Depth‐dependent attenuation in the uppermost inner core from the Taiwan short period seismic array PKP data

Abstract

Abstract. Inner core attenuation properties from two spots were examined in detail using PKIKP and PKP(BC) phases with a distance range of between 147 ø and 154 ø as recorded by both the short-period regional seismic array in Taiwan

Deep Earth Structure – The Earth’s Cores

“…The various studies come to a general agreement about low Q in the uppermost inner core, with values ranging from 100 to 400 in the uppermost 200 km, probably increasing with depth up to 600 at 400 km (Doornbos, 1974(Doornbos, , 1983Bolt, 1977;Cormier, 1981;Niazi and Johnson, 1992;Bhattacharyya et al, 1993;Souriau and Roudil, 1995;Tseng et al, 2001;Oreshin and Vinnik, 2004). Waveform modeling of PKP at nearly antipodal distances also shows a Q-increase at radius smaller than 500 km, together with a decrease in the scatter of the Q-values .…”

“…This central, high-Q zone corresponds approximately to the innermost inner core identified by Ishii et al (2002b) and Beghein and Trampert (2003) (Figure 14), and could correspond to a different fabric (Cormier and Stroujkova, 2005). Largescale regional variations of Q seem to be present, with a hemispherical pattern correlated to the one observed at greater depth (Tseng et al, 2001;Wen and Niu, 2002;Cao and Romanowicz, 2004b;Yu and Wen, 2006a). Largescale regional variations of Q seem to be present, with a hemispherical pattern correlated to the one observed at greater depth (Tseng et al, 2001;Wen and Niu, 2002;Cao and Romanowicz, 2004b;Yu and Wen, 2006a).…”

Deep Earth Structure: Q of the Earth from Crust to Core

“…From early on, measurements of amplitude ratios of PKP(DF) (sampling the inner core) and PKP(BC) (sampling the outer core) constrained Q a in the top 500 km of the inner core to be in the range 200-600 (e.g., Bhattacharyya et al, 1993;Bolt, 1977;Choy and Cormier, 1983;Cormier, 1981;Doornbos, 1974Doornbos, , 1983Ivan et al, 2005;Niazi and Johnson, 1992;Sacks, 1969;Song and Helmberger, 1993;Tseng et al, 2001). Most studies have suggested an increase of Q a with depth, although some find that Q a is constant with depth (e.g., Bhattacharyya et al, 1993;Niazi and Johnson, 1992).…”

Significant contribution of the shallow crust to seismic PKP travel-time residuals and implications: An example from Taiwan and nearby islands

“…Large deep events at a distance greater than 140°from South America are well recorded on the IESAS continuous data string. These seismic core phases have been employed to study the structure of the Earth's core (Tseng et al, 2001) and the rupture mechanisms of deep earthquakes (Huang, 2002).…”