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, UC Berkeley, 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 initial efforts to create this collaboration through the establishment of a memorandum of agreement and the development of the CISN strategic and implementation plans. The CISN is now in its fourth year of collaboration and its third year of funding from the California Governor's Office of Emergency Services.
The core CISN institutions (California Geological Survey, Caltech, UC Berkeley, USGS Menlo Park, and 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 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 is comprised of two representatives from each core institution and a representative from OES. The position of chair rotates among the institutions; Mike Riechle is the current 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 Bruce Clark of the California Seismic Safety Commission, although in the past year, Ron Tognazinni of LA Department of Water and Power has served as acting chair. The Advisory committee last met in September 2003 and the next meeting is planned for October 2004.
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.
The USGS Advanced National Seismic System (ANSS) is being developed along a regionalized model. 8 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.
Over the last 5 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, instruments at over 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. In the last year, Lind Gee joined the Technical Integration Committee (TIC), which oversees technical issues for the ANSS. Other BSL faculty and staff have been involved in several TIC working groups, including Doug Dreger, Pete Lombard, Doug Neuhauser, Bob Uhrhammer, and Stephane Zuzlewski.
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. Although at a reduced level of support from the previous year, these funds are critical to continued efforts in statewide integration.
The CISN funding from OES facilitated a number of activities at the BSL during the past year. However, the late award of the funding (the amended contract was received by UC Berkeley on May 13, 2004) complicated some aspects of the BSL activities, particularly those related to station installations and the development of the earthquake information distribution system.
The December 22, 2003, San Simeon earthquake provided the first significant test of CISN capabilities since the initiation of the statewide collaboration. The event highlighted some known issues and illuminated some areas where additional effort is required, particularly with respect to ShakeMaps. The PMG report (Gee et al., 2004a) documents the CISN response in detail.
Overall, the CISN performance for the distribution of information following the San Simeon earthquake was good. Automatic information about the location was available within 30 seconds and a final location with a reliable magnitude was released about 4.5 minutes after the event. The first ShakeMap was issued 8 minutes after origin time and distributed to OES and multiple Web servers. During the next 24 hours, additional information about aftershock probabilities, the fault rupture, and seismological/engineering aspects of interest were made available by the CISN.
However, one of the most challenging aspects of this event was the lack of modern stations with communication capabilities in the vicinity of the earthquake. This compromised the quality of the ShakeMaps for the mainshock and aftershocks and posed limitations in our ability to obtain reliable locations and magnitudes for the smaller events. Although the greater Los Angeles area and the San Francisco Bay region are approaching sufficient station density to provide data-driven ShakeMaps, significant portions of California lack the necessary coverage.
More information about the San Simeon earthquake is available in Chapter 9 on Northern California earthquake monitoring and in Chapter III in research contributions III.13 and III.14
In 2001-2002, the BSL purchased equipment for 5 BDSN stations, including STS-2 seismometers, Episensors, and Q4120 data loggers, and 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. This equipment allowed the BSL to add two broadband stations in 2002-2003 (PACP and MNRC, Figure 3.1).
In the past year, the BSL initiated the installation of a site at Alder Springs (GASB), California. This site has been under discussion for a number of years, initially as part of the National Tsunami Hazards Program. The efforts for site preparation and installation are more fully described in Chapter 3.
In the fall of 2004, the BSL will install a site near Pt. Reyes, at the Marconi Conference Center. This site will be partially funded by IRIS (part of the permanent component of USArray) and OES.
As part of the CISN project, the BSL purchased 23 upgrade kits for their Q4120 data loggers with the goal of improving remote diagnostic capabilities last year. 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.
Successful upgrade of the dataloggers requires a site visit to remove the datalogger and bring it back to the lab, installation of the boards, replacement of lattices on the CPU board, construction of new cables to transmit the mass position signals, and redeployment of the datalogger in the field. Of the 23 kits purchased, all but three have been installed as of June 30th, although a few sites still require new cables or replacement of the lattices.
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. In early 2004, Caltech and the BSL completed agreements with IRIS for the contribution of their stations to USArray. 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 needed to modify some aspects of their station operation in order to meet the USArray specifications. In particular, USArray calls for BH data sampling at 40 Hz, rather than the 20 Hz rate that has been standard in California. In the case of the BSL, all surface broadband stations were converted to 40 Hz over June 15-16th. The collaboration between the BSL and USArray is discussed more fully in Chapters 3 and 8.
One of the major accomplishments in FY01/02 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 2.1) with dual routers at each node.
As described last year, the CISN ring is up and operational. 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.
During the last year, the CISN performed a test to verify the failover and redundancy capabilities of the CISN ring. The goals of the test were to 1) verify that if a single segment of the CISN ring fails, the backbone routers will detect the outage in a timely fashion and will reroute traffic to all CISN sites around the remaining CISN ring segments, and 2) verify that if a site is completely disconnected from the CISN ring, the backbone routers will detect the outage in a timely fashion and will reroute traffic to/from that site over the backup Internet tunnels between the disconnected site and all other CISN sites.
The test conducted demonstrated that the CISN routers and ring are performing according to design. However, the CISN OES routers do NOT have public Internet connections yet, so they have no Internet tunnel connections. 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.
The CISN intends to test the failover capabilities of the ring regularly. The full report of the May 21 test is available at the CISN Web site, under the reports of the Standards Committee.
As part of their 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 9 describes the operations of the existing Management Center and reports on design discussions.
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 last year (Figure 2.3) to support the anticipated level of 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. In the past year, the BSL has been reconfiguring the 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. This configuration will allow the BSL to migrate acquisition from one T1 to the other if a failure occurs. These changes (which are still underway and will be completed in the fall of 2004) will improve the robustness of the BSL operations.
In the long term, the BSL and USGS Menlo Park hope to have a high-bandwidth microwave or satellite connection in addition to the current land lines. Unfortunately, we have not been able to obtain funding for this additional communication link at this time.
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 the minutes from meetings and conference calls at http://www.cisn.org/standards/meetings.html).
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 2.2). To achieve this, the BSL and Caltech both ordered the DLCIs (data link connection identifier) that allow the 2nd center to establish a PVC (permanent virtual circuit) to each station using the frame-relay network.
The Northern California Management Center 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 more sensitive to the background noise level.
Pick exchange was initiated between the Northern and Southern California Management Centers in 2001-2002. Although the CISN has developed software to exchange the reduced amplitude timeseries, this aspect of data exchange has been delayed while certain problems in the codes that generate the time series are addressed.
The CISN partners completed the final stage of a system to exchange peak ground motion data this year. Using a common format, the CISN partners are exchanging observations with one another following an event or a trigger. This step increases the robustness of generating products such as ShakeMap, since all CISN partners are now exchanging data directly with one another. It also improves the quality of ShakeMaps 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, it is a necessary step toward the goal of generating statewide ShakeMaps.
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 Northern and Southern California Management Centers is very different. 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 2002-2003, effort was focused on phase pickers (pick-ew), the association algorithm (binder), the location algorithm (hypoinverse), and magnitude estimation (various). In the last year, magnitude estimation continued 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 nearly a year. It performed well during the December 2003 San Simeon sequence.
In contrast, the calibration of magnitude has proven to be a more difficult problem, particularly local magnitude, . Last year, we reported initial results from two separate inversions of Wood Anderson amplitudes from the BDSN to estimate local magnitude adjustments. Bob Uhrhammer of the BSL and Jascha Polet of Caltech compared their independent results as a first step to determine a common set of adjustments. Jascha's method estimates the adjustments and attenuation relationship simultaneously, while Bob's uses a differential approach while fixing the attenuation relationship. The good agreement between the estimates of the adjustments provided confidence in the first step of the process.
However, efforts to combine BDSN and TriNet data in a single inversion have been challenging (Gee et al., 2003; 2004b). After much probing, it appears as if there is a bias between the northern and southern California magnitude estimates (Figure 2.4), as illustrated by the three lines of evidence. 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 were hampered by the lack of a good statewide dataset. We now have a good set of 86 events, but some effort remains to clean up the data set and remove observations of multiple channels at the same site for a given earthquake (that is, observations from the BH, HH, and HL channels for a single station) as this multiplicity results in overweighting of some stations. Potential sources of the magnitude discrepancy are drift in station adjustments, differences in the attenuation functions, and other path effects.
In parallel, the BSL has been working on other issues related to magnitude. We have installed a version of the TriNet software that processes waveforms to produce resampled timeseries of amplitudes as well as codes to compute magnitudes and peak ground motions from these timeseries. The system has been running since late 2003. In general, the amplitudes computed by the time-domain approach agree very well with the frequency domain approach that has been the core of the REDI system since 1994. However, the frequency domain amplitudes are consistently higher than the time domain amplitudes (Figure 2.5). The slight difference (the mean amplitude ratio is 1.05 from 781 observations) may be due to differences in using the full versus simplified instrument responses.
Magnitudes from the time-domain approach agree well with the frequency-domain method, although there is some scatter at lower magnitudes. This is due to differences in the window selection, use of signal to noise ratios to select stations, and differences in the attenuation relations.
Another issue facing the magnitude Working Group is the difference in the station distribution. In southern California, the density of broadband stations permits the computation of for every earthquake. In northern California, the more sparse station distribution does not allow the reliable estimate of below magnitude 3. As a result, the Working Group is looking into the necessary steps to implement on a statewide basis.
A final component of the magnitude efforts is the designation of a magnitude reporting hierarchy. There is general agreement at the low end and at the high end, but the working group is still reviewing issues related to transition points from one magnitude type to another. More details about the magnitude calibration effort are documented in Chapter 9.
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 currently generated on 5 systems within the CISN. 2 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.
Over last 6 months, the Working Group has addressed a number of issues in the standardization of ShakeMap. Initially focusing on the look and feel of the maps (topography, geology, faults, road, lake outlines, cities, and fonts), the Working Group has just started to review a comprehensive compilation of the differences in configuration among the 3 implementations. The remaining differences between the centers range from the small (URL used in the "addon" message) to the significant (use of regressions, linear versus log amplitude weighting). This effort 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 a number of issues related to ShakeMap and how to measure the quality of the product as well as quantify the uncertainty. Over the past 6 months, a subset of the Working Group has been working on this issue, based on the work of Hok and Wald (2003). One of the first projects has been to make a map to illustrate current CISN capabilities, based on the existing station distribution. The next step is to look at calculating uncertainty for some example earthquakes and comparing the uncertainty estimates with different realizations of the ShakeMap produced by using various subsets of the data. Once the method to quantify the uncertainty is validated, then we can use this information to determine a grade.
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. Over the past few months, USGS and UC Berkeley developers have been working to modify the Earthworm software to support the use of location codes. This effort is nearly complete and the centers are working on a plan to begin migration to the modified codes.
The CISN is also working on issues related to metadata exchange. This is an important component of CISN activities, as correct metadata are required to insure valid interpretation of data. A Standards Working Group has developed and initiated testing of a model for database replication of metadata, and is currently reviewing how much of the schema to exchange and how to address metadata from partners such as CGS, who do not currently maintain their metadata in a database.
Last year, 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 of their stations and other stations that enter into CISN processing through them. For example, Menlo Park is responsible for the NSMP, Tremor, and PG&E stations and Caltech is responsible for the Anza data. The Working Group believes that metadata exchange should proceed on a timely basis, not just when data are generated, and is testing an approach using database replication.
For database exchange, the Working Group proposed that each group or organization have a working or interim database as a staging area (a private sandbox) and a master database. The interim database would contain snapshots of the master tables (that the group/organization is responsible for) and the changes would be pushed manually to the master database by snapshot replication. Changes would be propagated among the master databases by multi-master replication.
To start this off, the Working Group agreed to test replication with a limited number of tables, focusing initially on tables relevant to the real-time system (but not sufficient for archiving). In order to test this solution, the NCMC and SCMC needed to resolve some inconsistencies in the database implementations. This included both differences in the physical schema as well as differences in use of the schema. The Working Group initiated a pilot test in early 2004, using the tables SimpleResponse and StaMapping and a test database at the NCMC and SCMC. The initial results were successful and the effort has expanded to other tables. As of June 2004, 11 tables are being replicated between the test databases. The next step for the Working Group is to validate the use of the metadata in the real-time system. When this is done, the database replication can be migrated to the primary databases.
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 and the V0 format was developed to allow for that. The Working Group developed the concept of a "dataless" V0 format (analogous to the dataless SEED files) which will be used to distribute the metadata. In the current plan, CGS will initially prepare and distribute dataless V0 files providing the current metadata for ShakeMap quality stations (i.e., with channels meeting CISN Reference Station or better standards) in the CGS network. These current-information metadata files for the stations will be distributed (probably using a mechanism like sendfile/getfile) and will also be placed at the CGS FTP site. As agreed, the comment field in the V0 header will be used to define the valid time period for the metadata. Each dataless V0 file will contain 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 NCMC 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.
In response to a request from the PMG, USGS and OES management established an Ad Hoc panel in May 2003 to develop specifications for an earthquake information system and to review existing systems as well as systems under development. Lind Gee of the BSL and David Oppenheimer of the USGS were asked to co-chair this panel and to provide a written report within 90 days. The panel met on July 9-10th at the BSL and the report was published on September 16 (Ad Hoc Panel on Earthquake Information Distribution, 2003). The panel reviewed the three major existing or planned distribution systems (QDDS, QuakeWatch, and ShakeCast) and noted that none of the systems addressed all the current needs for earthquake information distribution. In particular, firewalls are a growing problem for systems relying on socket-based connections. The panel recommended that a new system be developed, and outlined preliminary specifications for such as system.
Following the publication of the report, OES asked to BSL to write a proposal for the development of the Earthquake Information Distribution System or EIDS. OES approved the proposal and forwarded it to FEMA for review. FEMA agreed to provide $100,000 toward the development of the system out of the 2002 Emergency Management Program Grant to the State of California.
The award from FEMA was combined with the OES funding of the CISN and the contract was received by UC Berkeley on May 13th. In parallel, Lind Gee and David Oppenheimer worked with the members of the Ad Hoc panel to develop detailed specifications - appropriate for a Request For Proposal or RFP - based on the September 2003 report. The specifications were completed in late June and submitted to UC Berkeley Purchasing on July 6, 2004. Unfortunately, the late award of the funding combined with the difficulties of issuing an RFP are complicating efforts to award the funding in a timely fashion. The FEMA contract will terminate on September 30th, 2004.
[Update: In mid-August, the BSL decided to proceed with a sole source award to Instrumental Software Technologies, Inc (ISTI). Paul Friberg of ISTI was one of two vendors who made presentations to the AdHoc Panel in July of 2003 regarding an earthquake information distribution system. On September 28, the BSL was notified that an extension from FEMA has been awarded. Development is now under way.]
There has been significant progress at www.cisn.org in FY03/04. A year ago, the CISN shared the Web server at the Northern California Earthquake Data Center. With the purchase of new, dedicated Web computers, 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.
In early December, the CISN began offering a sign-up for earthquake notifications by email. Although both northern and southern California have offered individual sign-ups in the past, the new service provides uniform notification messages for earthquakes of M3.5 and higher in California. In addition, users can sign up to be notified when ShakeMaps are generated.
Design and content of 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.
Also in FY03/04, the CISN established a Web site dedicated for emergency managers. Following a suggestion from the Advisory Committee, we have designed a Web site to provide personalized access to earthquake information. Known at "myCISN", the Web site is available at eoc.cisn.org (Figure 2.6). 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 was purchased with FY03/04 funds and will either be installed in Sacramento or in southern California.
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, Wade Johnson, Bill Karavas, Pete Lombard, Doug Neuhauser, Charley Paffenbarger, Dave Rapkin, and Stephane Zuzlewski. Lind Gee contributed to this chapter. Additional information about the CISN is available through reports from the Program Management Committee (Hauksson et al., 2003).
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 using TERRASCOPE, Bull. Seis. Soc. Am., 83, 330-346, 1993.
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