Gillian Foulger

Challenging the mantle plume hypothesis, Foulger has posited that there is no chemical or isotopic data that require deep-plume origins nor are there anomalously elevated temperatures indicating the existence of such.[6] She further claims that reliable seismic-tomography results have yet to reveal concrete evidence of a plume. Plumes, in her estimation, cannot therefore account for the eruption rates of the largest flood basalts, which she suggests could be explained alternatively by rapidly draining reservoirs of molten rock that have accumulated over time.[6] Her research represents significant progress in developing an alternative model for anomalous volcanism.[7] This phenomenon, she has suggested, can be better explained as a passive reaction to the stretching of lithospheric plates — such as in rift valleys — which allows melt to rise from shallow depths in the mantle.[6] This work makes for an important contribution to the understanding of volcanic and earthquake areas such as the Hawaii, Iceland and Yellowstone hotspots.[7]

Foulger has suggested that, regarding the mantle plume controversy in Earth Science, the fundamental reasons for the ongoing developments of this controversy are not well established.[8] These factors according to Foulger are as follows: firstly, many observations conflict with the predictions of the original model. Secondly, that it is possible that the sort of convection necessary to generate thermal plumes in the Earth's mantle does not occur. Thirdly, that so many variants of the original model have been invoked to accommodate what she describes as conflicting data, that the plume hypothesis is in practice no longer testable; finally, that alternative models are viable, though she suggests that these alternatives have been largely neglected by researchers.[8]

From 1996 to 2004 Gillian Foulger, along with others such as Bruce Julian, Keith Richards-Dinger, and Francis Monastero monitored seismic activity using the arrival times of the U.S. Navy's seismometer network in the Coso Volcanic Field's geothermal area in California, in order to calculate the local-earthquake topography images.[9] The Coso geothermal area in which this project takes place is used by to produce ~250 megawatts of electricity. This project, created through the collaboration of the United States Geological Survey, the U.S Navy and the University of Utah, as well as funds from the United States Department of Energy has created a set of data in which numerous other studies have the potential to be produced. Foulger has used this ~80,000-earthquake dataset to analyze time-dependent seismic tomography, relative event relocations and moment-tensor analysis and aid in developing energy production strategies.[10]

In June 2021, Foulger reported that under her leadership experts from the Department of Earth Sciences at Durham University believed they had discovered a submerged continent stretching from Greenland to Europe. They have given it the name "Icelandia".[11][12] The theory is described in a chapter titled "Icelandia" in the publication In the Footsteps of Warren B. Hamilton: New Ideas in Earth Science.[13]