Space Daily- Staff Writes Sept 11 2013,Berkley CA (SPX)
This is a 3D view of the top 1,000 kilometers of the earth's mantle beneath the central Pacific showing the relationship between seismically-slow "plumes" and channels imaged in the study. Green cones on the ocean floor mark islands associated with "hotspot" volcanoes, such as Hawaii. Credit: Berkeley Seismological Laboratory, UC Berkeley.
Scientists at the University of California, Berkeley, have detected previously unknown channels of slow-moving seismic waves in Earth's upper mantle, a discovery that helps explain "hotspot volcanoes" that give birth to island chains such as Hawaii and Tahiti.
Unlike volcanoes that emerge from collision zones between tectonic plates, hotspot volcanoes form in the middle of the plates. The prevalent theory for how a mid-plate volcano forms is that a single upwelling of hot, buoyant rock rises vertically as a plume from deep within Earth's mantle the layer found between the planet's crust and core and supplies the heat to feed volcanic eruptions.
