Implementation of the Virtual Seismologist Early Warning Algorithm within the SeisComP3 Earthquake Processing System

The Virtual Seismologist (VS) earthquake early warning (EEW) methodology is a Bayesian approach to EEW, wherein the most probable source estimate at any given time is a combination of contributions from a likelihood function that evolves in response to incoming data from the on-going earthquake, and selected prior information, which can include factors such as network topology, the Gutenberg-Richter relationship or previously observed seismicity. The VS algorithm, implemented by the Swiss Seismological Service (SED) at ETH Zurich, is a fundamental component of the California Integrated Seismic Network (CISN) ShakeAlert system, and has been thoroughly tested in real-time the Southern California Seismic Network since July 2008, and at the Northern California Seismic Network since February 2009. SeisComP3 (SC3) is a fully featured automated real-time earthquake monitoring software developed by GeoForschungZentrum Potsdam in collaboration with commercial partner, gempa GmbH. It is becoming a community standard software for earthquake detection and waveform processing for regional and global networks across the globe, including at the SED. As part of efforts in the development of real-time seismology tools supported by the Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation (NERA), the VS EEW algorithm has been implemented within the SeisComP3 framework. We discuss the software design and development, as well as testing and performance evaluation on real-time and archived waveform data from the SED. The "VS in SC3" effort facilitates the seamless integration of real-time EEW within standard network processing at SED, as well as the distribution, installation, and real-time testing of the VS codes at various European networks, in particular, real-time test sites at Naples, Istanbul, Patras, and Iceland planned as part of FP7 project REAKT "Strategies and Tools for Real-Time Earthquake Risk Mitigation".