For years the earth’s core has been thought to be split into two layers – the outer core and the inner core. However recent discoveries have led scientists to theorise this is not the case. Through studying the reverberations of earthquakes, it has been found that the inner core may be split into two layers.
Both proposed layers are made of an iron-nickel alloy however these alloys contain different crystal structures; the transition between layers is believed to be very gradual. The exact properties of the two distinct layers remain unknown. Research has been conducted since the idea was first brought to light in 2002. In recent years many more seismic sensors have been installed therefore allowing scientist to more thoroughly analyse the weak signals produced from rebounding waves
It has been found that the inner core may be split into two layers.”
Researchers used the reflections of waves as they bounced from one side of the earth to the epicentre of the earthquake. Geophysicist Hrvoje Tkalčić (from the Australian National University) states, “Earth oscillates like a bell after a large earthquake, and not just for hours, but days,”. Some of the recorded waves travelled through the inner core five times.
Researchers used the reflections of waves as they bounced from one side of the earth to the epicentre of the earthquake.”
When waves reach the inner core, they travel faster through the innermost part. They also travel slower in one direction in the innermost inner core than in the other direction on the outer layer of the inner core. This shows that the iron in each layer is organised differently.
Researchers believe this discovery could help explain the formation of the earth’s magnetic field; the inner core provides the heat needed for convection currents in the outer core. The magnetic field plays a major role in protecting the earth from cosmic radiation therefore the study of the inner core can play a major role in the research of earth’s development.