Earthquake location, source magnitude and local intensity
A source location or magnitude does not describe the shaking experienced at every site.
Key knowledge
An earthquake's hypocenter or focus is the point where rupture initiates; its epicenter is the surface point above that origin. A fault rupture extends over an area, so its epicenter does not locate all slip. A magnitude characterizes source size using a specified scale, whereas intensity describes shaking effects at a particular location. One earthquake can therefore have different local intensities. Distance, source depth and rupture direction, propagation and local ground conditions affect those differences.
Conditions and scope
- Specify the magnitude and intensity scales; estimates from different methods can differ or be revised.
- Felt-effects intensity, measured ground-motion time histories and source moment are related but different observables. Intensity values alone do not supply a complete local risk assessment.
Sources · 3
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Rupture initiation versus extended slip, source magnitude versus spatially varying shaking intensity.
2026-10-10 · Independent Mathematics and Information editor (AI editorial/source review; not the Chemistry/Biology/Earth author). The specified introductory inventory has no unresolved demonstrated material gap after the changes and body-based reuse. Existing advanced references retain their historical scoped approvals. English-only reference prose and explicit Lithuanian-translation-pending status are preserved.
Foundational review
2026-10-10 · Independent AI editorial inspection of this new compact reference entry, its equations, applicability, sources and knowledge connections.
Sources from other places
Agreement within this scope
Focus/epicentre and magnitude versus local intensity.
Source size and local shaking effects are different measures.
Geoscience Australia
- Earthquake AustraliaEnglish
What is an earthquake?; Magnitude and intensity
- Earthquake
Entry details
Permanent link to this entry ↗- Record identity
- foundation-earth-earthquake-location-intensity
- Revision
- foundations-audit.1
- Structured reference record
- Foundational core completion