1868 Hayward earthquake
E425610
The 1868 Hayward earthquake was a powerful and destructive seismic event that struck the San Francisco Bay Area in California, causing extensive damage and loss of life and serving as a key historical benchmark for seismic risk on the Hayward Fault.
All labels observed (2)
| Label | Occurrences |
|---|---|
| 1868 Hayward earthquake canonical | 3 |
| Great San Francisco earthquake of 1868 | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T4267424 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: 1868 Hayward earthquake Context triple: [Hayward Fault, lastMajorEarthquakeName, 1868 Hayward earthquake]
-
A.
1906 San Francisco earthquake
The 1906 San Francisco earthquake was a devastating magnitude 7.8 seismic event that struck Northern California, causing widespread destruction and fires that nearly leveled San Francisco and became one of the worst natural disasters in U.S. history.
-
B.
Loma Prieta
Loma Prieta is a prominent peak in California’s Santa Cruz Mountains, best known for lending its name to the devastating 1989 Loma Prieta earthquake.
-
C.
1989 Loma Prieta earthquake
The 1989 Loma Prieta earthquake was a powerful magnitude 6.9 quake in Northern California that caused widespread damage in the San Francisco Bay Area, including freeway collapses and the disruption of the World Series.
-
D.
1968 Borrego Mountain earthquake
The 1968 Borrego Mountain earthquake was a powerful magnitude 6.5–6.8 temblor in Southern California that caused significant surface rupture and damage, and became an important case study in modern seismology and fault mechanics.
-
E.
1185 Lincoln earthquake
The 1185 Lincoln earthquake was a significant medieval seismic event in England that caused extensive damage in the city of Lincoln and led to major reconstruction of Lincoln Cathedral.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: 1868 Hayward earthquake Target entity description: The 1868 Hayward earthquake was a powerful and destructive seismic event that struck the San Francisco Bay Area in California, causing extensive damage and loss of life and serving as a key historical benchmark for seismic risk on the Hayward Fault.
-
A.
1906 San Francisco earthquake
The 1906 San Francisco earthquake was a devastating magnitude 7.8 seismic event that struck Northern California, causing widespread destruction and fires that nearly leveled San Francisco and became one of the worst natural disasters in U.S. history.
-
B.
Loma Prieta
Loma Prieta is a prominent peak in California’s Santa Cruz Mountains, best known for lending its name to the devastating 1989 Loma Prieta earthquake.
-
C.
1989 Loma Prieta earthquake
The 1989 Loma Prieta earthquake was a powerful magnitude 6.9 quake in Northern California that caused widespread damage in the San Francisco Bay Area, including freeway collapses and the disruption of the World Series.
-
D.
1968 Borrego Mountain earthquake
The 1968 Borrego Mountain earthquake was a powerful magnitude 6.5–6.8 temblor in Southern California that caused significant surface rupture and damage, and became an important case study in modern seismology and fault mechanics.
-
E.
1185 Lincoln earthquake
The 1185 Lincoln earthquake was a significant medieval seismic event in England that caused extensive damage in the city of Lincoln and led to major reconstruction of Lincoln Cathedral.
- F. None of above. chosen
Statements (50)
| Predicate | Object |
|---|---|
| instanceOf |
earthquake
ⓘ
historical event ⓘ natural disaster ⓘ |
| affectedCity |
Hayward
ⓘ
Oakland ⓘ San Francisco ⓘ San Jose ⓘ San Leandro ⓘ |
| alsoKnownAs |
Great San Francisco earthquake of 1868
ⓘ
linked to:
1868 Hayward earthquake
|
| casualties |
about 30
ⓘ
about 35 ⓘ |
| category |
1868 disasters in the United States
ⓘ
Earthquakes in California ⓘ History of the San Francisco Bay Area ⓘ |
| caused |
building collapses
ⓘ
ground shaking across the San Francisco Bay Area ⓘ landslides ⓘ surface rupture ⓘ |
| country |
United States
ⓘ
linked to:
United States of America
|
| date | 1868-10-21 ⓘ |
| deaths |
about 30
ⓘ
about 35 ⓘ |
| epicenter |
Hayward, California
ⓘ
linked to:
Hayward
|
| estimatedMagnitude |
6.8
ⓘ
7.0 ⓘ |
| fault | Hayward Fault ⓘ |
| faultType | right-lateral strike-slip fault ⓘ |
| followedBy | 1906 San Francisco earthquake ⓘ |
| isPartOf |
history of California
ⓘ
seismic history of the San Francisco Bay Area ⓘ |
| localTime | about 7:53 AM ⓘ |
| magnitudeType | moment magnitude scale ⓘ |
| maximumIntensity | X ⓘ |
| maximumIntensityScale | Modified Mercalli intensity scale ⓘ |
| notableDamage |
damage to buildings in San Francisco
ⓘ
damage to masonry structures throughout the East Bay ⓘ severe damage in Hayward ⓘ |
| plateBoundary | transform boundary between the Pacific Plate and North American Plate ⓘ |
| precededBy | 1865 San Francisco earthquake ⓘ |
| regionAffected |
East Bay
ⓘ
San Francisco Bay Area ⓘ |
| significance |
key historical benchmark for seismic risk on the Hayward Fault
ⓘ
one of the most destructive earthquakes in 19th-century California ⓘ |
| state |
California
ⓘ
linked to:
California, United States
|
| studiedBy | United States Geological Survey ⓘ |
| surfaceRuptureLength |
about 20 miles
ⓘ
about 32 km ⓘ |
| timeZone |
Pacific Time
ⓘ
linked to:
Pacific Time Zone
|
| usedFor | seismic hazard assessment on the Hayward Fault ⓘ |
| year | 1868 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: 1868 Hayward earthquake Description of subject: The 1868 Hayward earthquake was a powerful and destructive seismic event that struck the San Francisco Bay Area in California, causing extensive damage and loss of life and serving as a key historical benchmark for seismic risk on the Hayward Fault.
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: 1868 Hayward earthquake