Correlation of pseudo relative velocity spectra with site intensity, local soil classification and depth of sediments

Empirical regression equations are presented for scaling Pseudo Relative Velocity Spectra, PSV(T), in terms of the Modified Mercalli Intensity M.M.I., local soil classification at the recording site (‘rock’, stiff or deep soil), and local geological condition (depth of sediments). It is shown that both the local soil classification and the local geological depth of sediments should be used simultaneously in the evaluation of site specific response spectra.     

Clinoform deposition across a boundary between orogenic front and foredeep – an example from the Lower Cretaceous in Arctic Alaska

The Lower Cretaceous Fortress Mountain Formation occupies a spatial and temporal niche between syntectonic deposits at the Brooks Range orogenic front and post‐tectonic strata in the Colville foreland basin. The formation includes basin‐floor fan, marine‐slope and fan‐delta facies that define a clinoform depositional profile. Texture and composition of clasts in the formation suggest progressive burial of a tectonic wedge‐front that included older turbidites and mélange. These new interpretations, based entirely on outcrop study, suggest that the Fortress Mountain Formation spans the boundary between orogenic wedge and foredeep, with proximal strata onlapping the tectonic wedge‐front and distal strata downlapping the floor of the foreland basin. Our reconstruction suggests that clinoform amplitude reflects the structural relief generated by tectonic wedge development and load‐induced flexural subsidence of the foreland basin.     

Ecological controls on biogeochemical lfuxes in the western Antarctic Peninsula studied with an inverse foodweb model

Sea ice in the western Antarctic Peninsula (WAP) region is both highly variable and rapidly changing. In the Palmer Station region, the ice season duration has decreased by 92 d since 1978. The sea-ice...