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Deep-focus earthquake

earthquake with a hypocenter depth exceeding 300 km

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General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionSep 22, 2026
Entity authorityQ17006934 ↗
Source-derived summary

A deep-focus earthquake in seismology (also called a plutonic earthquake) is an earthquake with a hypocenter depth exceeding 300 km. They occur almost exclusively at convergent boundaries in association with subducted oceanic lithosphere. They occur along a dipping tabular zone beneath the subduction zone known as the Wadati–Benioff zone.

Discovery

Preliminary evidence for the existence of deep-focus earthquakes was first brought to the attention of the scientific community in 1922 by Herbert Hall Turner. In 1928, Kiyoo Wadati proved the existence of earthquakes occurring well beneath the lithosphere, dispelling the notion that earthquakes occur only with shallow focal depths.

Seismic characteristics

Deep-focus earthquakes give rise to minimal surface waves. Their focal depth causes the earthquakes to be less likely to produce seismic wave motion with energy concentrated at the surface. The path of deep-focus earthquake seismic waves from focus to recording station goes through the heterogeneous upper mantle and highly variable crust only once. Therefore, the body waves undergo less attenuation and reverberation than seismic waves from shallow earthquakes, resulting in sharp body wave peaks.

Focal mechanisms

The pattern of energy radiation of an earthquake is represented by the moment tensor solution, which is graphically represented by beachball diagrams.

Editorial summary

This brief starts where responsible research should: with the source description of “Deep-focus earthquake” as earthquake with a hypocenter depth exceeding 300 km. Everything that follows is an evidence route, not borrowed authority.

Editorial reviewA dependable orientation record for establishing vocabulary, names and a first evidence trail. The current lead gives the account dated anchors—1922, 1928—that can be checked directly. The selected authority fields contribute no independent date. The account is most persuasive where Deep-focus, earthquake and hypocenter can be independently traced.
Editorial analysis

Why this record matters

The subject matters to the general reference register because the source frames it as earthquake with a hypocenter depth exceeding 300 km. Its deeper value depends on whether names, dates, institutions and citations support that framing.

Evidence profile

The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 22, 2026. The linked authority identifier is Q17006934. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1922 and 1928.

Critical limits

A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.

How to read it

Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.

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The closest primary source, responsible institution and strongest cited specialist reference.

Three-step research path

  1. Establish the record: confirm the title “Deep-focus earthquake”, its source revision and the description used here.
  2. Expand the search: follow Deep-focus earthquake primary sources, Deep-focus earthquake archive and Deep-focus research across catalogues and specialist indexes.
  3. Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.

Questions for further research

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Source & attribution

This entry incorporates text from “Deep-focus earthquake” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.