Database of Ground Motions
For NGA East
A Presentation by Chris Cramer
at the Stakeholder NGA East Workshop
NIST Gaithersburg, MD
March 7, 2008
Overview
• Goal
• Previous Work
• Tasks
• Summary
Goal
Develop a database of Stable Continental
Region ground motions from Eastern
North America and around the world for
a broad range of geologic site
conditions for use in developing Next
Generation Attenuation (NGA) relations
that compliment the recently developed
PEER Center Active Tectonic Region
NGA relations.
Key
Gather representative ground motion and
geologic data for thin and thick soil
conditions over hard rock, as well as
hard rock sites, from Stable Continental
Regions worldwide.
Previous Work
Databases (Not Data Sources)
• LDEO/NCEER StrongMo Database
– Online, Searchable, Waveforms available
– Only pre-1990 (not actively maintained or added to)
• Atkinson and Boore, 2006 Electronic Supplement
– Table
– Hard Rock, Eastern Canada Only
• PEER NGA Database
– Online, Searchable, Waveforms available
– Parameter Table Available for Attenuation Relation
Developers
– Active Tectonic Regions Only
No Stable Continental Region
Database Available
• Needed Parameters for NGA
Development
• Current
• Worldwide
• Accessible Online
Tasks
General Steps
• Database Design
• Data Gathering
• Data Processing
• Data Simulation*
• Data Distribution
Database Design
• Based on PEER NGA Model:
– Database of Waveforms and Metadata (Station,
Earthquake, Record, Geology, etc. information)
– Parameter Flat File for Developers (i.e., PGA,
PGV, PGD, Sa at 102 periods, and earthquake,
station, seismological, and geotechical
information)
• Input from NGA East Participants (November
29, 2007 Workshop) and colleagues (2007
ES-SSA and Fall AGU meetings)
Data Gathering
• Geotechnical Data
– General Geology (Q, T, M, etc.)
– Regional Information (reference Vs
profiles, depth-to-bedrock)
– Site-Specific Profiles
• Available Profiles (Memphis, Charleston, St.
Louis, Evansville, some owners)
• Measurements at Important Stations*
Data Gathering
• Waveforms (Broadband and
Accelerometer) [Largest M down to M3]
– Eastern North America
•
•
•
•
IRIS Data Center
Canadian National Data Center
LDEO/NCEER StrongMo Database
Others (CERI, COSMOS, etc.)
– International*
• Europe
• India (some data at CERI, COSMOS)
• Australia
Data Processing
• Develop Processing and Quality Control
Standards and Procedures with aid of Advisory
Committee
–
–
–
–
Instrument Correction, Waveform Filtering
Acceleration, Velocity, Displacement
Response and Fourier Spectra
Extraction of Specified Parameters (Seismological and
Geotechnical)
• Apply to gathered data and load results into
database and then flat file for NGA East
developers
Data Simulation
• Extend database to be sure needed site
conditions (Vs30s), distances, and
magnitudes are represented for NGA
East relation development*
Data Distribution
• Flat file to NGA East developers
• Website for access to ground motion
database and flat file*
Summary
Conclusions
• Development of a Stable Continental Regions
database of ground motions for
representative site conditions is crucial for the
development of NGA relations for central and
eastern US as none is currently available.
• National and international support and
cooperation will be required for successful
development of this NGA East database.