Transcript Chiou_overview.ppt

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)
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
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 50th 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
http://peer.berkeley.edu/nga/search.html
– 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