Hf isotope ratios measured in igneous zircon are controlled by magmatic source, which may be linked to tectonic setting. Over the 200-500 Myr periodicity of the supercontinent cycle - the principal geological phenomenon controlling prevailing global tectonic style - juvenile Hf signals, i.e. most radiogenic, are typically measured in zircon from granites formed in arc settings (crustal growth),...

Hydrologic analyses are commonly based on a single conceptual model. Yet hydrologic environments are open and complex, rendering them prone to multiple interpretations and conceptualizations. Considering conceptual model uncertainty is a critical process for the assessment of hydrologic uncertainty. This study assesses recharge and geologic model uncertainty for the Climax Mine area of the Neva...

Advances in reservoir characterization and modeling have given the industry improved ability to build detailed geological models of petroleum reservoirs. These models are characterized by complex shapes and structures with discontinuous material properties that span many orders of magnitude. Models that represent fractures explicitly as volumetric objects pose a particular challenge to standard...

1. Abstract This paper summarizes our experiences in the analysis of the reliability of a military terrain analysis application developed at the Finnish Defence Forces. The logic of the analysis model and the variables in the model were assumed to be valid. The analysis of the reliability of the results was planned to be made by using the uncertainty measures of different source data sets and t...

Injection of CO2 in geological formations has been proposed as an effective strategy to reduce the emissions of greenhouse gases. The understanding of interactions and the design of operations at an aquifer scale require the use computationally intensive numerical simulations. These simulations require the specification of flow and transport parameters of the formation that in general are poorl...

Frequency-magnitude distributions, and their associated uncertainties, are of key importance in statistical seismology. When fitting these distributions , the assumption of Gaussian residuals is invalid since event numbers are both discrete and of unequal variance. In general, the observed number in any given magnitude range is described by a binomial distribution which, given a large total num...

Petroleum resources are found within sedimentary rocks that have a sufficient interconnected void space to store and transmit fluids. The actual flow of liquid and gas phases occurs on a micrometer scale in the void space between rock grains. On the other hand, the hydrocarbon is typically carried in rock zones that are a few tens of meters thick but extend several kilometers in the lateral dir...

This paper describes the application of approximate methods to invert airborne magnetic data as well as helicopter-borne frequency domain electromagnetic data in order to retrieve a joint model of magnetic susceptibility and electrical resistivity. The study area located in Semnan province of Iran consists of an arc-shaped porphyry andesite covered by sedimentary units which may have potential ...

What is the chance that an earthquake of magnitude 6.7 or greater will occur before the year 2030 in the San Francisco Bay Area? The U.S. Geological Survey estimated the chance to be 0.7 ± 0.1 (USGS, 1999). In this paper, we try to interpret such probabilities. Making sense of earthquake forecasts is surprisingly difficult. In part, this is because the forecasts are based on a complicated mixtu...

The Environmental Protection Agency (EPA) and U.S. Geological Survey (USGS) initiated a two-year regional pilot survey in 2007 to develop, test, and validate tools and approaches to assess the condition of northern Gulf of Mexico (GOM) coastal wetlands. Sampling sites were selected from estuarine and palustrine wetland areas with herbaceous, forested, and shrub/scrub habitats delineated by the ...