Two Novel Approaches toward the Reduction of False Alarms Due to Unknown Events in On-Site Earthquake Early Warning Systems

Two Novel Approaches toward the Reduction of False Alarms Due to Unknown Events in On-Site Earthquake Early Warning Systems

An on-site earthquake early warning system can provide more lead-time at regions that are close to the epicenter of an earthquake since only the seismic information of a target site is required. The on-site system extracts some P-wave features from the first few seconds of the vertical ground acceleration of a single station. It then predicts the intensity of the forthcoming earthquake at the same station according to these features. However, the system may be triggered by some vibration signals that are not caused by an earthquake or by interference from electronic signals, which may consequently result in a false alarm. Thus, this study proposes two approaches to distinguish the vibration signals caused by non-earthquake events from those caused by earthquake events, based on Support Vector Classification and Singular Spectrum Analysis. The results indicate that both of the proposed approaches effectively reduce the possibility of false alarms caused by an unknown vibration event.