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California Integrated Seismic Network

Subsections

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 was initiated under the TriNet Project in southern California, where Caltech, the then California Division of Mines and Geology, and the USGS combined their efforts to create a unified seismic system for southern California. With major funding provided by FEMA, OES, and the USGS, the TriNet project provided the opportunity to upgrade and expand the monitoring infrastructure, combining resources in federal, state, university partnership. More recently, the California Geological Survey, Caltech Seismological Laboratory, Berkeley Seismological Laboratory, USGS Menlo Park, and the USGS Pasadena have agreed to cooperate on a statewide basis, because of the obvious benefit to the state.

In the 2000-2001 Annual Report, we described the efforts to create this collaboration through the establishment of a memorandum of agreement and the development of the CISN strategic and implementation plans. In the last year, efforts to form the California Integrated Seismic Network (CISN) took a great leap forward.

CISN Background

Organization

The core CISN institutions (California Geological Survey, Berkeley Seismological Laboratory, Caltech, USGS Menlo Park, USGS Pasadena) and OES have signed a MOA (included in the 2000-2001 Annual Report) that describes the CISN organizational goals, products, management, and responsibilities of member organizations. To facilitate coordination of activities among institutions, the CISN has formed three management centers:

A goal of the CISN is for the Northern and Southern California Management Centers operate as twin earthquake processing centers. The Engineering Management Center has the lead responsibility for producing engineering data products.

The Steering Committee oversees CISN projects and is comprised of two representatives from each core institution and a representative from OES. Barbara Romanowicz was elected the first chair of the Steering Committee, and was succeeded in December 2001 by Lucy Jones of USGS Pasadena.

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 Bruce Clark of the California Seismic Safety Commission. The Advisory Committee has held meetings in July 2001 and 2002.

The Steering Committee has formed other committees, including a Program Mangement 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 Advanced National Seismic System (ANSS) is being developed along a regionalized model. 8 regions have been organized and the CISN represents the "California region". Over the last 3 years, ANSS funding in California has primarily been directed to the USGS Menlo Park to expand the strong-motion instrumentation in the San Francisco Bay Area. As a result, instruments at over 100 sites have been installed or upgraded, significantly improving the data available for ShakeMaps.

The CISN is currently developing plans for the FY 02-03 ANSS program.

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 FY 2001/2002, 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.

The CISN/OES program was publically announced on April 15, 2002, during a press conference held at the new headquarters of OES in Sacramento. Invited speakers included Dallas Jones, Director of OES; Darryl Young, Director of the Department of Conservation; Jim Davis, California State Geologist; and Lind Gee from the BSL.

2001-2002 Activities

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

Expanded Instrumentation

As part of the CISN/OES project, the BSL purchased equipment for 5 BDSN stations, including STS-2 seismometers, Episensors, and Q4120 data loggers. During 2001-2002, BSL staff initiated efforts to identify potential sites, considering such factors as the current distribution of stations, private versus public property, location of power and telecommunications, and geologic materials.

Two new sites north of the San Francisco Bay were located and permitted for development as broadband observatories. In Lake County, the BSL will build an observatory on the property of the Homestake Mining Company's McLaughlin Mine. Further north, the BSL will build an observatory at the Alder Springs Conservation Camp in the Mendocino National Forest. The status of permitting and site preparation is more fully described in Chapter 4.

Other areas under consideration for future installations include the Pt. Reyes area, the Santa Cruz Mountains (in collaboration with UC Santa Cruz), Pacheco Peak (in collaboration with the California Division of Forestry), Hat Creek (in collaboration with UC Berkeley Department of Astronomy), and Carmel Valley (UC Berkeley Hastings Preserve).

Network Operations and Maintenance

As part of the CISN project, the BSL purchased a number of upgrade kits for their Q4120 data loggers with the goal of improving remote diagnostic capabilities. Three different kits were purchased - power board only, calibration board only, and combined power and calibration boards - in order to ensure that every Q4120 has a power board and that every 8-channel Q4120 also has a calibration board. The power boards provide the capability to monitor battery voltage, allowing staff to discriminate between power and telemetry problems remotely. The calibration boards provide the capability to monitor mass position as well as allow remote calibration of the seismic sensors. Both boards also record data logger temperature.

The boards have not yet been received at the BSL. Prior to widespread upgrades, BSL staff will need to establish procedures for installing and testing these upgrades and then develop a plan for systematic deployment. One of the advantages of this upgrade is that the 21 Q4120 8-channel data loggers maintained by the BSL will be fully interchangeable, as will the 9 4-channel systems. This ability to swap data loggers will facilitate maintenance in the future.

Statewide Communications

One of the major accomplishments of the past year was the design and initial implementation of a CISN 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 3.1) with dual routers at each node. As of June 30, 3 of the 5 links have been ordered and installed (2 of which were ordered by the BSL). Caltech placed the orders for the remaining 2 links in July and installation is expected in September. Orders were also placed for 8 of the 10 routers needed to connect the CISN centers, as the BSL agreed to purchase the routers for the USGS Menlo Park, OES, and CGS, in addition to their own. Caltech's order for 2 routers were placed after July 1 - and delivery is expected in September.

When fully implemented, the CISN ring will have full T1 capacity between adjacent nodes with rapid falloever to secure Internet tunnels among the sites. The network will be able to survive the loss of a single node, T1 circuits, or router at any site. The routers will be configured to gracefully fail if one or both links at a node fail.

Figure 3.1: Map showing the geographical distribution of the CISN partners and centers. The communications "ring" is shown schematically with installed links (solid lines) and ordered links (dotted lines).
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Northern California Management Center

As part of this effort within the CISN, the BSL and the USGS Menlo Park have begun to plan for the next generation of the northern California joint notification system. Chapter 12 describes the operations of the existing Management Center and reports on design discussions.

Communications Infrastructure

In order to migrate to a design such as Figure 12.5, the BSL and the USGS Menlo Park need to enhance the communications infrastructure between their sites. Presently, data and information are shared on a dedicated frame-relay connection, with fallback to the Internet.

With OES funding, the BSL commissioned Telecommunications Design Services, Inc. to perform a feasibility study for a microwave communication link between Berkeley and Menlo Park. This study was conducted in June 2002 and a report delivered to the BSL, with copies given to the USGS Menlo Park.

The goal of the study was to evaluate options for a microwave communication link between the BSL and USGS elements of the Northern California Management Center. The report concludes that a repeater site will be required, given the length of the path and the obstructions (buildings, bridges, etc.). According to the report, the Space Sciences Laboratory at UC Berkeley will be a good site for the repeater.

The results of this study are under discussion between the BSL and the USGS. Further discussion is required before moving forward with issues of permission and purchase of hardware.

Computing Upgrade

The current data acquisition and processing computers used as part of the Northern California Management Center at the BSL are nearly 4 years old. As part of the OES project, the BSL purchased computers to replace these aging systems.

The BSL purchased five Sun 280R computers. Two of these will be used to immediately replace the current data acquisition and processing computers. One will be used to establish a second ShakeMap installation for northern California. (We currently have a "development" installation of ShakeMap operating at the BSL, which uses input from the finite-fault processing to predict ground motions in areas without stations. The new ShakeMap installation will completely parallel the installation in Menlo Park for redundancy.) The remaining two new computers will be used to set up a pilot system for statewide earthquake processing. In addition to the 280R computers, the BSL purchased two Sun StorEdge RAID disk systems. The additional disk systems are required by the expanded waveform exchange among the centers.

The new computer systems were delivered on June 30th. The systems will be deployed in racks in the BSL computer server room and will be configured during the next quarter.

Statewide Integration

In January, the BSL hosted a meeting of the CISN Standards Committee. This meeting was focused on issues related to establishing a statewide earthquake processing system. The Standards Committee defined and prioritized projects necessary to develop a prototype system and established working groups to address them (see the minutes from the meeting at http://www.cisn.org/standards/meetings.html).

The working groups include members from all CISN insitutions. Since the January meeting, the Standards Committee has held conference calls approximately every 2-4 weeks to review progress on these issues. The CISN Standards Committee plans to have meetings at least twice a year.

Software Calibration

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 Southern California Management Center is very different from the software implemented in the Northern California Management Center. Eventually, there may be standardization of software across the management centers, but in the short term, the focus is on calibrating the software to produce the same answers, given the same input data.

In the last year, effort was focused on phase pickers, the association algorithm (binder), the location algorithm (hypoinverse), and magnitude estimation (various). The USGS Menlo Park has taken the lead in testing configurations for a statewide version of the associator and for developing a version of hypoinverse that accounts for velocity models statewide.

The BSL has implemented the Earthworm picker, which is used at Caltech and the USGS Menlo Park, on the data from the Berkeley Digital Seismic Network. All three CISN centers are now running the same picking algorithm, although small differences in configuration exist. We spent some time experimenting with a configuration suitable for its broadband network, as the preliminary configuration produced very few picks. Additional effort is needed to improve the performance of the picker with broadband data.

A test of the association algorithm is underway at the USGS Menlo Park. A preliminary assessment showed that the Northern and Southern California centers use slightly different configurations of the associator and that these different configurations produce different results. A prototype statewide configuration has been developed and is being tested in Menlo Park and Pasadena.

Staff at the USGS Menlo Park are also working to establish a configuration of the location program for a statewide system. This problem is better defined, as the program can be structured to use different velocity models and station delays.

On the magnitude front, issues of calibration have been complicated by differences between the northern and southern California networks. In southern California, the TriNet upgrade has created a mostly digital seismic network. In northern California, the networks are dominated by analog instrumentation. This means that different magnitude methods are used by each center. A Standards Committee Working Group was tasked to look at the issues presented by this different in infrastructure.

As part of this effort, the BSL has been looking at some of the software developed under the TriNet project with the goal of adapting it for northern California. Of particular interest are the codes which continuously process waveform data to create timeseries of pre-computed amplitudes (Kanamori et al., 1999) such as Ml100 (local magnitude computed for a fixed distance of 100 km), Me100 (energy magnitude computed for a fixed distance of 100 km), peak ground acceleration, peak ground velocity, and spectral acceleration at 3, 1, and 0.3 seconds. The continuous processing of the amplitudes is advantageous in providing a steady computing load (as opposed to "peaking" during an earthquake) and rapid access to the data of interest.

Caltech has shared this software with the BSL. Unfortunately, the package could not be installed "as is" and modifications were required. In particular, changes were required to support network and location codes (the SNCL problem). Considerable time was spent in tracking timing discrepancies between the TriNet software and BSL codes for handling waveforms and a small bug in the TriNet codes was found.

As of June 30th, the BSL has adapted versions of the programs which place waveform data in a "common data area (cda)", extract data from the cda, process waveform data to produce reduced amplitude timeseries and write them an "amplitude data area (ada)", and read amplitudes from the ada.

The BSL plans to bring up these codes on the Sun Fire 280r computers as soon as the new computers are configured. This will allow the Northern and Southern California Management Centers to begin exchanging the reduced amplitude time series.

Beyond establishing the amplitude exchange between the centers, the next step for the NC center to modify the existing software to make use of these pre-computed amplitudes. This requires changes to several modules in the REDI system. BSL staff are considering several possible approaches. This aspect of the implementation is complicated by the fact that the original TriNet programs use commercial software to perform some functions.

Once the software is operational within the REDI system, the question of magnitude corrections will need to be addressed. Historically, Caltech and the BSL have held different views about the calibration of Wood-Anderson seismometers. As a result, the amplitudes computed from the TriNet software uses a different gain than that used in equivalent BSL processing. This difference will merit careful review in order to avoid introducing problems with the historical catalog.

Data Exchange

Pick exchange was initiated between the Northern and Southern California Management Centers during the previous quarter. With the implementation of the Earthworm picker at the BSL, picks from the BSL have been added to those from the USGS Menlo Park and Caltech.

In the spring, a CISN Standards WG proposed a model for exchanging the reduced amplitude timeseries. During this quarter, BSL staff developed software to use this model for exchange: ada2ring (which reads the amplitudes from an ada and writes them to an Earthworm ring) and ring2ada (which reads the amplitudes from an Earthworm ring and writes them to an ada. These programs will allow the CISN to begin exchanging the pre-computed amplitudes using existing Earthworm import/export software. The software developed at the BSL has been tested locally, and a copy given to Caltech so that the center-center feed may be tested. Full exchange will be implemented when the BSL has the new Sun Fire 280r computers configured.

Also during this year, Caltech and the BSL identified 20 stations (10 each) which will be configured to send data to both the Northern and Southern California Data Centers (Figure 3.2). Caltech and the BSL both ordered the DLCIs (data link connection identifier) which will allow the 2nd center to establish a PVC (permanent virtual circuit) to each station using the frame-relay network.

Doug Neuhauser began working on the necessary configuration changes to the Quanterra data loggers. The new Quanterra configuration will allow for 4 telemetry links at each data logger: 1 primary and 1 secondary link to the BSL, 1 link to Caltech, and 1 additional link.

BSL staff participated in a working group to define a new format for exchanging ground motion amplitudes. The purpose of this format is to insure all information necessary for building ShakeMaps and constructing Internet Quick Reports is available.

Figure 3.2: Map showing the 20 stations selected to send data directly to the northern and southern California processing centers.
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Statewide Earthquake processing

To establish a testbed for statewide processing, several elements must be in place;

At this point in time (a) is largely complete. Items (b) and (c) are underway. Additional work is required for items (d-f) at this time.

Acknowledgements

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

Barbara Romanowicz and Lind Gee are members of the CISN Steering Committee. Lind Gee is a member of the CISN Program Management Committee and she leads the CISN project at the BSL. Doug Neuhauser is chair of the CISN Standards Committee, which includes Lind Gee and Pete Lombard as members.

Because of the breadth of the CISN project, many BSL staff have been involved including: John Friday, Lind Gee, Bill Karavas, Pete Lombard, Doug Neuhauser, Charley Paffenbarger, Dave Rapkin, Cathy Thomas, and Jim Yan.

Lind Gee, Pete Lombard, and Doug Neuhauser contributed to this chapter.



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