Volcanic Substructure Inferred from Dredge Samples and Ocean-Bottom Photographs, Hawaii

摘要: Ocean-bottom photographs from 18 stations and dredge hauls 35 adjacent to the Island of Hawaii indicate that basaltic pillow lava fragments are dominant rock type on crest flanks submarine rift zone ridges, whereas glassy basalt sand scoria volcanoes directly downslope land. These relations three major units comprise different levels depending site eruption: (1) lavas below sea level erupted deep-water vents; (2) hyaloclastite rocks (vitric explosion debris, littoral cone ash, flow-foot breccias) mantle pillowed base volcano, shallow-water vents, subaerial vents in water-soaked ground, or produced where flows cross shoreline; (3) thin make up visible, shield built atop clastic layer, vents. This three-fold structure is similar table mountains Iceland by eruption beneath glacial ice. Large-scale slumping layer may modify slopes as well produce faulting movement parts overlying volcano. The slope change gentler meets steeper pile can be recognized older volcanoes, it has been submerged regional subsidence.