@article{GalettoGarciaCaselli2018, author = {Galetto, Antonella and Garcia, Victor Hugo and Caselli, Alberto}, title = {Structural controls of the Domuyo geothermal field, Southern Andes (36°38′S), Argentina}, series = {Journal of structural geology}, volume = {114}, journal = {Journal of structural geology}, publisher = {Elsevier}, address = {Oxford}, issn = {0191-8141}, doi = {10.1016/j.jsg.2018.06.002}, pages = {76 -- 94}, year = {2018}, abstract = {Geothermal fields in subduction-related orogens are closely linked to areas characterized by young magmatic and tectonic activity, both in arc- and back-arc settings. The spatio-temporal interaction of Quaternary volcanic complexes with regional extensional and transtensional structures might favor a hydrothermal circuit between meteoric water and magmatic fluids. This study encompasses a kinematic analysis of fault structures from the high-enthalpy system located at the western flank of the Domuyo volcano in Argentina. An analysis of remote sensing data was applied to detect regional lineaments, lineament density, and to identify fracture patterns possibly associated with the different deformational stages documented in the area. These results were combined with detailed fracture analysis and kinematic study of mesoscale faults, as well as existing geological, structural, and geophysical data. The integration suggests that the fluid dynamics of the Domuyo geothermal field are directly conditioned by pre-existing basement structures that were reactivated as normal faults during Pliocene to-Quaternary times. Furthermore, the intensely fracture late Triassic - early Jurassic units are interpreted as the potential level for the reservoir. The fault reactivation was likely associated with the accommodation of regional extension along pre-existing fault structures, and locally enhanced by hydrothermal effects of the Domuyo geothermal field.}, language = {en} } @article{OrtizSaezAlvaradoetal.2022, author = {Ortiz, Gustavo and Saez, Mauro and Alvarado, Patricia and Rivas, Carolina and Garc{\´i}a, V{\´i}ctor Hugo and Alonso, Ricardo and Zullo, Fernando Morales}, title = {Seismotectonic characterization of the 1948 (M-W 6.9) Anta earthquake Santa Barbara System, central Andes broken foreland of northwestern Argentina}, series = {Journal of South American earth sciences}, volume = {116}, journal = {Journal of South American earth sciences}, publisher = {Elsevier}, address = {Oxford}, issn = {0895-9811}, doi = {10.1016/j.jsames.2022.103822}, pages = {15}, year = {2022}, abstract = {The region of the Andean back-arc of northwestern Argentina has been struck by several magnitude >= 6 crustal earthquakes since the first historically recorded event in 1692. One of these events corresponds to the Anta earthquake on 25 August 1948, with epicenter in the Santa Barbara System causing three deaths and severe damage in Salta and Jujuy provinces with maximum Modified Mercalli seismic intensities (MMI) of IX. We collected and digitized analog seismograms of this earthquake from worldwide seismic observatories in order to perform first-motion analysis and modeling of long-period teleseismic P-waveforms. Our results indicate a simple seismic source of M0 = 2.85 x 1019 N m consistent with a moment magnitude Mw = 6.9. We have also tested for the focal depth determining a shallow source at 8 km with a reverse focal mechanism solution with a minor dextral strike-slip component (strike 20 degrees, dip 30 degrees, rake 120 degrees) from the best fit of waveforms. Using magnitude size empirical relationships, the comparison of the obtained Mw 6.9 magnitude value and the ca. 10,000 km2 area of MMI >= IX from our seismic intensity map, which was obtained from newspaper and many historical reports, indicates a rupture length of 42 +/- 8 km for the Anta earthquake. We show our results in a 3D geological model around the epicentral area, which integrates modern seismicity, geological data, and information of a previously studied east-west cross section located a few kilometers south of the 1948 epicenter. The integration of all available information provides evidence of the re-activation of the Pie de la Sierra del Gallo fault during the 1948 Mw 6.9 shallow earthquake; this thrust fault bounds the Santa Barbara System along its western foothill.}, language = {en} }