Evansville Area Earthquake Hazard Map Workshop
June 11, 2003
Participants introduced themselves.
What already has been done?
John Hill opened by describing what data they’ve collected at the Indian
Geological Survey. Geologic maps have been completed
for the Evansville North, Evansville South, Newburgh, and Daylight quads. These incorporate information from driller and gamma
logs and ~30-35 shear wave velocity profiles (although concentrated mostly
in two quads). All the information collected has been put into a GIS format
(ArcView 3.x project file with accompanying metadata, shape files, and data
tables for shear wave velocities and soil periods) and distributed on CD
to a number of people.
John Keifer noted that geologic maps exist for the entire state of Kentucky, but these focus on bedrock geology and not surficial materials.
Jennifer Haase and colleagues at Purdue have installed
and run the USGS National Seismic Hazard mapping software at Purdue, in preparation
for doing their own calculations.
Future data gathering and analysis activities already planned.
Dave Moore and Rich Harrison will be doing geologic mapping
in the area during FY04.
The Indiana Geological Survey has a GPR unit that could be used for future mapping.
The Indiana DOT has a CPT truck with shear velocity profiling capabilities that could be used. Geotechnical logs have not been collected from private and public sources, but certainly could be collected.
The Kentucky Geological Survey is planning to start surficial mapping, starting with the Henderson, West Franklin, Wilson, and South Evansville quads. Two people will be assigned to work on this full-time. Shear wave velocity profiles exist for the Henderson quad.
It was emphasized that Indiana and Kentucky geologic mapping needs to be closely coordinated, in insure that units are mapped similarly, etc.
What next?
Chris Cramer emphasized that critical information of the hazard calculations
are maps of depth to basement and shear wave velocities of the surficial materials
and basement (i.e. impedance contrasts).
Roger Lehman noted that DRC has a multi-hazard focus.
Peter Lyttle emphasized that the USGS Cooperative National mapping program was committed to working on this hazard mapping effort.
There was a clear consensus that liquefaction maps should be produced.
Consistency with National hazard maps and other urban hazard maps also was emphasized.
The group decided that the next meeting would be in Evansville sometime in late August or early September, with the larger group forming breakout groups focused on different aspects of producing hazard maps. The meeting would largely focus on technical issues, but not exclusively.
All participants at this
meeting (June 11th) would send a list to Buddy or Joan containing
the names of potential participants, their likely level of involvement, expertise,
contact information, and resources they would need/bring.
A ‘working group’ was identified,
tasked with drafting a straw man plan (Rich Harrison, John Keifer, John Hill,
Dick Berg, Joan Gomberg, Chris Cramer, Buddy Schweig, and Jennifer Haase). This plan would be distributed before the next meeting,
as a basis for discussion at the meeting. Joan and Chris will get the process
started and see that the straw man plan is complete enough to distribute before
the next meeting.