h levels <code>0</code> and <code>1</code>
giving the soil condition at the measuring station, either
soil or rock.
</p>
</dd>
<dt>accel</dt><dd>
<p>maximum horizontal acceleration observed (g).
</p>
</dd>
</dl>



<h3>Details</h3>

<p>Measurements recorded at available seismometer locations for 23
large earthquakes in western North America between 1940 and 1980.
They were originally given in Joyner and Boore (1981); are
mentioned in Brillinger (1987); and are analyzed in Davidian
and Giltinan (1995).
</p>
