Groundwater exploration using integrated geophysics method in hard rock terrains in Mount Betung Western Bandar Lampung,Indonesia

The presence of hard rock in Mount Betung has caused the misalignment of the groundwater aquifers,and resulted in many drilling failures for groundwater.An integrated geophysics method using gravity survey and Geoelectric Vertical Electrical Soundings(VES)were conducted to study the effect of basement and hard rock on groundwater prospects.From the gravity method,38 mapping points were carried out randomly,with a distance of 1-2 km in-between.Meanwhile,from the geoelectric method,51 VES points were acquired at the foot of Mount Betung.The acquisition was conducted with a Schlumberger configuration with AB/2=1 m to 250 m.The results show the Bouguer Anomaly in the west is 50-68 mgal due to the presence of hard rock in Mount Betung.This anomaly responds to relatively shallow hard rocks near surface.Hard rocks composed of andesite and breccia normally present at the depth of 5-180 m during well construction.Resistivity isopach mapping from VES data(at AB/2=50 m,100 m,and 150 m)shows the dominant constituents of hard rock.Fractures in hard rock contribute to secondary porosity,which could be a prospect zone that transmit groundwater.This finding shows that the fractures are randomly scattered,causing several well failures that have been worked.Furthermore,the fractures in the hard rock at the foot of Mount Betung acts as conduits between recharge at Mount Betung and the aquifer in the Bandar Lampung Basin.     

Land Water Storage Changes from Ground and Space Geodesy: First Results from the GHYRAF (Gravity and Hydrology in Africa) Experiment

This paper is devoted to the first results from the GHYRAF (Gravity and Hydrology in Africa) experiment conducted since 2008 in West Africa and is aimed at investigating the changes in water storage in different regions sampling a strong rainfall gradient from the Sahara to the monsoon zone. The analysis of GPS vertical displacement in Niamey (Niger) and Djougou (Benin) shows that there is a clear annual signature of the hydrological load in agreement with global hydrology models like GLDAS. The comparison of GRACE solutions in West Africa, and more specifically in the Niger and Lake Chad basins, reveals a good agreement for the large scale annual water storage changes between global hydrology models and space gravity observations. Ground gravity observations done with an FG5 absolute gravimeter also show signals which can be well related to measured changes in soil and ground water. We present the first results for two sites in the Sahelian band (Wankama and Diffa in Niger) and one (Djougou in Benin) in the Sudanian monsoon region related to the recharge–discharge processes due to the monsoonal event in summer 2008 and the following dry season. It is confirmed that ground gravimetry is a useful tool to constrain local water storage changes when associated to hydrological and subsurface geophysical in situ measurements.     

Spatial–temporal variations of water vapor content over Ethiopia: a study using GPS observations and the ECMWF model

GPS Solutions - We characterize the spatial–temporal variability of integrated water vapor (IWV) in Ethiopia from a network of global positioning system (GPS) stations and the European Center...     

Fossil fuels and other energy resources in the 21st century

We study the changing volumes and costs of the energy resources available in the coming century as a result of exploration, technical progress, and consumption. The most reliable and well-documented information involves fossil fuels, which account for nearly 80 percent of the energy mix today. Known and presumed resources are fairly well ranked by cost, and we can estimate future developments. We present two consumption scenarios: the more contrasted reference case and the ecologically driven case presented by the World Energy Council at its last congress (1992). Our scenarios take into account the twofold goal set forth at the Rio summit: to achieve sustainable development and to minimize the climatic effects of pollutant emissions.We show that the most cost-effective mineral resources, including uranium, will run out only gradually in the next century according to these hypotheses. As a result, marginal cost will grow relatively slowly. However, we presuppose a tough policy on curbing consumption and using renewable sources of energy.We point out the need for better cost ranking of energy saving and energy switch possibilities. Additionally, the ecological impact and cost of corrective measures will have to be evaluated. We believe that the medium- and long-term difficulties will stem chiefly from the contradiction between low energy prices and the commitments required. The danger of geopolitical tension will remain a serious concern.