Isoseismal
/ˌaɪsoʊˈsaɪzməl/adjective
Joining places that felt an earthquake with the same intensity.
The Greek roots
Literally: “of equal shaking”
The story of the word
Draw a line through every village that shook equally hard and you have an isoseismal. The word belongs to the vocabulary Robert Mallet assembled around 1857 while mapping the great Neapolitan earthquake, the same effort that handed English seismology and epicentre. Intensity is not magnitude, so the lines are drawn from what people felt and what walls did rather than from an instrument, which is why isoseismals bend around soft ground instead of forming neat rings.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 1850s
Same family
In a sentence
The isoseismal map showed the damage running down the valley, not outwards from the source.
Two towns the same distance from the epicentre sat on different isoseismals.