MAKE SENSE OF THIS EARTHQUAKE
15 km SW of Loyola, CA
A magnitude of 1.3 describes the size of this quake. The report has no shaking intensity yet. Explore the clues different intensities leave, and see why depth and local ground matter.
What this shaking can feel like
Watch the lamp, water and loose objects.
Illustrative object motion, not a recording of this earthquake.
No shaking intensity in this report yet · example level
Light
Modified Mercalli intensityMany indoors notice shaking; dishes or windows may rattle.
Watch the lamp and glass. Small household objects make the movement easier to notice.
THE SOURCE, BELOW THE EPICENTER
-0.2 km deep
The epicenter is the surface point above the source. Follow the wave from where the quake begins.
How much energy is M1.3?
M1.3 releases about 31.6 times as much energy as M0.3. Circle areas compare that energy.
10× measured-wave amplitude · 31.6× approximate energy. This comparison describes source size; it does not set local shaking.
The report has no published shaking intensity. The room starts with a clearly labeled example.
What these illustrations can tell you
The scene translates an intensity description into familiar visual cues. Object movement is illustrative, with no modeled building damage. A summary or reporting-area intensity is not the intensity at every address.
The reported depth is -0.2 km, outside the scene’s range. The source view uses the reported depth where available. Depth is on a fixed linear 1–700 km display scale; the horizontal distance scale is compressed. The illustrated landscape, wave timing and wave size are not measurements of this event. Reported values outside the controls’ ranges remain unchanged in the original report.
Magnitude and energy follow the standard approximate logarithmic relationship. Intensity describes a place and is never calculated from the magnitude slider. USGS: magnitude and intensity · MMI descriptions
SAME QUAKE. DIFFERENT GROUND.
Why nearby places
can feel it differently.
M1.3 describes the source. The ground under each location can change the shaking that arrives. Try changing one site below.
A controlled visual example, not measured motion or ground conditions at this event. Wave rhythm, soil layers and local geology all matter; soft ground does not amplify every wave equally. The houses stay intact because this illustration compares ground motion, not building damage.
What to take away for this earthquake
Magnitude is shared by the entire earthquake. Intensity varies from place to place. A farther location on softer ground can sometimes shake more than a closer location on rock. Use actual reporting areas and ShakeMap to understand this event’s geographic pattern.
These moving traces are illustrative. Their timing and height are not seismograms or predicted amplification factors. USGS research on local ground effects
Explore the real reporting areasA quick guide to reading this report
One source magnitude, many local intensities.
The magnitude tells you how big the earthquake was. Intensity describes shaking at a place. A larger source releases more energy, but distance, depth, ground and the building affect what reaches you. Open the energy comparison above to see how a one-unit magnitude change works.
A summary is a starting point.
A ShakeMap maximum describes the strongest modeled location. A community intensity combines what people reported. Neither says that every place experienced that intensity. Choose a real reporting area above or explore the event’s felt-report map for geographic detail.
Time and review status matter.
Origin time is when the earthquake happened; the update time is when USGS revised the report. Preliminary measurements can change. Nearby earthquakes are not automatically aftershocks.
If you feel shaking, drop, cover and hold on. Follow local emergency instructions. USGS safety guidance · Earthquake field guide