check_teleseism¶

Science¶

Do these picks fit the arrival pattern of a distant large earthquake already in the session's frozen bulletin snapshot? The tool takes USGS/EMSC events above magnitude 5, predicts IASP91 arrivals at the picked stations (TauP), and scores the fraction of picks that fall within 15 s of a predicted time inside a 2700 s search window.

matched_fraction is n_matched / n_scored, where n_scored is the number of picks that have an IASP91 arrival at all. passes_threshold is true when that fraction is at least 0.6. Live bulletin queries are not this tool; the snapshot is pinned to the session.

A non-match does not prove the event is local. It proves the picks are not explained by a catalogued M ≥ 5 event in this snapshot. Smaller or later-catalogued teleseisms are outside the screen.

References¶

Kennett, B. L. N. and Engdahl, E. R. (1991). Traveltimes for global earthquake location and phase identification. Geophysical Journal International. doi:10.1111/j.1365-246X.1991.tb06724.x
Crotwell, H. P., Owens, T. J. and Ritsema, J. (1999). The TauP Toolkit. Seismological Research Letters. doi:10.1785/gssrl.70.2.154

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	`external`
Class	3
Tool version	`1.0.0`
Highest declared tier	F
Timeout	15 s
Budget key	`none`
`readOnlyHint`	true
`idempotentHint`	true

Input¶

Field	Type	Required	Notes
`picks`	object	yes	The phase set a solution tool works on.
`picks.base`	object (kind `catalog` \| `none` \| `solution`)	yes	discriminated on `kind`
`picks.phase_set`	string ∈ {`all`, `p_only`}	yes
`picks.exclude_pick_ids`	array[integer]	no
`picks.add_picks`	array[object]	no
`picks.add_picks[].tool_call_id`	string	yes
`picks.add_picks[].pick_index`	integer	yes

Payload¶

Field	Type	Required	Notes
`candidates`	array[object]	yes
`candidates[].bulletin_event_id`	string	yes
`candidates[].source`	string	yes
`candidates[].origin_time_utc`	string	yes
`candidates[].latitude_deg`	number	yes
`candidates[].longitude_deg`	number	yes
`candidates[].depth_km`	number \| null	yes
`candidates[].magnitude`	number \| null	yes
`candidates[].magnitude_type`	string \| null	yes
`candidates[].region_name`	string \| null	yes
`candidates[].matched_fraction`	number	yes
`candidates[].n_matched`	integer	yes
`candidates[].n_picks`	integer	yes
`candidates[].n_scored`	integer \| null	no	default `null`
`candidates[].matched_picks`	array[object]	yes
`candidates[].matched_picks[].pick_ref`	object	yes
`candidates[].matched_picks[].phase_name`	string	yes
`candidates[].matched_picks[].predicted_time_utc`	string	yes
`candidates[].matched_picks[].residual_s`	number	yes
`best`	object \| null	yes
`best.bulletin_event_id`	string	yes
`best.matched_fraction`	number	yes
`best.passes_threshold`	boolean	yes
`thresholds`	object	yes
`thresholds.min_magnitude`	number	yes
`thresholds.search_window_s`	number	yes
`thresholds.resid_tol_s`	number	yes
`thresholds.min_fraction`	number	yes
`snapshot_id`	string	yes

Example request¶

{
  "picks": {
    "base": {
      "kind": "catalog",
      "event_id": 1001
    },
    "phase_set": "all"
  }
}

Example payload¶

{
  "candidates": [
    {
      "bulletin_event_id": "us7000abcd",
      "source": "usgs",
      "origin_time_utc": "2024-06-15T07:55:12.000Z",
      "latitude_deg": -6.1,
      "longitude_deg": 130.2,
      "depth_km": 110.0,
      "magnitude": 6.4,
      "magnitude_type": "mww",
      "region_name": "Banda Sea",
      "matched_fraction": 0.78,
      "n_matched": 7,
      "n_scored": 9,
      "n_picks": 9,
      "matched_picks": [
        {
          "pick_ref": {
            "kind": "catalog",
            "pick_id": 20001
          },
          "phase_name": "P",
          "predicted_time_utc": "2024-06-15T08:12:14.930Z",
          "residual_s": 4.2
        }
      ]
    }
  ],
  "best": {
    "bulletin_event_id": "us7000abcd",
    "matched_fraction": 0.78,
    "passes_threshold": true
  },
  "thresholds": {
    "min_magnitude": 5.0,
    "search_window_s": 2700.0,
    "resid_tol_s": 15.0,
    "min_fraction": 0.6
  },
  "snapshot_id": "usgs-emsc-2024-06-01"
}

What this tool does not tell you¶

What this tool does not tell you: that a non-match proves the event is local. It proves the picks are not explainable by a catalogued M ≥ 5 event in the snapshot. Smaller or later-catalogued teleseisms are not covered.