Enhancing Railway Earthquake Early Warning Systems with a Low Computational Cost STA/LTA-Based S-Wave Detection...

Area of Science:

• Geophysics
• Seismology
• Earthquake Engineering

Background:

• Real-time S-wave detection is critical for effective earthquake early warning (EEW) systems.
• Existing algorithms, like STA/LTA, face challenges in accurately distinguishing P- and S-waves, leading to potential false alarms.

Purpose of the Study:

• To enhance the robustness and computational efficiency of the STA/LTA algorithm for improved S-wave detection in railway EEW systems.
• To reduce false alarms in earthquake early warning systems, particularly for moderate earthquakes.

Main Methods:

• Modified the existing STA/LTA algorithm by incorporating pre-P-wave amplitude information.
• Introduced noise reflecting P-wave amplitude to better differentiate between P- and S-waves.
• Evaluated the method on seismic waveforms from earthquakes with M5.5-6.5 and depths ≤ 100 km within 100 km of the epicenter.

Main Results:

• Achieved a significant improvement in S-wave detection accuracy, reaching 81.0% within 1.5 seconds of manual picking.
• This represents a substantial increase from the 49.0% accuracy of the current operational railway EEW system.
• The enhanced method's computational cost is comparable to the existing system, facilitating easy integration.

Conclusions:

• The modified STA/LTA algorithm offers a more accurate and efficient solution for real-time S-wave detection in EEW systems.
• This advancement is crucial for minimizing false alarms and mitigating the social impact of unnecessary warnings.
• Future implementation into current systems will further enhance early warning capabilities.