1509 Constantinople earthquake
7.7-magnitude earthquake that struck İstanbul in northwestern Turkey on September 10, 1509
The 1509 Constantinople earthquake, or historically Kıyamet-i Suğra ('Minor Judgment Day'), occurred in the Sea of Marmara on 10 September 1509 at about 22:00. The earthquake had an estimated magnitude of 7.2 ± 0.3 on the surface-wave magnitude scale. A tsunami and 45 days of aftershocks followed the earthquake. The exact death toll of this earthquake is unknown; estimates range between 1,000 and 13,000.
Background
The Sea of Marmara is a pull-apart basin formed at a releasing bend in the North Anatolian Fault, a right-lateral strike-slip fault. This local zone of extension occurs where this transform boundary between the Anatolian plate and the Eurasian plate steps northwards to the west of Izmit from the Izmit Fault to the Ganos Fault. The pattern of faults within the Sea of Marmara basin is complex but near Istanbul there is a single main fault segment with a sharp bend. To the west, the fault trends west–east and is pure strike-slip in type. To the east, the fault is NW-SE trending and shows evidence of both normal and strike-slip motion. Major shocks occurred at half-hour intervals and were violent and protracted in nature, forcing residents to seek refuge in open parks and squares.
Begin with the source’s own compact description: “1509 Constantinople earthquake” is 7.7-magnitude earthquake that struck İstanbul in northwestern Turkey on September 10, 1509. The dossier treats that line as a proposition to test through Constantinople, earthquake and 7-magnitude, not as a finished interpretation.
Why this record matters
The phrase “7.7-magnitude earthquake that struck İstanbul in northwestern Turkey on September 10, 1509” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 7, 2026. The linked authority identifier is Q1188930. Authority coordinates are 40.900, 28.700. 2 of 2 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1509.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. 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.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “1509 Constantinople earthquake”, its source revision and the description used here.
- Expand the search: follow 1509 Constantinople earthquake primary sources, 1509 Constantinople earthquake archive and Constantinople research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “1509 Constantinople earthquake”?
- What terminology or title could unlock a more precise catalogue search?
- Which cited source is closest to the event, object or claim?
Search terms from this dossier
This entry incorporates text from “1509 Constantinople 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.