MAGNITUDE 3.9 EARTHQUAKE NEAR TURKEY ACCURATELY DETECTED USING ONLY ONE STATION
On December 4, 2021, at 13:01:10, a magnitude 3.9 earthquake struck the Greek Island of Chios, approximately 105km west of the city of Izmir in Turkey. Using only one seismic array located on the Turkish coast line, SeismicAI’s system accurately detected the event, providing 23 seconds of early warning.
Location of earthquake, array site and Izmir
BACKGROUND
Western Turkey’s Izmir, a city of over 4 million people, has experienced several large earthquakes throughout history. The last major quake was the 2020 Aegean Sea Earthquake, which hit approximately 70km southwest of the city. It had a magnitude of 7.0 and caused catastrophic damage, including over 100 casualties, thousands of serious injuries, and hundreds of destroyed buildings. Following the event, SeismicAI deployed a pilot earthquake early warning system that included two seismic arrays located close to the coast line aimed at rapidly detecting offshore incidents.
Timeline
On December 4, 2021, at 13:01:10, a magnitude 3.9 earthquake – one of the largest incidents since the pilot began – struck about 105km west of Izmir. The closest station, located about 37 km from the epicenter, detected the event at 13:01:15 when the P-wave arrived. Five seconds later, at 13:01:20, the S-wave arrived at the station and the system was able to determine the location and magnitude of the earthquake, leaving 23 seconds of warning time before the damaging S-wave hit Izmir at 13:01:43. Since the system operated as a pilot at the time, warnings were issued only to selected users and not to the general public.
Accuracy
Our estimate of the epicenter location, 38.2732°N 25.8137°E, was about 116 km from the city, very close to the real distance of 105 km. In addition, our magnitude estimate of 3.8 was very close to the catalog magnitude.
This is one of the world’s first large earthquakes to be accurately located in real time by just one seismic station, while providing considerable warning time. It demonstrates the tremendous potential of SeismicAI’s array technology for fast and accurate detection of offshore – and onshore – events.
