo major renovation works in the upcoming years. Our experiment shows that a network of these wireless sensing units is well suited to monitor the vibration characteristics of such a historical arch bridge and hence represents a low-cost and efficient solution for SHM
Forecasting the Preparatory Phase of Induced Earthquakes by Recurrent Neural Network
Full text linkEarthquakes prediction is considered the holy grail of seismology. After almost a century of efforts without convincing results, the recent raise of machine learning (ML) methods in conjunction with the deployment of dense seismic networks has boosted new hope in this field. Even if large earthquakes still occur unanticipated, recent laboratory, field, and theoretical studies support the existence of a preparatory phase preceding earthquakes, where small and stable ruptures progressively develop into an unstable and confined zone around the future hypocenter. The problem of recognizing the preparatory phase of earthquakes is of critical importance for mitigating seismic risk for both natural and induced events. Here, we focus on the induced seismicity at The Geysers geothermal field in California. We address the preparatory phase of M~4 earthquakes identification problem by developing a ML approach based on features computed from catalogues, which are used to train a recurrent neural network (RNN). We show that RNN successfully reveal the preparation of M~4 earthquakes. These results confirm the potential of monitoring induced microseismicity and should encourage new research also in predictability of natural earthquakes
Shallow geology characterization using Rayleigh and Love wave dispersion curves derived from seismic noise array measurements
No full textEvent-specific ground motion anomalies highlight the preparatory phase of earthquakes during the 2016–2017 Italian seismicity
No full textAlthough physical models are improving our understanding of the crustal processes that lead to large earthquakes, observing their preparatory phases is still challenging. We show that the spatio-temporal evolution of the ground motion of small magnitude earthquakes can shed light on the preparatory phase of three main earthquakes that occurred in central Italy between 2016 and 2017. We analyze systematic deviations of peak ground accelerations generated by each earthquake from the values predicted by a reference ground motion model calibrated for background seismicity and refer to such deviations as event-specific ground motion anomalies (eGMAs). The eGMA temporal behavior indicates that during the activation phase of the main earthquakes, the ground shaking level deviates, positively or negatively, from the values expected for the background seismicity. eGMA can be exploited as beacons of stress change and help to monitor the mechanical state of the crust and the nucleation of large earthquakes.The spatio-temporal properties of ground shaking and foreshocks are distinguishable from typical background seismicity using an approach that can pinpoint crustal stress changes before the 2016-2017 seismic sequence in central Italy
Rapid estimation of macroseismic intensity for on-site earthquake early warning in Italy from early radiated energy
No full textRapid estimation of macroseismic intensity for on-site earthquake early warning in Italy from early radiated energ
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