Eight years of permanent soil CO 2 diffuse degassing monitoring at Furnas and Fogo volcanoes shows that several environmental variables may influence soil CO 2 flux to a different extent depending on the location. Stepwise multivariate regression analysis applied to the data acquired by the permanent flux stations installed on São Miguel showed that the monitored environmental variables may influence the gas flux in a proportion between 18 and 51%. The external variables that most significantly correlate with the soil CO 2 flux values for Fogo and Furnas volcanoes monitoring sites are the rainfall/soil water content with its effect on permeability; the barometric pressure pumping effect; the wind speed owing to the atmospheric air intrusion and the air temperature through the action of atmospheric tides. These variables are responsible not only for spike-like oscillations in CO 2 emission, but also for the long-term oscillations with higher and lower values registered usually during winter and summer months, respectively. Residual time-series, calculated using regression models, are compared with other geophysical and geochemical monitoring data in order to recognize changes that may be correlated with the volcanic/hydrothermal systems.
Since settlement of São Miguel Island in the middle of the fifteenth century, several destructive landslides have occurred. These have been triggered by various factors, of which rainfall is the most common. Between 1900 and 2008, based on extensive documentary evidence, 193 landslide events with socio-economic impact have been identified. These events have been responsible for 67 deaths, about 20 people have been seriously injured, and dozens of houses destroyed and people rendered homeless. In this chapter, the Information Value Method is used to produce a landslide rupture susceptibility map for São Miguel. Success and prediction rate curves (SRC and PRC) are computed and areas under the curve (AUC) calculated in order to not only support the results of modelling, but also assess the robustness of the suggested susceptibility algorithm. Twelve predisposing factors are used as independent variables and a total of 9890 landslide depletion areas are used as the dependent variable. The AUC for both the SRC and the PRC was 0.90. The methodology used for the construction of the susceptibility map was shown to be both accurate and reliable. The map is an important tool for land-use/emergency planning and for landslide risk mitigation.
The use of dimension stones in architecture and civil engineering implies the knowledge of several mechanical, physical, and chemical properties. Even though it has been usual practice to measure physical and mechanical properties of dimension stones the same is not true for thermal properties such as thermal conductivity, thermal diffusivity, specific heat capacity, and heat production. These properties are particularly important when processes related with heating and cooling of buildings must be considered. Thermal conductivity, thermal diffusivity, and specific heat capacity are related with the way thermal energy is transmitted and accumulated in stones; heat production has to do with the amount of radioactive elements in the rocks and so with the environmental impact of radioactivity and public health problems. It is important to start to measure on a routine basis those four thermal properties in rocks and, in particular, in dimension rocks so that their application can be improved and optimized. With this is mind three sets of different rock types (granites, limestones, and marbles) were collected to measure the thermal conductivity, the thermal diffusivity, and the specific heat capacity with the objective of characterizing them in terms of those properties. Since the same set of rocks has also been studied for other physical properties, a correlation amongst all the measured properties is attempted. For each rock type several samples were used to measure the thermal conductivity, the thermal diffusivity, and the specific heat capacity, and average values were obtained and are presented. As an example, for granites the thermal conductivity varies between 2.87 and 3.75 W/mK; for limestones varies between 2.82 and 3.17 W/mK; and for marbles varies between 2.86 and 3.02 W/mK. It is hoped that measuring thermal properties on dimension stones will help to better adequate them to their use in civil engineering as well as to adequate their use in terms of a CE product.
The Nordeste Volcanic Complex is located in the NE sector of S. Miguel Island (Azores) and it is composed of geological formations with about 4 million years old, extremely weathered. This fact, allied to the steep slopes on the area, promotes the occurrence of slope instability phenomena. In particular, the Guilherme Creek watershed has a high recurrence of this type of geological hazard, mainly triggered by precipitation, which promotes a high density of landslides in the area. Considering as main objective the landslide susceptibility analysis in the Guilherme Creek watershed, using statistical/probabilistic methods, it is ongoing an inventory process of these phenomena in a GIS, based on the aerial photography interpretation and fieldwork. Currently, the inventory is concluded based on aerial photography from 1982 and Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates orthorectified aerial photography from 1995 to 2005. In order to validate and update the landslide inventory produced in the office, fieldwork has been carried out using, besides more traditional techniques, a drone (DJI Phatom 4 PRO). This tool has allowed studying steep slopes, which would otherwise be impossible to access in an area with a high forest density and very steep slopes. Until now, 517 landslides have been identified in the study area, mainly belonging to slides and falls typologies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.