Effect of filtering on event picking
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Series | Geophysical References Series |
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Title | Problems in Exploration Seismology and their Solutions |
Author | Lloyd P. Geldart and Robert E. Sheriff |
Chapter | 7 |
Pages | 221 - 252 |
DOI | http://dx.doi.org/10.1190/1.9781560801733 |
ISBN | ISBN 9781560801153 |
Store | SEG Online Store |
Problem
Figure 7.13a shows changes in wave-shape produced by the analog filtering in modern digital instruments. What can you conclude about the effects on picking?
Solution
The filtering on traces (b) and (c) is normal alias filtering for 2 ms and 4 ms sampling. Comparison of traces (a), (b), and (c) shows that lowering the high-frequency cut increases the delay. Comparing (c) and (d), we see that increasing the filter slope also increases the delay. Comparing traces (e) and (f) shows that changing the high-frequency slope changes the pulse shape but has little effect on the delay. Changing the low-frequency cut has a similar effect as seen by comparing (c) and (g). Narrowing the bandwidth results in shifting energy backward within the wavelet, decreasing the ability to pick early within the wavelet and increasing the likelihood of misinterpreting polarity.

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Filter effects on waveshape | Binary numbers |
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Characteristics of seismic events | Reflection field methods |
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- Filter effects on waveshape
- Effect of filtering on event picking
- Binary numbers