Modified Mercalli Intensity II MMI II: Weak shaking
MMI II is weak shaking. Felt only by a few persons at rest, especially on upper floors of buildings. Typical peak ground acceleration is 0.05–0.29% of gravity, and it causes no damage.
What MMI II does
- Perceived shaking
- Weak
- Damage potential
- None
- Peak acceleration
- 0.05–0.29% g
- Peak velocity
- 0.1–1.1 cm/s
What people feel
- Felt by few people, especially on upper floors
- Sensation of dizziness or nausea reported by some
- Those at rest are more likely to feel it
What objects do
- Delicately suspended objects swing slightly
- No rattling of windows or dishes
What happens to buildings
- No damage to structures
- Upper floors of tall buildings respond more
Also at this level, in other versions of the scale
- Sometimes birds, animals, reported uneasy or disturbed Wood & Neumann (1931), Bulletin of the Seismological Society of America 21, 277-283
- Bodies of water may sway Wood & Neumann (1931), Bulletin of the Seismological Society of America 21, 277-283
Sources: the USGS Modified Mercalli Intensity scale (Wood and Neumann, 1931; Richter, 1958); ground-motion ranges from the USGS ShakeMap documentation (Worden et al., 2012), approximate and overlapping between neighbouring levels. See instrumental intensity. An older example: MMI II on YouTube.
Recently at MMI II in our region
Earthquakes in the western United States and northern Mexico whose strongest shaking at a named place reached this level.
-
M3.6
31 km SW of Dana Point, CA
2026-10-05 · San Juan Capistrano, MMI 2.2 II -
M4.8
97 km W of Petrolia, CA
2026-09-29 · Eureka, MMI 2.1 II -
M4.1
20 km W of Preston, Nevada
2026-09-27 · Ely, MMI 2.1 II -
M4.1
21 km W of Preston, Nevada
2026-09-27 · Ely, MMI 2.2 II -
M3.7
36 km E of Hydesville, CA
2026-09-07 · Rio Dell, MMI 2.2 II
Seen on camera: no clips yet
Each clip is rated from the effects it shows. A rating describes one camera at one place, not a whole town.
How MMI II is estimated
From instruments
USGS ShakeMap converts peak ground acceleration and velocity recorded at seismic stations into intensity. About 0.05–0.29% g of acceleration corresponds to MMI II.
From people's reports
USGS Did You Feel It? turns answers from thousands of people into a community intensity for each place. If you felt an earthquake, report it there.
From footage
We rate each clip with questions built from the scale's own statements: what people, objects and buildings do on camera. A rating describes one camera at one place.
Common questions
What magnitude causes MMI II?
It depends on distance and ground conditions, not magnitude alone. In our region, MMI II has come from earthquakes such as M3.6 near Dana Point, CA (2026); M4.8 near Petrolia, CA (2026); M4.1 near Preston, Nevada (2026).
What does MMI II feel like?
Felt by few people, especially on upper floors. Sensation of dizziness or nausea reported by some. Those at rest are more likely to feel it.
How strong is the ground motion at MMI II?
Peak ground acceleration is typically 0.05–0.29% g and peak velocity 0.1–1.1 cm/s.
How is intensity different from magnitude?
Magnitude measures the energy an earthquake releases and is one number per earthquake. Intensity describes the shaking at one place, so a single earthquake produces many intensities, strongest near the fault and weaker with distance.