1. NGA Dataset
Brian Chiou
NGA Workshop #5
March 24, 2004

2. NGA data released on November 2003
Accomplishments since November 2003
Schedule for the 2nd release

3. Data Released (11/15/2003) 172 earthquakes
~ 1600 strong-motion stations
Information of earthquakes and stations (metadata) (compiled by PE&A)
MasterEQ_V009 (include finite fault models for 62 earthquakes)
SourceScaling_ALL_V008
NGA_Site_V015
cat (catalog of recordings)
Three are listed in EQ_Master, but ground-motion parameters were not collected yet. These earthquakes are:

4. Data Released (11/15/2003) A total of 3524 recordings
~ 7,000 (horizontal) response spectra files
Data flatfile (Version 1)
85 columns of metadata
102 columns of ground-motion parameters
PGA, PGV, PGD
LP, HP
5%-damped pseudo spectral accelerations (0.01sec to 10 sec) (97 periods)

8. Improved Data Coverage
Pre-NGA
EQID: 1 – 127 (1994 Northridge)
Total number of recordings = 1079
NGA
EQID: 1 – 175
Total number of recordings = 3524
Total number of ChiChi data = 1812

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

10. Histogram of Recordings - Distance

11. Histogram of Recordings - Mw

12. ChiChi & Aftershocks
NEHRP-A
NEHRP-B
Category
Missing
NEHRP-C
NEHRP-D
NEHRP-E

13. Data used for Extensional
Regime

14. Strike-Slip Earthquakes
Data in Somerville et al. 1997
NGA Dataset

15. Improved Consistency
Closest Distance to Fault vs. Joyner-Boore Distance (Current PEER database)

16. Improved Consistency
Closest Distance to Fault vs. Joyner-Boore Distance (NGA dataset)

17. II. Accomplishments Since November 2003

18. Reviews of Source-Path Metadata
PI: URS (Nancy Collins/Paul Somerville)
Progress (February 19, 2004)
Check calculations of distances
Completed; and they are computed correctly
Check calculations of directivity parameters
In progress
Review finite fault models used for calculations of distances and directivity parameters

19. Reviews of Source-Path Metadata
Source-path metadata: URS (Nancy Collins/Paul Somerville) (continued)
Review earthquake magnitude and uncertainty
Check the component orientation and other station data
In progress

20. Reviews of Site Metadata
PI: Donald Wells, Geomatrix
Check, for each station,
Station instrument setting classifications
Consistency between different site classifications
Update/Add site metadata
Data from Stewart/Yoojoong
Alaska stations data
Active Link to CISN Station Data web page (CISN EDC) for most CSMIP stations

21. Evaluations of Ground-Motion Parameters
PI: Walt Silva/Bob Darragh/Nick Gregor (PE&A)
PEER-COSMOS joint working group meeting (March 17, 2004)
Meeting summary: next presentation

22. Recent Work on Source-Path Metadata
Shallow vs. deep asperity event
Completed (Paul Somerville, URS)
For 18 earthquakes
Data for the isochrone-directivity model proposed by Spudich
In progress (PEER-LL)
Closest distance to the seismogenic portion of the rupture (as defined by Campbell)

23. Recent Work on Source-Path Metadata
Slip rate of causative fault
Completed (by USGS/Golden)
For 21 California earthquakes
Slip rate used in seismic hazard mapping project

24. Recent Work on Metadata
Basin depth information
N. Cal (USGS, Menlo Park)
In progress
Imperial Valley and Mendocino
Completed (Rob Graves, URS)
Shallow depth information (Bray’s definition)
Completed (Kevin Cohen, CGS)

25. Recent Work on Site Metadata
Vs30
California Strong Motion Sites
From SASW measurements at 60 sites (Rob Kayen, USGS)
Taiwan (ChiChi and aftershocks)
From SASW measurements at 38 Sites
26 sites by Prof. Stokoe, UT;
10 sites by Prof. Ni, NCKU, Taiwan
From P-S loggings at ~ 110 Sites (NCREE; Vs30 computed by Bob Nigbor, USC)
More 2002 drilling results

26. Recent Work on Site Metadata
Alaska (Denali earthquake)
Donald Wells (Geomatrix)

27. Recent Development of Ground Motion Parameters
Strike-normal, strike-parallel, and vertical components
In progress
Usable bandwidth for spectral accelerations
PEER
Data provider (CGS/USGS)
PGA, PGV & PGD from data provider
Uncorrected (Vol. 1) & corrected (Vol. 2) PGA (CGS/USGS)
Errata (PE&A)

28. Schedule
Second release of NGA dataset: April 23