Quarterly Report to the Harry Reid Center

UCCSN-DOE Cooperative Agreement

Task 12: Seismic Monitoring

PI: James N. Brune

UNR Seismological Laboratory

December 1999

 

Progress:

 

During the first quarter of the grant, we have maintained seismic operations under the procedures which were in place with the M&O.  This was a transition phase to HRC.  For October-December 1999, we located 418 earthquakes within the area of the SGBDSN (Southern Great Basin Digital Seismic Network).  The largest event in this time period was an ML = 2.2, indicative of very low seismic energy release within the network.

 

During the first quarter, we tested and prepared the Antelope recording system for routine work.  "Antelope" is a commercial, field-tested, system which replaces an adhoc system which has been in place here at UNRSL (U. Nevada Reno Seismological Laboratory) since 10/01/1995.  Preparations included a comparison of the old and new procedures for identifying and locating events within the SGBDSN and determining their magnitudes.  Based on a favorable analysis, the Antelope system was made operational on January 1, 2000.  New methods for daily processing, data backups, and reporting of preliminary events have been implemented.

 

We have made progress on preparing the data for the FY98-99 seismicity report. A large backlog of aftershocks (over 500) of the January 1999 Frenchman Lake earthquake remained to be processed at the start of FY2000, and we have now worked off over half of that.

 

A letter memorandum was submitted to DOE technical representatives on one earthquake near Yucca Mountain in the first quarter of FY2000.  Also, a technical memorandum on the strong motion recordings from the October Hector Mine, California, earthquake was submitted.

 

Plans:

 

We will decide on siting for two new permanent seismic stations in the second quarter of FY2000 and order the required equipment.  We will also decide which 10 stations will receive the strong-motion supplements and order that equipment.

 

We plan to fine-tune the Antelope system in regard to several needs in the second quarter: 1) reliable backups of data (DVD), 2) better near-real-time reporting of locations and magnitudes, 3) more complete event identification, and 4) more efficient daily event analysis.

 

We plan to install a small array of portable seismic recorders around Little Skull Mountain late in the second quarter to refine our understanding of location and attenuation issues.