<?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>M. Santoyo</dc:contributor>
  <dc:contributor>P. Bodin</dc:contributor>
  <dc:contributor>J. Gomberg</dc:contributor>
  <dc:creator>S.K. Singh</dc:creator>
  <dc:date>1997</dc:date>
  <dc:description>&lt;p&gt;We develop simple relations to estimate dynamic displacement gradients (and hence the strains and rotations) during earthquakes in the lake-bed zone of the Valley of Mexico, where the presence of low-velocity, high-water content clays in the uppermost layers cause dramatic amplification of seismic waves and large strains. The study uses results from a companion article (Bodin&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;et al.&lt;/i&gt;, 1997) in which the data from an array at Roma, a lake-bed site, were analyzed to obtain displacement gradients. In this article, we find that the deformations at other lake-bed sites may differ from those at Roma by a factor of 2 to 3. More accurate estimates of the dominant components of the deformation at an individual instrumented lake-bed site may be obtained from the maximum horizontal velocity and displacement,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;ν&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;u&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;, at the surface. The maximum surface strain&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;ɛ&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;is related to&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;ν&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;by&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;ɛ&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;=&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;ν&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;/&lt;i&gt;C&lt;/i&gt;, with&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;C&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;∼ 0.6 km/sec. From the analysis of data from sites equipped with surface and borehole sensors, we find that the vertical gradient of peak horizontal displacement (Δ&lt;i&gt;u&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;/Δ&lt;i&gt;z&lt;/i&gt;) computed from sensors at 0 and 30 m equals (&lt;i&gt;u&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;)&lt;sub&gt;z=0&lt;/sub&gt;/Δ&lt;i&gt;z&lt;/i&gt;, Δ&lt;i&gt;z&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;= 30 m, within a factor of 1.5. This is the largest gradient component, and the latter simple relation permits its estimation from surface records alone. The observed profiles of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;u&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;versus depth suggest a larger gradient in some depth range of 10 to 20 m, in agreement with synthetic calculations presented in Bodin&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;et al.&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(1997).&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1785/BSSA0870030540</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Seismological Society of America</dc:publisher>
  <dc:title>Dynamic deformations of shallow sediments in the Valley of Mexico, Part II: Single-station estimates</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>