Earth's Inner Core Isn't Solid After All, Claims New Study
"Illuminated by earthquakes in the crust and upper mantle, and observed by seismic observatories at Earth's surface, seismology offers the only direct way to investigate the inner core and its processes", said Rhett Butler, a geophysicist at the University of Hawai'i at Manoa's School of Ocean and Earth Science and Technology (SOEST).
Mr Butler and co-author of the study Seiji Tsuboi, research scientist at the Japan Agency for Marine-Earth Science and Technology, used data from seismometers directly opposite the location where an earthquake originated. To cover the whole inner core they established five pairings - Tonga–Algeria, Indonesia–Brazil and three between Chile–China – which were then assessed by a supercomputer, Japan's Earth Simulator.
A subsequent examination of the data revealed that the inner core is a heterogeneous structure.
"In stark contrast to the homogeneous, soft-iron alloys considered in all Earth models of the inner core since the 1970s, our models suggest there are adjacent regions of hard, soft and liquid or mushy iron alloys in the top 150 miles of the inner core. This puts new constraints upon the composition, thermal history, and evolution of Earth", said Rhett Butler.