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.
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 |
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 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 (1)
| Subject (surface form when different) | Predicate |
|---|---|
|
Richter magnitude scale
→
|
definedUsing |