Skip to content
Forecast BarA closer look at your world Get the app

READING THE NUMBERS

10 km S of Idyllwild, CA

Magnitude describes the source. Intensity describes what a place experienced.

← Back to this report

Shaking at a place

No shaking intensity has been published for this report yet.

See the actual reporting areas

MAGNITUDE · SOURCE SIZE

M1.0

Each one-unit increase represents about 32 times the energy released. Magnitude alone does not tell you how strongly a particular place shook.

DEPTH · BELOW THE EPICENTER

15.2 km · shallow

The epicenter is the surface point above the source. Shallow: under 70 km. Intermediate: 70–300 km. Deep: over 300 km.

Why local ground can change the shaking

SAME QUAKE. DIFFERENT GROUND.

Why nearby places
can feel it differently.

M1.0 describes the source. The ground under each location can change the shaking that arrives. Try changing one site below.

Site A · firm rockThe reference site
Site B · soft sedimentSame incoming wave, different ground
SAME INCOMING WAVE AT BOTH SITES
Soft layers can make some shaking larger and last longer. Send a wave to watch one possible response.
GROUND AT SITE B
TRY A WAVE RHYTHM
Ready

Illustrative ground motion, not measured conditions or building damage at this earthquake. Soft ground does not amplify every wave equally.

USGS: local ground effects

USGS magnitude & intensity · Report and alert questions