INVESTIGADORES
CRESPO Sebastian Andres
congresos y reuniones científicas
Título:
Meteorological triggers of debris flows in the Patagonian Andes
Autor/es:
CASTELLER ALEJANDRO; CRESPO SEBASTIAN; VILLALBA RICARDO; ARANEO DIEGO; STOFFEL MARKUS
Lugar:
Mendoza
Reunión:
Congreso; XI Congremet; 2012
Institución organizadora:
Sociedad Argentina de Meteorologos
Resumen:
Debris flows are common natural hazards affecting infrastructure in the Patagonian Andes. Previous studieshave shown that debris flows events have a strong correlation with local meteorological conditions, inparticular precipitation. In this study, we investigate the meteorological conditions that triggered eventsbetween 1864 and 2009 at the site ?Brazo Huemul?, Neuquén, Argentina (40°56´01´´S, 71°24´43´´W). In thisregion, written documents of this rapid mass-movement process are scarce, fragmented and limited in time.Dendrochronological methods were therefore used as a proxy record to reconstruct past events. We sampled43 trees, which showed external evidence of past debris-flow activity. Sampled species were Austrocedruschilensis (native) and Pseudotsuga menziesii (introduced from North America). We collected cross-sectionsand/or increment cores from the stems of both species, as well as exposed roots from selected trees. On eachsample, we dated and analyzed tree-ring indicators of debris flows activity, such as scars, tangential rows oftraumatic resin ducts, eccentricity variations, reaction wood and abrupt growth changes. Our results indicatethat although most events occurred during the dormant season of trees (between April and September),damage also occurred during the growing season. Regional temperature and precipitation records wereanalyzed to determine the meteorological conditions that triggered these events. Preliminary results suggestthat local precipitation, in many cases not registered at regional meteorological stations, are linked with thereconstructed events. We hypothesize that the presence of snow before rain events on the upper slopes of thecatchment area would facilitate the occurrence of debris flows.