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Distance weighting

Distance weights decide how much each station contributes to the stack of a node. The closest stations of a node constrain its location best, so they get full weight; more distant stations are tapered with a Gaussian decay. Qseek calculates a weight for every pair of station and node in the search volume, see stacking and migration.

Distance weighting

Weights of the stations for a single node (dots) and their cumulative weight (line). Three parameters shape the weights: (1) the number of closest stations with full weight, (2) the taper distance and (3) the waterlevel.

  • required_closest_stations get full weight, 4 by default.
  • distance_taper sets how fast the weight of more distant stations decays. By default it adapts to the network: twice the mean interstation distance.
  • waterlevel keeps a minimum weight for distant stations. With the default 0.0, stations far outside the taper do not contribute.

Tip

The defaults suit local and regional networks. If distant stations should still contribute to the stack, raise the waterlevel.

DistanceWeights
{
  "distance_taper": "mean_interstation",
  "required_closest_stations": 4,
  "waterlevel": 0.0
}

DistanceWeights pydantic-model

Bases: Model

Weights of the stations for every node of the search volume.

The closest stations of a node get full weight, more distant stations are tapered with a Gaussian decay. Close stations constrain the location of an event best.

Fields:

distance_taper pydantic-field 

distance_taper: (
    PositiveFloat | Literal["mean_interstation"]
) = "mean_interstation"

Distance in meters over which the weight of distant stations decays with a Gaussian function. "mean_interstation" uses twice the mean interstation distance of the network.

required_closest_stations pydantic-field 

required_closest_stations: PositiveInt = 4

Number of closest stations of a node that get full weight. Only more distant stations are tapered, so that the closest stations contribute equally and the most to the detection and localization.

waterlevel pydantic-field 

waterlevel: float = 0.0

Minimum weight of stations outside the taper, as a fraction of the full weight. With 0.0, distant stations do not contribute.