seismometer
Enable an agent to recognise a seismometer, assess whether its installation and response support a ground-motion measurement, and determine appropriate setup, monitoring and maintenance actions.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an agent to recognise a seismometer, assess whether its installation and response support a ground-motion measurement, and determine appropriate setup, monitoring and maintenance actions.
A seismometer is an instrument that senses ground motion, usually through the motion of an inertial mass relative to its supporting frame, and produces a signal from which ground displacement, velocity or acceleration can be determined using its calibrated response.
It can be Assess suitability for a specified ground-motion frequency and amplitude range using documented response and noise evidence.; Guide coupling, orientation and levelling using the applicable installation procedure.; Connect the sensor to compatible power and acquisition equipment and verify polarity and signal scaling.; Perform supported response checks or calibration procedures and associate results with the applicable configuration.; Diagnose suspect signals using sensor status, installation evidence and environmental observations.; Prepare the instrument for servicing or transport using its documented mass-locking and handling requirements..
Distinguishing features
Its intended measurement is ground motion transmitted through a documented installation, rather than an earthquake's magnitude or intensity directly.
Its documented response connects physical motion to sensor output; a recorder alone stores signals without providing this sensing function.
A seismometer may form part of a seismograph or integrated station, but the sensing function remains distinguishable from recording, timing and communications.
A geophone or accelerometer may overlap this category when used for seismic sensing; classification requires the intended role, measured quantity and response rather than the device name alone.
Scope
+ Ground-motion sensing principle and supported measurement components
+ Frequency response, sensitivity, noise and usable motion range
+ Ground coupling, orientation, levelling and environmental dependencies
+ Sensor outputs, power requirements and interfaces to acquisition equipment
+ Calibration, operating states and sensor-specific maintenance
- Earthquakes, seismic sources and earthquake magnitude estimation
- Seismic networks and observatories as managed systems
- Standalone digitizers, telemetry equipment and data archives
- Seismograms and derived seismic data products
- Product families and individual instrument asset records
- General-purpose vibration instruments outside their seismic sensing role
Characteristics
- Sensing principle
- Documented principle, such as passive inertial or force-feedback sensing; other or unknown Determines how motion produces an output and which setup and diagnostic procedures apply.
- Input motion quantity
- Displacement, velocity or acceleration, with the applicable response convention Prevents interpreting an output as a different physical quantity.
- Sensing components
- Number and arrangement of sensing axes, including physical and reported coordinate systems Establishes which motion components can be recovered.
- Instrument response
- Applicable response description, calibration record and configuration Connects the measured signal to physical motion and identifies the conditions under which conversion is valid.
- Usable frequency range
- Hz, with stated response tolerance and operating conditions Determines whether the instrument can support the intended seismic observation.
- Sensitivity
- Output per input motion quantity, such as V/(m/s), with reference frequency and gain setting Supports amplitude conversion and compatible acquisition settings.
- Self-noise
- Input-referred noise spectrum with physical quantity, spectral convention, frequency and test conditions Helps judge whether weak ground motion can be distinguished from instrument noise.
- Maximum usable input
- m, m/s or m/s² as applicable, with frequency and distortion or clipping criterion Identifies motion that may exceed the instrument's usable range.
- Installed orientation
- Axis azimuth and inclination in degrees, with reference frame and uncertainty Allows signals to be interpreted in the intended ground-coordinate system.
- Ground coupling
- Connection to substrate through a pier, pad, burial arrangement, borehole mount or other documented installation Determines whether housing motion is representative of the intended ground motion.
- Power and output interface
- Passive or powered operation; supply limits where applicable; analog or digital output specification Supports compatible connection and distinguishes power faults from sensing faults.
- Operating condition
- As applicable: transport-locked, settling, ready, calibrating, saturated, faulted or unknown Determines whether output is suitable for observation and which actions are appropriate.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Seismic sensing identity Establishes the sensing role, physical principle and component geometry.
An agent must distinguish a ground-motion sensor from its recorder and avoid treating overlapping instrument names as fixed technical boundaries.
Sensing role and boundary
Identifies the motion-sensing function within a standalone or integrated instrument.
Ground-motion sensing role
Record what physical motion is sensed and which parts of an integrated system provide sensing rather than recording or communication.
- What ground-motion quantity does this instrument sense, and how is that quantity represented at its output? definition
- Where does the seismometer function end and the digitizer, recorder or station function begin? boundary
Principle and components
Captures how sensing works and how the measured components relate to physical axes.
Sensing mechanism and axis map
Record the documented sensing mechanism, axis arrangement and any transformation from internal axes to reported components.
- Which sensing principle is documented, and does it involve active feedback? provenance
- How do physical sensing axes, channel labels and output polarity map to the reported motion components? measurement
Response and measurement limits Connects sensor output to ground motion and bounds usable measurements.
A signal cannot support quantitative interpretation without an applicable response and evidence about noise and overload.
Motion-to-output response
Identifies the response applicable to the sensor configuration.
Applicable response evidence
Associate sensitivity and frequency-dependent response with their configuration, provenance and validity conditions.
- Which calibration or response description applies to the present configuration, and what establishes its applicability? provenance
- What input quantity, output units, reference frequency and response tolerance are specified? measurement
Noise and overload envelope
Separates detectable motion from instrument noise and motion beyond the usable range.
Usable motion envelope
Record frequency-dependent noise and input limits while distinguishing sensor limits from acquisition limits.
- What self-noise and maximum-input evidence is available across the intended observation band? measurement
- Can an observed overload or noise floor be attributed to the sensor, the digitizer or the installation? boundary
Ground coupling and site effects Describes the mechanical and environmental conditions connecting the sensor to ground motion.
Installation motion, orientation errors and environmental disturbances can change what the instrument appears to measure.
Mounting and orientation
Captures attachment to the ground and alignment of sensing components.
Installed mechanical reference
Record substrate, mounting stability, level and axis orientation with their verification methods.
- How is the sensor coupled to the substrate, and what evidence supports the stability of that connection? provenance
- What are the installed axis orientations and level errors, including reference frame and uncertainty? measurement
Environmental disturbance
Identifies site conditions that may affect sensor behaviour or introduce unwanted motion.
Environmental susceptibility
Record applicable environmental limits and evidence of disturbance from temperature, moisture, tilt, cabling or nearby activity.
- Which environmental sensitivities and operating limits are documented for this instrument? provenance
- What observations or controlled checks could distinguish ground motion of interest from installation or environmental disturbance? action
Signal and power integration Makes the sensor usable within a measurement chain without absorbing the entire acquisition system.
Incorrect connections, scaling or component mapping can invalidate an otherwise functioning seismometer.
Electrical and output compatibility
Establishes compatible power, connections and signal handling.
Compatible sensor interface
Record supply requirements where applicable, connector assignments, output characteristics and acquisition compatibility.
- What supply, connector, grounding and input-loading requirements does the documented interface impose? provenance
- Which connection and signal checks establish compatibility before observations are accepted? action
Measurement-chain attribution
Tracks the boundary between sensor response and subsequent acquisition processing.
Traceable channel interpretation
Link sensor components and response to acquisition channels while identifying the equipment responsible for timing, sampling and conversion.
- Which device supplies timing, sampling and digital conversion, including any functions integrated into the sensor housing? boundary
- How are sensor sensitivity, acquisition gain, channel polarity and physical units verified together? measurement
Readiness, calibration and care Determines when measurements are usable and which interventions preserve or restore performance.
Transport restraints, settling, calibration signals and sensing-element faults require seismometer-specific interpretation and actions.
Sensing readiness
Interprets operating states and available diagnostics.
Observation readiness evidence
Record applicable indicators such as mass position, lock status, settling state and overload flags against documented acceptance criteria.
- Which status indicators establish readiness, and what thresholds or conditions does the applicable procedure specify? provenance
- Which supported action addresses an off-centre mass, persistent saturation or failure to settle? action
Response checks and handling
Controls calibration, servicing and transport interventions.
Verified intervention procedure
Identify supported tests and handling procedures, their effects on observations and the evidence needed before returning to service.
- What does the supported calibration or test procedure verify, and which parts of ground coupling or sensing remain untested? boundary
- What locking, shutdown, servicing and post-installation checks are required before moving the instrument or resuming observations? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This describes the instrument class, not a particular product or installed unit; all information is recalled rather than researched.
- Frequency limits and acceleration ranges are representative examples and require verification against a selected instrument's specifications.
- Terminology overlaps among seismometer, seismograph, geophone and accelerometer; the listed kinds mix response classes with deployment configurations.
- Which of these check these first hold for the sense of seismometer this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Short-period seismometer
- Broadband seismometer
- Long-period seismometer
- Strong-motion accelerometer
- Borehole seismometer
- Ocean-bottom seismometer
- Which of these kinds and varieties hold for the sense of seismometer this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Manufacturer model and serial number - Manufacturer-specific model designation and individual serial number - The model identifies a design; the serial number identifies a physical instrument.
- SEED network, station, location and channel codes - NET.STA.LOC.CHA - Identifies a seismic data stream and its deployment context, rather than uniquely identifying the physical sensor.
- Which of these identifiers and schemes hold for the sense of seismometer this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Detecting and locating earthquakes and estimating their magnitude
- Monitoring volcanic seismicity
- Imaging Earth's interior using seismic waves
- Monitoring induced seismicity near mines, reservoirs and subsurface injection operations
- Recording ambient ground vibration and strong earthquake motion
- Which of these real-world use hold for the sense of seismometer this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Broadband sensor frequency response - Approximately 0.0083-50 for a representative 120-second broadband instrument; response limits vary by design - Hz
- Number of measured motion components - 1 or 3; three-component instruments commonly measure one vertical and two horizontal components - components
- Strong-motion accelerometer full-scale acceleration - Common selectable limits include ±2 and ±4; these apply to strong-motion instruments rather than all seismometers - g
- Which of these typical measurements hold for the sense of seismometer this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Clipping or saturation when ground motion exceeds the instrument's measurement range
- Poor ground coupling, incorrect leveling or incorrect orientation degrading measurements
- Temperature changes, tilt, pressure changes and local activity introducing drift or noise
- Power loss, water ingress, corrosion or cable faults interrupting operation
- Incorrect response metadata or calibration producing erroneous motion amplitudes
- Which of these failure modes and hazards hold for the sense of seismometer this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Network and station naming practices vary among operators, although international waveform exchange commonly uses SEED-derived codes.
- Installation and environmental protection differ between polar, tropical, desert, borehole and submarine deployments.
- Which of these regional variation hold for the sense of seismometer this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Seismograph - Usually denotes the complete sensing and recording system; seismometer more specifically denotes the sensor, although usage overlaps.
- Seismogram - The recorded ground-motion time series, rather than the instrument that senses the motion.
- Geophone - Usually a relatively compact electromechanical ground-velocity sensor used in exploration or vibration surveys; it overlaps with the broader seismometer category.
- Accelerometer - Measures acceleration in many applications; a strong-motion seismic accelerometer is a ground-motion-specific member of that broader class.
- Seismoscope - Indicates that shaking occurred, sometimes with directional information, without necessarily producing a calibrated motion time series.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of seismometer this model covers, and on what evidence? provenance
What the second pass must settle
- Does the registry intend seismometer to include seismic accelerometers and geophones, and which neighbouring entries already own those kinds?
- Which authoritative sources establish performance terminology, calibration methods and applicable standards, including their issuing bodies?
- What sourced frequency ranges, noise levels, input limits, dimensions and power requirements are representative of the principal seismometer subtypes?
- Which response metadata conventions should this model reference for analog sensors and instruments with integrated digitizers?
- Which failure modes, maintenance needs, handling restraints and conformity requirements apply to particular designs rather than to all seismometers?