Taiwan Data: Examine, Zero Traces, Re-examine
Our third data set is another 2-D line of seismic data provided by Prof. Greg Moore of the University of Hawaii. This “Taiwan” data set was collected near the coast of Taiwan in 1995 (Berndt & Moore, 1999) by the University of Hawaii, San Jose State University, and National Taiwan University. The size of our shot gather file, Tshot.su, is 411 Mbytes. (We have only one Taiwan data set, the original shot gathers.) This data set is more difficult to process than the Nankai data set.
Below is the surange output of Tshot.su.
Keys tracl and tracr number the 25344 traces (although, they use different starting numbers).
Key fldr tells us there are 176 shot gathers (975-800+1).
Since the number of samples per trace (ns) is 3999 and the trace sample interval (dt) is 4000 microseconds, the trace length is 16 seconds (15.996 seconds)
Notice that the Taiwan shot gather trace headers already contain cdp values.
This data set has many acquisition key values such as source x-coordinate (sx), receiver x-coordinate (gx), receiver y-coordinate (gy), and source depth (sdepth).
Figure 12.1 is a chart of the number of traces per shot gather. (We describe the program, sukeycount, which generated the data for the figure in Appendix C.) The chart shows that every shot gather has 144 traces.
We do not want to process 16 seconds of data. Let's use the first 5 seconds:
The size of our windowed shot gather file is 133 Mbytes.
As we discussed in Section 10.2