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Earthquake Magnitude Calculation

Qseek supports earthquake magnitude calculation as Local Magnitudes in different attenuation models and Moment Magnitudes derived from forward-modelled attenuation curves.

Local Magnitude

Local magnitude calculation relies on a tuned attenuation model.

LocalMagnitudeExtractor Module

Local magnitude calculator for different regional models.

noise_window: 5.0

Waveforms to extract before P phase arrival. The noise amplitude is extracted from before the P phase arrival, with 0.5 s padding.

seconds_after: 4.0

Waveforms to extract after S phase arrival.

taper_seconds: 10.0

Seconds tapering before and after the extraction window. The taper stabalizes the restitution and is cut off from the traces before the analysis.

min_signal_noise_ratio: 1.5

Minimum signal-to-noise ratio for the local magnitude estimation. The noise amplitude is extracted from before the P phase arrival, with 0.5 s padding.

max_station_std: 3.0

Maximum standard deviation of the station magnitudes to include in the local magnitude estimation.

model: webnet-western-bohemia | southern-california | central-california | iaspei-southern-california | eastern-north-america | albania | south-west-germany | south-australia | norway-fennoscandia | iceland-askja | iceland-bardabunga | iceland-askja-bardabunga-combined | iceland-reykjanes | azores | argentina-volcanoes | netherlands-groningen

The amplitude attenuation model to use for calculating the local magnitude.

export_mseed

Path to export the processed mseed traces to.

JSON for LocalMagnitudeExtractor
{
  "magnitude": "LocalMagnitude",
  "noise_window": 5.0,
  "seconds_after": 4.0,
  "taper_seconds": 10.0,
  "min_signal_noise_ratio": 1.5,
  "max_station_std": 3.0,
  "model": "iaspei-southern-california",
  "export_mseed": null
}

Moment Magnitude

Based on forward-modelled attenuation curves using Pyrocko-GF. For more information on the method see Dahm et al., 2024.

MomentMagnitudeExtractor Module

Moment magnitude calculator from peak amplitudes.

noise_window: 5.0

Waveforms to extract before P phase arrival. The noise amplitude is extracted from before the P phase arrival, with a one second padding.

seconds_after: 4.0

Waveforms to extract after S phase arrival.

taper_seconds: 10.0

Seconds tapering before and after the extraction window. The taper stabalizes the restitution and is cut off from the traces before the analysis.

min_signal_noise_ratio: 1.5

Minimum signal-to-noise ratio for the magnitude estimation. The noise amplitude is extracted from before the P phase arrival, with 0.5 s padding.

max_station_std: 3.0

Maximum standard deviation of the station magnitudes to include in the local magnitude estimation.

gf_store_dirs

The directories of the Pyrocko GF stores.

export_mseed

Path to export the processed mseed traces to.

models

The peak amplitude models to use.

JSON for MomentMagnitudeExtractor
{
  "magnitude": "MomentMagnitude",
  "noise_window": 5.0,
  "seconds_after": 4.0,
  "taper_seconds": 10.0,
  "min_signal_noise_ratio": 1.5,
  "max_station_std": 3.0,
  "gf_store_dirs": [
    "."
  ],
  "export_mseed": null,
  "models": [
    {
      "gf_store_id": "moment_magnitude",
      "quantity": "displacement",
      "frequency_range": [
        2.0,
        20.0
      ],
      "max_distance": 100000.0,
      "source_depth_delta": 1000.0,
      "reference_magnitude": 1.0,
      "rupture_velocities": [
        0.8,
        0.9
      ],
      "stress_drop": [
        1000000.0,
        10000000.0
      ],
      "gf_interpolation": "multilinear",
      "nsl_id": null,
      "peak_amplitude": "absolute",
      "station_epicentral_range": [
        1000.0,
        100000.0
      ]
    }
  ]
}