Surficial and Shallow Subsurface Geology of the Northern and Central Exuma Cays, The Bahamas

2021 ◽  
Vol 51 (2) ◽  
Author(s):  
Paul J. Hearty ◽  
Joni T. Backstrom
2010 ◽  
Vol 119 (4) ◽  
pp. 683-708 ◽  
Author(s):  
Taku KOMATSUBARA ◽  
Geo-Database Information Committee, ◽  
Jun TSUKAHARA ◽  
Masato SANO ◽  
Shigehiko FUJIWARA ◽  
...  

Author(s):  
Rafiu Adegbola ◽  
Kayode Oyedele ◽  
Elizabeth Abidoye

Introduction: Geophysical characterization refers to the collection of information associated with subsurface features. Geotechnical involves engineering structural performance studies which are used to obtain information on the physical properties of soil and rock around a site to design earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions. Aim: The study was aimed at characterizing the subsurface formations for the purpose of determining its capacity to withstand engineering structures. Materials and Methods: Geophysical techniques involving eight (8) vertical electrical sounding (VES) and Wenner array were carried out with two (2) traverses. Geotechnical investigation involving cone penetration test (CPT) was also carried out. Results: The results obtained were presented as 1D resistivity profiles and Pseudo-sections of 2-D. Three (3) geo-electric layers were delineated within the study area and these comprise of topsoil, peat or clay and silty sand. The CPT results were used in the calculation of bearing capacity using Bustamante and Gianeselli equation for pile foundations and Meyehorf equation to determine the maximum load the materials can withstand respectively. Conclusion: The shallow subsurface geology was adjudged to be mechanically unstable with low penetration resistance values up to the depth of 11m. The methods conformed and confirmed that shallow foundation was considered unsuitable for the intended engineering structure. Keywords: Meyehorf, Bustamante and Gianeselli, Subsurface, Geology, Unstable, Foundation.


2016 ◽  
Author(s):  
Paolo Boncio ◽  
Giuliano Milana ◽  
Fabrizio Cara ◽  
Giuseppe Di Giulio ◽  
Deborah Di Naccio ◽  
...  

Abstract. We present detailed geological investigations aimed at the reconstruction of the shallow subsurface geology, and associated local seismic hazard, of the Avezzano town in the Quaternary Fucino basin (central Apennines). This work shows a basic (Level 1) seismic microzonation (SM) of the Avezzano town, focusing the attention on geologic constraints. We also discuss some methodological procedures of SM. Level 1 SM involves a reconstruction of the subsurface geological model achieved by a multidisciplinary approach synthesized in two main thematic maps and geologic sections. The first map, containing essential geologic information, is formed by overlapping layers (geological units, litho-technical units, and geomorphological/structural features). The second map is a summary map, easily accessible to non-geologist earthquake scientists/technicians, which synthesizes surface geology, subsurface data and resonance frequencies into homogeneous microzones. The two maps are tools for land and urban planning. The Avezzano area provides a case study of shallow subsurface geology and site effects in a deep continental basin environment, and is of potential interest for similar geologic contexts worldwide. Within the investigated area, almost all the possible earthquake-induced effects can occur, such as (a) stratigraphic amplifications in a wide range of resonance frequencies (from 0.4 to > 10 Hz); (b) liquefaction; (c) coseismic surface faulting; (d) basin-edge effects; and (e) slope instability.


1978 ◽  
Author(s):  
Robert A. Morton ◽  
Joseph H. McGowen ◽  
Henry L. Berryhill ◽  
Charles W. Holmes

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