Project Title/ID Number Checking and Augmentation of NGA Database—1L09
Start/End Dates 5/1/03 – 4/30/04
Project Leader Nancy Collins (URS Corporation/I)
Team Members Paul Somerville (URS/I), Robert Graves (URS/I), Carla Willis (URS/I)

F=faculty; GS=graduate student; US=undergraduate student; PD=post-doc; I=industrial collaborator; O=other

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1. Project Goals/Objectives:

Review of the NGA database including earthquake source parameters, station distance and directivity parameters, orientation of recorded components, and station locations and other items as may be deemed pertinent. Addition to the database of depth to Vs isosurfaces; basin outlines at the ground surface; other basin parameters that more fully describe the geometric relation of source, basin, and site; and a flag indicating shallow vs. deep asperities of fault models. Calculate residuals of 3D basin simulations with respect to the Abrahamson and Silva (1997) model.

2. Role of this project in supporting PEER’s mission (vision):

The NGA attenuation relations will be used widely in engineering practice to develop seismic design criteria.

3. Methodology Employed:

Review of literature and both the URS and the COSMOS strong motion databases and calculation of parameters as needed.

4. Brief Description of past year’s accomplishments (Year 6) & more detail on expected Year 7 accomplishments:

To date we have reviewed the magnitudes of major earthquakes in the database and documented references used. Finite fault models have been checked in detail for 9 complex earthquakes and, to a less detailed extent, for 19 others, and results entered in the database. Correctness of the calculation of closest distance and component orientation has been checked. Basin depth information has been added to the flat file.

5. Other Similar Work Being Conducted Within and Outside PEER and How This Project Differs:

This work supports the data base development being done by Pacific Engineering and Analysis.

6. Plans for Year 8 if project is expected to be continued:


7. Describe any actual instances where you are aware your results have been used in industry:

When completed, the NGA ground motion models will be used widely in industry.

8. Expected Milestones & Deliverables:

Review of the database will be completed by April 16, 2004.

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