Quarterly Report to the Harry Reid Center

UCCSN-DOE Cooperative Agreement

Task 12: Seismic Monitoring

PI: James N. Brune

UNR Seismological Laboratory

Report Period: 04/01/2002 – 06/30/2002

Progress:

During this reporting period (Apr.-Jun. 2002), we have maintained seismic operations under the QA procedures which have been established with the HRC. Seismic network uptime has been 99.8%.

On June 14, an earthquake of M_L 4.4 occurred near the site of the original 1992 M_L 5.6 Little Skull Mountain earthquake. With both weak-motion and strong-motion data being telemetered, we were able to post a preliminary report on this earthquake to our web site within three days. Strong-motion accelerograms from telemetered and non-telemetered sites have also been posted since then. Analysis of strong motion, determination of magnitude and moment, locations of aftershocks, study of tectonic implications, and other facets are ongoing for this event.

The FY01 seismicity report has passed technical and QA review and is ready for submittal to the DOE. The associated data have been submitted to the HRC data center. The summary report on the seismic parameter “kappa” is still in progress.

At the end of this quarter, we have completed analyzing the earthquakes within the YM monitoring network through May 19, 2002.

The software program REF2ORB was baselined with the Software Configuration Management in this quarter.

An instrumentation order (Kinemetrics) for the three wells on the pad of the proposed Waste Handling Building was submitted for purchase.

The station Hell’s Gate in Death Valley has been brought online in June. This brings the total to 30 digital stations in our permanent monitoring network around Yucca Mountain. Maintenance was performed on several other permanent seismic stations. The technicians were able, under escort, to complete station maintenance at two sites on NAFB in April. The Guralp CMG-40 seismometers at three stations were changed over to Geotech S-13 seismometers, thus completing the removal of Guralp broad-band instruments.

The project to transcribe older seismic data from 9-track and 4-mm tapes is proceeding well. Restorations of CUSP-era (1989-1999) data are nearly complete and approaching a clean-up phase. Waveform recovery has been about 95% from tapes available here; RPC copies of these tapes may enable us to improve this percentage.

Problems:

We have been unable to close the gap on routine location of events within the network. It now stands at about 40 days. The number of events within the network has risen in the past few months and especially following the ML 4.4 earthquake on 14 June. Completion of routine analysis on a delayed basis is acceptable because the entire set of station triggers is reviewed within 2-3 days and because all events larger than roughly M 2 are always analyzed within 1-2 days.

Status of Funds:

As of the end of June, we are at roughly 72% of our budgeted spending on the contract; We anticipate spending out to nearly the full funded level by the end of September 2002.

Plans:

We will complete the compendium report of NSL work on the seismic parameter kappa.

We will complete the transfer of the older analog network data from tapes to Unix disk files this quarter. We will complete a local earthquake data set for the SGBDSN for the years FY96-FY01 and submit it to the TDB.

We will take delivery on equipment to be installed in the tunnel and on the pad and install it.

We will close the gap on routine location of events within the network to 10 days or less, using extra student help through the summer.