Wood–Anderson torsion seismometer
E77001
The Wood–Anderson torsion seismometer is an early 20th-century mechanical seismograph designed to measure local earthquake ground motion with high sensitivity, forming the instrumental basis for the original Richter magnitude scale.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Wood–Anderson torsion seismometer canonical | 3 |
| Wood–Anderson seismograph | 1 |
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
mechanical seismograph
ⓘ
scientific instrument ⓘ seismometer ⓘ torsion seismometer ⓘ |
| calibrationReferenceFor | Richter local magnitude ML ⓘ |
| component |
damped horizontal pendulum
ⓘ
lightweight mirror ⓘ photographic recording drum ⓘ torsion wire ⓘ |
| dampingType | aperiodic damping ⓘ |
| dataUsedFor | earthquake catalogs in early 20th century ⓘ |
| designedBy |
Harry O. Wood
ⓘ
John A. Anderson ⓘ |
| developedInPeriod | early 20th century ⓘ |
| eraOfMainUse |
1930s
ⓘ
mid-20th century ⓘ |
| field | seismology ⓘ |
| formsBasisOf |
Richter magnitude scale
ⓘ
surface form:
original Richter magnitude scale
|
| hasInfluenceOn | standardization of earthquake magnitude measurements ⓘ |
| hasKeyRoleIn | Richter magnitude scale ⓘ |
| hasOutput | seismogram ⓘ |
| historicalSignificance | provided first standardized instrumental basis for earthquake magnitude ⓘ |
| inspiredDevelopmentOf | later standardized short-period seismometers ⓘ |
| locationOfOriginalUse | Southern California ⓘ |
| measurementType | horizontal ground motion ⓘ |
| namedAfter |
Harry O. Wood
ⓘ
John A. Anderson ⓘ |
| notOptimizedFor | teleseismic (distant) earthquakes ⓘ |
| operatingPrinciple | torsional suspension of a horizontal pendulum ⓘ |
| optimizedFor | local and regional earthquakes ⓘ |
| orientation | typically installed in orthogonal horizontal components ⓘ |
| recordingMethod | optical recording on smoked paper or photographic paper ⓘ |
| relatedTo |
Richter magnitude scale
ⓘ
surface form:
Richter scale
local magnitude scale ⓘ |
| replacedBy | modern broadband seismometers ⓘ |
| requires | careful mechanical calibration ⓘ |
| requiresInstallation | rigid pier or foundation ⓘ |
| sensitivity | high sensitivity to local earthquakes ⓘ |
| standardInstrumentFor | original local magnitude (ML) scale ⓘ |
| status | largely obsolete ⓘ |
| typicalMagnification | about 2800 at 0.8 seconds ⓘ |
| typicalNaturalPeriod | approximately 0.8 seconds ⓘ |
| usedAt | Seismological Laboratory at Caltech ⓘ |
| usedBy | early 20th-century seismological observatories in California ⓘ |
| usedFor |
determining earthquake magnitude
ⓘ
measuring local earthquake ground motion ⓘ recording seismic waves ⓘ |
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Wood–Anderson seismograph