Subsections


Director's Report

Introduction

As in previous years, I am pleased to introduce the 2008-09 Berkeley Seismological Laboratory Annual Report. This report covers two interrelated activities at BSL: basic research and real time earthquake monitoring operations. Chapter 2 describes the research accomplishments; Chapter 3 details progress in our development of infrastructure and facilities.

The basic research spans many topics in seismology and tectonics. They range from studies of the earth's deep structure and dynamics to various aspects of earthquake physics; from microearthquakes and tremor studies to studies of earthquake mechanisms and rupture spanning different times scales; and from slow tectonic deformation, to real time seismology and earthquake early warning. These are described in 30 short contributions in Chapter 2 of this report.

This year, I wish to particularly highlight two major accomplishments on the operational side of the BSL. First, after almost ten years of sustained efforts involving our CISN partners at the US Geological Survey and Caltech, and after many intermediate steps, we finally have a completely integrated earthquake notification system across the State of California. Notably, as of June 2009, completely mirrored systems operate continuously and in real time across the San Francisco Bay (at Berkeley and USGS Menlo Park), backing each other up in case of downtime due to failure or maintenance. This system relies on complementary seismic data from the Berkeley and USGS Northern California networks. The next step, which we are starting to plan, is to integrate real time GPS data into the system. This involves coordination with USGS Menlo Park in Northern California, and with various partners in southern California (i.e. USGS, UCSD). Towards this goal, we have continued to convert GPS data acquisition from our continuous GPS BARD (BARD network) to high rate sampling (1Hz), and have recently reorganized and consolidated the BARD data acquisition and processing system. Second, in March 2009, the autonomous ocean floor broadband station MOBB (Monterey Bay Ocean Bottom Broad Band Observatory), which we have operated in collaboration with the Monterey Bay Aquarium Research Institute (MBARI) since 2002, was connected to the MARS cable (http://www.mbari.org/mars). It is now sending data continuously and in real time to the BSL, where we are integrating the data with those of the land-based stations, as a demonstration project for earthquake real-time notification.

Finally, I note that the development of replacement electronics for the STS-1 very broadband seismometers, under the technical leadership of our collaborator, Metrozet, Inc. has been completed. We are now actively assisting Metrozet in the ambitious goal of building a modernized version of the mechanical sensor. This unique seismometer, which revolutionized global seismology in the last 20 years, has not been produced by Streckeisen & Co. for several years. This raised considerable concerns in the international community. The BSL spearheaded the new development effort and helped secure funding for it from the NSF EAR-Instruments and Facilities program. We are designing a new baseplate for these seismometers, as well as participating in the testing of the new sensors.

The following sections give a brief historical overview of the BSL, and finally some BSL staff news.

History and Facilities

The Berkeley Seismological Laboratory (BSL), formerly the Berkeley Seismographic Station (BSS), is the oldest Organized Research Unit (ORU) on the UC Berkeley campus. Its mission is unique in that, in addition to research and education in seismology and earthquake-related science, it is responsible for providing timely information on earthquakes (particularly those that occur in northern and central California) to the UC Berkeley constituency, to the general public, and to various local and state government and private organizations. The BSL is therefore both a research center and a facility/data resource, which sets it apart from most other ORUs. A major component of our activities is focused on developing and maintaining several regional observational networks, and participating, along with other agencies, in various aspects of the collection, analysis, archival, and distribution of data pertaining to earthquakes, while maintaining a vigorous research program on earthquake processes and Earth structure. In addition, the BSL staff spends considerable time on public relations activities, including tours, talks to public groups, responding to public inquiries about earthquakes, and, more recently, World-Wide-Web presence (http://seismo.berkeley.edu/).

UC Berkeley installed the first seismograph in the Western Hemisphere at Mount Hamilton (MHC) in 1887. Since then, it has played a leading role in the operation of state-of-the-art seismic instruments and in the development of advanced methods for seismic data analysis and interpretation. Notably, the installation, starting in 1927, of Wood-Anderson seismographs at 4 locations in northern California (BKS, ARC, MIN and MHC) allowed the accurate determination of local earthquake magnitude ($M_{L}$) from which a unique historical catalog of regional earthquakes has been maintained to this day, providing crucial input to earthquake probabilities studies.

Over the years, the BSS continued to keep apace of technological improvements. The first centrally telemetered network using phone lines in an active seismic region was installed by BSS in 1960. The BSS was the first institution in California to operate a 3-component ``broadband" system (1963). It played a major role in the early characterization of earthquake sources using ``moment tensors" and source-time functions. The BSS also made important contributions to the early definitions of detection/discrimination of underground nuclear tests and, jointly with UCB Engineering, to earthquake hazards work. Starting in 1986, the BSS acquired 4 state-of-the-art broadband instruments (STS-1), while simultaneously developing PC-based digital telemetry, albeit with limited resources. As the telecommunication and computer technology made rapid progress, in parallel with broadband instrument development, paper record reading was completely abandoned in favor of largely automated digital data analysis.

The current facilities of BSL have been built progressively over the last two decades, efforts initiated by significant ``upgrade" funding from UC Berkeley in 1991-1995. The BSL currently operates and acquires data, continuously and in real-time, from over 60 regional observatories. These house a combination of broadband and strong motion seismic instrumentation installed in vaults, borehole seismic instrumentation, the permanent GPS stations of the Bay Area Regional Deformation (BARD) network, and electromagnetic sensors. The seismic data are fed into the BSL real-time processing and analysis system. Since 1996, they are used in conjunction with data from the USGS NCSN network in the joint earthquake notification program for northern California. This program capitalizes on the complementary capabilities of the networks operated by each institution to provide rapid and reliable information on the location, size and other relevant source parameters of regional earthquakes. In recent years, a major emphasis in BSL instrumentation has been in densifying the state-of-the-art seismic and geodetic networks. At the same time, research efforts have been directed toward the development of robust methods for quasi-real time, automatic determination of earthquake source parameters and predicted strong ground motion, using a sparse network combining broadband and strong motion seismic sensors, as well as permanent geodetic GPS receivers. Recently researc emphasis has been directed toward the development of ``earthquake early warning'' capabilities

The Berkeley Digital Seismic Network (BDSN), a regional network of 32 digital broadband and strong motion seismic stations with continuous telemetry to UC Berkeley, is the backbone of the BSL operations. This network provides the basic regional data for the real-time estimation of location, size and rupture parameters for earthquakes of M 3 and larger in central and northern California, within our Rapid Earthquake Data Integration (REDI) program. It is the Berkeley contribution to the California Integrated Seismic Network (CISN). The REDI program was replaced this June by the CISN software (see 8). The data from the BDSN also provide a fundamental database for the investigation of three-dimensional crustal structure and its effects on regional seismic wave propagation. This is ultimately crucial for estimating ground shaking for future earthquakes. Most stations also record auxiliary temperature/pressure channels, valuable in particular for background noise quality control. Complementing this network is a $\sim 25$ station ``high-resolution" network of borehole seismic sensors located along the Hayward Fault (HFN) and under the Bay Area bridges, operated jointly with the USGS/Menlo Park and linked to the Bridge Safety Project of the California Department of Transportation (Caltrans). The latter has facilitated the installation of sensor packages at 15 bedrock boreholes along 5 east bay bridges in collaboration with Lawrence Livermore National Laboratory (LLNL). A major science goal of this network is to collect high signal-to-noise data for micro-earthquakes along the Hayward Fault to gain insight into the physics that govern fault rupture and its nucleation. The BSL also operates and maintains the 13 element Parkfield borehole seismic array (HRSN). This array provides high quality data on micro-earthquakes, clusters and most recently tremors, and is an important reference for the San Andreas Fault Observatory at Depth (SAFOD). Since April 2002, the BSL collaborates with MBARI on the operation of a permanent broadband ocean bottom station, MOBB.

In addition to the seismic networks, the BSL operates, maintains and processes data from the 30 permanent geodetic stations of the BARD Network. It archives and distributes this data as well. Where possible, BARD sites are collocated with BDSN sites to minimize telemetry costs. In particular, sites are progressively being upgraded to 1 Hz sampling. This will support one focus of BSL research, the development of analysis methods which will combine seismic and geodetic data to rapidly estimate source parameters of significant earthquakes.

Finally, two of the BDSN stations (PKD, SAO) also share data acquisition and telemetry with 5-component electromagnetic sensors installed with the goal of investigating the possibility of detection of tectonic signals. In 2002-2003, automated quality control software was implemented to monitor the electromagnetic data.

Archival and distribution of data from these and other regional networks is performed at the Northern California Earthquake Data Center (NCEDC), operated at the BSL in collaboration with USGS/Menlo Park. The data reside on a mass-storage device (current holdings $\sim 40$ terabytes), and are accessible ``on-line'' over the Internet (http://www.ncedc.org). Among others, data from the USGS Northern California Seismic Network (NCSN), are archived and distributed through the NCEDC. The NCEDC also maintains, archives and distributes the ANSS earthquake catalog.

Core University funding to our ORU has until now provided salary support for one staff scientist and several technical and administrative staff members, representing about 30% of the total infrastructure support. The remaing support comes from extra-mural grants and contracts, primarily from the USGS, NSF, and the State of California, through its Emergency Managment Agency (CalEMA, formerly OES). We acknowledge valuable recent contributions from other sources such as Caltrans and PEER, as well as our Earthquake Research Affiliates. The effects of drastic budget cuts in FY09-10 are temporarily being offset by ARRA funding from the USGS. Over the next two years, these funds will allow us to upgrade the aging equipment at most of our remote observatories. This will put us in a better position to design the next generation earthquake notification system, the move towards earthquake early warning, using a combination of seismic and geodetic data.

BSL staff news

Changes in BSL staff in 2008-09 are as follows.

In the past year, the following graduate students associated with BSL completed their PhD's: Ahyi Kim joined Schlumberger in Cambridge (UK) in summer 2009; Sean Ford is now a post-doc at Lawrence Livermore National Laboratory.

In the global seismology group, post-doc Laurent Stehly left for a research position at the University of Nice (France). Post-doc Nicolas Houlié left in July 2009 and now holds a research position at the University of Leeds (UK). There have been several new arrivals: Scott French, Patrick Statz-Boyer, Ana Luz Acevedo-Cabrera and Hong-Han Huang joined the BSL as graduate students in the Fall of 2009. Mathias Obrebski joined Richard Allen's group as a post-doc in the Fall of 2008. Ingrid Johanson returned to Roland Burgmann's group as a post-doc in October 2009. Since Nicolas Houlié's departure in the Summer of 2009, she is helping out with the BARD program. After a brief stay in Hawaii, where she is finishing up a research project, she will take on an assistant researcher's position at BSL and provide guidance to the field and data acquisition staff on matters related to BARD, and participate in the development of high rate GPS data assimilation in our earthquake notification system.

BSL hosted the following visiting scientists in 08-09: Liang Zhao (Institute of Geophysics, Chinese Academy of Sciences, Beijing) and Michael Slawinski (Department of Earth Sciences at Memorial University in Newfoundland, Canada). Shweta Sangewar (India Institute of Technology) and Fabian Walter (ETH Zrich, Switzerland) were summer interns in 2008.

As a result of a campus wide reorganization of the research administration of Organized Research Units, our four administrative staff have been laid off, effective November 30, 2009. Kristen, Tina and Yolanda have been rehired at RES (Research Enterprise Services), the new agency which will provide business administration to ORUs at Berkeley. Meanwhile, Kate is enjoying her new baby daughter Audrey and prospecting for job opportunities. They have been outstanding members of the BSL team, and we are sorry to see them go in spite of all our efforts. I wish them all the best for the future.

The greater BSL family has also grown, almost explosively, in the past year. We have welcomed four children of BSL staff and students in the past year. A baby boy, Kaito Taira, was born to Taka'aki Taira and his wife Akiko in August. Kate Lewis and her husband Justin had a girl, Audrey, in October. November brought two, somewhat early arrivals: Freeman McCarty was born to Jennifer Taggart and her husband Kevin McCarty, and Arieh Wurman-Fenton was born to Gilead Wurman and his wife Lori Fenton. We wish them all happiness and health.

Acknowledgements

I wish to thank our technical and administrative staff, scientists and students for their efforts throughout the year and their contributions to this Annual Report. Individual contributions to activities and report preparation are mentioned in the corresponding sections, except for the Appendix section, which was prepared by Kate Lewis, Kristen Jensen and Jennifer Taggart.

I also wish to specially thank the individuals who have regularly contributed to the smooth operation of the BSL facilities: Mario Aranha, Rich Clymer, Doug Dreger, John Friday, Jarrett Gardner, Peggy Hellweg, Nicolas Houlié, Bill Karavas, Oleg Khainovski, Rick Lellinger, Pete Lombard, Rick McKenzie, Bob Nadeau, Doug Neuhauser, Charley Paffenbarger, Jennifer Taggart, Bob Uhrhammer, and Stephane Zuzlewski, and in the administrative office, Kristen Jensen, Kate Lewis, Tina Barber-Riggins and Yolanda Andrade. I also wish to thank our undergraduate assistants, Chris Rawles, Danny Feucht, Josef Matlak, Eric Winchell, Alicia Adams and Amanda Truyol for their contributions to our research and operations activities. I am particularly grateful to Jennifer Taggart and Peggy Hellweg, for their help in putting together this Annual Report, and bringing it to closure under the present difficult circumstances. The Annual Report of the Berkeley Seismological Laboratory is available on the WWW at http://seismo.berkeley.edu/annual_report.


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