weak earthquake; light earthquake
Refers to an earthquake of low intensity, typically one that is barely felt or causes minimal shaking. Often used in news reports and seismic terminology.
昨夜、関東地方で軽震が観測された。
A weak earthquake was observed in the Kanto region last night.
A weak earthquake occurred in the Kanto region this morning.
A light earthquake causes almost no damage.
The Meteorological Agency recorded a weak earthquake in this area.
強震 refers to a strong, clearly felt earthquake, standing in contrast to the mild 軽震.
微震 denotes an even fainter tremor than 軽震, often imperceptible, while 軽震 is a slightly stronger but still weak shake.
弱震 is the older seismic-scale term for a somewhat stronger shake than 軽震, and the two are easily confused in historical reports.
Compound of 軽 (light, slight) and 震 (earthquake, tremor). The term is used in modern Japanese seismic intensity scales to describe low-level shaking.