Violent
Violent shaking · Heavy damage potential
General panic. Well-designed structures thrown out of plumb; great damage in substantial buildings with partial collapse. Buildings shifted off foundations.
Effects
People & Response
- General panic; widespread fear
- Difficult or impossible to stand outdoors
Objects & Furnishings
- Water reservoirs seriously damaged
- Underground pipes broken
Structures & Environment
- Well-designed frame structures thrown out of plumb
- Buildings shifted off foundations; walls collapse
- Ground cracked conspicuously
- Considerable damage even in specially designed structures
Also at this level, in other versions of the scale
- Damage great in substantial buildings, with partial collapse USGS, The Modified Mercalli Intensity Scale (table image on that page)
Simulated at this level
Our physics animations of familiar objects, shaken by the ground motion estimated for a city at intensity IX.
Video Example
Descriptions are verbatim from the USGS MMI Scale, based on Wood & Neumann (1931) and Richter (1958). Source: USGS Modified Mercalli Intensity Scale .
Instrumental intensity values and PGA/PGV ranges from USGS ShakeMap V4 Technical Documentation (Worden et al.). Intensity Lab reports MMI derived via the Worden et al. (2012) GMICE, interpolated from USGS ShakeMap. PGA/PGV ranges are approximate; actual values overlap between adjacent levels.