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Article Dans Une Revue Geophysical Journal International Année : 2022

Global reference seismological data sets: multimode surface wave dispersion

P Moulik
V Lekic
Z Ma
  • Fonction : Auteur
T Ho
G Ekström
K. Sigloch

Résumé

Global variations in the propagation of fundamental-mode and overtone surface waves provide unique constraints on the low-frequency source properties and structure of the Earth's upper mantle, transition zone and mid mantle. We construct a reference data set of multimode dispersion measurements by reconciling large and diverse catalogues of Love-wave (49.65 million) and Rayleigh-wave dispersion (177.66 million) from eight groups worldwide. The reference data set summarizes measurements of dispersion of fundamental-mode surface waves and up to six overtone branches from 44 871 earthquakes recorded on 12 222 globally distributed seismographic stations. Dispersion curves are specified at a set of reference periods between 25 and 250 s to determine propagation-phase anomalies with respect to a reference Earth model. Our procedures for reconciling data sets include: (1) controlling quality and salvaging missing metadata; (2) identifying discrepant measurements and reasons for discrepancies; (3) equalizing geographic coverage by constructing summary rays for travel-time observations and (4) constructing phase velocity maps at various wavelengths with combination of data types to evaluate inter-dataset consistency. We retrieved missing station and earthquake metadata in several legacy compilations and codified scalable formats to facilitate reproducibility, easy storage and fast input/output on high-performance-computing systems. Outliers can be attributed to cycle skipping, station polarity issues or overtone interference at specific epicentral distances. By assessing inter-dataset consistency across similar paths, we empirically quantified uncertainties in traveltime measurements. More than 95 per cent measurements of fundamental-mode dispersion are internally consistent, but agreement deteriorates for overtones especially branches 5 and 6. Systematic discrepancies between raw phase anomalies
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Dates et versions

hal-03765070 , version 1 (30-08-2022)

Identifiants

Citer

P Moulik, V Lekic, B Romanowicz, Z Ma, A Schaeffer, et al.. Global reference seismological data sets: multimode surface wave dispersion. Geophysical Journal International, 2022, 228 (3), pp.1808 - 1849. ⟨10.1093/gji/ggab418⟩. ⟨hal-03765070⟩
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