In Switzerland EEW has been in a demonstration phase for more than a decade. EEW systems and underlying algorithms are tested worldwide (e.g., Allen and Melgar, 2019), including Europe ( Clinton et al., 2016) and Switzerland ( Behr et al., 2015). EEW systems are used to deliver public warnings in Japan ( Doi, 2011), Mexico ( Cuéllar et al., 2014), South Korea ( Sheen et al., 2017), Taiwan ( Hsiao et al., 2009), and along the west coast of the United States of America ( Given et al., 2018). If appropriate protective actions are promptly taken, the impact of an earthquake can be reduced. Operating on the Swiss Seismic Network, that is being continuously optimised for EEW, the SED-ETHZ SeisComP EEW system is achieving performance that is comparable to operational EEW systems around the world.Įarthquake Early Warning (EEW) aims to detect seismic events and quantify their impact as soon as possible after they occur, ideally allowing seconds of warning time in advance of the arrival of strong ground motion in affected areas. This is documented with the case of a moderate M3.9 event that occured seconds after a quarry blast, where picks from both events produced a 4 s delay in the pick-based VS, while FinDer performed as expected. We demonstrate that operating two independent algorithms provides redundancy and tolerance to failures of a single algorithm. The median value for the travel time of the P waves from event origin to the fourth station accounts for 3.5 s of delay with an additional 1.4 s for real-time data sample delays. In real time performance, the median delay for the first VS alert is 8.7 s after origin time (56 earthquakes since 2014, from M2.7 to M4.6), and 7 s for FinDer (10 earthquakes since 2017, from M2.7 to M4.3). Both algorithms are observed to be similarly fast and can often produce first EEW alerts within 4–6 s of origin time. In this paper, we benchmark the performance of this SeisComP-based EEW system using recent seismicity in Switzerland. Together these methods can provide EEW for all event dimensions from moderate to great, if a high quality, EEW-ready, seismic network is available. FinDer matches growing patterns of observed high-frequency seismic acceleration amplitudes with modeled templates to identify rupture extent, and hence can infer on-going finite-fault rupture in real-time. VS provides rapid EEW magnitudes building on existing SeisComP detection and location modules for point-source origins. To date, implementations of the Virtual Seismologist (VS) and Finite-Fault Rupture Detector (FinDer) EEW algorithms are available. The SED has built a comprehensive set of SeisComP modules that can provide EEW solutions in a quick and transparent manner by any seismic service operating SeisComP.
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The Swiss Seismological Service (SED) at ETH has been developing methods and open-source software for Earthquake Early Warning (EEW) for more than a decade and has been using SeisComP for earthquake monitoring since 2012. Swiss Seismological Service, ETH Zürich, Zürich, Switzerland.Frédérick Massin*, John Clinton and Maren Böse