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Title: | Upper mantle anisotropy in the S.W. Pacific from earthquake travel-time analysis |
Authors: | Galea, Pauline |
Keywords: | Anisotropy Earthquake intensity Seismic traveltime inversion Seismology -- Observations |
Issue Date: | 1993-03 |
Publisher: | Elsevier |
Citation: | Galea, P. (1993). Upper mantle anisotropy in the SW Pacific from earthquake travel-time analysis. Physics of the earth and planetary interiors, 76(3-4), 229-239. |
Abstract: | The negative P-residuals, from readings at stations on Niue, Rarotonga and the Chatham Islands of shallower events along the Tonga-Kermadec trench and below the North Island, New Zealand, exhibit a scatter too large to be accounted for solely by observation and mislocation errors. The corresponding wavepaths cover a range of propagation azimuths between N30°E and N180°E. Travel times from a large number of events reveal a variation of P-velocity with azimuth which is consistent with large scale upper mantle anisotropy in this area. The P-velocity varies from a maximum of 8.4 km s−1 along N62°E to a minimum of 7.8 km s−1 along a perpendicular axis, perhaps indicating a fossil spreading direction along N62°E. There is also a very consistent, but unexplained, variation of P-residuals with earthquake depths between 0 and 100 km; an observation warranting further study. |
URI: | https://www.um.edu.mt/library/oar/handle/123456789/94733 |
Appears in Collections: | Scholarly Works - FacSciGeo |
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