Overview of NGA Database, Model Development to Date, and Next Steps PEER-NGA Workshop April 12, 2005

NGA Database Overview 173 earthquakes ~ 1600 strong-motion stations 3547 recordings

NGA Database Overview Metadata –Earthquake Source Basic source parameters (hypocenter, magnitude, strike, dip, rake, ….. Finite source parameters (fault length and width) –Distance measures –Footwall/hanging –Directivity parameters –Recording Site Site location, owner, Station ID number, geology, …… Soil condition –Geomatrix’s classifications –Vs30 (measured or inferred)

Previous Data New EQ Data - Kobe - Kocaeli - ChiChi - Duzce - Hector Mine - Denali

NGA Database Overview Ground Motion Data –Processed time histories (baseline corrected and filtered) –Rotation to strike-normal and strike-parallel directions – Ave. horizontal component at random orientation Defined as the 50 th percentile value of the geometric mean over the non-redundant 90 degree range of rotation (Dave Boore, 2005) –Time histories and response spectra

NGA Database Overview Flatfile –A table of selected metadata and response spectra –New version of flatfile in mid March Ave. horizontal component with random orientation Fault normal and fault parallel components Closest distance to the seismogenic zone

NGA Database Overview NGA data on PEER’s web site (Debra Bartling) –Prototype on –For trial use Searchable Content of flatfile Time history data file –Documentation will be added later –Feedbacks to PEER

Model Development Preliminary model for PGA and pseudo spectral acceleration at 0.1, 0.2, 0.5, 1, and 3 seconds –Changes since last December Chance to give developers feedbacks before models are finalized

Next Steps Workshop #9, September 21, 2005 –Final NGA models for Ave. horizontal component, with directivity effect Strike-normal and strike-parallel components USGS ground motion workshop (October 2005) –Reviews and discussions of NGA models