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Hawaiian Trough
The Hawaiian Trough, otherwise known as the Hawaiian Deep, is a moat-like depression of the seafloor surrounding the Hawaiian Islands. The weight from the volcanic island chain depresses the plastic lithosphere that is already weakened by the underlying thermal hotspot, causing subsidence to occur. The location with the greatest rate of subsidence is directly above the hotspot with a rate of about per year. The Hawaiian Trough is about deep and has a radius of about .Rees, B. A., Detrick, R. S., & Coakley, B. J. (1993). Seismic stratigraphy of the Hawaiian flexural moat. ''Geologic Society of America Bulletin'', ''105'', 189–205. The subsiding lithosphere is balanced out and through the concept of isostasy a part of the crust surrounding the trough is levered upwards creating the Hawaiian Arch. The Hawaiian Arch extends about above the surrounding ocean floor, and contains tilted coral reefs. Trough Development The Hawaiian Trough is filled with a stratified sedimentar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moat
A moat is a deep, broad ditch, either dry or filled with water, that is dug and surrounds a castle, fortification, building or town, historically to provide it with a preliminary line of defence. In some places moats evolved into more extensive water defences, including natural or artificial lakes, dams and sluices. In older fortifications, such as hillforts, they are usually referred to simply as ditches, although the function is similar. In later periods, moats or water defences may be largely ornamental. They could also act as a sewer. Historical use Ancient Some of the earliest evidence of moats has been uncovered around ancient Egyptian castles. One example is at Buhen, a castle excavated in Nubia. Other evidence of ancient moats is found in the ruins of Babylon, and in reliefs from ancient Egypt, Assyria, and other cultures in the region. Evidence of early moats around settlements has been discovered in many archaeological sites throughout Southeast Asia, including ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
