Sergio A. Sepúlveda

Tsunamigenic, earthquake-triggered rock slope failures during the April 21, 2007 Aisén earthquake, southern Chile (45.5°S)

El 21 de abril de 2007 un terremoto superficial cortical (Mw 6,2) en el area del Fiordo Aisen desencadeno cientos de remociones en masa en la zona epicentral. Entre estas, se generaron varias inestabilidades en laderas rocosas escarpadas, tales como deslizamientos, caidas y avalanchas de rocas. El violento impacto de las masas disgregadas de roca en las aguas del fiordo genero tsunamis locales, que causaron diez victimas fatales y un importante dano en granjas salmoneras ubicadas a lo largo de las costas del fiordo. Observaciones de terreno sugieren controles geotecnicos y geomorfologicos en la ubicacion y modos de falla de las remociones en masa, asociados a la presencia de fallas y relieve abrupto, respectivamente. Este evento es un ejemplo de un tipo de peligro geologico que no ha sido previamente detectado ni abordado en los fiordos de la Patagonia Chilena, revelando la necesidad de identificar y comprender estos fenomenos geologicos en futuras evaluaciones de peligro en la region.

New Findings on the 1958 Las Melosas Earthquake Sequence, Central Chile: Implications for Seismic Hazard Related to Shallow Crustal Earthquakes in Subduction Zones

On the 4th of September 1958, a sequence of 3 earthquakes of magnitude 6.7–6.9 struck the Andean Main Cordillera at the latitude of Santiago, Central Chile. The quakes were preceded by a magnitude 6.0 foreshock one week earlier. This seismic sequence provided the only documented effects of strong shaking related to shallow earthquakes in a subduction-zone environment in which seismicity is dominated by interplate and intermediate-depth intraplate earthquakes. The 1958 earthquake sequence is reviewed as part of a project of seismic hazard assessment of the densely populated region of Santiago. We reinterpret historical documents and carried out field observations to obtain new intensity estimates, and we estimate ranges of peak acceleration values based on geotechnical back-analyses of earthquake-induced landslides. Estimated peak intensities of 9 and peak accelerations close to 1 g illustrate the significant seismic hazard in areas around active faults in the region and the need to adapt the building codes to these rare but potentially highly destructive types of earthquakes.

Suction-assisted lipectomy fails to improve cardiovascular metabolic markers of disease: a meta-analysis.

BACKGROUND The purpose of this study was to determine whether suction-assisted lipectomy (SAL) decreases the incidence of early cardiovascular disease risk factors or its biochemical and clinical risk indicators. METHODS A systematic review of the literature was performed by conducting a predefined, sensitive search in MEDLINE without limiting the year of publication or language. The extracted data included the basal characteristics of the patients, the surgical technique, the amount of fat extracted, the cardiovascular risk factors and the biochemical and clinical markers monitored over time. The data were analysed using pooled curves, risk ratios and standardised means with meta-analytical techniques. RESULTS Fifteen studies were identified involving 357 patients. In all of the studies, measurements of predefined variables were recorded before and after the SAL procedure. The median follow-up was 3 months (interquartile range (IQR) 1-6, range 0.5-10.5). The mean amount of extracted fat ranged from 2063 to 16,300 ml, with a mean ± standard deviation (SD) of 6138 ± 4735 ml. After adjusting for time and body mass index (BMI), leptin and fasting insulin were the only markers that were significantly associated with the amount of aspirated fat. No associations were observed for high sensitive C-reactive protein (hCRP), interleukin-6 (IL-6), adiponectin, resistin, tumour necrosis factor-α (TNF-α), Homeostasis Model of Assessment (HOMA), total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides, free fatty acids or systolic blood pressure. CONCLUSIONS Based on the results of our analysis, we conclude that there is no evidence to support the hypothesis that subcutaneous fat removal reduces early cardiovascular or metabolic disease, its markers or its risk factors.

Megalandslides in the Andes of central Chile and Argentina (32°–34°S) and potential hazards

Abstract This review deals with an integration and update of the knowledge about large-volume landslides in the Central Andes at 32–34°S. An integrated landslide inventory for megalandslides in central Chilean and Argentinean Andean basins was developed, and dispersed chronological data on palaeolandslides were compiled, showing a dominance of Late Pleistocene and Holocene ages. Traditional hypotheses adopted for explaining landslide occurrence in the Central Andes are contrasted. Whereas seismic tremors have been widely suggested as the main triggering mechanism in Chilean collapses, palaeoclimatic conditions are considered as the main cause of Argentinean giant landslides. These different approaches denote the lack of multidisciplinary studies focused on the controversy about seismic or climate trigger mechanisms in the Central Andes. These studies are also essential to understand failure mechanisms and assessment of the related hazard and risk, which are essential to reduce social and economic impacts on vulnerable communities from future landslide events.

Catastrophic, rainfall-induced debris flows in Andean villages of Tarapacá, Atacama Desert, northern Chile

In March 2012, during the rainy season in the Altiplano plateau, a >100-year return period rainfall event affected the deeply incised valleys of the Precordillera of the Tarapacá Region, northern Chile. This extreme event in a very arid region triggered a number of debris and mud flows that caused severe damage and destruction in several small villages along the Camiña and Tarapacá valleys. The highly vulnerable location of the villages on top of alluvial fans due to socioeconomic and cultural reasons is a key factor to explain the level of destruction in most villages. In this paper, this unusual, remarkable landslide event is described, and the hazard faced by these settlements for future rainfall episodes and possible mitigation measures are discussed.

Geodynamic Processes in the Andes of Central Chile and Argentina

This Special Publication arises from the UNESCO-sponsored IGCP 586-Y project ‘The tectonics and geomorphology of the Andes (32°–34°S): interplay between short-term and long-term processes’. It includes state-of-the-art reviews and original articles from a multidisciplinary perspective that investigate the complex interactions of tectonics and surface processes in the subduction-related orogen of the Andes of central Chile and Argentina ( c. 27°–39°S). It aims to improve our understanding of tectonic and landscape evolution of the Andean range at different time scales, as well as the mutual relationship between internal and external mechanisms in Cenozoic deformation, mountain building, topographic evolution, basin development and mega-landslides occurrence across the flat slab to normal subduction segments. The geodynamic processes of the Andes of central Chile and Argentina are analysed from a number of subdisciplines of the Earth sciences, including tectonics, petrology, geophysics, geochemistry, structural geology, geomorphology, engineering geology, stratigraphy and sedimentology.

Landslides cause tsunami waves : insights from Aysen Fjord, Chile

On 21 April 2007, an Mw 6.2 earthquake produced an unforeseen chain of events in the Aysen fjord (Chilean Patagonia, 45.5°S). The earthquake triggered hundreds of subaerial landslides along the fjord flanks. Some of the landslides eventually involved a subaqueous component that, in turn, generated a series of displacement waves—tsunami-like waves produced by the fast entry of a subaerial landmass into a water body—within the fjord [Naranjo et al., 2009; Sepulveda and Serey, 2009; Hermanns et al., 2013]. These waves, with run-ups several meters high along the shoreline, caused 10 fatalities. In addition, they severely damaged salmon farms, which constitute the main economic activity in the region, setting free millions of cultivated salmon with still unknown ecological consequences.

Long-Term Quality-of-Life Outcomes After Body Contouring Surgery: Phase IV Results for the Body-QoL® Cohort

Background Body contouring surgery (BCS) is becoming increasing popular for aesthetic and reconstructive purposes, particularly among patients with massive weight loss (MWL). However, data on quality of life (QoL) following the surgery are limited, especially long-term QoL. Objectives The authors evaluated the effect of BCS on QoL and the durability of this effect over time. Methods QoL was measured with the Body-QoL® instrument at 3 time points among consecutively treated patients: the day before BCS, 1 to 9 months postoperatively (short term), and 1 to 2.7 years postoperatively (long term). Total Body-QoL scores were compiled, as were scores for the instruments main domains: body satisfaction, sex life, self-esteem and social performance, and physical symptoms. Scores were examined for the entire study population and separately for the cosmetic and MWL cohorts. Results Fifty-seven of the 112 patients participated in the short-term assessment and 84 in the long-term assessment. Total Body-QoL scores increased significantly (P < 0.0001), from 44.0 ± 14.1 preoperatively to 85.5 ± 17.5 short-term postoperatively and to 84.4 ± 12.7 long-term postoperatively. Scores for the 2 postoperative assessments did not differ significantly. Similar results were observed for scores on each separate domain. Although preoperative scores were lower for the MWL cohort than the cosmetic cohort (33.9 ± 15.6 vs 46.1 ± 12.8; P = 0.0002), they improved substantially after BCS, approaching scores for the cosmetic cohort. Conclusions QoL increases significantly after BCS. This favorable outcome remained stable throughout long-term follow-up and was true for the cosmetic and MWL cohorts. Level of Evidence 4

Earthquake-Triggered Subaerial Landslides that Caused Large Scale Fjord Sediment Deformation: Combined Subaerial and Submarine Studies of the 2007 Aysén Fjord Event, Chile

On 21 April 2007 (Mw 6.2) an earthquake triggered more than 500 landslides near the epicenter along the Aysen fjord, Chile. One of the major failures occurred at the Punta Cola Valley involving a volume of 20.9 million cubic meters of rock. The main rockslide was followed by a rock/debris avalanche involving talus and glacio-fluvial deposits in the slope toe and valley floor that added a volume of 7.3 million cubic meters as entrained material. About half of the material involved in the rockslide-debris avalanche reached the shoreline and entered the fjord pushing deltaic deposits offshore while inducing a shoreline retreat of 100 m. The impact of the debris avalanche deformed an area of 7.6 km2 of the otherwise featureless and smooth sedimented fjord floor. The central part of the deformed area is currently deeper with respect to the undeformed floor, which suggests that between 1 and 10 m of sediment were eroded from an area of 1.85 km2 due to the direct impact of the avalanche. The combination of debris avalanche impact of this and other landslides, subaqueous failures and fjord floor deformation generated a series of displacement waves within the fjord with several meters to tens of meters high run-up along the shoreline.

Geodynamic processes in the Andes of Central Chile and Argentina: an introduction

Abstract The Andes, the worlds largest non-collisional orogen, is considered the paradigm for geodynamic processes associated with the subduction of an oceanic plate below a continental plate margin. In the framework of UNESCO-sponsored IGCP 586-Y project, this Special Publication includes state-of-the-art reviews and original articles from a range of Earth Science disciplines that investigate the complex interactions of tectonics and surface processes in the subduction-related orogen of the Andes of central Chile and Argentina (c. 27–39°S). This introduction provides the geological context of the transition from flat slab to normal subduction angles, where this volume is focused, along with a brief description of the individual contributions ranging from internal geodynamics and tectonics, Quaternary tectonics and related geohazards, to landscape evolution of this particular segment of the Andes.