j. louie 12/10/2003 using refraction microtremor reconnaissance: rapid surveys take advantage of...
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J. Louie 12/10/2003J. Louie 12/10/2003
Using Refraction Microtremor reconnaissance: Rapid surveys take advantage of urban noise More details at www.seismo.unr.edu/hazsurv
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Surveying Seismic Microzonation in Surveying Seismic Microzonation in Urban AreasUrban Areas
J. Louie 12/10/2003J. Louie 12/10/2003
ReMi measures Rayleigh dispersion with linear refraction arrays (paper by Louie, April 2001 BSSA).
Refraction Microtremor for Shallow Shear VelocityRefraction Microtremor for Shallow Shear Velocity
100-m depth resolution
Initial funding from SCEC, UNR, VUW, Optim LLC
J. Louie 12/10/2003J. Louie 12/10/2003
ReMi has classified hard and soft sites around the world by measuring V30, average shear velocity to 30 m depth.
Refraction Microtremor for Shallow Shear VelocityRefraction Microtremor for Shallow Shear Velocity
J. Louie 12/10/2003J. Louie 12/10/2003
Local reconnaissance was first test.Reno TransectReno Transect
Supported by UNR and IRIS-PASSCAL
J. Louie 12/10/2003J. Louie 12/10/2003
Unexpected results: high V30 in active alluvium.Reno TransectReno Transect
West East
Ta
J. Louie 12/10/2003J. Louie 12/10/2003
Lack of V30 correlation to geologic or soil maps
Reno TransectReno Transect
Only Tertiary Andesite (Ta) shows a characteristic V30
J. Louie 12/10/2003J. Louie 12/10/2003
The First Reno Hazard MapThe First Reno Hazard Map
J. Louie 12/10/2003J. Louie 12/10/2003
July 2003 San Gabriel Valley & Los AngelesShallow Shear-Velocity TransectsShallow Shear-Velocity Transects
B
C
D
E
Transect mapped on NEHRP hazard class map by Wills, from SCEC Phase 3 Report
Supported by USGS, NEHRP ERP and IRIS-PASSCAL
J. Louie 12/10/2003J. Louie 12/10/2003
200 shallow Vs profiles from San Gabriel Riv.
Los Angeles TransectLos Angeles Transect
San Gabriel Mts.are C, not B.
Alamitos Bayis D, not E.
V30 may correlate with hydraulic gradient.
J. Louie 12/10/2003J. Louie 12/10/2003
No V30 correlation with active vs. older alluvium; R2 = 0.2!Los Angeles TransectLos Angeles Transect
J. Louie 12/10/2003J. Louie 12/10/2003
Las Vegas route from Cheyenne to Tropicana
1-km-deep basin
3-km-deep basin
Supported by DOE-LLNL and IRIS-PASSCAL
Shallow Shear-Velocity TransectsShallow Shear-Velocity Transects
J. Louie 12/10/2003J. Louie 12/10/2003
Some correlation to faulting, soil type?Las Vegas TransectLas Vegas Transect
J. Louie 12/10/2003J. Louie 12/10/2003
No correlation between V30 and geologic map.Las Vegas TransectLas Vegas Transect
J. Louie 12/10/2003J. Louie 12/10/2003
Correlation with clay soils, caliche in Las Vegas?Las Vegas TransectLas Vegas Transect
J. Louie 12/10/2003J. Louie 12/10/2003
Shallow section & V100 hint at stratigraphy, faulting?
Las Vegas TransectLas Vegas Transect
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Fault?
Caliche?
J. Louie 12/10/2003J. Louie 12/10/2003
A Preliminary A Preliminary Las Vegas Las Vegas
Hazard MapHazard Map
Transect V30 values correlated with soil-map units across 4 quadrangles in Las Vegas Valley
J. Louie 12/10/2003J. Louie 12/10/2003
Example of public outreach:Discoveries and Breakthroughs Inside Science, news shorts funded by AIP, AGU, etc.
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OutreachOutreach
KFSN-TV Fresno, CAKGBT-TV Harlingen, TXKJTV-TV Lubbock, TXKTRK-TV Houston, TXKNBC-TV Burbank, CAKNSD-TV San Diego, CAKQTV-TV St. Joseph, MOKNTV-TV San Francisco, CAKRQE-TV Albuquerque, NMKTSM-TV El Paso, TXKTVN-TV Reno, NVKWQC-TV Davenport, IAKXAS-TV Fort Worth, TXWAGM-TV Presque Isle, MEWTEN-TV Albany, NYWCAU-TV Philadelphia, PAWCMH-TV Columbus, OHWCYB-TV Bristol, VAWEWS-TV Cleveland, OHWFTS-TV Tampa, FLWLUK-TV Green Bay, WIWBBH-TV Fort Myers, FL
WHIO-TV Dayton, OHWIS-TV Columbia, SCWJAR-TV Cranston, RIWLBT-TV Jackson, MSWMAQ-TV Chicago,ILWNBC-TV New York, NYWNCN-TV Raleigh, NCKTSM-TV Omaha, NEWPBN-TV Traverse City, MIWSYM-TV Lansing, MIWTVJ-TV Miami, FLWVIT-TV Hartford, CTWVTM-TV Birmingham, ALWXYZ-TV Southfield, MIWJXT-TV Jacksonville, FLWTXL-TV Tallahassee, FLWIVT-TV Binghamton, NYWEVV-TV Evansville, INWCJB-TV Gainesville, FLWPXI-TV Pittsburgh, PACHAT-TV Medicine Hat, ALB K. Heineman, NewsProNet, Producers
Technology Transfer: Commercial ReMi is now in use by geotechnical consultants and agencies worldwide.