摘要： ► Relative PKP delay times across the Taiwan Island are determined. ► Current travel-time tomographic models cannot well explain those PKP delay times. ► The extra contribution of delay times from shallow crustal structures beneath Taiwan. Array observations indicate that the relative PKP travel-time residuals in the Taiwan region vary from −2.5 to+2.0s, a range greater than the largest known teleseismic travel-time residuals from deep Earth. PKP waves are generally employed to probe structures of the deep Earth; however, the contribution of shallow geological structures to PKP waves is generally undefined and the implications of such a contribution have rarely been discussed. Current travel-time tomographic models of Taiwan are able to predict less than 40% of the observed PKP residuals, and the PKP residuals are consistent with the pattern of station corrections used in determining local earthquakes. Detailed island-wide gravity measurements indicate that the distribution of Bouguer anomalies, which were previously proposed to be induced by thick sedimentary deposits in large tectonic basins, is consistent with the pattern of PKP travel-time residuals. In conclusion, the observed PKP residuals are strongly affected by shallow sediments. Therefore, the contribution of residuals from shallow crustal structures should be carefully considered when employing PKP observations for imaging structures of the deep Earth or the deep crust and upper mantle. 出版者： Elsevier Ltd 出版日期： 2012-03-02 出處： Journal of Asian earth sciences, 2012-03, Vol.46, p.86-91 資源來源： Elsevier ScienceDirect Journals Complete 版權： 2011 Elsevier Ltd 識別號： ISSN: 1367-9120 識別號： EISSN: 1878-5786 識別號： DOI: 10.1016/j.jseaes.2011.11.008
