預警系統
There were also cases where large differences between estimated intensities by the Earthquake Early Warning system and the actual intensities occurred in the aftershocks and triggered earthquakes. Such discrepancies in the warning were attributed by the JMA to the system's inability to distinguish between two different earthquakes that happened at around same time, as well as to the reduced number of reporting seismometers due to power outages and connection fails. The system's software was subsequently modified to handle this kind of situation.