Launched in 2014, the Global Precipitation Measurement (GPM) mission aimed at ensuring the continuity with the Tropical Rainfall Measuring Mission (TRMM) launched in 1997 that has provided unprecedented accuracy in Satellite Precipitation Estimates (SPEs) on the near-global scale. Since then, various SPE versions have been successively made available from the GPM mission. The present study assesses the potential benefits of the successive GPM based SPEs product versions that include the Integrated Multi–Satellite Retrievals for GPM (IMERG) version 3 to 5 (–v03, –v04, –v05) and the Global Satellite Mapping of Precipitation (GSMaP) version 6 to 7 (–v06, –v07). Additionally, the most effective TRMM based SPEs products are also considered to provide a first insight into the GPM effectiveness in ensuring TRMM continuity. The analysis is conducted over different geomorphic and meteorological regions of Pakistan while using 88 precipitations gauges as the reference. Results show a clear enhancement in precipitation estimates that were derived from the very last IMERG–v05 in comparison to its two previous versions IMERG–v03 and –v04. Interestingly, based on the considered statistical metrics, IMERG–v03 provides more consistent precipitation estimate than IMERG–v04, which should be considered as a transition IMERG version. As expected, GSMaP–v07 precipitation estimates are more accurate than the previous GSMaP–v06. However, the enhancement from the old to the new version is very low. More generally, the transition from TRMM to GPM is successful with an overall better performance of GPM based SPEs than TRMM ones. Finally, all of the considered SPEs have presented a strong spatial variability in terms of accuracy with none of them outperforming the others, for all of the gauges locations over the considered regions.

A natural phenomenon (hazard) may be characterized in terms of temporal, spatial and magnitude probabilities. The effects of the interaction between the hazard and the exposed element depend on the intensity of the hazard and on the resistance, sometimes called susceptibility, of the element at risk, which describes the propensity of a building or other infrastructure to suffer damage from a specific hazard impact. Consequently, a modern concept of vulnerability must consider the intensity of the hazard as well as the structural resistance of the exposed infrastructure. This concept is referred to as physical vulnerability, and the most accepted definition is a representation of the expected degree of loss quantified on a scale of 0 (no damage) to 1 (total destruction). Thus, this work presents a mathematical model for landslide physical vulnerability assessment, here named the T-Model, based on the “Principle of Natural Proportionality” and calibrated with field observations of the massive rainfall-triggered landslide event that occurred in Nova Friburgo, Brazil in November of 2011. The model was also calibrated for a flow-type movement that is based on field observations of the failure of a tailing dam that affected the district of Bento Rodrigues, Brazil in November of 2015. The results showed a good agreement between predictions and the observed level of damages. Thus, it is possible to conclude that from a mathematical point of view, the model may be qualified as universal. It is recognized that a real universal objective model for vulnerability to landslides is not practical at present. More important than the model itself is the methodology that is presented here, which leads the user to take qualitative damage information from the field and develop it into a quantitative mathematical framework. Potential users of the T-Model must be cautious regarding the values of parameters that are presented in this paper. The T-Model is just a modest proposal that requires further calibration and deep expert criticisms.

Este artículo presenta un análisis y evaluación cuantitativa de la amenaza, la vulnerabilidad y el riesgo asociados a deslizamientos superficiales en una subcuenca del Valle de Aburrá (Colombia). Se integra el modelo TRIGRS mediante una simulación de Montecarlo para la estimación de la probabilidad de falla en la subcuenca empleando una altura del nivel freático como factor desencadenante, que junto con su probabilidad de ocurrencia anual permiten la evaluación de la amenaza. Se emplea un modelo que cuantifica la vulnerabilidad física de estructuras basándose en la intensidad del deslizamiento y la resistencia del elemento expuesto. El riesgo anual se estima para una vivienda del sitio de estudio como el producto de la amenaza y el valor de la pérdida dado el evento catastrófico, considerando la vulnerabilidad. La metodología empleada se enfoca en el deslizamiento ocurrido el 26 de octubre de 2016 en un talud dentro del sitio de estudio que afectó la vivienda que es objeto de análisis.

The application of geophysical monitoring technologies may offer an opportunity to understand the dynamic of slopes in response to factors triggering their instability. In this study, Ambient Noise Interferometry was used as a monitoring approach on a man-made reduced-scale vertical slope and on a natural-scale landslide in Sobradinho (Brazil), under the influence of mechanical stress and rainfall, respectively. For both experiments, we adopted similar data acquisition system and processing workflow. After preprocessing of ambient seismic noise, the time-lapse changes were determined in terms of relative velocity changes using the moving window cross spectral technique. For the vertical slope, terrestrial laser scanning was also performed to detect crack or fissure generation. The prototype experiment results showed a decreasing trend of relative velocity changes and reached a minimum value of -0.6% at the end of the experiment. No change was detected on the digital elevation model that was computed from terrestrial laser scanning images, due to the absence of centimeter scale superficial fissures. At natural scale (Sobradinho landslide), no significant variation in relative velocity changes was detected for the rainy and non-rainy days, mainly because of the inadequate change in the degree of saturation, which was found within a relatively short period of data acquisition.

O presente estudo tem por objetivo fazer uso de tecnologia GPR (Ground Penetration Radar), também conhecido como Georadar, para distinguir os materiais aluvionares, coluvionares e eluvionares depositados nas encostas e planícies da fazenda Vão do Buraco, calha do Contagem, porção leste do Planalto Central, na região do Distrito Federal. Foram definidas três encostas: côncava fechada (E1), côncava aberta (E2) e convexa (E3), para a aquisição de dados dos perfis de GPR, onde já se tinham descrições prévias dos materiais depositados, apresentando elúvio no topo, colúvio na média encosta e colúvio/aluvião na planície com formação de um leque aluvial. Fez-se uso de uma antena de 400 MHz para a sondagem, resultando em radargramas com informações de refletância. Devido às diferenças de composição entre o aluvião e o coluvião, seus contatos são abruptos. O alúvio, por apresentar cascalhos em sua composição, é definido por um número maior de alvos e alta refletância. Já o colúvio é constituído por materiais de granulometria mais fina (silte e argila), apresentando baixa refletância com alvos difusos.