Inner core differential motion confirmed by earthquake waveform doublets

Publication Type  Journal Article
Year of Publication  2005
Authors  Zhang, J.; Song, X. D.; Li, Y. C.; Richards, P. G.; Sun, X. L.; Waldhauser, F.
Journal Title  Science
Volume  309
Issue  5739
Pages  1357-1360
Journal Date  Aug 26
ISBN Number  0036-8075
Accession Number  ISI:000231543300039
Key Words  super-rotation; teleseismic doublets; scale heterogeneity; seismic network; travel-times; california; existence; mantle; fault

We analyzed 18 high-quality waveform doublets with time separations of up to 35 years in the South Sandwich Islands region, for which the seismic signals have traversed the inner core as PKP(DF). The doublets show a consistent temporal change of travel times at up to 58 stations in and near Alaska, and they show a dissimilarity of PKP(DF) coda. Using waveform doublets avoids artifacts of earthquake mislocations and contamination from small-scale heterogeneities. Our results confirm that Earth's inner core is rotating faster than the mantle and crust at about 0.3 degrees to 0.5 degrees per year.


959TXTimes Cited:16Cited References Count:27

DOI  DOI 10.1126/science.1113193