{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"6aa6c53eabc5d8bd4015420022693fb39ce74fb4fe15c03bbfde4ec7d9f5ed7c","created":"2026-10-03T07:18:03Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"23b3c9f185e39e113190915710c32c40ad552c3f9e7f4a1303d2b270d96230b9","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"earth.inner-core.rotation-oscillation","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"Earthquake waves passing through the inner core change slightly over decades, suggesting it spins a little faster or slower than the rest of Earth. Whether it speeds ahead, oscillates back and forth, or changes shape instead is disputed.","posed_since":"1996","precise":"Using temporal changes in PKIKP waveforms from repeating earthquakes and explosions since the 1960s, determine the differential rotation rate history $\\omega_{\\mathrm{ic}}(t)$ of the inner core relative to the mantle and whether it is a steady super-rotation, a multidecadal oscillation (period near 70 yr), a shorter oscillation (about 6 yr), or an artifact of inner-core surface deformation. An answer is $\\omega_{\\mathrm{ic}}(t)$ with uncertainties that jointly fits seismic, length-of-day and geodetic data.","problem_ref":null,"references":"","settled_by":"A global, consistent analysis of repeating-earthquake doublets that separates rotation from local inner-core boundary changes.","status_note":"Yang and Song 2023 and Wang and coauthors 2024 report a recent slowdown or backward motion relative to the mantle; Vidale and coauthors 2025 (Nature Geoscience, https://doi.org/10.1038/s41561-025-01642-2) report annual-scale changes of both rotation and the inner-core near surface, so rotation and boundary deformation are not yet separated.","title":"How does the inner core rotate relative to the mantle?","topic_ref":"7cfe9fc58e1f6e93abcae219320fa93156a5400d6286e67a83bb0bb8981c5f56"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"892e7283b8ee05504212fd08ce7584b892306e4a3dc7c58d4b0afcc62ca94c61","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"cf1c5860b11617c8827a503b71c3756d81594f81f3c6a1b649eee63358fb5659","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"XM_4PWuFDXKQXI-VoSyKTqH4d1GRid4j-YFfQD_u2EyU4cC8YGYY1keKC7U0XWxxupagw98brwMya5yRBRkxAw"},"schema":"pubphys.envelope/1"},"record_hash":"892e7283b8ee05504212fd08ce7584b892306e4a3dc7c58d4b0afcc62ca94c61","leaf_index":1334}