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Linear programming approach to moment tensor inversion of earthquake sources and some tests on the three-dimensional structure of the upper mantle

Tanimoto, Toshiro and Kanamori, Hiroo (1986) Linear programming approach to moment tensor inversion of earthquake sources and some tests on the three-dimensional structure of the upper mantle. Geophysical Journal of the Royal Astronomical Society, 84 (2). pp. 413-430. ISSN 0016-8009. http://resolver.caltech.edu/CaltechAUTHORS:20141111-144830664

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Abstract

A new method of moment tensor inversion is developed, which combines surface wave data and P-wave first motion data in a linear programming approach. Once surface wave spectra and first motion data are given, the method automatically obtains the solution that satisfies first motion data and minimizes the L1 norm of the surface wave spectra. We show the results of eight events in which the method works and is stable even for shallow events. We also show one event in which surface wave data and P-wave first motion data seem to be incompatible. In such cases, our method does not converge or converges to a solution which has a large minor (second) double couple component. It is an advantage that the method can determine the compatibility of two data sets without trial and error. Laterally heterogeneous phase velocity corrections are used to obtain spectra at the source. The method is also applied to invert moment tensors of eight events in two recent three-dimensional (3-D) upper mantle structures. In both 3-D models, variances of spectra are smaller than those in a laterally homogeneous model at 256 s. Statistical tests show that those reductions are significant at a high confidence level for five events out of eight examined. For three events, we examined those reductions at shorter periods, 197 and 151 s. The reduction of variances is comparable to the results at 256 s and is again statistically significant at a high confidence level. Orientation of fault planes does not change very much by incorporation of lateral variations of phase velocity or by doing inversions at different periods. This is mainly because of the constraints from P-wave first motion data. Scatter of phase spectra at shorter periods, especially at 151 s, is great and suggests that surface wave ray paths deviate from great circle paths substantially and these effects cannot be ignored.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1111/j.1365-246X.1986.tb04363.xDOIArticle
http://gji.oxfordjournals.org/content/84/2/413.abstractPublisherArticle
Additional Information:Copyright © 1986 The Royal Astronomical Society. Accepted 1985 July 12, Received 1985 July 12, in original form 1984 December 11. This research was supported by the Earth Sciences Section, National Science Foundation grant number CEE-8303647. Contribution number 4165, Division of Geological and Planetary Sciences, California Institute of Technology.
Funders:
Funding AgencyGrant Number
NSFCEE-8303647
Subject Keywords:inversion, moment, tensor
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Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences4165
Record Number:CaltechAUTHORS:20141111-144830664
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20141111-144830664
Official Citation:Toshiro Tanimoto and Hiroo Kanamori Linear programming approach to moment tensor inversion of earthquake sources and some tests on the three-dimensional structure of the upper mantle Geophys. J. Int. (1986) 84 (2): 413-430 doi:10.1111/j.1365-246X.1986.tb04363.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51600
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:11 Nov 2014 23:06
Last Modified:11 Nov 2014 23:06

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