Severe
Severe shaking · Moderate to heavy damage potential
Damage slight in specially designed structures; considerable with partial collapse in ordinary buildings; great in poorly built structures.
Effects
People & Response
- Drivers strongly disturbed
- General panic; people difficult to control
- Difficult to stand even outdoors
Objects & Furnishings
- Heavy furniture overturned and displaced
- Sand and mud ejected from ground
- Springs and wells affected; water levels change
Structures & Environment
- Brick buildings moderately to extremely damaged
- Walls fall; stone walls cracked seriously
- Chimneys, stacks, and columns fall
- Tree branch and trunk breakage
Also at this level, in other versions of the scale
- Monuments fall USGS, The Modified Mercalli Intensity Scale (table image on that page)
- Considerable damage in ordinary substantial buildings, with partial collapse USGS, The Modified Mercalli Intensity Scale (table image on that page)
- Damage great in poorly built structures USGS, The Modified Mercalli Intensity Scale (table image on that page)
Observed at this level
Camera footage our reviewer rated VIII from the effects it shows. All 4 clips at VIII · Random clip at VIII
Simulated at this level
Our physics animations of familiar objects, shaken by the ground motion estimated for a city at intensity VIII.
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.