scholarly journals Spatial and temporal variations of diffuse CO2degassing at El Hierro volcanic system: Relation to the 2011-2012 submarine eruption

2014 ◽  
Vol 119 (9) ◽  
pp. 6976-6991 ◽  
Author(s):  
Gladys Melián ◽  
Pedro A. Hernández ◽  
Eleazar Padrón ◽  
Nemesio M. Pérez ◽  
José Barrancos ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Submarine Eruption ◽  
Volcanic System ◽  
El Hierro

Spatial-temporal variations of surface diffuse CO2 degassing at El Hierro volcano, Canary Islands

2020 ◽  
Author(s):  
Pedro A. Hernández ◽  
Christopher A. Skeldon ◽  
Jingwei Zhang ◽  
Fátima Rodríguez ◽  
Cecilia Amonte ◽  
...  
Keyword(s):  
Canary Islands ◽  
Temporal Variations ◽  
Graphical Analysis ◽  
Homogeneous Distribution ◽  
Submarine Eruption ◽  
El Hierro ◽  
North East ◽  
The North ◽  
Total Data ◽  
Destructive Processes

<p>El Hierro (278 km<sup>2</sup>), the youngest, smallest and westernmost island of the Canarian archipelago, is a 5-km-high edifice constructed by rapid constructive and destructive processes in ~1.12 Ma, with a truncated trihedral shape and three convergent ridges of volcanic cones. It experienced a submarine eruption from 12 October, 2011 to 5 March 2012, off its southern coast that was the first one to be monitored from the beginning in the Canary Islands. As no visible emanations occur at the surface environment of El Hierro, diffuse degassing studies are a useful geochemical tool to monitor the volcanic activity in this volcanic island. Diffuse CO<sub>2</sub> emission surveys have been performed at El Hierro Island since 1998 in a yearly basis, with much higher frequency during the period 2011-2012. At each survey, about 600 sampling sites are selected to obtain a homogeneous distribution. Measurements of soil CO<sub>2</sub> efflux are performed in situ following the accumulation chamber method. During pre-eruptive and eruptive periods, the diffuse CO<sub>2</sub> emission released by the whole island experienced significant increases before the onset of the submarine eruption and the most energetic seismic events of the volcanic-seismic unrest (Melián et al., 2014. J. Geophys. Res. Solid Earth, 119, 6976–6991). The most recent diffuse CO<sub>2</sub> efflux survey was carried out in July 2019. Values ranged from non-detectable to 28.9 g m<sup>−2</sup> d<sup>−1</sup>. Statistical-graphical analysis of the data shows two different geochemical populations; Background (B) and Peak (P) represented by 97.5% and 0.5% of the total data, respectively, with geometric means of 1.2 and 23.6 g m<sup>−2</sup> d<sup>−1</sup>, respectively. Most of the area showed B values while the P values were mainly observed at the interception center of the three convergent ridges and the north-east of the island. To estimate the diffuse CO<sub>2</sub> emission for the 2019 survey, we ran about 100 sGs simulations. The estimated 2019 diffuse CO<sub>2</sub> output released to atmosphere by El Hierro was 214 ± 10 t d<sup>-1</sup>, value lower than the background average of CO<sub>2</sub> emission estimated on 412 t d<sup>-1</sup> and slightly higher than the background range of 181 t d<sup>-1</sup> (−1σ) and 930 t d<sup>-1</sup> (+1σ) estimated at El Hierro volcano during the quiescence period 1998-2010 (Melián et al., 2014, JGR). Monitoring the diffuse CO<sub>2</sub> emission has proven to be a very effective tool to detect early warning signals of volcanic unrest at El Hierro.</p>

scholarly journals Spatial and temporal variations of faecal indicator bacteria in Lake Bunyonyi, South-Western Uganda

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Alex Saturday ◽  
Thomas J. Lyimo ◽  
John Machiwa ◽  
Siajali Pamba
Keyword(s):  
Health Risks ◽  
Rank Correlation ◽  
Temporal Variations ◽  
Indicator Bacteria ◽  
Spatial And Temporal Variations ◽  
Wet Season ◽  
Recreational Waters ◽  
Faecal Indicator Bacteria ◽  
E Coli ◽  
Spearman’S Rank Correlation

AbstractBackground Microbial water quality serves to indicate health risks associated with the consumption of contaminated water. Nevertheless, little is known about the microbiological characteristics of water in Lake Bunyonyi. This study was therefore undertaken to examine the spatial and temporal variations of faecal indicator bacteria (FIB) in relation to physicochemical parameters in Lake Bunyonyi. Result The FIB concentration was consistently measured during sampling months and correlated with each other showing the presumed human faecal pollution in the lake. The highest concentration values for E. coli (64.7 ± 47.3 CFU/100 mL) and enterococci (24.6 ± 32.4 CFU/100 mL were obtained in the station close to the Mugyera trading centre. On a temporal basis, the maximum values were recorded during the rainy season in October 2019 (70.7 ± 56.5 CFU/100 mL for E. coli and 38.44 ± 31.8 CFU/100 mL for enterococci. FIB did not differ significantly among the study stations (p > 0.05) but showed significant temporal variations among the months (p < 0.05) with concentrations being significantly high in wet season than dry season (U = 794, p < 0.0001 for E. coli; U = 993.5, p = 0.008 for enterococci). Spearman’s rank correlation revealed that FIB concentrations were significantly positively correlated with turbidity and DO concentration levels (p < 0.05). Approximately 97.2% of the water samples had E. coli and enterococci concentrations levels below USEPA threshold for recreational waters. Likewise, 98.1 and 90.7% of samples recorded E. coli and enterococci counts exceeding the UNBS, APHA, WHO and EU threshold values for drinking water. Conclusion The FIB counts show that the Lake Bunyonyi water is bacteriologically unsuitable for drinking unless it is treated since the FIB pose health risks to consumers. Besides, the water can be used for recreational purposes.

Spatial and temporal variations in acoustic propagation characteristics at the new england shelfbreak front

2003 ◽  
Vol 28 (1) ◽  
pp. 129-150 ◽  
Author(s):  
J.F. Lynch ◽  
A.E. Newhall ◽  
B. Sperry ◽  
G. Gawarkiewicz ◽  
A. Fredricks ◽  
...  
Keyword(s):  
New England ◽  
Acoustic Propagation ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Propagation Characteristics

scholarly journals Spatial and temporal variations in Spain in the standardised ratio of in-hospital mortality due to colorectal cancer, 2008–2014

BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
J. M. García-Torrecillas ◽  
M. C. Olvera-Porcel ◽  
M. Ferrer-Márquez ◽  
F. Rubio-Gil ◽  
M J. Sánchez ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Hospital Mortality ◽  
Temporal Variations ◽  
Spatial And Temporal Variations

Spatial and temporal variations in fish larvae assemblages of Ilha Grande National Park, Brazil

2012 ◽  
Vol 22 (1) ◽  
pp. 95-105 ◽  
Author(s):  
Tatiane M. Gogola ◽  
Paulo V. Sanches ◽  
Éder A. Gubiani ◽  
Pedro R. L. da Silva
Keyword(s):  
National Park ◽  
Fish Larvae ◽  
Temporal Variations ◽  
Spatial And Temporal Variations

scholarly journals Tibetan tectonic evolution inferred from spatial and temporal variations in post-collisional magmatism

2005 ◽  
Vol 68 (3-4) ◽  
pp. 173-196 ◽  
Author(s):  
Sun-Lin Chung ◽  
Mei-Fei Chu ◽  
Yuquan Zhang ◽  
Yingwen Xie ◽  
Ching-Hua Lo ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Temporal Variations ◽  
Spatial And Temporal Variations
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