Jennifer Jenkins‘s PhD research aims to investigate deep Earth structure beneath Iceland.
Seismic tomography models observe a slow wave speed anomaly located beneath Iceland, which is generally interpreted as a region of higher temperature, causing the large amounts of volcanic activity observed in Iceland. The real question is how deep does this seismic anomaly extend? Does the anomaly exist only within the upper few hundred kilometres, or is it caused by a deep sourced mantle plume rising from the core-mantle boundary? Inherent problems with seismic tomography mean that narrow hot plumes are very difficult to observe at great depth, even if they are present.
The mantle transition zone from 410 to 660km depth separates the Earth’s upper and lower mantle, defined by mineral phase transitions (olivine-to-spinel at 410km and spinel-to-perovskite at 660km). Discontinuities defined by these phase transitions can be observed using seismic data, and the inferred depth of the discontinuity varies laterally as a function of temperature and composition. Therefore, the depths of transition zone discontinuities beneath Iceland provide a way to investigate the depth extent and location of deep mantle temperature anomalies.
In my research I use receiver functions generated from P-to-S wave conversions at discontinuities within the Earth, to investigate depth variations across the Iceland region. Eventually I hope to combine these observations with other seismic data such as SS and PP precursors.