Earthquake24 reference
Earthquake guides and seismic science
Source-reviewed explanations of earthquake measurements, terminology and the limits of reported seismic data.
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Can earthquakes be predicted?
No reliable method can specify an earthquake's exact time, location and magnitude in advance. Forecasts and early warning answer different questions.
Seismic referenceEarthquake aftershocks explained
Aftershocks are earthquakes in the source region after a larger mainshock. Their labels and sequence statistics are retrospective and probabilistic.
Seismic referenceEarthquake depth explained
Reported depth locates the hypocenter below a reference surface. It is an estimate, not a danger rating or a shaking radius.
Seismic referenceEarthquake intensity scale explained
Intensity describes shaking at a location. It is not the earthquake's magnitude, energy or a universal damage forecast.
Seismic referenceEarthquake magnitude and depth explained
A clear guide to Mw, the Richter scale, earthquake depth, shaking intensity, PAGER, VEI and volcano alert systems.
Seismic referenceEarthquake magnitude scale and classes
Magnitude estimates earthquake source size. The scale is logarithmic, and the reported type matters as much as the number.
Seismic referenceEarthquakes and tsunamis
A tsunami requires substantial displacement of water. An offshore earthquake can be large without generating a damaging tsunami.
Seismic referenceEpicenter vs hypocenter
The hypocenter is where rupture begins inside Earth. The epicenter is the point on the surface directly above it.
Seismic referenceForeshocks and earthquake swarms
Sequence labels describe observed relationships. A foreshock is known only after a larger event, while a swarm has no clear mainshock.
Seismic referenceHow Earthquake24 processes USGS earthquake and volcano data
From seismic networks and USGS HANS notices to validated, versioned JSON delivered through Cloudflare's edge network.
Seismic referenceHow earthquakes are measured
A seismic network turns recorded ground motion into estimates of origin time, location, depth, magnitude and review status.
Seismic referenceHow to read a USGS earthquake report
A catalog record combines a preferred source solution with timestamps, status and optional impact products. Each field answers a different question.
Seismic referenceRichter scale vs moment magnitude
Richter usually means local magnitude, ML. Moment magnitude, Mw, measures source size differently and works better for very large ruptures.
Seismic referenceSeismic waves explained
Earthquakes release energy as body and surface waves. Their speed, motion and path help locate the source and shape recorded ground motion.
Seismic referenceTectonic plates, faults and earthquakes
Plates move continuously, while locked faults can accumulate strain and release it through sudden slip. Not every earthquake lies exactly on a plate boundary.