NGA-Subduction site database - eScholarship

16 th World Conference on Earthquake Engineering, 16WCEE 2017 Santiago Chile, January 9th to 13th 2017 Paper N° 4926 Registration Code: S-X1463264880 NGA-SUBDUCTION SITE DATABASE S.K. Ahdi (1) , T.D. Ancheta (2) , V. Contreras (3) , T. Kishida (4) , D.Y. Kwak (5) , A.O. Kwok (6) , G.A. Parker (7) , Y. Bozorgnia (8) , J.P. Stewart (9) Graduate Student, Civil & Environmental Engineering Department, University of California, Los Angeles, USA, sahdi@ucla.edu Modeler, Risk Management Solutions, Inc., tim.ancheta@rms.com Graduate Student, Civil & Environmental Engineering Department, UCLA, USA, vcontreras@ucla.edu Assistant Project Scientist, University of California, Berkeley, USA, tkishida@berkeley.edu Postdoctoral Scholar, Civil & Environmental Engineering Department, UCLA, USA, dykwak@seas.ucla.edu Assistant Professor, National Taiwan University, Taiwan, annieonleikwok@ntu.edu.tw Graduate Student, Civil & Environmental Engineering Department, UCLA, USA, parker@seas.ucla.edu Professor in Residence, University of California, Berkeley, USA, yousef@berkeley.edu Professor and Chair, Civil & Environmental Engineering Department, UCLA, USA, jstewart@seas.ucla.edu Abstract The NGA-Subduction site database, which is currently in development, contains information on site condition and instrument housing for 5520 strong motion stations with recordings that are being used for ground motion model development. The stations are from coastal and inland regions that have recorded subduction zone earthquakes (both interface and intra-slab), mostly in Japan, Taiwan, South America, and the Pacific Northwest and Alaska regions of North America. The principal site parameter is the time-averaged shear wave velocity in the upper 30 m (V S30 ), which we characterize using geophysical measurements where available (approximately 2486 stations to date) and proxy-based relationships otherwise. A secondary site parameter is basin depth, measured both to the 1.0 and 2.5 km/s shear-wave velocity horizons. Here we document the geophysical data sources that have been leveraged in this process and regional considerations regarding the use of proxies to estimate V S30 . We also describe data sources for basin depth and the protocols for assigning V S30 and its uncertainty to strong motion recording sites. Keywords: Shear-wave velocity, site effects, ground motions, subduction zones