Intensity Lab
MMI Scale › Level VII
VII

Very Strong

Very strong shaking · Moderate damage potential

PGA
18 – 34 %g
PGV
31 – 60 cm/s
I II III IV V VI VII VIII IX X

Difficult to stand. Noticed by drivers. Damage negligible in well-built structures; considerable in poorly built ones.

Effects

People & Response

  • Difficult to stand; movement hard to control
  • Noticed by drivers of motor vehicles
  • General alarm; many people run outdoors

Objects & Furnishings

  • Large church bells ring
  • Heavy furniture overturned
  • Waves on ponds; water turbid with mud

Structures & Environment

  • Chimneys cracked considerably
  • Plaster falls in large amounts
  • Trees and bushes shaken moderately to strongly
  • Considerable damage in poorly built structures
Typical PGA (ShakeMap) 18 – 34 %g
Typical PGV (ShakeMap) 31 – 60 cm/s
PGA/PGV ranges are approximate; values overlap between adjacent levels. See Instrumental Intensity for details.

Video Example

MMI VII shaking example video thumbnail
Watch on YouTube ↗
← VI Strong Severe VIII →

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.