Christiansen and others suspect that magma is produced in the subduction zone, the border between the diving plate and the lower mantle.
Because the ocean floor moves like a conveyor belt, rising to form ridges and diving back into the earth in a process called subduction, Hagstrum says, "half of the ocean floor has .
In the subduction volcano, the magma is composed largely of andesite, which is a melt relatively rich in silica, water vapor and other gases.
New 'embryonic' subduction zone found A new subduction zone forming off the coast of Portugal heralds the beginning of a cycle that will see the Atlantic Ocean close as continental Europe moves closer to America.
June 17, 2013 - Science Daily
Past megaquakes left mark on Canadian coast By Becky OskinLiveScienceThanks to decades of geologic detective work, scientists know that on Jan. 26, 1700, at 9 p.m., a massive earthquake and tsunami hit the Pacific Northwest.Born from the Cascadia Subduction Zone, the earthquake may have cleaved the 620-mile-long (1,000 kilometers) offshore fault from Northern California to Canada. Researchers don't yet know; they must play connect the ...
June 17, 2013 - NBC NEWS
New Subduction Zone Forming Off Spain's Coast A budding subduction zone offshore of Spain heralds the start of a new cycle that will one day pull the Atlantic Ocean seafloor into the bowels of the Earth, a new study suggests.
June 14, 2013 - LiveScience.com via Yahoo! News
Jay Inslee in Seattle Times Citing the parallels between that area's geological vulnerability and a large fault off Washington state, Inslee said, "The Cascadia subduction zone is the evil twin of the Indonesian fault zone, where that disaster happened."