<?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>John C. Roller</dc:contributor>
  <dc:creator>C.A. Borcherdt</dc:creator>
  <dc:date>1968</dc:date>
  <dc:description>&lt;p&gt;A reversed seismic-refraction profile extending northeastward from Greycliff, Montana, across the Large Aperture Seismic Array (LASA) to Charleson, North Dakota, indicates that the crust of the earth consists of two layers with P-wave velocities of 6.1 km/sec and 6.7 km/sec, and that the upper-mantle velocity is 8.3 km/sec. The Mohorovicic discontinuity is 50-km deep at Charleson and remains at nearly the same depth southwestward for a distance of about 300 km, from where it slopes upward to the southwest at about 2° to a depth of 41 km near Greycliff, Montana.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.3133/ofr6815</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>U.S. Geological Survey</dc:publisher>
  <dc:title>Preliminary interpretation of a seismic-refraction profile across the Large Aperture Seismic Array, Montana</dc:title>
  <dc:type>reports</dc:type>
</oai_dc:dc>