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Electrical structure of Plaine des Sables caldera, Piton de la Fournaise volcano (Reunion Island)
P. A. Schnegg
Annals of Geophysics , 1997, DOI: 10.4401/ag-3913
Abstract: An Audio Magnetotelluric (AMT) profile has been carried out across the Plaine des Sables, a former caldera of the active Piton de la Fournaise volcano, Reunion Island. Located in the Western Indian Ocean, between the Mascarene and Madagascar basins, this basaltic shield volcano originates from the activity of a hot spot. Our aim was to determine the internal structure of the volcano, in particular the shallow electrical properties of an area extending between the old and the new caldera rims. Although several teams had already conducted AMT work in this region a few years ago, there was a need for more a detailed, in depth survey. Our final model displays a noticeable slope of the Plaine des Sables basement oriented toward the present Fournaise summit. This slope is interpreted as resulting from successive landslides toward the ocean. We conclude that this dipping, electrically good conducting layer, probably belongs to the flat layering of an older caldera.
Acid gas hazards in the crater of Villarrica volcano (Chile)
Witter,Jeffrey B.; Delmelle,Pierre;
Revista geológica de Chile , 2004, DOI: 10.4067/S0716-02082004000200006
Abstract: the atmospheric concentrations of the acid gases so2, hcl, and hf were measured during austral summer 2001 in the summit crater area of villarrica volcano using 'filter packs'. these data were collected in order to assess the acid gas hazards to tourists who ascend the volcano. the authors compared their acid gas concentration results with exposure limits outlined by the national institute of occupational safety and health (niosh-united states of america). the authors conclude that tourists who visit the summit crater of villarrica may be exposed to non-lethal concentrations of so2 and hcl that exceed the recommended exposure limits defined by niosh, while atmospheric concentrations of hf do not exceed the recommended exposure limits
Acid gas hazards in the crater of Villarrica volcano (Chile)  [cached]
Jeffrey B. Witter,Pierre Delmelle
Revista geológica de Chile , 2004,
Abstract: The atmospheric concentrations of the acid gases SO2, HCl, and HF were measured during austral summer 2001 in the summit crater area of Villarrica volcano using 'filter packs'. These data were collected in order to assess the acid gas hazards to tourists who ascend the volcano. The authors compared their acid gas concentration results with exposure limits outlined by the National Institute of Occupational Safety and Health (NIOSH-United States of America). The authors conclude that tourists who visit the summit crater of Villarrica may be exposed to non-lethal concentrations of SO2 and HCl that exceed the recommended exposure limits defined by NIOSH, while atmospheric concentrations of HF do not exceed the recommended exposure limits Peligros de gases ácidos en el cráter del volcán Villarrica (Chile). Las concentraciones atmosféricas de los gases ácidos SO2, HCl y HF se midieron durante el verano austral de 2001 en el área del crater somital del volcán Villarrica, usando paquetes de filtro, para evaluar los peligros de gases ácidos para los turistas que ascienden el volcán. Los autores compararon los resultados de los gases ácidos con límites de exposición delineados por el 'National Institute of Occupational Safety and Health' (NIOSH-Estados Unidos de Norteamérica). Los autores concluyeron que los turistas que visiten el cráter somital del volcán Villarrica pueden estar expuestos a concentraciones no letales de SO2 y HCl que exceden los límites de exposición recomendados por NIOSH, en tanto las concentraciones atmosféricas de HF no exceden los límites de exposición recomendados
Low Malaria Prevalence in HIV-Positive Patients in Bamenda, Cameroon
Journal of Microbiology Research , 2012, DOI: 10.5923/j.microbiology.20120203.03
Abstract: Data on the prevalence of HIV and malaria coinfection in Cameroon is scanty. The objective of this study was to determine the prevalence of the coinfection in Bamenda which is the major urban city of the North West region of Cameroon, as well as to determine the risk factors that predispose HIV patients in Bamenda to infection with malaria. Subjects were randomly selected as they come for treatment in the HIV treatment center of Bamenda Regional Hospital and screened for malaria parasite. Of the 312 HIV patients who enrolled into the study, 231 (74%) were females and 81 (26%) were males. The median age of the participants was 38years. 80% of the HIV patients were on treatment for HIV and other opportunistic infections. 90 (28·8%) admit using mosquito net meanwhile 222 (71·2%) did not. Upon examining the blood sample from these patients, 7(2·24%) were coinfected with malaria. Among these 7 patients, only 2 were using mosquito net, and a majority of them were females (6). We therefore came to the conclusion that the prevalence rate of HIV and malaria coinfection was low and not using mosquito net is not a major risk factor (OR=1·01, P=1·0) for coinfection with malaria in HIV patients in Bamenda.
Environmental Consequences of Rapid Urbanisation: Bamenda City, Cameroon  [PDF]
Emmanuel M. Nyambod
Journal of Environmental Protection (JEP) , 2010, DOI: 10.4236/jep.2010.11003
Abstract: Human settlement conditions in many parts of the world, particularly the developing countries, are deteriorating. Natu-ral hazards now occur right at our door steps and the frequency of occurrence and magnitude of damages that they cause is seen to be on an increase especially in poor urban communities. The natural environment is deteriorating at a rate faster than the rate at which natural occurring processes and resources available within the environment can re-plenish. If left unabated, landslides, flooding, sporadic fire outbreaks, collapse of major road axis, houses and bridges have the potential of plunging urban centre’s into an abyss of environmental chaos. This paper chooses Bamenda city- Cameroon, a rapidly expanding city in the third world as an example. The paper therefore assesses the overall situation of deteriorating urban quality by randomly selecting some of the quarters within Bamenda city that are generally con-sidered as hazard prone. It was noticed that deteriorating urban quality stems from the phenomenon of rural exodus. The situation is further exacerbated by inappropriate systems of land administration, poverty and an overall anarchy and ignorance in the handling of environmental issues. This paper therefore calls for a multidisciplinary and holistic range of approaches to solving present day environmental hazards of Bamenda. It calls for the adoption of modern technology and the systematization of the processes of land acquisition and registration especially at state and local government levels.
Volcanic hazards and risk perception at the "Zoque" community of Chapultenango: El Chichón volcano, Chiapas, México
Limón-Hernández, C;Macías, J. L.;
Geofísica internacional , 2009,
Abstract: after 22 years of the 1982 eruption of el chichón volcano, we conducted a statistically based survey of the residents of the community of chapultenango (10 km east of the volcano) to assess their perception of volcano hazards and risk. the survey used: interviews with 90 adults who survived the 1982 eruption, and completion of questionnaires by 210 students, who were born after the eruption. while adult interviewees recognized the volcanic phenomena of the 1982 eruption, many remained poorly informed about volcanic hazards. surprisingly, only 12% of the interviewees believe that the volcano could erupt again. the students are more educated and better informed, and most of them believe that the volcano could erupt again and are well aware of the hazards posed. in case of future eruption, of the students answered that they would abandon their homes to save their lives; 66% knew the evacuation routes. the results demonstrate that people of chapultenango -particularly the older residents- have an inadequate perception of volcanic hazards and risk, despite proximity to an active volcano. unfortunately, no long-term governmental programs to increase public awareness of volcano hazards and to develop hazards-mitigation strategies have been implemented at chapultenango or other localities surrounding the volcano.
Volcanic hazards and risk perception at the “Zoque” community of Chapultenango: El Chichón volcano, Chiapas, México
C. Limón-Hernández,J. L. Macías
Geofísica internacional , 2009,
Abstract: After 22 years of the 1982 eruption of El Chichón volcano, we conducted a statistically based survey of the residents of the community of Chapultenango (10 km east of the volcano) to assess their perception of volcano hazards and risk. The survey used: interviews with 90 adults who survived the 1982 eruption, and completion of questionnaires by 210 students, who were born after the eruption. While adult interviewees recognized the volcanic phenomena of the 1982 eruption, many remained poorly informed about volcanic hazards. Surprisingly, only 12% of the interviewees believe that the volcano could erupt again. The students are more educated and better informed, and most of them believe that the volcano could erupt again and are well aware of the hazards posed. In case of future eruption, of the students answered that they would abandon their homes to save their lives; 66% knew the evacuation routes. The results demonstrate that people of Chapultenango -particularly the older residents- have an inadequate perception of volcanic hazards and risk, despite proximity to an active volcano. Unfortunately, no long-term governmental programs to increase public awareness of volcano hazards and to develop hazards-mitigation strategies have been implemented at Chapultenango or other localities surrounding the volcano.
Magnetic study of the Furnas caldera (Azores)  [cached]
I. Blanco,A. Garcìa,J. M. Torta
Annals of Geophysics , 1997, DOI: 10.4401/ag-3917
Abstract: A local ground magnetic study of the Furnas caldera (S. Miguel Island, Azores) has provided new insight into the magnetic structure of this volcano. Analysis of the data comprised removal of the IGRF, reduction to the pole, pseudogravity integration and upward continuation. Also, a spectral method was applied to estimate the depth to the magnetic sources, as well as a 2.5D forward modelling technique. Magnetic properties obtained at the laboratory for some representative sample rocks were considered in the modelling process. The most relevant features are the existence of an important negative anomaly inside the caldera and of an intense positive anomaly to the south of the coast. The former points out a decrease in the magnetization of the caldera filling materials with respect to the surrounding rocks, which could be explained as the result of post-eruption processes such as hydrothermal alteration. This is expected as Furnas has an active hydrothermal system probably related with a magmatic reservoir at high temperature. The positive anomaly suggests the existence of a strongly-magnetized body beneath the south coast.
Disruptive colonial boundaries and attempts to resolve land/boundary disputes in the Grasslands of Bamenda, Cameroon
EM Mbah
African Journal on Conflict Resolution , 2009,
Abstract: The 1990s ushered in an unprecedented wave of violent land/boundary disputes between village-groups in the Grasslands of Bamenda, North-West Province of Cameroon, on a scale that had never been witnessed before. Widespread hardship, introduced by the prevailing economic crisis was blamed for these disputes. But on closer examination it became clear that land/boundary disputes in the region have their roots in European colonialism, and derive largely from administrative policies that were disruptive on inter-village boundaries. Despite the efforts of British colonial authorities at resolving these disputes before the close of the colonial era, they have persisted because post-colonial administrations in Cameroon have failed to judiciously address them.
A Comment on “A major Change in the Stratigraphy of the Santorini Volcano in Greece”  [PDF]
Timothy H. Druitt
International Journal of Geosciences (IJG) , 2017, DOI: 10.4236/ijg.2017.89063
Abstract:
Friedrich and coauthors [1] propose that two prominent eruption deposits of Santorini Volcano are in fact the same unit, resulting in a major reinterpretation of the volcanic history of this caldera. Here I summarize published field and petrological evidence showing that their proposal is not correct.
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