Subsections


California Integrated Seismic Network

Introduction

Advances in technology have made it possible to integrate separate earthquake monitoring networks into a single seismic system as well as to unify earthquake monitoring instrumentation. In California, this effort began in the south with the TriNet Project. There Caltech, the California Division of Mines and Geology, now called the California Geological Survey (CGS), and the USGS combined their efforts to create a unified seismic system for southern California. With major funding provided by the Federal Emergency Management Agency (FEMA), the California Governor's Office of Emergency Services (OES), and the USGS, the TriNet project provided the opportunity to upgrade and expand the monitoring infrastructure, combining resources in a federal, state and university partnership. More recently, the integration effort has been expanded to the entire State in a cooperation between the California Geological Survey, Caltech, UC Berkeley, USGS Menlo Park, and the USGS Pasadena called the California Integrated Seismic Network (CISN).

The initial efforts to create this collaboration are described in the 2000-2001 Annual Report. The CISN is now in the sixth year of collaboration and its fifth year of funding from the OES.

CISN Background

Organization

The organizational goals, products, management, and responsibilities of the CISN member organizations are described in the founding MOU and in the strategic and implementation plans. To facilitate coordination of activities among institutions, the CISN has formed three management centers:

One important goal of the CISN is for the Northern and Southern California Management Centers to operate as twin statewide earthquake processing centers while the Engineering Strong Motion Data Center has the responsibility for producing engineering data products and distributing them to the engineering community.

The Steering Committee oversees CISN projects and comprises two representatives from each core institution and a representative from OES. The position of chair rotates among the institutions; Woody Savage is currently the chair of the Steering Committee.

An external Advisory Committee, representing the interests of structural engineers, seismologists, emergency managers, industry, government, and utilities, has been formed for review and oversight. The Advisory Committee is chaired by Stu Nishenko of Pacific Gas and Electric Company. The Advisory Committee last met in October 2005. The agendas from previous meetings and the resulting reports may be accessed through the CISN Web site (http://www.cisn.org/advisory). The next meeting is planned for August 2006.

The Steering Committee has formed other committees, including a Program Management Group to address planning and coordination, a Strong Motion Working Group to focus on issues related to strong-motion data, and a Standards Committee to resolve technical design and implementation issues.

In addition to the core members, several organizations contribute data that enhances the capabilities of the CISN. Contributing members of the CISN include: University of California, Santa Barbara; University of California, San Diego; University of Nevada, Reno; University of Washington; California Department of Water Resources; Lawrence Livermore National Lab; and Pacific Gas and Electric.

CISN and ANSS

The USGS Advanced National Seismic System (ANSS) is being developed along a regionalized model. Eight regions have been organized, with the CISN representing California. David Oppenheimer of the USGS serves as the CISN representative to the ANSS National Implementation Committee (NIC).

Over the past 7 years, ANSS funding in California has been directed primarily to the USGS Menlo Park to expand the strong-motion instrumentation in the San Francisco Bay Area. As a result, more than 100 sites have been installed or upgraded, significantly improving the data available for ShakeMaps.

As the ANSS moves forward, committees and working groups are being established to address issues of interest. BSL faculty and staff have been involved in several working groups of the Technical Integration Committee, including Doug Dreger, Pete Lombard, Doug Neuhauser, Bob Uhrhammer, and Stephane Zuzlewski.

CISN and OES

The California Governor's Office of Emergency Services has had a long-term interest in coordinated earthquake monitoring. The historical separation between northern and southern California and between strong-motion and weak-motion networks resulted in a complicated situation for earthquake response.

OES has been an advocate of increased coordination and collaboration in California earthquake monitoring and encouraged the development of the CISN Strategic and Implementation Plans. In FY01/02, Governor Gray Davis requested support for the CISN, to be administered through OES. Funding for the California Geological Survey, Caltech and UC Berkeley was made available in spring 2002, officially launching the statewide coordination efforts.

Following the first year of funding, OES support led to the establishment of 3-year contracts to the UC Berkeley, Caltech, and the California Geological Survey for CISN activities. The first multi-year award covered activities in 2002-2005. The first year of the current, three-year contract has just been completed.

Statewide Communications

One of the major accomplishments in FY01/02 was the design and initial implementation of a CISN "backbone" communications infrastructure. Doug Neuhauser of the BSL took the lead in investigating options and the CISN partners decided to establish a ``ring" of T1 communication links (Figure 39.1) with redundant routers at each site. The CISN backbone will gracefully revert to routing traffic through encrypted tunnels over the Internet should the T1 circuits fail at a site.

The CISN backbone has been operating since FY03/04. It is being used to transmit seismic waveform data and parametric data, including strong motion parameters, between the management centers and to distribute ShakeMaps to OES. It is also used to support mirroring of the CISN Web server.

All of the routers, with the exception of those at OES, have Internet connections for backup tunnels over the Internet if the T1 circuits fail. However, if the CISN T1 circuits were to go down at OES, OES would be completely isolated from the CISN network and all CISN partners. This continues to be an issue of major concern.

2005-2006 Activities

The CISN funding from OES facilitated a number of activities at the BSL during the past year.

FEMA Hazard Grant Mitigation Program Funds

The San Simeon and Parkfield earthquakes highlighted the sparseness of high quality instrumentation in northern California, outside of the Bay Area. In both cases, the initial ShakeMaps were not well constrained, due to the lack of digital instrumentation with real-time communications. One major difference between these two events is that the Parkfield area is very densely instrumented, particularly with accelerometers deployed by the California Geological Survey. However, since these instruments were primarily analog, the data were not available until several days after the event.

As a result of the San Simeon earthquake and other disasters, FEMA has made funds available to OES under the Hazard Grant Mitigation Program (HGMP). The BSL, Caltech, and CGS submitted joint applications for funds to two of the HGMP programs, which were funded in August 2005 and May 2006. Funds to BSL from the first grant have been used to purchase equipment for one broadband station, and to relocate the data acquisition and processing systems from McCone Hall to 2195 Hearst (described in Chapter 44). The seismic equipment will be installed at the USArray station RAMR near the epicenter of the San Simeon event. The second grant will be used to purchase equipment for three further broadband stations, which will be installed in sparsely instrumented areas. One will also be in central California at HAST. The two other new stations will be located along the northern California coast, another seismically active region with few stations.

Expanded Instrumentation

In the past year, the BSL completed the installation broadband stations at two sites, Alder Springs, California, and the Marconi Conference Center, near Pt. Reyes, California (GASB and MCCM, Figure 37.4). The station at GASB has been under discussion for a number of years, initially as part of the National Tsunami Hazards Program. It has been transmitting data since November, 2005. MCCM has been partially funded by IRIS, as a permanent component of USArray, and by USGS and OES. The first data were recorded in early February, 2006, with the installation of power, and telemetry commenced later in the month, when the ANSS VSAT system was installed.

With the completion of GASB and MCCM, the BSL has installed 4 of the 5 sets of site equipment purchased in the first year of the CISN. The efforts at GASB and MCCM are more fully described in Chapter 38.

Network Operations

With funding from the CISN project, the BSL purchased upgrade kits for 23 Q4120 data loggers to improve remote diagnostic capabilities. Three types of kits were purchased - power board only, calibration board only, and combined power and calibration boards - so that each Q4120 has a power board and that each 8-channel Q4120 also has a calibration board. The power boards allow battery voltage to be monitored, so staff can discriminate between power and telemetry problems remotely. The calibration boards provide the capability to monitor mass position and allow remote calibration of the seismic sensors. Both boards also record data logger temperature. To upgrade the dataloggers they must be returned to the lab, where the boards are installed and the lattices on the CPU board replaced. New cables must be prepared to transmit the mass position signals. When the upgrade is complete, the datalogger is redeployed to the field. The 3 remaing upgrades were completed this year, with cables or lattices being replaced where necessary.

Collaboration with USArray

In late 2003, the CISN concluded a memorandum of agreement with the Incorporated Research Institutions in Seismology (IRIS) covering the duration of the USArray project in California. As a result 19 stations operated by the BSL and 41 stations operated by Caltech are part of USArray during its California deployment. Both Caltech and the BSL modified some station operations in order to meet the USArray specifications. In particular, USArray requires BH data to be sampled at 40 sps, rather than the 20 sps as was standard in California. The surface broadband stations of BDSN were converted to 40 sps over June 15-16th, 2004. The BSL has also provided accelerometers for use at USArray sites which may be of interest as future BDSN stations. We continue to monitor the data from these stations in real time, and use the data in ShakeMaps and moment tensors. The collaboration between the BSL and USArray is discussed more fully in Chapters 38 and 44, including the telemetry the BSL provides for the two USArray stations RAMR and SUTB.

Figure 39.1: Map showing the geographical distribution of the CISN partners and centers. The communications ``ring" is shown schematically with installed links (solid lines).
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bbllx=42,bblly=94,bburx=565,bbury=690}\end{center}\end{figure}

Figure 39.2: Map showing the 30 stations selected to send data directly to the Northern and Southern California processing centers, and the 5 stations that send data directly to the Engineering Data Center and the Southern California processing center.
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Northern California Earthquake Management Center

As part of their effort within the CISN, the BSL and the USGS Menlo Park have begun to implement the next generation of the northern California joint notification system. Chapter 45 describes the operations of the existing Management Center and reports on design discussions.

Communications Infrastructure

In order to move ahead with plans for restructuring the northern California earthquake monitoring system, the USGS Menlo Park and BSL have been working to improve their communications infrastructure.

At present, the BSL and the USGS Menlo Park are connected by two dedicated T1 circuits. One circuit is a component of the CISN ring, while the second circuit was installed in 2004-2005 (Figure 39.3) to support dedicated traffic between Berkeley and Menlo Park above and beyond that associated with the CISN.

The installation of the second dedicated T1 between Berkeley and Menlo Park freed up a frame-relay connection deployed by the BSL as part of the CalREN project in mid-1990s. The BSL has reconfigured this frame-relay circuit to serve as a second data acquisition link. The plan is to distribute the BDSN data acquisition between the two frame-relay T1 circuits, eliminating what had been a single point of failure. A second component of the plan is to establish an additional Permanent Virtual Circuit (PVC) at each BDSN site so that each station has connections to both T1s.

The acquisition of seismic data is now distributed between the two T1s and a second PVC is established at each frame-relay site. This effort has improved the robustness of data acquisition at the BSL by providing redundancy in the incoming circuit.

In the long term, the BSL and USGS Menlo Park hope to be connected by high-bandwidth microwave or satellite service. Unfortunately, we have not been able to obtain funding for this additional communication link at this time.

Figure 39.3: Schematic diagram illustrating the connectivity between the real-time processing systems at the USGS Menlo Park and UC Berkeley, forming the northern California Management Center, and with other elements of the CISN.
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Statewide Integration

BSL staff are involved in many elements of the statewide integration effort. The Standards Committee continues to define and prioritize projects necessary to develop a prototype system and establish working groups to address them (see minutes from meetings and conference calls at http://www.cisn.org/standards/meetings.html).

Dual Station Feeds

One of the major accomplishments in the first few years has been the establishment of ``dual station feeds" at 30 stations (15 in northern California and 15 in southern California) (Figure 39.2). To achieve this, the BSL and Caltech both ordered the DLCIs (data link connection identifier) that allow the 2nd center to establish a PVC to each station using the frame-relay network.

The Northern California Earthquake Management Center (NCEMC) is using data from the Southern California stations to estimate magnitudes on a routine basis. A subset of these stations are being used for the moment tensor inversions, a computation that is sensitive to the background noise level.

Data Exchange

Pick exchange was initiated between the NCEMC and its Southern California counterpart in 2001-2002. The software CISN has developed to produce and exchange the reduced amplitude timeseries has been completed. Currently, these timeseries are being exchanged at the NCEMC, but not yet statewide.

Using a common format, the CISN partners continue to exchange observations of peak ground motion with one another following an event or a trigger. This step increases the robustness of generating products such as ShakeMap, since all CISN partners now exchange data directly with one another. This also improves the quality of ShakeMaps for events on the boundary between northern and southern California, such as the San Simeon earthquake, by allowing all data to be combined in a single map. Finally, this is a necessary step toward the goal of generating statewide ShakeMaps.

Software Calibration & Standardization

The CISN partners are working together on the problem of software calibration, particularly as it pertains to automated earthquake processing. Currently, the software implemented in the NCEMC and in Southern California Management Center is very different. Initially, the CISN focused on the issue of calibration although the last year has seen an increased focus on standardization.

In 2002-2003, effort was focused on phase pickers (pick-ew), the association algorithm (binder), the location algorithm (hypoinverse), and magnitude estimation (various). Since then, magnitude estimation continues to be a significant area of focus, as well as ShakeMap configuration, metadata exchange, and database standardization.

At this point, the issues of a statewide detection and location system are largely addressed. Configuration files have been standardized and a statewide system has been running in Menlo Park for more than a year. It performed well during the December 2003 San Simeon sequence and the 2004 Parkfield earthquake. A number of outstanding issues still remain to be addressed.

Magnitude: Calibrating magnitude estimates has proven to be more difficult than the CISN originally anticipated. As described in 2003-2004, three lines of evidence indicate that there is a bias between the northern and southern California magnitude estimates. First, a comparison of nearly 500 earthquakes over a 20 year period in central California recorded by both networks shows a bias of 0.14 magnitude units, with NC magnitudes higher than SC magnitudes. Second, efforts to invert Wood Anderson amplitudes using a differential approach, a constraint that the BKS and PAS adjustments sum to zero, and fixing the attenuation relationship to one determined by Kanamori (1993), indicates a bias of 0.14. Finally, an independent inversion of a different dataset (absolute approach, a different set of station constraints, and simultaneous inversion for attenuation) suggests a bias of 0.20.

Efforts to understand this issue have been hampered by the lack of a good statewide dataset. In 2005-2006, Bob Uhrhammer selected data from 180 earthquakes distributed throughout the state and comprising recordings from 976 horizontal components from the AZ, BK, CI and NC networks. He has begun to assess station-specific corrections for $M_{L}$ by determining the difference for each station-component pair. State-wide, the average difference is -0.039. The primary advantage of using this differencing method is that the results are independent of a reference station.

A final component of the magnitude efforts is the designation of a magnitude reporting hierarchy. After many discussions, there is general agreement that, at least for the near future, each region will continue to use its own preferences for magnitude reporting.

ShakeMap: In addition to the efforts in standardizing earthquake locations and magnitudes, a CISN working group has been addressing issues related to ShakeMaps. At present, ShakeMaps are generated on 5 systems within the CISN. Two systems in Pasadena generate ``SoCal" Shakemaps; 2 systems in the Bay area generate ``NoCal" Shakemaps; and 1 system in Sacramento generates ShakeMaps for all of California. The Sacramento system uses QDDS to provide the authoritative event information for northern and southern California.

During the past year, the Working Group has continued to address standardization issues for ShakeMap. Initially efforts focused on the look and feel of the maps (topography, geology, faults, road, lake outlines, cities, and fonts). The Working Group reviewed a comprehensive compilation of the differences in configuration among the 3 implementations. Efforts continue to address the remaining differences between the centers, which range from the small (URL used in the ``addon" message) to the significant (use of regressions, linear versus log amplitude weighting). Resolving these differences will move the CISN forward toward having fully standardized ShakeMaps.

The lack of stations in the near source region of the 2003 San Simeon earthquake raised the issues of how to measure the quality of a ShakeMap and to quantify the uncertainty. A subset of the Working Group has been working on this issue, based on the work of Hok and Wald (2003). Lin et al (2006) presented progress toward quantifying ShakeMap uncertainty. When the method is validated, we can use this information to determine a grade.

Toward the goal of improving access to ShakeMap, the working group has put together an outline of how to create a unified set of Web pages. With general agreement about what to do, small progress has been made on actual implementation. The primary difficulty has been time, since creating unified Web pages requires a separation between product generation and Web page generation.

A second goal of this effort was to improve the robustness of ShakeMap generation and delivery by taking advantage of the fact that ShakeMaps are generated in the Bay Area, Pasadena, and Sacramento. Renewed efforts in this direction will likely be based on the new USGS ShakeMap webpages at the National Earthquake Information Center. Work in this direction continues in the coming year.

Location Codes: The CISN adopted a standard for the use of ``location" codes (part of the Standard for the Exchange of Earthquake Data (SEED) nomenclature to describe a timeseries based on network-station-channel-location) in the late fall of 2003. USGS and UC Berkeley developers have modified the Earthworm software to support the use of location codes. The migration to their use is awaiting the transition at USGS Menlo Park away from the CUSP analysis system.

Metadata Exchange: The availablity and exchange of metadata is vital to CISN activities, as correct metadata are required to insure valid interpretation of data. CISN is also working on issues related to the reliable and timely exchange of these data.

Several years ago, the Metadata Working Group compiled a list of metadata necessary for data processing and developed a model for exchanging metadata. In this model, each CISN member is responsible for the metadata for its stations and for other stations that enter into CISN processing through it. For example, Menlo Park is responsible for the NSMP, Tremor, and PG&E stations, while Caltech is responsible for the Anza data.

Initially, the exchange of metadata was to be accomplished through database replication. In the past two years, individual developments at the various CISN partners have made this an unwieldy solution. At the present time, dataless SEED volumes are being used to exchange metadata between the NCEMC and the SCMC, while the Metadata Working Group develops a better and more robust means of exchange. In the long term, it will be important to develop a vehicle for the exchange of a more comprehensive set of metadata than is permitted in dataless SEED volumes. They cannot encompass, for example, all the parameters which must be included in V0 formatted data.

In parallel, the Working Group has developed a plan for importing metadata from CGS. Their metadata is not currently stored in a database and is maintained in simple files. Their policy is to distribute the metadata as part of a waveform package using the especially developed V0 format. The Working Group developed the concept of a "dataless" V0 format (analogous to the dataless SEED files) which is used to distribute the metadata. The CGS now provides dataless V0 files containing current metadata for ShakeMap quality stations (i.e., with channels meeting CISN Reference Station or better standards) in the CGS network. They are being distributed and are also placed at the CGS FTP site. As agreed, the comment field in the V0 header defines the valid time period for the metadata. Each dataless V0 file contains the 3 channels of the reference sensor at the site. The Working Group plan includes the ability to handle corrections, as well as updates as stations are serviced.

In order to make use of the dataless V0 file, tools have been developed to parse the file and write an XML file containing the information (an expansion of capabilities of the v02ms program). The NCEMC has taken advantage of previously existing tools to create a system where the XML is converted into a spreadsheet format and then imported into the database. This plan will be further tested as CGS generates more dataless V0 files and the database is populated.

As part of this process, the issue of mapping the sensor orientation into the SEED channel nomenclature has come up. The v02ms program now uses the same algorithm for generating channel names as used by CGS.

Standardization The CISN's focus on standardization, rather then calibration of software continues. For example, the BSL and the USGS Menlo Park are adapting the software running at the SCMC for use at the NCEMC and are currently testing its various elements. Examples of collaboration include the development of the CISN Messaging Service - software designed to replace the commercial SmartSockets package used in the initial development of TriNet, implementation of the RequestCardGenerator and Jiggle in northern California, and ongoing efforts to develop specifications for a magnitude coordinator.

CISN Display

CISN Display is an integrated Web enabled earthquake notification system, designed to provide earthquake information for emergency response at 24/7 operations centers. First-responders, organizations with critical lifelines and infrastructure, and emergency responders are invited to register for an account at http://www.cisn.org/software/cisndisplay.htm.

The application provides users with maps of real-time seismicity, and automatically provides access to Web-related earthquake products such as ShakeMaps. CISN Display also offers an open source GIS mapping tool that allows users to plot freely available layers of public highways, roads and bridges, as well as private layers of organizational-specific infrastructure and facilities information. The current version of CISN Display is 1.31.

Earthquake Information Distribution

The USGS hosted a workshop in October 2004 to develop plans for the installation and use of the EIDS software. Doug Neuhauser and Pete Lombard participated in this workshop, which resulted in a document outlining the steps necessary for the installation and migration of the earthquake notification system from the current Quake Data Distribution Servies (QDDS) to EIDS.

Outreach

There has been progress at www.cisn.org in FY05/06. The CISN Web site is now supported by two servers located at Berkeley and Caltech. The Web servers are set up so that the load can be distributed between them, providing improved access during times of high demand. With the increased robustness provided by the new servers, the CISN has begun to provide access to certain earthquake products directly from www.cisn.org. For example, ShakeMaps are now served directly from the CISN Web site, in addition to being available from several USGS Web servers and the CGS.

The design and content of http://www.cisn.org continues to evolve. The Web site is an important tool for CISN outreach as well as for communication and documentation among the CISN partners.

The CISN continues to support the dedicated Web site for emergency managers. Following a suggestion from the Advisory Committee, we have designed a Web site to provide personalized access to earthquake information. Known as ``myCISN," the Web site is available at eoc.cisn.org. Access to the Web site is limited to registered users in order to provide highly reliable access. At present, ``myCISN" is a single Web server located at UC Berkeley. However, modifications to the database are underway to allow for multiple servers in the future. A second computer, already purchased, will either be installed in Sacramento or in southern California.

As part of the CISN, the BSL also contributed to efforts to raise awareness during 1906 centennial activities. In particular, we co-hosted the 1906 Earthquake Conference contributed to the preparation of the CISN booth at the meeting (see Chapter 46)

Acknowledgements

CISN activities at the BSL are supported by funding from the Governor's Office of Emergency Services.

Barbara Romanowicz and Peggy Hellweg are members of the CISN Steering Committee. Peggy Hellweg is a member of the CISN Program Management Group and she leads the CISN project at the BSL, with support from Doug Neuhauser during the transition. . Doug Neuhauser is chair of the CISN Standards Committee, which includes Peggy Hellweg and Pete Lombard as members.

Because of the breadth of the CISN project, many BSL staff have been involved including: John Friday, Peggy Hellweg, Bill Karavas, Pete Lombard, Doug Neuhauser, Charley Paffenbarger, Bob Uhrhammer and Stephane Zuzlewski. Peggy Hellweg contributed to this chapter. Additional information about the CISN is available through reports from the Program Management Committee.

References

Ad Hoc Panel on Earthquake Information Distribution (L. Gee and D. Oppenheimer, chairs), Requirements for an Earthquake Information Distribution System, http://www.cisn.org/ahpeid/ahpeid_final.pdf, 2003.

Gee, L., D. Dreger, G. Wurman, Y, Gung, B. Uhrhammer, and B. Romanowicz, A Decade of Regional Moment Tensor Analysis at UC Berkeley, EOS Trans. AGU, 84(46) , Fall Meet. Suppl., Abstract S52C-0148, 2003.

Gee, L., D. Oppenheimer, T. Shakal, D. Given, and E. Hauksson, Performance of the CISN during the 2003 San Simeon Earthquake, http://www.cisn.org/docs/CISN_SanSimeon.pdf, 2004a.

Gee, L., J. Polet, R. Uhrhammer, and K. Hutton, Earthquake Magnitudes in California, Seism. Res. Lett., 75(2), 272, 2004b.

Hauksson, E., L. Gee, D. Given, D. Oppenheimer, and T. Shakal, Report to the CISN Advisory and Steering Committees, #5, http://www.cisn.org/oes/2003.05.30.pdf, 2003.

Hok, S., and D. J. Wald, Spatial Variability of Peak Strong Ground Motions: Implications for ShakeMap Interpolations, EOS. Trans. AGU, 84(46), F1121, 2003.

Kanamori, H., J. Mori, E. Hauksson, T. Heaton, L. Hutton, and L. Jones, Determination of earthquake energy release and $M_{L}$ using TERRASCOPE, Bull. Seis. Soc. Am., 83, 330-346, 1993.

Lin, K-W., D. Wald, B. Worden and A.F. Shakal, Progress toward quantifying CISN ShakeMap uncertainty, Eighth National Conference on Earthquake Engineering, San Francisco, California, April 18-21, 2006.

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