Hanging objects such as lamps swing significantly, and dishes in cupboards rattle. Hanging objects such as lamps swing slightly.įelt by most people in buildings. Imperceptible to people, but recorded by seismometers.įelt slightly by some people keeping quiet in buildings.įelt by many people keeping quiet in buildings. Human perception and reaction, indoor situation, outdoor situation Seismic intensity The information outlined here is regularly checked at intervals of about five years, and is updated in line with actual phenomena observed in new cases or improvements in the earthquake resistance of buildings and structures.Not all phenomena described for each intensity level may necessarily occur. In some cases, the level of damage may be greater or less than specified. This document describes typical phenomena that may be seen at individual levels of seismic intensity.Sites with the same level of seismic intensity will not necessarily suffer the same degree of damage, as the effect of tremors depends on the nature of the seismic motion (such as amplitude, period and duration), the type of construction and underground conditions.In addition, the amplitude of seismic motion generally differs by floor and location within the same building, as shaking on upper floors may be considerably amplified. Seismic intensity is the value observed at a site where a seismic intensity meter is installed, and may vary even within the same city. Seismic ground motion is significantly influenced by underground conditions and topography.Seismic intensities are not determined from the observed phenomena described here. ![]() This document describes the phenomena and damage that may be observed for individual seismic intensity levels. As a rule, seismic intensities announced by JMA are values observed using seismic intensity meters installed on the ground or on the first floor of low-rise buildings.Influence on utilities and infrastructure, etc.Human perception and reaction, indoor situation, outdoor situation.Tables explaining the JMA Seismic Intensity Scale Contents
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