@article{RoveratoLarreaCasadoetal.2018,
  author    = {Roverato, Matteo and Larrea, Patricia and Casado, Ismael and Mulas, Maurizio and Bejar, Gustavo and Bowman, Luke},
  title     = {Characterization of the Cubilche debris avalanche deposit, a controversial case from the northern Andes, Ecuador},
  series = {Journal of volcanology and geothermal research},
  volume    = {360},
  journal   = {Journal of volcanology and geothermal research},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0377-0273},
  doi       = {10.1016/j.jvolgeores.2018.07.006},
  pages     = {22 -- 35},
  year      = {2018},
  abstract  = {In areas characterized by many volcanoes, identifying the source of a deposit may not be trivial. This becomes much more complicated when looking for the source of a debris avalanche deposit (DAD), the common products of catastrophic volcanic edifice collapses. To overcome this problem, in this work a methodology is proposed based on the integration of texture features and areal distribution of the deposit, comparison between the petrography of the coarser clasts within the DAD and of the proximal products, grain-size analysis, and the volumetric estimations of the deposit and the volume missing from the volcanic edifice. This methodology has been tested to a DAD occurred near the city of Ibarra (Imbabura Province; Northern Ecuador), having a controversial source. Two main volcanic edifice are located in proximity of the DAD, the Cubilche volcano (3826 m.a.s.l.), located immediately south of and east of the colossal dormant Imbabura volcano. The former displays a sharp horseshoe shaped scar towards the north and inside this post-collapse edifice, that we name old Cubilche volcano (OCV), is located the young Cubilche volcano (YCV) that refilled a portion of the collapse scar and partially covered the southern flank of the OCV. Detailed knowledge of Cubilche volcano is critical because of its close proximity and interspersed activity with Imbabura volcano. In fact, Imbabura most recent edifice was built over the northwestern slope of the OCV and partially covered it. Recent studies linked the studied DAD to both Imbabura volcano as a product of its northern sector collapse, as well as neighboring Cubilche volcano. Our data points to Cubilche as the most likely source for this DAD. A perspective view of the shaded relief image of the present day OCV shows that the morphology of the volcano is well-preserved on its southern, eastern, and western flanks. This allows us to reconstruct the morphology of the OCV previous to the collapse through interpolation of elevation and altitude data of preserved flanks. A DEM of the present day topography was used for extrapolating the morphology. Using similar methodology, the post collapse base of the amphitheater was reconstructed by removing the relief of the present day YCV. The reconstructed topography of the OCV shows that it could have been a symmetric cone, reaching a maximum elevation of similar to 4100 m.a.s.l. with a lack volume of similar to 3.5 km(3). Based on this scenario, the deposit originated from the OCV main collapse should have a volume >3-3.5 km(3) in accordance to the volume calculated for the studied DAD. (C) 2018 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{HimiCasadoSendrosetal.2018,
  author    = {Himi, Mahjoub and Casado, Ismael and Sendros, Alex and Lovera, Raul and Rivero, Lluis and Casas, Albert},
  title     = {Assessing preferential seepage and monitoring mortar injection through an earthen dam settled over a gypsiferous substrate using combined geophysical methods},
  series = {Engineering geology},
  volume    = {246},
  journal   = {Engineering geology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0013-7952},
  doi       = {10.1016/j.enggeo.2018.10.002},
  pages     = {212 -- 221},
  year      = {2018},
  abstract  = {For several decades the Sant Llorenc de Montgai reservoir has experienced different problems that could affect the safety of the engineering structure. For this reason, several corrective actions have been taken over the years. Here, we present a study involving complementary geophysical methods including electrical resistivity tomography, seismic refraction tomography and frequency-domain electromagnetic surveys. The analysis of the inverted electrical resistivity tomography cross-sections combined with the seismic refraction results and land subsidence monitoring data show the likely mechanism of abnormal seepage. The areas where mortar injections were applied as a corrective measure are also clearly delineated. In addition, the evolution of the state of the embankment has been established from two successive electrical resistivity tomography surveys in the last two decades. The results show areas where corrective mortar injections have been effective, while in other areas new abnormal seepage has been detected. The lithological heterogeneity of the bedrock, especially the dissolution of gypsum-rich rocks, induced subsidence effects and caused abnormal seepage in different areas along the embankment. Our results indicate how corrective solutions can be optimized to reduce the cost of corrective engineering interventions.},
  language  = {en}
}