AVN Dashboard — Data & Processing

Data Source

Raw MiniSEED data from the Tensora Linode S3 bucket tensora-data. Network 2J, AVN-family fibre-optic borehole strainmeters in Osage County, Oklahoma (clustered within ~700 m near 36.534°N, -96.081°W). V-band channels sampled at 0.2 Hz.

Stations & Data Availability

Active = currently recording. Inactive = decommissioned or offline; data is archive-only and never re-fetched on a schedule. AVN3 is a 3-gauge instrument (no VS0 / VS4); regional-strain rotation plots are not available for it. The AVN1, AVN2, and AVN4 stations exist in the bucket but are not displayed (tilt-only and B-band — different processing).

Processing Pipeline

Applied in order to each station on every processing run:

1. Despiking — median-filter MAD detector removes transient spikes from each gauge channel
2. Offset removal — step-change detector finds discontinuities; fits a linear slope to 500 samples before each offset and extrapolates across it to remove jumps
3. Barometric correction — 3-parameter OLS fit s = c₀ + c₁·t + c₂·b using raw (unfiltered) pressure. Bootstrap over 1000 iterations of 7-day sliding windows; selects window with lowest MSE. Corrected strain = strain − c₂_best × pressure
4. Tidal fit — 25 harmonic constituents (Agnew 2012), plus DC offset + linear drift terms. QR decomposition. Rayleigh criterion drops constituents unresolvable given the record length. Tidal residual = corrected strain − fitted tide
5. Regional strain (4-gauge stations only) — 4-gauge tensor geometry (VS1=0°, VS2=45°, VS3=90°, VS4=135° clockwise). Orientation matrix produces: EA (areal), ED (E-W differential), ES (shear)
6. Tidal calibration — fits M2 amplitude in the EA channel, compares to theoretical body tide. Scale factor converts radians → nanostrain

Units: raw data in radians of optical phase; calibrated output in nanostrain (nɛ).

High-Frequency (C-band) Data

None of the AVN stations have C-band data. A full sweep of the S3 bucket (87,372 MiniSEED files across all 5 stations) found zero CS* channels. C-band recording is currently NCF1-only, with sampling beginning 2025-11-20. The Seismic Spectrogram tab does not apply to AVN stations.

Processing follows the Tensora report spec, Feb 2026.