NCEDC News/Blog

YBH Broadband Seismometer Change

Categories:   Broadband Instruments  |  Data Center Operations

May 17, 1996 

May 17, 1996

The 3-component broadband seismometer at YBH has temporarily been changed from STS-1s to an STS-2 as of 96.138.0000 UTC, and will likely remain so (perhaps for a few months) until the defective STS-1V seismometer is repaired and re-installed. The SEED instrument response has been updated to reflect this change.

This change will effect the YBH broadband response primarily at long periods and at high frequencies in the following ways:

  • At periods longer than 360 sec the velocity sensitivity is reduced by a factor of 14.4 or 93 percent. For example, the semi-diurnal tide signal will be ~240 counts P-P instead of ~3500 counts P-P.
  • At frequencies higher than 5 Hz (the STS-1 2PLP corner frequency), the sensitivity increases with frequency (f) like:
sens = (15/24)*(f/5)**2
  • Owing to the flat passband response of the STS-2 seismometer to 70 Hz. For example, the sensitivity at 32 Hz (FIR corner on HH data stream) is increased by a factor of 25.6. Thus the recording of local and regional earthquakes will be enhanced.

If you have questions about this change, please contact: