Very Slow Rotation of Earth's Inner Core From 1971 to 1974
Abstract The rate that Earth's inner core rotates relative to the mantle and crust has been debated for decades. Nonrotational processes, including internal deformation and flow in the outer core, have also been proposed to explain observed seismic changes. The observed changes thus far have be...
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| Language: | English |
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Wiley
2019-08-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2019GL083774 |
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| author | John E. Vidale |
| author_facet | John E. Vidale |
| author_sort | John E. Vidale |
| collection | DOAJ |
| description | Abstract The rate that Earth's inner core rotates relative to the mantle and crust has been debated for decades. Nonrotational processes, including internal deformation and flow in the outer core, have also been proposed to explain observed seismic changes. The observed changes thus far have been so inconsistent and weak as to hamper convincing interpretation. Here, we examine waves backscattered from within the inner core, which can more robustly evaluate rotation, from two nuclear tests 3 years apart in Novaya Zemlya, Russia. We have extended our previous analysis of these explosions using precise station corrections and the full Large Aperture Seismic Array, thus revealing how the time shifts depend on slowness and lag time and halving our rotation rate estimate. Our derived 0.07°/year inner core superrotation rate from 1971 to 1974 is more robust and slower than most previous estimates and may require interesting reinterpretations of localized signals previously interpreted as inner core rotation. |
| format | Article |
| id | doaj-art-6bf2e5a68e0b4c44a51cf01c33cfa88f |
| institution | OA Journals |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2019-08-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-6bf2e5a68e0b4c44a51cf01c33cfa88f2025-08-20T02:12:20ZengWileyGeophysical Research Letters0094-82761944-80072019-08-0146169483948810.1029/2019GL083774Very Slow Rotation of Earth's Inner Core From 1971 to 1974John E. Vidale0Department of Earth Sciences University of Southern California Los Angeles CA USAAbstract The rate that Earth's inner core rotates relative to the mantle and crust has been debated for decades. Nonrotational processes, including internal deformation and flow in the outer core, have also been proposed to explain observed seismic changes. The observed changes thus far have been so inconsistent and weak as to hamper convincing interpretation. Here, we examine waves backscattered from within the inner core, which can more robustly evaluate rotation, from two nuclear tests 3 years apart in Novaya Zemlya, Russia. We have extended our previous analysis of these explosions using precise station corrections and the full Large Aperture Seismic Array, thus revealing how the time shifts depend on slowness and lag time and halving our rotation rate estimate. Our derived 0.07°/year inner core superrotation rate from 1971 to 1974 is more robust and slower than most previous estimates and may require interesting reinterpretations of localized signals previously interpreted as inner core rotation.https://doi.org/10.1029/2019GL083774core rotationarray seismologybeam formingtime‐dependent seismologyinner corenuclear tests |
| spellingShingle | John E. Vidale Very Slow Rotation of Earth's Inner Core From 1971 to 1974 Geophysical Research Letters core rotation array seismology beam forming time‐dependent seismology inner core nuclear tests |
| title | Very Slow Rotation of Earth's Inner Core From 1971 to 1974 |
| title_full | Very Slow Rotation of Earth's Inner Core From 1971 to 1974 |
| title_fullStr | Very Slow Rotation of Earth's Inner Core From 1971 to 1974 |
| title_full_unstemmed | Very Slow Rotation of Earth's Inner Core From 1971 to 1974 |
| title_short | Very Slow Rotation of Earth's Inner Core From 1971 to 1974 |
| title_sort | very slow rotation of earth s inner core from 1971 to 1974 |
| topic | core rotation array seismology beam forming time‐dependent seismology inner core nuclear tests |
| url | https://doi.org/10.1029/2019GL083774 |
| work_keys_str_mv | AT johnevidale veryslowrotationofearthsinnercorefrom1971to1974 |