NGA Dataset
Brian Chiou
NGA Workshop
July 19, 2004
• Version 1 - November 2003
• Version 2 – June 04, 2004
– Used for preliminary data analysis
• Version 3 – August, 2004
– Final
NGA Data Set
Flatfile
– MasterEQ_V012 (include finite
fault models for 62 earthquakes)
– SourceScaling_ALL_V012
– NGA_Site_V017
– 060104.cat (catalog of
recordings)
– ……
Status of Data (07/15/2004)
• 173 earthquakes
• ~ 1600 strong-motion stations
• 3547 recordings
– 22 more records
•
•
•
•
•
16 USGS records (Stevens and Boore, USGS), Loma Prieta
3 records from Stone Canyon (Event 0139)
Hector, Hector Mine earthquake
Jensen Filter Plant Generator Bldg, Northridge earthquake
TCU088 of ChiChi
Data Coverage
• Pre-NGA
– EQID: 1 – 127 (1994 Northridge)
– Total number of recordings = 1079
• NGA
– EQID: 1 – 175
– Total number of recordings = 3547
– Total number of ChiChi data = 1812
8
Previous Data
New EQ Data
- Kobe
- Kocaeli
- ChiChi
- Duzce
- Hector Mine
- Denali
Magnitude
7
6
5
4
0.1
1
10
Distance (km)
100
1000
0
200
400
Counts
600
800
1000
Histogram of Recordings - Distance
-1
0
1
Log10(Distance)
2
3
0
200
400
Counts
600
800
1000
Histogram of Recordings - Mw
4
5
6
Magnitude
7
8
1000
800
600
0
200
400
Counts
Data used for Extensional
Regime
4
5
6
Magnitude
7
8
Recent Improvement on SourcePath Metadata
• Isochrone-directivity parameters (USGS
Open File Report)

m5 , c~, R, D
Recent Improvement on Site
Metadata
California/Nevada
Review & revision of Geomatrix 3-letters
classification (D. Wells, Geomatrix Consultants
Inc.)
Alaska (Denali earthquake)
– Geomatrix 3-letters classification (D. Wells,
Geomatrix Consultants Inc.)
Recent Improvement on Site
Metadata
• Vs30
Taiwan (ChiChi and aftershocks)
– Measured Vs30 at 125 Sites (NCREE’s P-S
logging)
– Geomatrix 3-letters classification (D. Wells,
Geomatrix Consultants Inc.)
– Inferred Vs30
ChiChi & Aftershocks
4
5
6
7
8
March, 2004
A
B
NEHRP-A
Category
Missing
800
NEHRP-B
600
400
Counts
200
0
800
C
D
E
NEHRP-C
NEHRP-D
NEHRP-E
600
400
200
0
4
5
6
7
8
4
Magnitude
5
6
7
8
5
6
7
8
July, 2004
A
B
NEHRP-A
800
NEHRP-B
600
400
Count
200
0
800
C
D
NEHRP-C
NEHRP-D
E
NEHRP-E
600
400
200
0
5
6
7
8
5
Magnitude
6
7
8
Recent Improvement on Site
Metadata
• Basin depth information
• Z1.5 = depth to the Vs=1.5km/sec isosurface
Bay Areas (J. Boatwright/USGS, Menlo Park)
Los Angels Areas, Imperial Valley, and
Mendocino (Rob Graves, URS/John Stewart,
UCLA)
Development of Ground Motion
Parameters
• Strike-normal, strike-parallel, and vertical
components
– In progress (N. Abrahamson)
• PGA, PGV & PGD from data provider
– Uncorrected (Vol. 1) & corrected (Vol. 2) PGA
(CGS/USGS)
Recent Development of Ground
Motion Metadata
• A simple (and conservative) rule to
determine lowest usable frequency for
spectral accelerations
– Based on several factors: filter type, corner
frequency, instrument type
• A more rigorous rule – D. Boore
0.1
1
10
100
Magnitude: 4.4 to 4.8
Magnitude: 4.8 to 5.2
Magnitude: 5.2 to 5.5
Magnitude: 5.5 to 5.9
Magnitude: 5.9 to 6.3
Magnitude: 6.3 to 6.7
1
0.1
0.01
0.001
PGA (g)
1
0.1
0.01
0.001
Magnitude: 6.7 to 7.1
Magnitude: 7.1 to 7.5
Magnitude: 7.5 to 7.9
1
0.1
0.01
0.001
0.1
1
10
100
0.1
Distance (km)
1
10
100
0.1
1
10
100
Magnitude: 4.4 to 4.8
Magnitude: 4.8 to 5.2
Magnitude: 5.2 to 5.5
Magnitude: 5.5 to 5.9
Magnitude: 5.9 to 6.3
Magnitude: 6.3 to 6.7
1
0.1
0.01
0.001
Sa [T=1Sec]
1
0.1
0.01
0.001
Magnitude: 6.7 to 7.1
Magnitude: 7.1 to 7.5
Magnitude: 7.5 to 7.9
1
0.1
0.01
0.001
0.1
1
10
100
0.1
Distance (km)
1
10
100
0.1
1
10
100
Magnitude: 4.4 to 4.8
Magnitude: 4.8 to 5.2
Magnitude: 5.2 to 5.5
Magnitude: 5.5 to 5.9
Magnitude: 5.9 to 6.3
Magnitude: 6.3 to 6.7
0.1
0.01
Sa [T=3Sec]
0.001
0.1
0.01
0.001
Magnitude: 6.7 to 7.1
Magnitude: 7.1 to 7.5
Magnitude: 7.5 to 7.9
0.1
0.01
0.001
0.1
1
10
100
0.1
Distance (km)
1
10
100
Schedule
• Final release of NGA dataset: early August