In 2004-2005, BSL's activities have centered around two major projects: the continuation of CISN and our participation, at various levels, in three components of the national Earthscope program: the deployment in California of the BigFoot component of USArray, the preparation for archival of borehole strainmeter data and for acting as ``analysis center" for continuous GPS data, in the framework of the Plate Boundary Observatory (PBO), and the preparation for archival of the data from the San Andreas Fault Observatory at Depth (SAFOD).
The main goal of the CISN (see Chapter 4) is to ensure a more uniform system for earthquake monitoring and reporting in California. The highest priority, from the point of view of emergency responders in California, is to improve the robustness of statewide real-time notification and to achieve a uniform interface across the State to the California OES and other emergency responders. This represents a major challenge, as the CISN started as a heterogeneous collection of networks with disparate instrumentation, software systems and culture. The M 6.0 September 28th Parkfield earthquake provided a significant opportunity to test the CISN capabilities. CISN funds were used to establish new broadband stations at Alder Springs, CA (GASB), which has been completed, and at the Marconi Conference Center near Point Reyes (MCCM), which is under construction. We also upgraded remote diagnostic capabilities at 23 of our sites equipped with Quanterra Q4120 data loggers. As in previous years, the emphasis has been on improvement of Statewide Communications. In the past year, BSL has worked with SBC to distribute the acquisition of seismic data between the two frame-relay T1 circuits connecting BSL and USGS/Menlo Park, and to establish a second Permanent Virtual Circuit (PVC) at each frame-relay site, to improve the robustness of data acquisition. Efforts to develop the next generation of the northern California joint notification system are underway and described in chapter 9.
The CISN partners completed the final stage of a system to exchange peak ground motion data this year, which improves the robustness of ShakeMaps and their quality on the boundary between northern and southern California. Efforts have also gone towards improving the standardization of ShakeMaps across the State and statewide software calibration.
BSL staff continue to spend considerable efforts in organizational activities for CISN, notably by participating in the CISN Project Management Group (Gee and now Neuhauser), which includes weekly 2 hour phone conferences, and the Standards Committee (Neuhauser-chair, Gee, Lombard), which strives to define and coordinate software development tasks. Romanowicz and Gee have continued to serve on the CISN Steering Committee. The CISN also represents California as a designated region of ANSS (Advanced National Seismic System) and the BSL is actively involved in planning activities for the ANSS.
The BSL concluded an agreement in June 2004 with IRIS to contribute 19 stations of the BDSN to USArray, while the experiment is deployed in California. This includes 17 existing stations and the two new sites mentioned above: GASB and MCCM. The 19 BDSN sites provide USArray with a running start in Northern California. In the past year, BSL staff have worked with USArray to establish several new USArray sites in northern and central California, from which data are being sent both to BSL and the Array Network Facility. BSL staff have been working to identify 8 potential sites that may become permanent BDSN sites, many at UC reserves and field stations. As part of the USArray collaboration, the BSL has converted most of the BDSN broadband data streams from 20 samples per second to 40 samples per second.
The BSL has been actively working to relocate the critical operations of data acquisition, processing, archiving and data distribution to 2195 Hearst (``SRB-1"), a recently completed building on Oxford Tract, which was constructed to current seismic codes, with special attention to post-earthquakes operability of the campus computer facility. The computer center contains state-of-the-art seismic bracing, UPS power and air conditioning with generator back-up and extensive security and equipment monitoring. BSL has moved almost all of its data acquisition, real-time earthquake processing computers and data archive and distribution computers to the new facility, including telemetry equipment. The latter is in the course of being completed.
This past year has been exceptionally busy for the borehole Parkfield project (HRSN, see chapter 6), with the 28 September 2004 repeat of the long awaited M6 Parkfield earthquake, the discovery of nonvolcanic tremor activity (see research part of the report) and the on-going SAFOD project. Several steps have been taken towards enhancing the performance, and in particular upgrading aging components of the systems. HRSN data have played a key role in characterizing the SAFOD drilling site. Monitoring the evolution of nonvolcanic tremors and microseismicity, particularly in the SAFOD drilling and target zone, are primary objectives of the HRSN project. The numerous and on-going aftershocks from the December 2003 M6.5 San Simeon and Sept 2004 M6.0 Parkfield earthquakes have called for a significant revision of the ``traditional" processing scheme used since 1987.
The Northern Hayward Fault Network (NHFN, see chapter 5) has seen equipment upgrades in anticipation of installing Q4120 data loggers and real time telemetry. Mini-PBO stations SVIN and SBRN, which became fully operational this past year (see chapter 8) have added coverage to the north side of the north bay and east side of the south bay, respectively.
Continued acquisition of data from the BARD GPS network (see chapter 7) has been occurring at a sampling rate of 30 seconds. We have now converted the acquisition rate to 1 sec at 7 stations in the San Francisco Bay Area, which allows us to measure dynamic displacements due to large earthquakes. Additional conversions await resolving telemetry bandwidth limitations. The GPS team has also been busy preparing for the transfer of several UC Berkeley operated and maintained BARD stations to PBO. Berkeley will retain control over those stations that have real time telemetry and are collocated with broadband instrumentation. We are, in particular, continuing to develop joint real-time analysis methods of GPS and seismic broadband data.
The NCEDC (see Chapter 11), continues archiving and distribution of on-line of data from expanding BDSN, NHFN, HRSN, BARD, Mini-PBO, and other networks and data collections in northern California and Nevada. In 2005, the NCEDC started acquiring telemetered continuous data from USArray stations in northern California and vicinity. We are continuing to receive data from the SAFOD pilot hole and main hole, and data from 15 SCSN (southern California) broadband sites as part of the CISN robust ``backbone". Efforts are continuing to develop software and acquire hardware to archive continuous NCSN seismograms directly onto the NCEDC archive for the future, as well as transfer from tapes to complete the collection retroactively.
Finally, through Dr Lind Gee's (and now Peggy Hellweg's) efforts, BSL has continued to be actively involved in the preparation of UC Berkeley's participation in the commemoration activities of the centennial anniversary of the 1906 earthquake (see Chapter 12). These activities include a joint SSA/EERI/DRC conference to be held in San Francisco in April 2006 as well as many exhibits, classes, and public lectures on the UC Berkeley Campus, the first of which was held on October 20th, 2005.
Berkeley Seismological Laboratory
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