;
<code>12</code> &lt; <code>19</code> &lt; <code>5</code> &lt; <code>9</code> &lt; <code>1</code> &lt;
<code>2</code> &lt; <code>17</code> &lt; <code>11</code> indicating the earthquake
on which the measurements were made.
</p>
</dd>
<dt>Richter</dt><dd>
<p>a numeric vector giving the intensity of the earthquake on
the Richter scale.
</p>
</dd>
<dt>distance</dt><dd>
<p>the distance from the seismological measuring station to the
epicenter of the earthquake (km).
</p>
</dd>
<dt>soil</dt><dd>
<p>a factor wit