get_noise_baseline¶

Science¶

A weekly probabilistic power spectral density (PPSD) summary for one station and channel class (Z or horizontals). The precomputed bands are 0.5-2, 1-5, 2-8, 5-15 and 1-20 Hz. Levels are in dB relative to 1 (m/s²)²/Hz, the ObsPy PPSD convention.

Percentiles p10_db, p50_db and p90_db describe the distribution of segment spectra in that ISO week, not the noise in the ten seconds around an arrival. A stored week is used only when it has enough finite segments (n_segments ≥ 24 and p50_db above −200 dB). Otherwise the nearest usable week within ± 2 weeks is substituted (low_confidence_fit), or the tool errors E_DATA_UNAVAILABLE with reason: no_baseline.

McNamara and Buland's PPSD, and Peterson's new low-noise / high-noise models, are the usual language for these numbers. The tool does not compare a week to those models; it returns the station's own percentiles.

References¶

McNamara, D. E. and Buland, R. P. (2004). Ambient noise levels in the continental United States. Bulletin of the Seismological Society of America. doi:10.1785/012003001
Peterson, J. (1993). Observations and modeling of seismic background noise. U.S. Geological Survey Open-File Report 93-322. https://pubs.usgs.gov/of/1993/0322/
Beyreuther, M. et al. (2010). ObsPy: A Python toolbox for seismology. Seismological Research Letters. doi:10.1785/gssrl.81.3.530

Contract¶

Generated from the live registry (ToolSpec). Field names, types and defaults come from the input and payload models; they are not hand-typed.


Group	`inventory`
Class	2
Tool version	`1.0.0`
Highest declared tier	E
Timeout	5 s
Budget key	`none`
`readOnlyHint`	true
`idempotentHint`	true

Input¶

Field	Type	Required	Notes
`station_id`	string	yes
`t_utc`	string	yes
`channel`	string ∈ {`Z`, `horizontals`}	yes
`bands`	array[string] \| null	no	default `null`

Payload¶

Field	Type	Required
`station_id`	string	yes
`channel`	string ∈ {`Z`, `horizontals`}	yes
`week`	object	yes
`week.from_utc`	string	yes
`week.to_utc`	string	yes
`bands`	array[object]	yes
`bands[].band_hz`	string	yes
`bands[].p10_db`	number	yes
`bands[].p50_db`	number	yes
`bands[].p90_db`	number	yes
`bands[].n_segments`	integer	yes
`table_version`	string	yes
`units`	string	yes
`definitions`	object	yes

Example request¶

{
  "station_id": "XX.STA1",
  "t_utc": "2024-06-15T08:12:03.417Z",
  "channel": "Z",
  "bands": [
    "1-20",
    "2-8"
  ]
}

Example payload¶

{
  "station_id": "XX.STA1",
  "channel": "Z",
  "week": {
    "from_utc": "2024-06-10T00:00:00.000Z",
    "to_utc": "2024-06-17T00:00:00.000Z"
  },
  "bands": [
    {
      "band_hz": "1-20",
      "p10_db": -152.1,
      "p50_db": -146.3,
      "p90_db": -138.0,
      "n_segments": 1180
    }
  ],
  "table_version": "2024-06-01"
}

What this tool does not tell you¶

What this tool does not tell you: the actual noise in your ten-second window. It is a weekly statistical baseline.

Warnings named for this tool¶

Code	When
`low_confidence_fit`	the nearest usable ISO week within ±2 weeks was substituted

Errors named for this tool¶

Code	When
`E_DATA_UNAVAILABLE`	`reason` is `no_baseline` — no usable week for the station