Retrospective performance analysis of a ground shaking early warning system for the 2023 Turkey–Syria earthquake

Recently developed earthquake early warning systems rely on the idea of combining the measured ground motion and the source parameter estimate to issue an alert based on the ground shaking prediction at sites where high potential damage is expected. Here we apply a P-wave, shaking-forecast method that can track and alert in real-time the area where peak ground motion is expected to exceed a user-set threshold during the earthquake. The system performance in providing a fast and reliable warning during the Mw 7.8, February 6 Turkey–Syria earthquake is investigated by the real-time simulated playback of the near-source hundred accelerograms. With an instrumental intensity threshold an alert issued 10–20 s after the event origin, results in 95% of successful warning (positive and negative) and lead-times of 10–60 s within the potential damage zone. Setting a higher intensity threshold requires larger alert times (50–60 s) to achieve 90% of successful warning and overall shorter lead-times. Our simulation shows that the P-wave predicted, strong-shaking zone can be rapidly detected only 20 s after the mainshock nucleation. As the time increases, it well delineates the NE-SW bi-lateral rupture development as inferred by kinematic source models.