%0 Conference Proceedings %B Abstracts with Programs - Geological Society of America %D 1999 %T Factors influencing groundwater inflows in a newly constructed cross-strike tunnel, eastern Massachusetts; 3, Surface vs. subsurface fracture characteristics %A Stephen B Mabee %A Williams, Katherine W. %A Curry, Patrick J. %A Hardcastle, Kenneth C. %K #StaffPubs %K BEDROCK %K controls %K eastern Massachusetts %K factors %K fractures %K ground water %K Hydrogeology 21 %K massachusetts %K measurement %K movement %K New England %K outcrops %K spatial distribution %K tunnels %K United States %X Major fracture sets (dip >45 degrees ), their geographic distributions (domains), and their characteristics (spacing, trace length, and planarity) were measured in surface outcrops and in a 9 km section of the tunnel (Curry et al., this volume) to determine how well fracture data collected at widely-spaced surface exposures can be extrapolated to a depth of 70 to 90 meters. For the surface fracture data set, fracture sets and domains were determined from 1513 measurements collected at 21 outcrops located within 3 km of the trace of the tunnel. Spacing, trace length, and planarity were determined from scanline measurements (n = 899). For the tunnel data set, 413 fracture measurements were made to determine major sets and domains and a smaller subset (n = 156) was used to estimate fracture characteristics.Five fracture sets (14, 38, 86, 117, and 171) were identified in the outcrops and seven sets (13, 29, 41, 62, 132, 159, and 175) in the tunnel. The 14 and 171 sets correspond well with the 13 and 175 sets in the tunnel. The 38 set observed at the surface includes parts of the 29 and 41 sets in the tunnel. The 86 set does occur in the tunnel but is undersampled because it is aligned with the tunnel. The 62 and 159 sets occur in the tunnel but are not seen at the surface. Although large areas are devoid of outcrops, comparison of surface and subsurface fracture domains indicates that only the 14 and 171 sets show a reasonable overlap with the 13 and 175 domains in the tunnel. These latter sets are the fractures generating most of the groundwater inflow into the tunnel. Median fracture spacing and trace lengths for the 13 and 175 sets in the tunnel are significantly wider and longer than the corresponding 14 and 171 sets at the surface. Fracture planarities showed no significant differences between any of the surface and subsurface fracture sets. %B Abstracts with Programs - Geological Society of America %I Geological Society of America (GSA) : Boulder, CO, United States %C United States %V 31 %P 348 - 348 %8 1999/01/01/ %@ 00167592 %G eng %N 77 %! Abstracts with Programs - Geological Society of America %0 Conference Proceedings %B Abstracts with Programs - Geological Society of America %D 2005 %T Fracture characterization maps; a new type of geologic map for hydrogeologic applications %A Stephen B Mabee %A Joseph P Kopera %K #StaffPubs %K applications %K aquifers %K BEDROCK %K characterization %K classification %K crystalline rocks %K exploration %K fractures %K ground water %K hydrodynamics %K Hydrogeology 21 %K mapping %K movement %K overburden %K permeability %K potentiometric surface %K spatial distribution %K surficial aquifers %K thickness %K water wells %K water yield %X Integration of a wide array of structural data with well-field hydrologic testing is increasingly recognized as a critical step in understanding groundwater flow behavior and recharge in crystalline bedrock aquifers (Lyford et al., 2003, Walsh and Lyford, 2002). As part of its rejuvenated mapping program, The Massachusetts Office of the State Geologist has been producing fracture characterization maps as a value-added accompaniment to traditional 1:24:000-scale bedrock mapping. Fracture characterization maps reclassify bedrock into domains of varying hydrologic significance, by combining rock properties (foliation steepness and development, partings, sheeting development, etc...) and type of overburden (permeable vs. non-permeable). The goal of these maps is to better understand preferential flow directions in the bedrock and the potential hydraulic connections between surficial and bedrock aquifers. Each fracture characterization map contains several summary panels, including standard geologic map bases overlain by typical rose diagrams and stereonets displaying fracture domains and trajectories, sheeting distribution, foliation trajectories, bedrock elevations, generalized piezometric surface configuration, and overburden type and thickness with separations into permeability class. A GIS well database is also included, showing well distribution, yield, bedrock elevation, and "hot-linked" well log images. All maps and raw data are made available to the public in paper, digital (PDF) or GIS format. We believe this approach will provide hydrologists and consultants with basic framework data that will expedite and improve the planning of subsurface investigations, construction activities, and groundwater exploration. %B Abstracts with Programs - Geological Society of America %I Geological Society of America (GSA) : Boulder, CO, United States %C United States %V 37 %P 145 - 145 %8 2005/10/01/ %@ 00167592 %G eng %U https://gsa.confex.com/gsa/2005AM/finalprogram/abstract_94576.htm %N 77 %! Abstracts with Programs - Geological Society of America %0 Conference Proceedings %B Abstracts with Programs - Geological Society of America %D 1996 %T Fracture characterization; valuable inputs for modeling groundwater flow in fractured bedrock %A Stephen B Mabee %A Hardcastle, Kenneth C. %K #StaffPubs %K BEDROCK %K boreholes %K California %K discontinuities %K experimental studies %K field studies %K fractured materials %K fractures %K ground water %K Hydrogeology 21 %K Madera County California %K models %K movement %K observation wells %K Raymond California %K site exploration %K spatial distribution %K transmissivity %K United States %K wells %B Abstracts with Programs - Geological Society of America %I Geological Society of America (GSA) : Boulder, CO, United States %C United States %V 28 %P 77 - 77 %8 1996/02/01/ %@ 00167592 %G eng %N 33 %! Abstracts with Programs - Geological Society of America