The system is highly effective, but it is not perfect. In some cases, the system may not be able to detect an earthquake in time to issue an alert. For example, if an earthquake occurs very close to a populated area, the shaking may begin before the system can issue an alert. Additionally, the system may not be able to detect earthquakes that occur very deep underground or in remote areas.

Why Did it Failed This Time during 2024 Japan Earthquake?

Nevertheless, Japan’s early warning system should have kicked in. It didn’t. Officials at the Japan Meteorological Agency (JMA) say that the system, meant to give at least 10 seconds’ warning of an earthquake, missed the incident because it was a borderline case.

Map of Japan locating the epicentre of a 7.5-magnitude earthquake on January 1 – Via AFP / AFP

How Does it Work?

The system is composed of three main components: the seismometers, the data processing center, and the alert distribution system. The seismometers are located throughout Japan and are used to detect earthquakes. The data processing center receives data from the seismometers and uses it to estimate the location and magnitude of the earthquake. The alert distribution system then issues alerts to the public through a variety of channels.

When an earthquake is detected, the system estimates the location and magnitude of the earthquake and issues an alert to the public. The alert provides information about the location and magnitude of the earthquake and advises people to take appropriate action, such as seeking shelter or evacuating the area.

According to the California Institute of Technology, early-warning alerts are typically delivered three to five seconds after an earthquake starts. This is the time it takes for seismic waves to travel to the closest stations and for computers to analyze the data.

Japan’s earthquake early warning system is a highly effective system that is designed to detect earthquakes and issue alerts to the public before the shaking begins. The system works by detecting the fast-moving P-waves that are generated by an earthquake and using them to estimate the location and magnitude of the earthquake. While the system is highly effective, it is not perfect, and there are some cases where it may not be able to detect an earthquake in time to issue an alert. Nonetheless, the system has saved countless lives and is an important tool for mitigating the impact of earthquakes in Japan.