Implementing the ElarmS Earthquake Early Warning Algorithm on the Israeli Seismic Network

Abstract

Earthquake early warning systems (EEWS) are being operated and tested increasingly around the globe in recent years. Following the Israeli government’s decision to build an EEWS in Israel, and as the Californian EEWS (ShakeAlert) moves toward its operational phase, we demonstrate implementation of one of its three algorithms, ElarmS, to the Israel region. We provide new tools and approaches for implementing and assessing ElarmS outside of California. The main challenges of this research are to identify, verify, and adjust the embedded location‐dependent parameters in ElarmS to the Israeli region, utilizing an unoptimized seismic network and low seismicity rate. To this end, we run ElarmS in three different modes: (1) historical playbacks, (2) real‐time continuous data processing, and (3) simulated data playbacks. These modes enable us to overcome the limitations of low seismicity rates in the region and evaluate the performance of ElarmS with the network that is currently available. We use historical playbacks to adjust the magnitude estimation equations of ElarmS. We then analyze real‐time processing results and provide detailed analysis of two significant events in the region ( M D 5.5 and 4.4). Finally, we provide the first case of how to use synthetic data to evaluate the performance of ElarmS. We find that alert times are mostly affected by the network geometry and also by data delays. Alerts are typically issued within 80 ms after the arrival of the required four P ‐wave triggers data to the system. Magnitude estimations are reliable for events with M D>3.5 within 100 km of the Israeli network using a locally adjusted magnitude relation equation.