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On June 5, 2015, transient electromagnetic (TEM) data were acquired on the baseball field at the East Falmouth, Massachusetts Elementary School approximately 30 m north the well MA-FWS-750. Transient electromagnetic induction (TEM) surveys provide resistivity soundings of the subsurface, which can be related to lithology and hydrogeology. Electrical current is cycled through a wire placed on the land surface in a transmitter loop (Tx), which in turn produces a static magnetic field. When the current is abruptly terminated, an instantaneous current is induced in the earth, and it moves downward and outward as the induced current decays with time. The decay is controlled by the resistivity of the earth. One or more...
Tags: Borehole Logging,
East Falmouth,
Electromagnetic,
Groundwater,
Massachusetts, All tags...
Nantucket Sound,
Resistivity,
TEM,
Time Domain,
Transient Electromagnetic,
environment,
geoscientificInformation, Fewer tags
In March 2016, the U.S. Geological Survey drilled a borehole, MA-FSW-750-0100, through the unconsolidated sediments and 1.5 m into the bedrock in East Falmouth, Massachusetts, to improve understanding of the glacial history and hydrologic properties of the Cape Cod aquifer. Prior to drilling, candidate sites were investigated using surface geophysical methods. Passive seismic horizontal-to-vertical spectral ratio (HVSR) methods were used to estimate the depth of the unconsolidated deposits over bedrock. Transient electromagnetic (TEM) surveys were conducted to characterize the lithology and salinity of formation water in the subsurface, which was used to plan the borehole completion. The specific conductance of...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Borehole Logging,
Conductivity,
East Falmouth,
Electromagnetic Induction (EMI),
Electromagnetic Surveying, All tags...
Gamma-Ray Logging,
Groundwater,
Horizontal to Vertical Spectral Ratio Seismic (HVSR),
Massachusetts,
Nantucket Sound,
Nuclear Magnetic Resonance (NMR),
Passive Seismic,
Resistivity,
Seismic Methods,
Time Domain,
Transient Electromagnetics (TEM),
USGS Science Data Catalog (SDC),
environment,
geoscientificInformation, Fewer tags
A pulsed magnetic resonance borehole tool was used to characterize hydraulic properties of the aquifer. Borehole nuclear magnetic resonance (bNMR) logs were collected to measure the water content and to estimate the pore-size distribution and hydraulic conductivity (K) over the depth of the borehole. The bNMR data were collected July 25-26, 2016, and were processed August 2016.
In March 2016, the U.S. Geological Survey drilled a borehole, MA-FSW-750, through the unconsolidated sediments and 1.5 m into the bedrock in East Falmouth, Massachusetts, to improve understanding of the glacial history and hydrologic properties of the Cape Cod aquifer. Polyvinyl casing was set through the overburden and into the bedrock. About 10 days after borehole MA-FSW-750 was drilled, it was logged with geophysical methods including natural gamma radiation and electromagnetic induction (EMI) logs to identify changes in the lithology and fluid properties of the subsurface. In addition, the gamma and EMI logs were collected about 100 days after drilling, which allowed the drilling fluids to be displaced and natural...
Tags: Borehole Logging,
Conductivity,
East Falmouth,
Electromagnetic Induction (EMI),
Electromagnetic Surveying, All tags...
Gamma-Ray Logging,
Groundwater,
Massachusetts,
Nantucket Sound,
Natural Gamma Radiation,
Resistivity,
Seismic Methods,
environment,
geoscientificInformation, Fewer tags
Passive seismic horizontal-to-vertical spectral ratio (HVSR) methods were used to estimate the depth of the unconsolidated deposits over bedrock. The HVSR method uses a three-component seismometer to measure the vertical and two horizontal components of ambient seismic noise. Seismic noise in the range of ~0.1 to 1 Hertz (Hz) is caused by ocean waves, large regional storms, and tectonic sources. A resonance frequency (f0) is induced in the unconsolidated deposits when there is a substantial contrast (> 2:1) in shear-wave acoustic impedance between the overburden and the bedrock. The f0 is determined from the analysis of the spectral ratio of the horizontal and vertical components of the seismic data. The thickness...
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