NGA-Subduction: Development of the Largest Ground Motion Database for Subduction Events

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2 NGA-Subduction: Development of the Largest Ground Motion Database for Subduction Events Tadahiro Kishida. Ph.D., and Yousef Bozorgnia, Ph.D., P.E. University of California, Berkeley 1

3 Probabilistic Seismic Hazard Analysis (PSHA) Seismic source model Ground Motion Prediction Equation (GMPE), or Attenuation Model Probabilistic hazard model

4 Ground Motion Model (GMM) It is a model to scale ground motion with magnitude, source-to-site distance, local soil condition,... It used to be called Attenuation relationship A bad name It is also named Ground Motion Prediction Equation (GMPE) It is not a great name 3

5 NGA= Next Generation Attenuation Relations The most common and successful GMMs are Next Generation Attenuation (NGA) models Coordinated by PEER Models to scale ground shaking with respect to fundamental parameters such as earthquake magnitude, site-to-source distance, local soil condition,... For any seismic design or evaluation you need such scaling models They are heavily used in Probabilistic Seismic Hazard Analysis (PSHA) And in National Seismic Hazard maps that are basic data for seismic design 4

6 NGA projects Three separate NGA projects: For active crustal EQs (like California, Japan, Turkey, Taiwan, ): NGA-West Stable continental regions (like central & eastern US, a good portion of Europe, South Africa, ): NGA-East For subduction EQs (like Pacific Northwest and northern California, Japan, Chile, Peru, ): NGA-Sub 5

7 NGA projects Three separate NGA projects: For active crustal EQs (like California, Japan, Turkey, Taiwan, ): NGA-West Stable continental regions (like central & eastern US, a good portion of Europe, South Africa, ): NGA-East For subduction EQs (like Pacific Northwest and northern California, Japan, Chile, Peru, ): NGA-Sub 6

8 In all NGA projects We develop databases of empirical and simulated ground motion data Databases are public Researchers and practitioners use databases continuously Highly collaborative and teamwork research among researchers and practitioners For example for NGA-West2, 32 people worked on the project For NGA-East, 55 people worked on the project 7

9 NGA-West Shallow Crustal Earthquakes 8

10 NGA-West1 (Original NGA Project) Initiated October 2003 A very comprehensive database of ground motions recorded in shallow crustal earthquakes in active tectonic regions was compiled Numerous supporting research studies were also carried out Finished in 2008 The US National Hazard Maps adopted the models for the 2008 edition of the maps NGA-West2 was a follow-up of NGA-West1 9

11 NGA-West2 database 10

12 Update worldwide database 11

13 Update worldwide database 12

14 Update worldwide database 13

15 Update worldwide database NGA-West2 database includes over 21,000 three-component recordings (over 63,000 records) From NGA-West1 to NGA-West2 the size of database was increased by a factor of 6 14

16 It is a worldwide database 15 Source: Ancheta, et al. (2014)

17 NGA-West2 GMMs for horizontal motion Five teams of GMM developers worked interactively and developed five GMPEs for horizontal components Abrahamson-Silva-Kamai (ASK team) Boore-Stewart-Seyhan-Atkinson (BSSA) Campbell-Bozorgnia (CB) Chiou-Youngs (CY) Idriss (I) 16

18 NGA-Subduction 17

19 NGA-Sub database NGA-Subduction is a large multidisciplinary, multi-year research program to develop database and ground motion models (GMMs) for subduction-zone earthquakes The database currently includes 60,376 three-component recordings 181,128 records Most of recordings are from digital instruments 18

20 NGA-Sub database The database spans: 743 worldwide earthquakes Magnitudes from 4 to 9 Interface, Intraslab ( slab ) classifications Finite-fault models have been collected for about 80 earthquakes 19

21 A typical subduction zone Forearc Backarc Interface EQs Slab EQs (Source: USGS) 20

22 NGA-Sub ground motion The database includes: Pseudo-spectral acceleration response spectra (PSA) for periods: sec For 11 damping values between 0.5% and 30% Fourier amplitude spectra (FAS) for frequencies from 0.1 to 100 Hz Significant durations based on Arias Intensity 21

23 NGA-Sub database: Event distribution Database includes events since early 1970s to present, including recent significant earthquakes: 2010 Maule, Chile 2011 Tohoku, Japan Database includes more data than all previously compiled databases (e.g. BCHydro 2016) 22

24 NGA-Sub: Database distribution Japan and Taiwan provide the largest number of records South/Central America is the region with the largest number of subduction events Most of events have moment magnitude Some smaller events (M < 5.0) have M S, m b and M L 23

25 NGA-Sub database: Event distribution BCHydro data 24

26 NGA-Sub database: Event distribution 25

27 NGA-Sub database: Data sources Recorded time series were obtained from regional and global networks Processed following PEER comprehensive data processing method Region Japan Taiwan Pacific Northwest Alaska South/ Central America Data Source Agencies K-NET, KiK-net, PARI, JMA, NOAA, Hi-net CWB, IES CESMD, COSMOS, IRIS, NSMP, NCEDC, GSC CESMD, COSMOS, IRIS, GSC CESMD, COSMOS, NOAA, IRIS, GFZ, RENADIC, CSN, CISMID, NORSAR, Other regional networks 26

28 NGA-Sub database: Magnitude vs Distance 2011 Tohoku, Japan 2010 Maule, Chile Taiwan Alaska Pacific Northwest 27

29 Hypocentral Depth Distribution 2011 Tohoku, Japan 2010 Maule, Chile South /Central America events 28

30 Recordings Distribution 29

31 Events Distribution 30

32 Magnitude Distribution 31

33 Interface/Slab Distribution 32

34 A typical subduction zone Forearc Backarc Interface EQs Slab EQs (Source: USGS) 33

35 5,520 recoding stations 34

36 Backarc and Forearc distribution 35

37 Example of Time Series and Durations 2011 M9.0 Tohoku, Japan 1989 M6.9 Loma Prieta (crustal EQ) PEER Subduction Database 36

38 Example of Time Series and Durations 2010 M8.8 Maule, Chile 1989 M6.9 Loma Prieta 10/xx/2016 PEER Subduction Database 37

39 Duration Ground motion durations in large subduction events can be very long Their effects on nonlinear structural and geotechnical responses are being investigated 38

40 Status of NGA-Subduction The database is being finalized Ground motion modeling by different teams is on-going Ground motion simulations for deep slab events will be carried out to understand the scaling issues and uncertainty The plan is to complete the project by Fall 2017 In near future, time series of about 500 records will be released to the public via 39 an Internet search engine

41 Summary NGA-Sub database is the largest database of subduction events Ground motions have been uniformly processed Includes over 181,128 records, and 743 worldwide earthquakes Metadada are being compiled: Magnitude, distances, Vs30,... Ground motion data include: PSA for periods sec, at 11 damping values FAS AI Duration 40

42 Summary (cont d) Database includes: Interface Slab Ground motion modelers are developing GMMs for subduction events Database and models will be completed by Fall

43 THANK YOU! Questions? 42