NGA Dataset
Brian Chiou
NGA Workshop #5
March 24, 2004
• NGA data released on November 2003
• Accomplishments since November 2003
• Schedule for the 2nd release
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
– 101503.cat (catalog of recordings)
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)
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
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
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
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
ChiChi & Aftershocks
4
5
6
7
8
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
1000
800
600
0
200
400
Counts
Data used for Extensional
Regime
4
5
6
Magnitude
7
8
90
Strike-Slip Earthquakes
80
Data in Somerville et al. 1997
NGA Dataset
70
degrees)
60
50
40
30
20
10
0
0
0.2
0.4
0.6
Length Ratio (X)
0.8
1
Improved Consistency
5
4
Ratio (J-B/ClstD)
• Closest Distance
to Fault vs.
Joyner-Boore
Distance
(Current PEER
database)
3
2
1
0
0.1
1
10
100
Closest Distance to Fault (km)
1000
Improved Consistency
5
4
Ratio (J-B/ClstD)
• Closest Distance
to Fault vs.
Joyner-Boore
Distance (NGA
dataset)
3
2
1
0
0.1
1
10
100
Closest Distance to Fault (km)
1000
II. Accomplishments Since
November 2003
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
• In progress
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
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
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
Recent Work on Source-Path
Metadata
• 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)
• In progress (PEER-LL)
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
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)
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
Recent Work on Site Metadata
Alaska (Denali earthquake)
– Donald Wells (Geomatrix)
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)
Schedule
• Second release of NGA dataset: April 23