摘要
Attenuation of PKP（DF） in the Eastern Hemisphere is examined in terms of multiple scattering to simultaneously explain a puzzling relationship, a relatively fast velocity anomaly corre- sponding to strong attenuation. Reflectivity synthetics with one-dimensional random velocity fluctua- tions are compared with observations of PKP（DF）/PKP（Cdiff） amplitude ratios and differential travel times of PKP（Cdiff）-PKP（DF） for the equatorial paths. A Gaussian distribution of P-wave velocity fluctuations with the standard deviations of 5%, 6%, and 7% in the uppermost 200 km of the inner core is superimposed on the velocity structure that is slightly faster than the typical structure in the Eastern Hemisphere, which is likely to explain both the travel time and amplitude data as far as only the one-dimensional structure is considered. Further examinations of the statistic characteristic of scat- terer distribution in two and three-dimensions are required to obtain a realistic conclusion.
Attenuation of PKP（DF） in the Eastern Hemisphere is examined in terms of multiple scattering to simultaneously explain a puzzling relationship, a relatively fast velocity anomaly corre- sponding to strong attenuation. Reflectivity synthetics with one-dimensional random velocity fluctua- tions are compared with observations of PKP（DF）/PKP（Cdiff） amplitude ratios and differential travel times of PKP（Cdiff）-PKP（DF） for the equatorial paths. A Gaussian distribution of P-wave velocity fluctuations with the standard deviations of 5%, 6%, and 7% in the uppermost 200 km of the inner core is superimposed on the velocity structure that is slightly faster than the typical structure in the Eastern Hemisphere, which is likely to explain both the travel time and amplitude data as far as only the one-dimensional structure is considered. Further examinations of the statistic characteristic of scat- terer distribution in two and three-dimensions are required to obtain a realistic conclusion.
基金
supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (No.21340132)
