<?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:creator>R.G. Henderson</dc:creator>
  <dc:date>1960</dc:date>
  <dc:description>&lt;p&gt;&lt;span class="ScopusTermHighlight"&gt;In&lt;/span&gt;&lt;span&gt;&amp;nbsp;the&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;interpretation&lt;/span&gt;&lt;span&gt;&amp;nbsp;of&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;magnetic&lt;/span&gt;&lt;span&gt;&amp;nbsp;and&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;gravity&lt;/span&gt;&lt;span&gt;&amp;nbsp;anomalies, downward continuation of fields and calculation of first and second vertical derivatives of fields have been recognized as effective means for bringing into focus the latent diagnostic features of the data.&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;A&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;comprehensive&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;system&lt;/span&gt;&lt;span&gt;&amp;nbsp;has been devised for the calculation of any or all of these derived fields on modern electronic digital computing equipment. The integral for analytic continuation above the plane is used with&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;a&lt;/span&gt;&lt;span&gt;&amp;nbsp;Lagrange extrapolation polynomial to derive&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;a&lt;/span&gt;&lt;span&gt;&amp;nbsp;general determinantal expression from which the field at depth and the various derivatives on the surface and at depth can be obtained. It is shown that the general formula includes as special cases some of the formulas appearing&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;in&lt;/span&gt;&lt;span&gt;&amp;nbsp;the literature. The process involves&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;a&lt;/span&gt;&lt;span&gt;&amp;nbsp;"once for all depths" summing of grid values on&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;a&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;system&lt;/span&gt;&lt;span&gt;&amp;nbsp;of concentric circles about each point followed by application of the appropriate one or more of the 19 sets of coefficients derived for the purpose. Theoretical and observed multilevel data are used to illustrate the processes and to discuss the errors. The coefficients can be used for less extensive computations on&amp;nbsp;&lt;/span&gt;&lt;span class="ScopusTermHighlight"&gt;a&lt;/span&gt;&lt;span&gt;&amp;nbsp;desk calculator.&amp;nbsp;&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1190/1.1438736</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Society of Exploration Geophysicists</dc:publisher>
  <dc:title>A comprehensive system of automatic computation in magnetic and gravity interpretation</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>