from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Characterised by up-and-down oscillations of large amplitude, usually with reference to earthquakes.
from The Century Dictionary and Cyclopedia
- Exhibiting an up-and-down vibration of long amplitude, which causes a jumping movement: descriptive of a variety of earthquake shock.
From Italian sussultare ("jump up"). (Wiktionary)