Emperor Seamounts
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The Emperor Seamounts are a chain of seamounts (submerged volcanic mountains) extending from the northwestern Hawaiian Islands (see Kure and Midway atolls) in a northwesterly direction until approximately 170º east longitude where they trend abruptly northward towards the tip of the Aleutian Islands and the Kamchatka Peninsula. The chain's name reflects the naming of many of the individual volcanoes for legendary and historic emperors of Japan (Yuryaku, Kimmei, Nintoku and Suiko are examples). They were named by Robert S. Dietz in 1954.
The Emperors are the submerged remnants of volcanic islands of what we now call the Hawaiian Islands and are part of the Hawaiian-Emperor seamount chain. The age and depth of the ancient volcanoes increases toward the northern tip of the chain. Most of the older Emperors are flat topped seamounts (or guyots) showing evidence of once having been reef encircled, high islands and then coral atolls.
The change in trend of the seamounts has been regarded as evidence of directional change of the Pacific Plate as it moved over the "fixed" hot spot that created each volcanic island that latter subsided to a seamount. The plate is being subducted at the trenches bordering the North Pacific rim. One explanation of the northward trend of the Emperors has been that they represent a hard plate portion that distorted the trench system of the North Pacific forming an apex seen at the Kuril-Aleutian Trench junction. A look at the USGS map on the Origin of the Hawaiian Islands (http://pubs.usgs.gov/gip/hawaii/page07.html) clearly shows this "spearpoint". However, how or why such a change in direction occurred has generally defied explanation. Recent research shows that the hot spot itself may be moving southward (Tarduno et al., 2003).
References
Tarduno, John A., Robert A. Duncan, David W. Scholl, Rory D. Cottrell, Bernhard Steinberger, Thorvaldur Thordarson, Bryan C. Kerr, Clive R. Neal, Fred A. Frey, Masayuki Torii, and Claire Carvallo. 2003. The Emperor Seamounts: Southward Motion of the Hawaiian Hotspot Plume in Earth's Mantle. Science, July 24, 2003; 10.1126/science.1086442 (Science Express Research Articles).
See also
External links
- Evolution of Hawaiian Volcanoes (http://wwwhvo.wr.usgs.gov/volcanowatch/1995/95_09_08.html) from the USGS.
- The Formation of the Hawaiian Islands (http://www.soest.hawaii.edu/GG/HCV/haw_formation.html) with tables and diagrams illustrating the progressive age of the volcanoes.
- Hot Spots and Mantle Plumes (http://volcano.und.nodak.edu/vwdocs/vwlessons/hot_spots/introduction.html)ja:天皇海山群