THRESHOLD COMPLEX EXPLORATION LOG
Designation / Log ID: 28-Y25
Apparent Date/Time: 31 August 2026 / 04:47 (local) — secondary stamp reads 09:22 14 March 1971
Entry Method: Steel door marked “C-7 COMPRESSOR GALLERY – AUTHORIZED PERSONNEL ONLY”. Door swing measures 0.92 m. Threshold height measures 0.0 m on entry and 0.07 m on exit.
Environmental Baseline
Lighting: industrial LED panels, color temperature measured at 4100 K. Intensity constant at 118 lux.
Ambient temperature: 19.8 °C. Humidity: 47 %.
Background sound: continuous compressor thrum at 47 Hz. Amplitude 38 dB.
Air movement: lateral draft of 0.4 m/s from west wall vents. Barometric pressure 1012.1 hPa on entry; 1005.6 hPa after 12 m of travel.
Spatial Observations
Chamber estimated 28 m long by 9.5 m wide by 5.8 m high. Laser measurement returns 17 m long by 12.3 m wide by 4.9 m high.
Floor: sealed concrete with residual oil stains. Stain patterns remain fixed after four passes.
Walls: painted block with peeling sections. Peeling orientation is uniform.
Ceiling: exposed pipe runs and cable trays. Pipe inventory returns 11 discrete runs. Visual count remains fixed at 11 after six passes.
Repeating motif: every 2.9 m a pressure gauge is mounted at 1.4 m height. Gauge faces measure 0.15 m diameter. Needle position is identical across all units.
Anomalies
Visual inventory of active compressors returns 4. Physical inventory returns 4. Compressor housing volume measures 1.8 m³ while internal displacement calculates to 0.9 m³.
Floor remains level under spirit level. Measured oil surface in the collection trench slopes 1.7° toward the east wall. Slope reverses after 7 minutes of continuous observation without change in physical orientation.
Discharge pressure at primary unit measures 0 bar while motor current is fully engaged. Motor housing temperature measures 61.3 °C regardless of ambient.
Sound of exhaust valve release arrives 1.8 seconds before corresponding vibration is detected at the floor. Delay increases by 0.28 s for every additional 2.8 m of distance from the west wall.
Humidity at mid-chamber remains 47 % while condensation forms on the gauge faces after 5 minutes of observation. Condensation evaporates without measurable change in local humidity.
Local magnetic field strength measures 0.6 gauss at floor level and 2.1 gauss at 1.5 m height. Field direction reverses after 9 minutes without change in compressor state.
Entity Notes
None observed.
At the 9 m mark a localized temperature rise of 3.4 °C occurs across a 1.9 m radius. Rise persists for 11 seconds then collapses. No visible source or airflow change accompanies the event.
Exit / Continuity Status
Exit achieved by retracing path to the steel door. Door released with moderate resistance.
Exterior time on exit: 05:29 local. Elapsed interior time: 42 minutes. Wristwatch confirms same interval.
Residual effects: residual compressor thrum audible for 9 minutes after exit. Temporary inability to resolve gauge needle positions under normal lighting for 16 minutes.