Modified Mercalli Intensity I MMI I: Not felt
MMI I means the shaking is not felt. Not felt except by a very few under especially favorable conditions. Typical peak ground acceleration is under 0.05% of gravity, and it causes no damage.
What MMI I does
- Perceived shaking
- Not felt
- Damage potential
- None
- Peak acceleration
- under 0.05% g
- Peak velocity
- under 0.1 cm/s
What people feel
- Not generally felt by people
- Detected only by sensitive instruments
- Birds and animals may become uneasy
What objects do
- Trees and structures may sway very slowly
- Doors may swing very slowly
What happens to buildings
- No damage to structures
- No perceptible ground motion
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 I on YouTube.
Recently at MMI I in our region
Earthquakes in the western United States and northern Mexico whose strongest shaking at a named place reached this level.
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M3.3
19 km W of Preston, Nevada
2026-10-06 · Ely, MMI 1.0 I -
M3.5
25 km WNW of Preston, Nevada
2026-10-06 · Ely, MMI 1.1 I -
M3.8
20 km WSW of Gerlach, Nevada
2026-09-16 · Johnstonville, MMI 1.3 I -
M3.4
10 km ENE of Coso Junction, CA
2026-08-23 · China Lake Acres, MMI 1.2 I -
M3.5
26 km WNW of Ludlow, CA
2026-04-17 · Mountain View Acres, MMI 1.1 I
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 I is estimated
From instruments
USGS ShakeMap converts peak ground acceleration and velocity recorded at seismic stations into intensity. About under 0.05% g of acceleration corresponds to MMI I.
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 I?
It depends on distance and ground conditions, not magnitude alone. In our region, MMI I has come from earthquakes such as M3.3 near Preston, Nevada (2026); M3.5 near Preston, Nevada (2026); M3.8 near Gerlach, Nevada (2026).
What does MMI I feel like?
Not generally felt by people. Detected only by sensitive instruments. Birds and animals may become uneasy.
How strong is the ground motion at MMI I?
Peak ground acceleration is typically under 0.05% g and peak velocity under 0.1 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.