GEOL 2207 Lecture Notes - 1964 Alaska Earthquake, Subsidence, Subduction
Document Summary
Gravitational effects of moon and sun: tides. Atmosphere circulation/ocean currents: el nino, la nina, difference in water temperature in pacfic. Eustatic effects: global sea level, based on how much water in ocean, glacio-eustasy. Melts when warm, freezes when cool (snow back on top of snow pack) Steric effects: change of density of water and temperature, as you heat it up, volume increases. Isostatic effects: the balance or equilibrium between adjacent portions of the lithosphere floating on the asthenosphere, thicker the crust, the more buoyant, glaciation on land loads the crust, causes it to sink a bit in asthenosphere. When ice is gone, crust moves up. Sediment loading: mississippi delta, big mass of sediments causing the land to sink on the asthenosphere. Tectonic uplift or subsidence: very slow; subduction, Earthquakes: uplift of seafloor near seattle by earthquake 1000 years ago, subsidence by earthquakes; uplift of crust (the furthest part of crust) and subsidence behind the uplift.
