日本地震情報

Current and past earthquake information is displayed in a list.

Red Mac is an earthquake with a maximum seismic intensity of 5 or more.
Gold Mac is an earthquake with a maximum seismic intensity of 5 or less and 3 or more.
Green Mac is an earthquake with a maximum seismic intensity of 3 or less.

The list is colored, so it is easy to understand.

In addition, as soon as the Japan Meteorological Agency announces earthquake information, it is added to the list.
Tapping the list will display detailed earthquake information.
Tapping the "Go to Map" button will display the corresponding epicenter on a map.

Difference between magnitude and seismic

intensity Magnitude is a scale originally invented by American seismologist Richter, and was used as a means of indirectly expressing the amount of energy of seismic waves emitted from the epicenter. It is defined as a logarithmic value obtained by reading the half amplitude (half the amplitude) of the record of a Wood Anderson seismograph installed 100 km from the epicenter (the surface directly above the epicenter) in micrometers (1/1000 mm). It is called the Richter scale. Originally, the magnitude was intended for shallow earthquakes that occur in California, so the depth of the epicenter was ignored. Subsequent research on earthquakes revealed that there are seven different magnitudes because the nature of earthquakes is diverse and one scale cannot accurately express the scale of an earthquake. The magnitude commonly used in Japan is the Japan Meteorological Agency magnitude, which has been improved to most easily express earthquakes observed in Japan that occur around Japan. The Japan Meteorological Agency magnitude is represented by M. Depending on the magnitude
M, earthquakes are classified as "major earthquakes" if M is 7 or more, "medium earthquakes" if M is 5 or more but less than 7, "small earthquakes" if M is 3 or more but less than 5, "microearthquakes" if M is 1 or more but less than 3, and "ultra-microearthquakes" if M is less than 1. Earthquakes of magnitude 7.8 or more are sometimes called "huge earthquakes."

Seismic intensity indicates the degree of shaking of an earthquake at a certain point. The shaking at a certain point depends not only on the energy scale (magnitude) of the earthquake, but also on the distance from the epicenter to that point, the depth of the epicenter, the propagation path, and the ground conditions around that point.
When considering the seismic intensity at a certain point, if all other conditions are the same, the greater the magnitude, the greater the seismic intensity, but in the case of a shallow, direct-hit earthquake, even if the magnitude is not that great, the seismic intensity is high only around the epicenter (the area where the energy accumulated by the earthquake is released), and it can cause great damage in a small area.
Traditionally, the Japan Meteorological Agency determined seismic intensity based on the sensation of the earthquake, the damage situation, or the degree of the earth's deformation.