Details of Award
NERC Reference : NE/C518030/1
An integrated seismological study of the heterogeneity and anisotropy of the lowest mantle
Fellowship Award
- Fellow:
- Professor J Wookey, University of Bristol, Earth Sciences
- Grant held at:
- University of Bristol, Earth Sciences
- Science Area:
- Earth
- Overall Classification:
- Earth
- ENRIs:
- Global Change
- Environmental Risks and Hazards
- Science Topics:
- Tectonic Processes
- Properties Of Earth Materials
- Mantle & Core Processes
- Abstract:
- In order to understand the issues which affect our environment it is important to understand how the Earth has changed over the 5 billion years of its history. One of the driving forces of these changes are the way that the Earth convects. Convection is the motion of material caused by heating, for example the movement of the blobs in a lava lamp, where cold blobs sink, get heated up at the bottom and rise again. Convection happens mainly in two parts of the Earth: the outer core and the mantle (the solid 3000km thick shell which surrounds the core). The liquid outer core convects rapidly, and this motion is the engine which produces the Earth's magnetic field. The solid mantle also convects, but much more slowly than the core. It takes hundreds of millions of years for the 'blobs' that are the hot and cold parts of the mantle to rise to the surface and fall to the core. This long term motion is connected to the movement of the tectonic plates which make up the Earth's surface (very large, solid 'rafts' of rock). This movement of the plates are the cause of the most devastating natural phenomena we see, such as earthquakes, tidal waves and volcanoes. It also causes long term changes in the Earth's atmosphere. For these reasons, understanding the Earth's solid and liquid convection is important for understanding many other things in the environmental sciences. It is also important as we try and understand the structure and history of our planet, such as how it formed. In order to understand the Earth's convective processes, we need to understand what factors influence them. Arguably the most important factor is the conditions at the boundaries of the system (in the case of the lava lamp for example, how hot the base is). The liquid core convection has two boundaries: the interface between the liquid outer-core and the solid inner-core, and one between the outer-core and the solid mantle (the core-mantle boundary or CMB). The mantle convection system is driven by heat from the core, at its lower boundary (again the CMB) and its upper boundary is the Earth's surface. So to understand the convection in both of these systems, understanding what the conditions are like at the CMB is critical. Above the CMB lies an enigmatic and poorly understood region of the Earth, often referred to as the 'lowermost mantle'. This region appears to be like a mirror image of the variation we see at the surface with large differences in temperature, composition (the minerals which it contains) and structure. These properties will strongly influence convection in the Earth. It is this part of the Earth that my project aims to study. The most powerful way we have of studying the structure and composition of the deep parts of the Earth is seismology. Seismology is the study of seismic waves: vibrations that travel huge distances through the Earth from earthquakes. This is similar to the way sound travels through the air. By recording and studying these seismic waves using sensitive instruments (seismometers) we can determine some of the properties of the materials through which they have travelled. By studying earthquakes using the most sophisticated equipment we can measure at seismic waves which have travelled near the CMB, and begin to understand the properties of this boundary. The research project I have proposed is to study the CMB using seismology in the region beneath the Indian Ocean. This is a particularly interesting part of the Earth as it shows evidence of being a change between a hot, rising part and cold sinking part of the mantle. My research will make use of many seismometers in Africa, recording earthquakes from the plate boundaries in the western Pacific, the seismic waves from which pass close to the CMB. I will apply a wide range of cutting-edge techniques (developed by myself and my collaborators) to study the properties of this region associated with convection, temperature and composition.
- NERC Reference:
- NE/C518030/1
- Grant Stage:
- Completed
- Scheme:
- Postdoctoral Fellow
- Grant Status:
- Closed
- Programme:
- Postdoctoral Fellowship
This fellowship award has a total value of £132,503
FDAB - Financial Details (Award breakdown by headings)
| Total - Staff | Total - T&S | Total - Other Costs |
|---|---|---|
| £100,103 | £3,900 | £28,500 |
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