Jurnal Internasional Shoreline Slope Breaks Revisi Memahami Evolusi Gunung Api Perisai Hawaii – Taylor – – Geokimia, Geofisika, Geosystems
Slope gradient map of bathymetry plots around the island of Hawaii found 12 protective slope breaks associated with formerly submerged shorelines, ranging from age back to 5 Ma. The age of sinking correlates with the waning of tholeiitic volcanism which no longer forms a coastline between the beginning and end of the final shield stage. The slope cracks in the northeast and southwest Mauna rifts are consistent with it being in the waning stages of the shield building. The superposition of the shorebreak shows that the Hualālai shield is older than Mauna Kea. We found evidence for the three volcanic shields that make up Ka'ena Ridge, for the waning of the Maui – Lāna'i – Kaho'olawe shield building simultaneously and the initiation of the Kohala shield building at 1.3 Ma, and for Mahukona which grew slightly above sea level around 0.6 Ma. The adjacent coastal slope breaks ~ 1.8 Ma at the end of the end of the West Moloka'i shield and the end of the East Moloka'i shielding stage. At its western end, the shield tilted away from, rather than towards, this slope broke. Likewise, the short slope of Hualālai fell to the north, as opposed to what was expected for the loading of the volcano to the south. Locally tilted shields of paleoshorelin may be associated with landslides causing the dorsal back to tilt away from unloaded footwall. The Nu'uanu and Wailau slides and Pololū's slump are mostly side shields of the grill that cuts slightly to the previous coastline, enough to prefer forward erosion nucleation through river flow.