@article{BecerrilUbideSudoetal.2016, author = {Becerril, Laura and Ubide, Teresa and Sudo, Masafumi and Marti, Joan and Galindo, Ines and Gale, Carlos and Maria Morales, Jose and Yepes, Jorge and Lago, Marceliano}, title = {Geochronological constraints on the evolution of El Hierro (Canary Islands)}, series = {Journal of African earth sciences}, volume = {113}, journal = {Journal of African earth sciences}, publisher = {Elsevier}, address = {Oxford}, issn = {1464-343X}, doi = {10.1016/j.jafrearsci.2015.10.012}, pages = {88 -- 94}, year = {2016}, abstract = {New age data have been obtained to time constrain the recent Quaternary volcanism of El Hierro (Canary Islands) and to estimate its recurrence rate. We have carried out Ar-40/Ar-39 geochronology on samples spanning the entire volcanostratigraphic sequence of the island and C-14 geochronology on the most recent eruption on the northeast rift of the island: 2280 +/- 30 yr BP. We combine the new absolute data with a revision of published ages onshore, some of which were identified through geomorphological criteria (relative data). We present a revised and updated chronology of volcanism for the last 33 ka that we use to estimate the maximum eruptive recurrence of the island. The number of events per year determined is 9.7 x 10(-4) for the emerged part of the island, which means that, as a minimum, one eruption has occurred approximately every 1000 years. This highlights the need of more geochronological data to better constrain the eruptive recurrence of El Hierro. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @article{YepesAudinAlvaradoetal.2016, author = {Yepes, Hugo and Audin, Laurence and Alvarado, Alexandra and Beauval, Celine and Aguilar, Jorge and Font, Yvonne and Cotton, Fabrice}, title = {A new view for the geodynamics of Ecuador: Implication in seismogenic source definition and seismic hazard assessment}, series = {Tectonics}, volume = {35}, journal = {Tectonics}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0278-7407}, doi = {10.1002/2015TC003941}, pages = {1249 -- 1279}, year = {2016}, abstract = {A new view of Ecuador's complex geodynamics has been developed in the course of modeling seismic source zones for probabilistic seismic hazard analysis. This study focuses on two aspects of the plates' interaction at a continental scale: (a) age-related differences in rheology between Farallon and Nazca plates—marked by the Grijalva rifted margin and its inland projection—as they subduct underneath central Ecuador, and (b) the rapidly changing convergence obliquity resulting from the convex shape of the South American northwestern continental margin. Both conditions satisfactorily explain several characteristics of the observed seismicity and of the interseismic coupling. Intermediate-depth seismicity reveals a severe flexure in the Farallon slab as it dips and contorts at depth, originating the El Puyo seismic cluster. The two slabs position and geometry below continental Ecuador also correlate with surface expressions observable in the local and regional geology and tectonics. The interseismic coupling is weak and shallow south of the Grijalva rifted margin and increases northward, with a heterogeneous pattern locally associated to the Carnegie ridge subduction. High convergence obliquity is responsible for the North Andean Block northeastward movement along localized fault systems. The Cosanga and Pallatanga fault segments of the North Andean Block-South American boundary concentrate most of the seismic moment release in continental Ecuador. Other inner block faults located along the western border of the inter-Andean Depression also show a high rate of moderate-size earthquake production. Finally, a total of 19 seismic source zones were modeled in accordance with the proposed geodynamic and neotectonic scheme.}, language = {en} }