000005800 001__ 5800
000005800 005__ 20220929123348.0
000005800 0247_ $$2DOI$$ahttps://doi.org/10.1016/j.jsames.2022.103887
000005800 037__ $$aSCART-2022-0072
000005800 100__ $$aValenzuela-Malebrán, Carla
000005800 245__ $$aSource mechanisms and rupture processes of the Jujuy seismic nest, Chile-Argentina border
000005800 260__ $$c2022
000005800 520__ $$aThe Altiplano-Puna plateau, in Central Andes, is the second-largest continental plateau on Earth, extending between 22° and 27°S at an average altitude of 4400 m. The Puna plateau has been formed in consequence of the subduction of the oceanic Nazca Plate beneath the continental South American plate, which has an average crustal thickness of 50 km at this location. A large seismicity cluster, the Jujuy cluster, is observed at depth of 150-250 km beneath the central region of the Puna plateau. The cluster is seismically very active, with hundreds of earthquakes reported and a peak magnitude MW 6.6 on 25th August, 2006. The cluster is situated in one of three band of intermediate-depth focus seismicity, which extend parallel to the trench roughly North to South. It has been hypothesized that the Jujuy cluster could be a seismic nest, a compact seismogenic region characterized by a high stationary activity relative to its surroundings. In this study, we collected more than 40 years of data from different catalogs and proof that the cluster meets the three conditions of a seismic nest. Compared to other known intermediate depth nests at Hindu Kush (Afganisthan) or Bucaramanga (Colombia), the Jujuy nest presents an outstanding seismicity rate, with more than 100 M4+ earthquakes per year. We additionally performed a detailed analysis of the rupture process of some of the largest earthquakes in the nest, by means of moment tensor inversion and directivity analysis. We focused on the time period 2017-2018, where the seismic monitoring was the most extended. Our results show that earthquakes in the nest take place within the eastward subducting oceanic plate, but rupture along sub-horizontal planes dipping westward. We suggest that seismicity at Jujuy nest is controlled by dehydration processes, which are also responsible for the generation of fluids ascending to the crust beneath the Puna volcanic region. We use the rupture plane and nest geometry to provide a constraint to maximal expected magnitude, which we estimate as MW ~6.7.
000005800 594__ $$aNO
000005800 700__ $$aCesca, Simone
000005800 700__ $$aLópez-Comino, José Ángel
000005800 700__ $$aZeckra, Martin
000005800 700__ $$aKrüger, Frank
000005800 700__ $$aDahm, Torsten
000005800 773__ $$pJournal of South American Earth Sciences$$y2022
000005800 8560_ $$fmartin.zeckra@observatory.be
000005800 905__ $$apublished in
000005800 980__ $$aREFERD