Stability of source mechanisms inverted from P-wave amplitude microseismic monitoring data acquired at the surface

0429492 - ÚSMH 2015 RIV NL eng J - Článek v odborném periodiku
Staněk, František - Eisner, Leo - Moser, T.J.
Stability of source mechanisms inverted from P-wave amplitude microseismic monitoring data acquired at the surface.
Geophysical Prospecting. Roč. 62, č. 3 (2014), s. 475-490. ISSN 0016-8025. E-ISSN 1365-2478
Grant CEP: GA ČR GAP210/12/2451
Institucionální podpora: RVO:67985891
Klíčová slova: microseismic monitoring * inversion * ray modelling * source mechanism
Kód oboru RIV: DC - Seismologie, vulkanologie a struktura Země
Impakt faktor: 1.467, rok: 2014

We study the stability of source mechanisms inverted from data acquired at surface and near-surface monitoring arrays. The study is focused on P-wave data acquired on vertical components, as this is the most common type of acquisition. We apply ray modelling on three models: a fully homogeneous isotropic model, a laterally homogeneous isotropic model and a laterally homogeneous anisotropic model to simulate three commonly used models in inversion. We use geometries of real arrays, one consisting in surface receivers and one consisting in ‘buried’ geophones at the near-surface. Stability was tested for two of the frequently observed source mechanisms: strike-slip and dip-slip and was evaluated by comparing the parameters of correct and inverted mechanisms. We assume these double-couple source mechanisms and use quantitatively the inversion allowing non-double-couple components to measure stability of the inversion. To test the robustness we inverted synthetic amplitudes computed for a laterally homogeneous isotropic model and contaminated with noise using a fully homogeneous model in the inversion. Analogously amplitudes computed in a laterally homogeneous anisotropic model were inverted in all three models. We show that a star-like surface acquisition array provides very stable inversion up to a very high level of noise in data. Furthermore, we reveal that strike-slip inversion is more stable than dip-slip inversion for the receiver geometries considered here. We show that noise and an incorrect velocity model may result in narrow bands of source mechanisms in Hudson's plots.
Trvalý link: http://hdl.handle.net/11104/0234597