SOUTHERN CALIFORNIA EARTHQUAKE CENTER SCEC Decade 1 Bernard

SOUTHERN CALIFORNIA EARTHQUAKE CENTER SCEC: Decade 1 Bernard Minster SCEC Annual meeting, 2000 9/18/00 SCEC: Decade 1

SOUTHERN CALIFORNIA EARTHQUAKE CENTER SCEC and its Mission • The Southern California Earthquake Center’s mission is to promote earthquake loss reduction by: – Defining when and where future damaging earthquakes will occur in Southern California, – Calculating the expected ground motions, and – Communicating this information to the public. 9/18/00 SCEC: Decade 1 2

SOUTHERN CALIFORNIA EARTHQUAKE CENTER SCEC Objectives • To estimate the earthquake potential, or the probability of earthquake occurrence as a function of location, magnitude, and time, • To advance our understanding of earthquake rupture dynamics and source physics, • To understand the nature of wave propagation through complex geology, • To predict ground motions, or complete theoretical seismograms, at any site from plausible future damaging earthquakes, and • To transfer this knowledge to communities of end users. 9/18/00 SCEC: Decade 1 3

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Master Model "… the goal of SCEC is to integrate research findings from various disciplines in earthquake-related science to develop a prototype probabilistic seismic hazard model (master model) for southern California. ” (Keiiti Aki, 1989) 9/18/00 SCEC: Decade 1 4

SOUTHERN CALIFORNIA EARTHQUAKE CENTER 9/18/00 SCEC: Decade 1 5

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Seismicity of Southern California 9/18/00 SCEC: Decade 1 8

SOUTHERN CALIFORNIA EARTHQUAKE CENTER GPS Velocity Map of Southern California 9/18/00 SCEC: Decade 1 9

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Southern California Integrated GPS Network (S�CIGN) § 168 stations installed § 78 more to be installed (by late 2000)… § Total of 250 stations 9/18/00 SCEC: Decade 1 10

SOUTHERN CALIFORNIA EARTHQUAKE CENTER GPS in the Los Angeles Basin The Los Angeles basin is being squeezed closed (e. g. , Palos Verdes is moving towards JPL). 9/18/00 SCEC: Decade 1 11

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Integration of GPS into Risk Estimation 9/18/00 SCEC: Decade 1 13

SOUTHERN CALIFORNIA EARTHQUAKE CENTER 9/18/00 SCEC: Decade 1 14

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Regional stress changes caused by the Landers, Big Bear and Joshua Tree earthquakes. Areas in red are regions where nearby faults are brought closer to failure. Note that segments of the San Andreas fault pass through red zones. From R. S. Stein, G. C. P. King and J. Lin (Science, 1992), G. C. P. King, R. S. Stein and J. Lin [BSSA, 1994) 9/18/00 SCEC: Decade 1 15

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Evidence for Fault Zone Healing following the 1992 Landers Earthquake from Fault Zone Trapped Waves and Body Waves. Left Panel: Shot points (SP-X) and receiver locations (Lines 1 and 3) along Johnson Valley segment. Center Panels: Time differences in arriving phases between 1994 and 1996 as a function of distance from the fault trace along Line 1. Right Panels: Time differences in arriving phases between 1996 and 1998 as a function of distance from the fault trace along Line 1. (From Li, 2000) 9/18/00 SCEC: Decade 1 16

SOUTHERN CALIFORNIA EARTHQUAKE CENTER The probability of a large earthquake on the San Bernardino segment of the San Andreas fault was increased by the 1992 Landers and 1999 Hector Mine earthquakes. 9/18/00 SCEC: Decade 1 17

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Sub-Surface Fault Map of the Los Angeles Area (Dolan, 2000) 9/18/00 SCEC: Decade 1 19

SOUTHERN CALIFORNIA EARTHQUAKE CENTER The Puente Hills Blind Thrust Fault and 1987 Whittier Narrows Earthquake Sequence 9/18/00 SCEC: Decade 1 23

SOUTHERN CALIFORNIA EARTHQUAKE CENTER SCEC Phase III Report An investigation of how and if site effects can be accounted for in probabilistic seismic hazard analysis (PSHA) in southern California Conclusions: is justified map. (but may be corrections. 9/18/00 1) Detailed classification (beyond rock versus soil) with the Wills et al. (2000) 2) Basin depth is a significant factor, even for PGA a proxy). 3) Uncertainty (sigma) remains high after site SCEC: Decade 1 24

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Deterministic Ground Motion Prediction: Input to Performance-based Engineering Design 9/18/00 SCEC: Decade 1 25

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Los Angeles Regional Seismic Experiment LARSE Top panel: Crustal structure image across the Los Angeles basin and San Gabriel Mountains from seismic transect. Bottom panel: Interpretation of fault structure based on data from top panel. 9/18/00 SCEC: Decade 1 26

SOUTHERN CALIFORNIA EARTHQUAKE CENTER LARSE II Transect from Santa Monica Bay to the Mojave Desert Features crossed include: • • • • 9/18/00 Santa Monica Fault Santa Monica Buried Thrust Fault Santa Monica Mountains San Fernando Valley/Basin 1994 Northridge Earthquake Fault Santa Susana Thrust Fault Santa Susana Mountains San Gabriel Fault Central Transverse Ranges San Andreas Fault Mojave Block Garlock Fault Tehachapi Mountains SCEC: Decade 1 27

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Fence Diagram from the SCEC Seismic Velocity Model of Southern California 9/18/00 SCEC: Decade 1 29

SOUTHERN CALIFORNIA EARTHQUAKE CENTER The Basin-edge Effect from the 1994 Northridge Earthquake 9/18/00 SCEC: Decade 1 30

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Simulating Dynamics of Fault Rupture Tough computational problem because. . . Inner scales are small: +46 < 10 meter <. 01 second Outer scales are large: > 100 kilometers > 100 years 9/18/00 SCEC: Decade 1 31

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Critical Point Model • The largest earthquake on a given fault network is possible only when the network is in a critical state. • The crust is not in a continual critical state. Earthquake cycles can be viewed as repeated approaches and retreats from the critical state. • The critical state is characterized by spatial stress correlations at all scales up to the size of the regional fault network. • A large earthquake destroys the stress correlation on its regional fault network, producing a quiescent period for intermediate and large events. • Small earthquakes rebuild stress correlation, making the next large earthquake possible. Each earthquake roughens the stress field at longer wavelengths and smoothes it at shorter ones. 9/18/00 SCEC: Decade 1 32

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Simulations for the San Andreas Fault (Olsen, 2000) 9/18/00 SCEC: Decade 1 34

SOUTHERN CALIFORNIA EARTHQUAKE CENTER 9/18/00 SCEC: Decade 1 35

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Collaboration between Earth Scientists and Engineers 9/18/00 SCEC: Decade 1 37

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Partners in Academia State National International 7 SCEC Institutions: Caltech; UC San Diego, Davis, Santa Barbara, Los Angeles; USC; SDSU CSUN, CSULB, UC Berkeley, SFSU, Stanford, UC Irvine, CS Fullerton, CSULA, Whittier College PEER CUREe 2 SCEC Institutions: Columbia; UNR Carnegi-Mellon Central WA University GA Institute of Technology Harvard, MIT, NAU, OSU, Texas Tech Univ. , U of AK, U of CO, U of DE, U of Memphis (CERI), U of WA, U of NM, Woods Hole Oceanographic Inst. , Univ of Utah DLESE MCEER MAE IRIS, EERI CICESE, Mexico Institute de Physique du Globe, Paris Univ of Athens & Thessaloniki, Greece Istituto Nazionale de Geofisica, Rome State Seismology Bureau, China Building Research Institute, Japan Disaster Prevention Research Institute, Kyoto, Japan Geological Surveys of Canada, Japan Univ of Tokyo Earthquake Research Institute 9/18/00 SCEC: Decade 1 38

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Partners in Education (980) SCEC Community of Researchers, Students USGS (Civic presentations; web-based curricula; K-12 products) PEER (interns) CUREe (Woodframe Project, Engineering/Science Symposia, HAZUS, E-3 Project) California K 12 Alliance (education modules creation and review) 9/18/00 IRIS (E-3 Project, middle school education modules support DLESE (E-3 Project, digital libraries community involvement) Museums (earth science / earthquake exhibits, docent training, educational curricula, hands-on activities, field trips) LACOE (earth science curricula) ARC (earth science curricula) IBHS (Seismic Sleuths video) AGU, FEMA (Seismic Sleuths curriculum revisions) SCEC: Decade 1 39

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Partners in Government Local (679) State (230) Federal (328) Cities and Counties of southern California: Building Officials Emergency Planners & Responders Urban Planners Public Utilities (water, power) CA Div Mines & Geology CA OES CA Seismic Safety Commission NV Bureau Mines & Geology USGS FEMA / NEP National Labs: NASA’s JPL, Lawrence Livermore, Los Alamos 9/18/00 SCEC: Decade 1 40

SOUTHERN CALIFORNIA EARTHQUAKE CENTER Partners in Industry (For-profit, Non-profit) Private/For-profit (2538) Nonprofit (150) Insurers & Reinsurers Institute for Business & Home Safety Risk Analysis Consultants Design, Engineering Consultants Geotechnical Consultants Contingency Planning Consultants Media Organizations 9/18/00 Insurance Education Association CA Assoc. of Insurance Professionals SEAOSC American Red Cross BICEPP Assoc. of Contingency Planners California Earthquake Authority EERI EPARR (Emerg. Prep. Response & Recovery Committee) SCEC: Decade 1 41

SOUTHERN CALIFORNIA EARTHQUAKE CENTER SCEC Webservices www. scec. org ~4, 500 Visitors per week www. scecdc. scec. org ~250, 000 Visitors per week 1200 view Outreach 1000 view INSTANe. T News 1000 view Research 300 view worldwide Eq’s 300 view “About SCEC” 9/18/00 SCEC: Decade 1 42

SOUTHERN CALIFORNIA EARTHQUAKE CENTER “Putting Down Roots in Earthquake Country” a USGS-SCEC Product • Largely funded by USGS • Produced by SCEC Outreach • 1. 8 million distributed by SCEC, USGS, local community • Featured on local TV, at earthquake fairs each April 9/18/00 SCEC: Decade 1 43

SOUTHERN CALIFORNIA EARTHQUAKE CENTER SCEC Transition Process • Funding as NSF S&T Center ends 02/02 – STC funding base: $1. 4 M – Cannot be renewed under STC Program • Joint proposal to NSF/EAR and USGS to be submitted in 12/00 • Transition objectives – Strengthen partnership with USGS – Tie in with NSF Earth. Scope initiatives – Increase integrated, system-level studies of earthquake phenomena – Augment strong Education & Outreach program 9/18/00 SCEC: Decade 1 44

SOUTHERN CALIFORNIA EARTHQUAKE CENTER The Beginning! 9/18/00 SCEC: Decade 1 45