Tokyo'sThe core of EEW lies in millisecond level tracking and intelligent analysis of two types of seismic waves. When an earthquake occurs,P-waves (longitudinal waves) will arrive at the ground first, followed closely by S-waves（transverse wave）The EEW system consists of 4200 monitoring stations“neural network”Real time capture of two seismic waves with distinct propagation characteristics，combined algorithmAfter completing magnitude estimation and source localization,Complete warning before seismic waves reach the cityTransforming the passive response of traditional earthquake monitoring into active defense.

On October 1, 2007, when a 6.9 magnitude earthquake occurred in the northwest of Chiba Prefecture, the EEW systemearthquakeBefore arrivalAn alert is issued to the Tokyo Metropolitan Government in 8.5 seconds, which is three times faster than traditional earthquake monitoring. This historic breakthrough marks Japan as the first country in the world to achieve city level earthquake warning. In the 2011 Great East Japan Earthquake, the EEW system faced the test of a 9.0 magnitude super strong earthquake for the first time, and was detected underwater in Miyagi Prefectureseismic waveStrive for Tokyo29 second warning time.

Technological iteration always accompaniesEEW system growth. In 2016, the system introduced AI magnitude estimation algorithm, which improved the accuracy of early warning for earthquakes with a magnitude of 7 or above from 78% to 92%; Completed in 2020“The unity of heaven and earth”Construction and integration of monitoring network4200 ground-based seismometers and InSAR data from 3 satellites，EEW system response speed has increased by 40% compared to 2007，answerAccuracy of early warning for earthquakes with a magnitude of 7 or abovearriveextend92%, with an average response time reduced to 8.6 seconds. In the 2024 Noto Peninsula earthquake, the EEW system demonstrates evolved capabilities，First implementation of secondary rupture warning.

EEW systemAlso makesCross departmental collaboration mechanismanti-seismicConstantly adjusting in actual combat. Tokyo Metropolitan Disaster Prevention Center launches simultaneously“City Guardian”plan，Deploying ittwo30000 unitsAed18000 underground water reservoirs are monitored for water quality, and 347 community shelters are equipped with air purification systems. When the warning is triggered, Tokyo Electric Power Company automatically cuts off the power supply of 26000 kilometers of underground cables to prevent secondary fires; Fire department activated“Honeycomb Rescue”pattern,1300 fire trucks form automatically based on GPS heat maps; Medical system adjusts 48000 beds 72 hours ahead of scheduleearthquake proof constructionThis precise coordination has enabled Tokyo to rank first in Asia in the 2025 Global Resilient City Assessment.

Standing at Marunouchi Exit of Tokyo Station,The ticking warning countdown on the electronic screen of the EEW system has become a part of the city's pulse. This mega city has proven in 30 years that when technology and institutions resonate, humans can completely tear open a passage of life in the waves of death caused by earthquakes.