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- Written by: Mindy Weisberger, CNN
- Category: Geo-Thermal
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‘It’s almost science fiction’: Scientists say the shape of Earth’s inner core is changing
By Mindy Weisberger, CNN Mon February 10, 2025CNN Science Original CNN Science Article
Link to Research in Nature AND Associated Research Link to Associated Research
""Abstract
The inner core has been inferred to change its rotation rate or shape over years to decades since the discovery of temporal variability in seismic waves from repeating earthquakes that travelled through the inner core. Recent work confirmed that the inner core rotated faster and then slower than the rest of Earth in the last few decades; this work analysed inner-core-traversing (PKIKP) seismic waves recorded by the Eielson (ILAR) and Yellowknife (YKA) arrays in northern North America from 121 repeating earthquake pairs between 1991 and 2023 in the South Sandwich Islands. Here we extend this set of repeating earthquakes and compare pairs at times when the inner core re-occupied the same position, revealing non-rotational changes at YKA but not ILAR between 2004 and 2008. We propose that these changes originate in the shallow inner core, and so affect the inner-core-grazing YKA ray paths more than the deeper-bottoming ray paths to ILAR. We thus resolve the long-standing debate on whether temporal variability in PKIKP waves results from rotation or more local action near the inner-core boundary: it is tentatively both. The changes near the inner-core boundary most likely result from viscous deformation driven by coupling between boundary topography and mantle density anomalies or traction on the inner core from outer-core convection.""
CNN Science Article —
Scientists who just months ago confirmed that Earth’s inner core recently reversed its spin have a new revelation about our planet’s deepest secrets — they identified changes to the inner core’s shape. Earth’s innermost layer is a hot, solid ball of metal surrounded by a liquid metal outer core. For decades, planetary scientists suspected that the solid inner core deformed over time as it spun. Now, researchers have found the first evidence of changes taking place over the past 20 years in the shape of the inner core.
Signs of the core’s deformation appeared in waves from earthquakes that were strong enough to reach Earth’s centre. The research team used that same earthquake data for a 2024 study to resolve a longstanding debate over the inner core’s rotation. They found that the inner core once spun faster than Earth itself. But beginning around 2010, the solid inner core’s spin slowed. It’s now revolving backward, relative to the rest of the planet.
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- Written by: J C Burke
- Category: Geo-Thermal
- Hits: 2277
European Geothermal Congress {EGC 2025} is calling for abstracts that explore all aspects of geothermal energy use: power generation, heating and cooling supply, underground thermal storage, and mineral extraction. We are interested in both technological and socio-economic aspects.
The programme is divided into four thematic streams, each designed to cover specific aspects of geothermal energy.
Why submit an abstract?
- International Visibility: Present your work to a diverse audience and gain recognition in the geothermal community.
- Networking Opportunities: Connect with experts, researchers, and professionals from around the world.
- Make an Impact: Contribute to the advancement and promotion of geothermal energy as a sustainable solution.
Conference Streams
- Research and Development (TRL: 1-5)
- Technology and Innovation (TRL: 6-9)
- Geothermal Solutions for Energy System Integration
- Financing, Regulations, Policy, Communications, and Market
Submission Deadline: 15 October 2024
- Details
- Written by: J C Burke
- Category: Geo-Thermal
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March 2022: PDF to download from EGEC Geothermal [Click Here]
The term ‘geothermal energy’ refers to any heat derived from the ground, from depths of a few metres to multiple kilometres beneath the Earth’s surface.
Low-grade heat stored in the shallow subsurface (<200 m) is largely derived from solar radiation that is absorbed by the ground and distributed via natural groundwater systems and artificial structures such as flooded coal mines. The ground acts as a solar battery and, for this heat, utilisation usually requires a heat pump. This energy is widely described as ‘ground-source energy’ or ‘shallow geothermal energy’.
There is no strict definition for ‘deep geothermal energy’, but the UK Government has adopted the term to refer to heat resources derived from depths of >500 m. The heat of the Earth increases with depth, a phenomenon described as the geothermal gradient. This heat is partly the primordial heat from when the Earth was formed and partly heat generated from within the Earth’s crust from the decay of mildly radioactive elements. This upward heat flux varies across the globe, but in the UK is around 27°C/km (Busby, 2014). Assuming an average annual air temperature of 12°C, this means that subsurface temperatures at 1000 m, 3000 m and 5000 m are around 39°C, 89°C and 139°C, respectively.