Estimation of inner-core rotation rate by using the Earth's free oscillation

• Autorzy: Tomiyama K. , Oda H.
• Języki publikacji: EN

Abstrakty

EN

We estimate a rate of inner-core differential rotation from time variations of splitting functions of seven core modes of the Earth’s free oscillations excited by eight large earthquakes in a period of 1994–2003. The splitting functions and moment tensor elements are simultaneously determined for each core mode by a spectral fitting technique. The estimated moment tensor well agrees with Harvard CMT solution. The splitting functions are corrected for the effect of mantle heterogeneity using a 3D mantle velocity model. Inner-core rotation angle about the Earth’s spin axis is determined for each core mode as a function of event year by comparison of the corrected and reference splitting functions. Mean rotation rate of six core modes is estimated at 0.03š0.18° per year westward, and this value is insignificantly different from zero. Therefore, the inner core is not rotating at a significant rate relatively to the crust and mantle.

Słowa kluczowe

EN

inner-core rotation; Earth’s free oscillation; modal splitting function; spectral fitting inversion

• Wydawca: Instytut Geofizyki PAN ; Springer
• Czasopismo: Acta Geophysica
• Rocznik: 2008
• Tom: Vol. 56, no. 4
• Strony: 939--956
• Opis fizyczny: Bibliogr. 26 poz.

Twórcy

autor

Tomiyama K.

autor

Oda H.

• Department of Earth Sciences, Okayama University, Okayama, Japan,

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