Plate Motion Rate & Distance Projector

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Earth & Space (astronomy, orbital mechanics, meteorology, geology, geodesy, oceanography)

Tranche

tranche-7

Evidence ID

t7-096

Ledger rows

1

No ledger note is attached.

Review findings

The arithmetic method is valid for a constant scalar rate, but the instrument specification is incomplete for a scientifically honest plate-motion lookup tool. The preset table needs a defined source release, reference frame, epoch, geographic basis, and vector-to-scalar reduction method. The UI must explicitly support and validate the inverse operation t = d/rate.

Formula and scope findings

• The distance formula d = rate × time is correct for constant scalar speed with consistent units.
• The claimed inverse operation, time to travel a distance, requires the additional formula t = d ÷ rate; that inverse formula is not stated.
• A named tectonic plate does not uniquely determine one scalar velocity. Plate motion is a vector whose magnitude and direction depend on the reference frame, geographic location, observation site, epoch, and selected model.
• The preset-rate table must specify its model/version, reference frame, epoch, geographic reference point or averaging method, and whether each value is a magnitude or a signed component.
• The instrument needs a constraint that rate must be positive and nonzero for time-to-distance calculations; zero rate causes division by zero and negative scalar rates are ambiguous unless direction is represented separately.
• For very long geological time spans, constant present-day rate extrapolation is scientifically unsuitable unless the result is explicitly labeled as a kinematic projection rather than a historical reconstruction.

Unit assumptions

• Rates are interpreted as centimeters per Julian year unless the input explicitly specifies another time unit.
• The Julian year is exactly 365.25 days under the IAU standard convention; for rate calculations, years are treated as the same unit on both sides, so the day conversion is not needed unless the user enters days.
• SI decimal length conversions are exact: 1 m = 100 cm and 1 km = 100000 cm.
• Distance is treated as the scalar magnitude of displacement along a straight-line path; no spherical-geodesic correction or direction calculation is included.
• Preset rates are assumed to be rounded representative scalar magnitudes, not complete plate-motion vectors.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The inverse time operation is undefined for zero rate and must reject distance=100 cm with rate=0 cm/yr. A second hazard is the unclarified treatment of negative custom rates, which can produce either signed displacement or an invalid input depending on the UI convention.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "operation": "distance",
    "rate": 1,
    "rate_unit": "cm/yr",
    "time": 365.25,
    "time_unit": "Julian years",
    "plate": "custom"
  },
  "expected_outputs": {
    "distance_cm": 365.25,
    "distance_m": 3.6525,
    "distance_km": 0.0036525
  },
  "reference_data": {
    "custom_rate_cm_per_year": 1,
    "source_convention": "User-specified custom rate; 1 cm/yr is a realistic slow plate-motion magnitude",
    "julian_year_days": 365.25,
    "julian_year_source_convention": "IAU standard Julian year, exact convention",
    "centimeters_per_meter": 100,
    "kilometers_to_centimeters": 100000,
    "length_conversion_source_convention": "SI decimal-prefix definitions, exact"
  },
  "working": "d = rate × time = 1.0 cm/yr × 365.25 yr = 365.25 cm. Convert to meters: 365.25 cm ÷ 100 cm/m = 3.6525 m. Convert to kilometers: 3.6525 m ÷ 1000 m/km = 0.0036525 km. The 365.25-day Julian-year table entry is exact, although the calculation cancels the year unit directly."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json