This system was created by Evan Li. It is an experimental earthquake early warning system that utilizes USGS public SeedLink data streams to detect seismic events in real time.
As of April 2026, this system is unable to detect earthquake magnitude accurately. Alerts should be treated as preliminary detections only. For accurate and authoritative seismic information, please refer to the USGS Earthquake Hazards Program.
Earthquake detection uses the STA/LTA algorithm (Short-Term Average / Long-Term Average), a classic technique in seismology for identifying the onset of seismic waves in a continuous data stream.
The algorithm continuously computes two running averages of the raw seismogram amplitude:
When ground motion suddenly increases — as it does during a P-wave arrival — the STA rises sharply while the LTA remains low, causing the ratio to spike above the threshold and trigger an alert. Because this method only detects energy onset, it cannot reliably compute magnitude without additional processing steps such as peak amplitude measurement and distance correction, which this system does not yet perform.