On the Use of Data Noise as Site-Specific Weight Parameter in a Hierarchical Bayesian Moment Tensor Inversion: The Case Study of The Geysers and Long Valley Caldera Earthquakes

Scientific paper - Original scientific paper

• Author: Marija Mustać
• Author: Hrvoje Tkalčić
• Author's institution: University of Zagreb; Faculty of Science; (Department of Geophysics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geophysics; Seismology and Physics of the Earth's Interior

Abstract (english)

We expand a method for seismic moment tensor inversion using probabilistic Bayesian inference, which yields parameter uncertainties and includes a thorough treatment of noise in the data, to include additional noise parameters that weight the contributions of particular stations. In a synthetic test, we show that having individual noise parameters for each station gives an optimal fit to the data. The noise determines the level of data fit at each station, and in turn weights their contribution in the final solution. Apart from the noise level, an empirically determined data covariance matrix accounts for noise correlations present in waveform data. This improves the estimate of the centroid location and the non-double-couple components. We apply the method to two earthquakes, one from a volcanic (Long Valley caldera) and another from a geothermal (The Geysers) environment in California, which are likely to have non-double-couple components in the source mechanism. We confirm a significant isotropic component for the Long Valley caldera earthquake. Implementing a cosine data covariance matrix reduces the trade-off between the isotropic and compensated linear vector dipole components for The Geysers earthquake, and yields considerably higher non-double-couple components. This shows the importance of adequate noise treatment for earthquakes in complex tectonic environments.

• Keywords (english): probabilistic Bayesian inference
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Accepted version
• Journal title: Bulletin of the Seismological Society of America
• Numbering: vol. 107, no. 4, pp. 1914-1922
• p-ISSN: 0037-1106
• DOI: https://doi.org/10.1785/0120160379
• URN:NBN: urn:nbn:hr:217:487708
• Publication: 2017-08
• Document URL: http://mr.crossref.org/iPage?doi=10.1785%2F0120160379
• Type of resource: Text
• Access conditions: Open access
• Public note: This is a post-print version accepted by the journal, but does not contain journal layout. http://dx.doi.org/10.1785/0120160379
• Created on: 2021-09-14 11:04:02