The first Tessar appeared with a maximum aperture of f/6.3, but by 1907, the maximum aperture had been increased to f/4.5. The set of interfaces cemented in the posterior element had 3 functions: to reduce the spherical aberration reduce the overcorrected spherical-oblique aberration reduce the gap found between astigmatic foci. The frontal element of the Tessar, like that of the Anastigmat, had little power since its only function was to correct the few aberrations produced by the powerful posterior element. In 1902, he realized that the two cemented interfaces had many virtues, so he reinserted them in the back of his Anastigmat, maintaining the "air gap" of the previous part of the Unar, thus creating the Tessar design (from the Greek word τέσσερα ( téssera, four) to indicate a design of four elements) of 1902. In 1899 he separated the lenses in the Anastigmat to produce the fourth element, a group of four Unar lenses (which replaced the two interfaces cemented by the aforementioned device). In addition, this allowed the photographers to have greater freedom when choosing the lenses. Later, Rudolph thought that a narrow airgap in the form of a positive lens would correct the spherical aberration (as did HL Aldis in 1895) and that this device was much better than the lenses cemented. Paul Rudolph designed the Anastigmat with two lenses cemented in 1890. Based on our data, we postulate that the outcrop is part of a dextral strike-slip zone that was reactivated by glacial isostatic adjustment.Despite common belief, the Tessar was not developed from the 1893 Cooke triplet design by replacing the rear element with a cemented achromatic doublet. Studying deformation bands in unconsolidated sediments with GPR is therefore a powerful approach in paleoseismological studies. This allows correlation of the bands with the regional fault trend. With the 3-D analysis, it is further possible to derive the orientation and geometry of the bands. The study shows that deformation-band arrays can clearly be detected using GPR and quickly mapped over larger sediment volumes. This, together with the partially-developed weak calcite cementation and the distinct offset along the bands, are likely the main reasons for the clear and unambiguous expression of the shear-deformation bands in the radar survey. Thus they have a lower porosity and smaller pore sizes and therefore, in the vadose zone, the deformation bands have a higher water content due to enhanced capillary forces.
Thin sections of sediment samples show that the analysed shear-deformation bands have a denser grain packing than the host sediment. 3-D interpretation of the 2-D radar sections shows that the bands have near-planar geometries that can be traced throughout the entire sediment volume. The shear-deformation bands are partly represented by inclined reflectors and partly by the offset of reflections at delta clinoforms.
Features in the radargrams could be directly tied to the exposure. A dense grid (spacing 0.6 m) of GPR profiles was measured on top of a 20 m-long outcrop that exposes shear-deformation bands. Using ground-penetrating radar (GPR), we investigated an array of shear-deformation bands that developed in unconsolidated Pleistocene glacifluvial Gilbert-type delta sediments. Deformation bands in unconsolidated sediments are of great value for paleoseismological studies in sedimentary archives.
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