Kohl, T. (2016): Resistivity distribution from mid-crustal conductor to near-surface across the 1200 km long Liquiñe-Ofqui Fault System, southern Chile.

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Optically active poly(amide-imide) oligomers were synthesized by direct polycondensation between an aromatic diamine and a dicarboxylic acid both containing a diphenylsilylene unit. The reaction was carried out using triphenyl phosphite/pyridine in the presence of CaCl2 and N-methyl-2-pyrrolidone as solvent. Oligomers were obtained in good yields and showed high solubility in common aprotic polar solvents. The precursors, monomers and poly(amide-imide) oligomers were characterized using elemental analysis and Fourier transform infrared and NMR (1H, 13C, 29Si) spectroscopy. Additionally, themain vibrations of the functional groups (C O, C C or N–H) in the oligomers with respect to temperature were characterized using Raman spectroscopy. The glass transition temperature was determined by studying the Raman spectra and corroborated using differential scanning calorimetry. The thermal stability was studied using thermogravimetric analysis. The molecular mass of the compounds was obtained from matrix-assisted laser desorption ionization time-of-flight mass spectrometry and their optical properties were analyzed using UV-visible diode array spectrophotometry. The electronic properties of the oligomers as well as the delocalization of charge carriers within their structures were analyzed using conductance-voltage curves, which showed that thesematerials are excellent candidates for integrated optoelectronic applications.MECESUP UCH 0601 and FONDECYT (grants 1100015, 1095151, 1100882

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The geoelectric properties of the geothermal system associated with the Tolhuaca volcano were investigated by three-dimensional (3D) inversion of magnetotelluric (MT) data. This study presents the first resistivity model of the Tolhuaca volcano derived from 3D MT inversion to have a better understanding of its magmatic and hydrothermal system. We selected data from 54 MT stations for 3D inversion. We performed a series of 3D MT inversion tests by changing the type of data to be inverted, as well as the starting model to obtain a model in agreement with the geology. The final 3D MT model presents a conductive body (<20 Ωm) located 2 km below the summit of Tolhuaca volcano, inferred as a shallow magmatic storage compartment. We also distinguish a ~300 m thick layer of high conductivity (<10 Ωm) corresponding to argillic hydrothermal alteration. The MT model includes two resistive bodies (~200 Ωm) in the upper crust below the laterally displaced argillic alteration layer to the west beneath the extinct Tolhuaca, which would correspond to a shallow reservoir (~1000 m from the surface) and a deep reservoir (>1800 m from the surface) that had so far not been identified by previous resistivity models. The result of this study provides new insights into the complexity of the Tolhuaca geothermal system.