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Event Classification P-wave arrival times are picked by amplitude or frequency changes. Events <br />without four or more arrival times were catalogued for ground-motion statistical purposes only; <br />events with four or more arrival times are input to the location process. Figure 2 shows the <br />recording of a typical event at WTM. <br />80000 <br />62000 <br />44000 <br />26000 <br />5000 <br />-10000 <br />-1 E5 <br />2E5 <br />1.64E5 <br />1.288 <br />-16000 <br />-1.24E5 <br />WTM V <br />Aug 12 (224), 2006 <br />No Origin Specified <br />Max Value = -84481. <br />WTM N <br />Aug 12 (224), 2006 <br />23:00:35.000 <br />NE) Oigin fled <br />Max Value =142817. <br />-1.6E5 <br />0 6.75 <br />2E5 <br />1.64E5 <br />1.28E5 <br />92000 <br />56000 <br />20000 <br />-16000 <br />-1.24E5 <br />-1.68 <br />13.5 20.25 27 33.75 40.5 47.25 54 60.75 67.5 <br />WTM E <br />Aug 12 (224), 2006 <br />23:00:35.000 <br />Max Value =158706. <br />Seconds Relative to Reference Time <br />Figure 2 Typical Seismic Event Recorded at WTM. Vertical axis is digital counts. Note vertical <br />axis change between channels. Horizontal components of ground motion are about twice vertical <br />motions <br />Velocity Model <br />The largest contributor to reliable location of seismic events is the velocity model utilized in the <br />hypocenter determinations. The model is typically defined for compressional wave arrivals and <br />may take several different forms depending upon the location algorithm utilized. In this report, we