Around the world, few countries have a seismic warning system: Japan, China, Romania and Taiwan are among them. However, they do not all work in the same way, nor do they have the same scope.
Below all the details.
To date, the most advanced system is that of Japan, in force since 2007. Located on the Pacific Ring of Fire, the Asian country is prone to earthquakes, such as the one in 1923 or 2011, which left thousands dead, the latter causing a tsunami and a disaster at the Fukushima nuclear power plant.
The Japanese system detects the movements, calculates the epicenter and sends warnings from the 1,000 seismographs that it has distributed in the country. It is capable of measuring P waves (first, they are the first evidence of an earthquake) and S waves (secondary, the most destructive). It is managed by the National Research Institute for Earth Science and Disaster Prevention, although it is the Agency Japan Meteorological which sends the warnings.
There are also private early warning systems, operating mainly in offices and factories. Operated by the National Service of Meteorology and Hydrology, it detects earthquakes greater than magnitude 5, on the Shindo scale, or 4.5, on the Richter scale.
Unlike Mexico, the alerts in Japan come in the form of images with warnings that an earthquake is approaching. They can be via message on the cell phone, television and the audio is also transmitted on the radio. Some cable television providers have a paid service to notify customers. The sound is very different from the Mexican alert. It is designed to try to prevent panic among people.
The Japan Meteorological Agency (JMA) has two earthquake early warning systems, one for advanced users and one for the general public. P-waves are detected by more than 4,235 seismometers installed across Japan since April 1, 2010, the JMA automatically analyzes and predicts the epicenter area and warns people in the danger zone through the television and radio only if a strong tremor is expected.
Earthquake early warning is broadcast to the general public via television, radio, text messages, computer alerts, etc. It is displayed when the JMA detects an earthquake greater than 5 degrees on the Shindo scale.
On the other hand, the prediction type early warning is issued to advanced users when the earthquake exceeds 3 degrees Shindo.
Taiwan has a regional system, developed by the Central Climate Bureau, the National Center for High Performance Computing, the Center for Earthquake Engineering Research, and the National Center for National Science and Technology and Disaster Reduction, with a cost equivalent to one million dollars.
The system is installed in just over 200 schools, although the goal is to alert the rest of the population. In some cases, in addition to an audible tone, the warning works by flashing LED lights to alert students.
The 1977 earthquake served for Romania to start implementing seismic risk reduction measures. This strategy includes the development and implementation of improved building codes, the identification of risk structures and the development of different programs to improve the safety of the region. All these measures have had continuity, one of them was the implementation of the Vrancea Early Warning System.
The Vrancea Early Warning System project started in 2003. To date, a total of 60 powerful Pavian sirens have been installed in the danger zones. The control center of the system is located in the city of Focsani. Communications within the system are carried out through an analog radio channel characterized by rapid system activation and high signal transmission security.
Some of the sirens in the system communicate directly with the communication repeater units, while others are managed locally.