Gradient measurements at volcanoes: Options, questions, pitfalls
| Autor: | Wassermann, Joachim, Braun, Thomas, Bernauer, Felix, Keil, Sabrina, Mattio, Laurent, Guattari, Frederic, Igel, Heiner |
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| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| Popis: | The recent advances in the hardware development of instruments that record gradients of the seismic wavefield made several novel measurement strategies at active volcanoes possible. Especially the recording of rotational motions is a prominent candidate to solve some of the problems that are eminent in volcano monitoring. Near field recordings of volcano-induced events often suffer from unaccounted effects of local tilt and unknown shallow velocity structure. In addition, if the station number is limited moment tensor inversions (MTI) are very often unconstrained. However, possible advantages of gradient measurements in these fields come also with a price: the wavefield gradient is very sensitive to local site conditions/heterogeneities. To investigate the advantages and drawbacks of the combined recording of translational and rotational motion measurements (6C), we designed an experiment using six blueSeis-3A rotational motion sensors together with six TrilliumCompact seismometers at Stromboli volcano, Italy. In order to estimate the responses of different sites as well as to evaluate the performance of 6C recordings for location and moment tensor inversion, the stations were distributed along two rings at different height levels. Standard estimates of backazimuth and 1D-velocity profiles using 6C are performed. The results are compared to synthetic data which involve growing complexity of the modelled structure. The results of this tests confirm that local heterogeneities play a key role in the complexity of the recorded gradient wavefield. This complexity needs to be accounted for in order to be able to perform a MTI which should reduce the ambiguity using sparse seismic networks. The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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