Beneath Earth’s surface, scientists find long ‘fingers’ of heat

Scientists seeking to understand the forces at work beneath the surface of the Earth have used seismic waves to detect previously unknown “fingers” of heat, some of them thousands of miles long, in Earth’s upper mantle. Their discovery helps explain the “hotspot volcanoes” that give birth to island chains such as Hawai’i and Tahiti.
Source: http://www.sciencedaily.com/releases/2013/09/130905142815.htm