Catálogo de publicaciones - revistas

<jats:p> Sand intrusions pose significant risks to river embankments due to potential flow pathways that can lead to instability during flood events. Visual inspection is a first step to recognize critical segments, but it does not deliver information about the subsurface. In this context, the electromagnetic induction (EMI) technique is a useful method for preliminary zoning at regional scale while the electrical resistivity tomography (ERT) method, widely used for hydrological purposes, is considered among the most reliable techniques for local subsurface imaging. A major sand intrusion within the levees of the Brenta River, located near Venice (northern Italy), resulted in water seeping during seasonal floods and posed severe threats to embankment stability. ERT and EMI techniques, along with geotechnical investigations, were the best survey choices to address the problem. Resistivity profiling successfully imaged the sand body geometry within and underneath the levee, and results correlated nicely with borehole stratigraphy. A first multiarray EMI device, which represented a faster and less expensive survey, was deployed to map further anomalies along nearby levees, but results were not satisfactory because the inverted profile failed to image the known intrusion. A second multiarray EMI device, with larger coil spacing, was also tested. Although it performed better in detecting the intrusion, results were still below expectations. A calibration procedure based on Pearson's coefficients and using ERT as a reference was then devised and implemented to correct the EMI data prior to carrying out inversion. The procedure was successful for both EMI data sets, leading to realistic subsurface resistivity in the inverted sections. EMI measurements could then be recovered and interpreted correctly to estimate subsurface textures. The possibility of calibrating EMI data and obtaining subsurface resistivity images comparable to standard ERT profiling is an important improvement for cost-effective EMI surveying of river embankments to mitigate flood hazards. </jats:p>

<jats:p> The complex pore structure of carbonate aquifers presents a challenge to interpreters analyzing geophysical logs and geologic data. A significant task is to develop physical rock models to determine the microstructure that provides information about flow-zone paths within the aquifer. In an attempt to achieve this task, an algorithm is devised to predict the secondary porosity formed by stiff macropores, compliant micropores, touching vugs, and pore aspect ratios from sonic logs. The pore aspect ratios are classified in intervals that delineate permeable and low permeability zones of aquifers. This provides information about the presence of isolated vugs, which do not contribute to the flow and connect or touch vugs that are part of the flow zones. The inversion results determined that permeable channels have pore aspect ratios 0.01–0.2. Alternatively, vugs with aspect ratios 0.5–1 are not forming permeable paths because they are isolated and are not contributing to flow zones. The inversion of P- and S-wave velocity logs using density and total porosity logs obtains the secondary porosity and pore aspect ratios. It found optimum correlation coefficients of 0.9975 for S-wave and 0.9405 for P-wave velocities by constraining the solution with the natural relation of the total porosity versus primary plus secondary porosities. The Port Mayaca aquifer includes Stoneley-wave permeability, formation microimager logs, and microresistivity logs, which together with pore aspect ratio and secondary porosity logs delineate and characterize the flow zones. In addition, data integration demonstrates that the vug porosity log detects fractures in resistive, permeable, and dense cemented zones. This new finding creates vug signatures, with their maximums resembling the shapes of the corresponding resistivity heights in the microresistivity log. In conclusion, it is shown that the anomaly zones correspond to water production regions, and their presence is confirmed with flow meter logs. </jats:p>

<jats:p> Landslides are a frequent natural hazard that affect millions of people globally and cause considerable damage and fatalities each year. Changing climate patterns and expanding urban areas are leading to an increased landslide risk. Thus, there is a need for novel methods to mitigate the hazard. Here, we provide an overview of recent work conducted within the densely populated San Francisco Bay Area, where geophysical characterization and monitoring are used to gain a predictive understanding of landslide processes. First, we show how geophysical and remote sensing can be used to map the landslide hazard, and then we show how geophysical data can be used to estimate the temporal variability of the hazard and possibly to provide landslide early warning. To estimate variations in soil properties and deformations across the site, we installed a wireless sensor network. We show how data from this network can be used to provide a predictive estimation of critical conditions. Eventually, the data presented here will be used by site management to address and mitigate the landslide hazard. </jats:p>

<jats:p> The American Geosciences Institute (AGI) invites teachers, students, the general public, and geoscience professionals to celebrate Earth Science Week (ESW) from 8–14 October 2023. </jats:p>

<jats:p> Coordinated by members of SEG's Justice, Equity, Diversity, and Inclusion (JEDI) Committee, TLE's Geoscientists Around the Globe department features geoscientists from technically, geographically, and culturally diverse backgrounds. In this inaugural installment, JEDI Committee Chair Lillian Flakes interviews Kelsey Bufford, environmental programs manager for the Oklahoma Department of Environmental Quality. </jats:p>

<jats:p> Big Data Analytics in Earth, Atmospheric, and Ocean Sciences, edited by Thomas Huang, Tiffany Vance, and Christopher Lynnes, 2022. </jats:p>

<jats:p> SEG Board of Directors and Executive Committee actions from June and July 2023. </jats:p>

<jats:p> Applications for Active membership have been received from the candidates listed herein. </jats:p>

<jats:p> The Meetings Calendar chronologically lists professional events of interest to SEG members and means by which further information can be obtained. </jats:p>

<jats:p> Lia Martinez shares critical skills that are necessary to network successfully. She explains why seven follow-ups is the magic number, the importance of establishing credibility early, and how to use note-taking to your advantage. </jats:p>