compute_magnitude¶

Science¶

Local magnitude on the IASPEI 2013 ML scale, using a simulated Wood-Anderson response on archive traces around a referenced origin. Each contributing station returns its own ML, the displacement amplitude, hypocentral distance, SNR, and whether it entered the network value.

The network magnitude is the aggregate of station magnitudes that pass the frozen cuts: maximum distance 800 km, SNR at least 2.0, and at least two station magnitudes. Below that minimum magnitude_ml is null on purpose. A single-station ML is not reported as the network value.

The default station set is QC-list stations in range that the availability table marks delivering. If that table has no row for the origin day, the tool falls back to the origin's picked stations (never inventing ids) and warns availability_stale. hypothesis is an unused optional string.

References¶

Bormann, P. and Dewey, J. W. (2014). The new IASPEI standards for determining magnitudes from digital data and their relation to classical magnitudes. New Manual of Seismological Observatory Practice 2 (IS 3.3). doi:10.2312/GFZ.NMSOP-2_IS_3.3

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	`solution`
Class	3
Tool version	`1.1.0`
Highest declared tier	F
Timeout	30 s
Budget key	`none`
`readOnlyHint`	true
`idempotentHint`	true

Input¶

Field	Type	Required	Notes
`origin_ref`	object (kind `catalog` \| `solution` \| `value`)	yes	discriminated on `kind`
`stations`	array[string] \| null	no	default `null`
`hypothesis`	string \| null	no	default `null`

Payload¶

Field	Type	Required
`magnitude_ml`	number \| null	yes
`station_count`	integer	yes
`stations`	array[object]	yes
`stations[].station_id`	string	yes
`stations[].ml`	number \| null	yes
`stations[].amplitude_nm`	number \| null	yes
`stations[].hypocentral_km`	number	yes
`stations[].snr`	number \| null	yes
`stations[].used`	boolean	yes
`stations[].reason_excluded`	string ∈ {`no_data`, `snr_below_min`, `too_far`, `no_response`} \| null	yes
`method`	string	yes
`constants`	object	yes
`constants.max_distance_km`	number	yes
`constants.snr_min`	number	yes
`constants.min_station_magnitudes`	integer	yes

Example request¶

{
  "origin_ref": {
    "kind": "catalog",
    "event_id": 1001
  },
  "stations": [
    "XX.STA1",
    "YY.STA3"
  ]
}

Example payload¶

{
  "magnitude_ml": 2.1,
  "station_count": 3,
  "stations": [
    {
      "station_id": "XX.STA1",
      "ml": 2.05,
      "amplitude_nm": 412.5,
      "hypocentral_km": 43.0,
      "snr": 6.1,
      "used": true,
      "reason_excluded": null
    }
  ],
  "method": "IASPEI 2013 ML, simulated Wood-Anderson",
  "constants": {
    "max_distance_km": 800.0,
    "snr_min": 2.0,
    "min_station_magnitudes": 2
  }
}

What this tool does not tell you¶

What this tool does not tell you: a magnitude from fewer than two stations. A single-station ML is not published as the network value; below the two-station minimum the network value is null on purpose.

Warnings named for this tool¶

Code	When
`availability_stale`	the availability table has no row for the origin day (fallback to picked stations)