Secondary microseism blind source separation
| Autor: | Stutzmann, E., Meschede, M., Schimmel, Martin, Benbelkacem, N., Farra, V. |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | The continuous Earth's seismic wave field is mostly generated in the oceans as a result of ocean wave interactions. We analyze secondary microseisms recorded by a seismic array in the period band 3-10 sec. We use a beamforming approach for extracting sources everywhere in the oceans by considering slownesses of P, PKP and PKIKP body waves. The detected sources are frequency dependent and they vary over time. For a given day, several sources can be recorded intermittently over the day. Blind source separation technique enables to identify and isolate these intermittent signals. We use non-negative matrix factorization to decompose continuous seismic array records. We model the recorded energy as a mixture of a few components with static slowness-frequency and time dependent amplitudes. Components and amplitudes are fitted to optimally explain the recorded seismic energy over time. Each component reveals the geographical origin and time evolution of an active secondary microseism with high precision. This technique is applied to a large dataset and relative travel times are automatically extracted for the signals that correspond to a specific component. This travel time database will be used for tomography. |
| Databáze: | OpenAIRE |
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