<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>J. H. Healy</dc:contributor>
  <dc:creator>W. H. Jackson</dc:creator>
  <dc:date>1964</dc:date>
  <dc:description>A study of first-arrival amplitudes from 6 water shotpoints and 7 drill-hole shotpoints in parts of central and western United States indicate a variation of over 100 to 1 between the best and poorest shotpoints. Water shotpoints are, in general, superior to drill-hole shotpoints; however, one drill-hole shotpoint produced higher signal amplitudes than more than half of the water shotpoints. Signal amplitudes from drill-hole shotpoints varied by a factor of over 20. Saturated clay shooting medium appears to be the best shooting medium. Amplitudes from water shotpoints varied by a factor of about 10. Signal amplitude increases, in general, with water depth for bottom shots.</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.3133/70039542</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>U.S. Geological Survey</dc:publisher>
  <dc:title>Preliminary report on some factors affecting shotpoint efficiency</dc:title>
  <dc:type>reports</dc:type>
</oai_dc:dc>