During review of Waveforms Without Events (WFNE), I found some event waveform
collections that appear to have been damaged some time after they were
acquired, either within CUSP, or during the conversion from CUSP mem/grm to
miniSEED. This damage is probably similar to what was found several years ago
in event waveforms at the NCEDC. 

There are basically two versions of the damage: 788 events in 1997 - 1999; and 4
events in 2000 and 2001

Group A 1997 - 1999: 
- A single transition (all at same time within on event) where DC offset,
  noise level and signal characteristics change within most waveforms on an
  event. This transition appears near the start, in the middle, or near the
  end of the waveforms.

- Sometimes the transition is a simple step. At other times, there is an
  intervening spike with one or more peaks.

- The most obvious problem is that the IRIG-E time signal appears in normally
  seismic SNCLs. A cursory check does not show this happening for the WWVB
  (IRIG-H) channel. Note that jiggle is normally configured (via DB table) not
  to show time code SNCLs. My WFNE event viewer shows waveforms for all SNCLs.

- Decoding the IRIG-E time signal on several events shows it to be offset from
  the nominal miniSEED time, perhaps by the time interval from start of trace
  to transition step.

- The times in the Waveform DB table appear to match with the miniSEED
  waveform times.

- Phase arrivals for archived events during the miniSEED time do not match
  with phase arrivals visible in waveforms.

- Picker/binder event solutions on these damaged waveforms generally have
  high RMS. Presumably this is because the waveforms are not tied to the
  correct SNCL, and hence sensor location of the waveforms are incorrect.


Group B 2000 - 2001:
- Several transitions in each waveform.

- Most obvious is that small blocks of IRIG-E time code appear in seismic
  SNCLs. These are too short to code. (One IRIG-E frame is 10 seconds long.)