# abstract.template -- MMA Memo Series Electronic Abstract Template
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# Comments are preceded by the "#" symbol.  Anything following a "#" is
# ignored.
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# The following entry is for internal use only.  Do not fill it in.
#Number:


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# Enter the MMA memo title in the following section
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#Title:
Spatial Distribution of Near-Surface Soil Resistivity 
in the Cerro Chascon Science Preserve
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# List the MMA memo authors in the order that they appear on the paper.
# Use a comma to separate the names of multiple authors.  List each author's
# affiliation in parenthesis following the name.
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#Authors:
Seiichi Sakamoto, and Tomohiko Sekiguchi
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#Date:
01/27/01
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# Enter a list of keywords which might be used to find this memo in an
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#Keywords:
site testing, underground, soil resistivity, grounding, lightning
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# Enter a plain ASCII abstract between here and the #END symbol
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#Abstract:
We examined near-surface soil resistivity of twenty-one locations 
in the Cerro Chascon science preserve area in the Wenner method 
with a fixed electrode spacing of 2 m.  
There were systematic differences in soil resistivity near 
the surface (down to a few meters):  
The values in the Pampa La Bola area were around 1000 Ohm-m, 
whereas those in the Llano de Chajnantor area were much higher 
and > 4400 Ohm-m in most locations topographically suitable 
for antenna pads.  
Special treatment may be needed for each pad to meet 
the Chilean regulation for grounding.  
A factor $\sim$ 1.3 difference expected from the 1.8deg C 
temperature difference between the Llano de Chajnantor and Pampa La Bola 
areas is not enough to explain all of the measured difference.  
The trend that quebradas systematically had higher values than their 
adjacent arroyos supports the idea that the difference primarily reflects 
probable difference of water content due to local topography and drainage.  
#END