Earthquake Early Warning due to long-period ground motion

When a large-scale earthquake such as the Nankai Trough earthquake occurs, a slow and large shaking with a long period (the time it takes for one round trip) occurs. Such ground motions are called long-period ground motions.

Based on the degree of difficulty in human behavior during an earthquake targeting high-rise buildings and the degree of damage such as the movement and fall of furniture and fixtures, set by the Japan Meteorological Agency. It is an index divided into classes.

Basic knowledge and explanatory videos on long-period ground motions are posted on the Japan Meteorological Agency website linked below.

Measures to prevent furniture from falling, moving, and falling furniture are also very important as long-period seismic motion measures. In particular, if the shaking is large, the furniture etc. cannot be fixed sufficiently, and the door may be blocked due to a fall or colliding with the window glass and fall to the ground. It is also important to consider the location where furniture is to be installed, assuming in advance.