Seismic tests at Southern Ute Nation coal fire site

Line 2: Across the burn front and many fissures

The second transect was recorded along a line running approximately NW-SE. The NW end of the line is within an area above burned coal and the SE end is in an area thought to be above unburned coal. The line crosses many mapped fissures, particularly toward the NW end of the line.

Figures 7(a)-8(b) and 8(a)-8(f) show shot gathers from shots at approximately 0 m, $12$ m, $24$ m, $50$ m, $72$ m and $77$ m, along Line $2$. An averaged and normalized frequency spectrum of data recorded at Line 2 is shown in Figure 3. The data of the shot gather in Figure 7(a) is rather jumbled due to nearby fissures, the interleaving technique is not so effective. Data quality is generally worse than for line $1$, and is particularly poor for the NW end of the line. At the SE end of the line, the data more closely resemble those for line $1$, and the previously mentioned reflection may be visible between position $45$ m to $60$ m in Figure 8(d). The interleaving technique falls apart for these data due to strongly heterogeneous wave propagation, larger topographical variations, and the many fissures. There is a high frequency event visible in almost all shot gathers; this is the air wave. Note how the interleaving technique works quite well for that event, as the event is neither jumbled nor aliased. For all of these line $2$ data plots, NW is to the left.

Seismic tests at Southern Ute Nation coal fire site