C. Guney Olgun Department of Civil and Environmental Engineering, Virginia Tech Thomas A. Barham, Morgan A. Eddy, Mark Tilashalski, Martin C. Chapman, Adrian Rodriguez-Marek GSA 2015 Baltimore, Maryland 3 November 2015 Seismic Hazard Mapping of the National Capital Region Using Random Field Models
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C. Guney Olgun Department of Civil and Environmental Engineering, Virginia Tech Thomas A. Barham, Morgan A. Eddy, Mark Tilashalski, Martin C. Chapman,
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C. Guney OlgunDepartment of Civil and Environmental Engineering,
Virginia Tech
Thomas A. Barham, Morgan A. Eddy, Mark Tilashalski,
Martin C. Chapman, Adrian Rodriguez-Marek
GSA 2015Baltimore, Maryland3 November 2015
Seismic Hazard Mapping of the National Capital Region Using Random Field
Models
2011 Mineral Virginia Earthquake
M5.8 Earthquake occurred August 23, 2011 at 1:51pm
Light to moderate damage in DC area, about 130 km away
Regional geological conditions contributed to significant soil amplification
PGA for DC area estimated 0.02-0.03g on rock and 0.06g at soil sites
Structural Damage in the Area
National Park Service
M.A. Eddy
Atlantic Coastal Plain Geology
(Ator et al. 2005)
Regional geology along the Atlantic coastal plain area dominated by several physiographic provinces
Shallow soils over rock (Piedmont, Fall Line)
Deep tertiary and cretaceous marine deposits over rock (Coastal Plain)
Sharp impedance contrasts between different geologic units (residual, young alluvial, tertiary and cretaceous marine, rock)
Washington D.C. Geology
Idealized Subsurface Cross-section for Washington, D.C.0 2 4 km
Horizontal
Legend
Alluvial Soil
Potomac Formation
Residual Soil
Weathered Rock
Rock
Piedmont Fall Line Coastal Plain
Meters
Vertical0
50
100
0 500 1000 1500 20000
10
20
30
40
50
60 Vs (m/s)
Dep
th (
m)
Weathered Rock
Residual
1
0 400 800 1200 16000
20
40
60
80
100 Vs (m/s)
Dep
th (
m)
Alluvial
Potomac Formation
3
1. Piedmont 2. F
all L
ine
3. Coastal Plain
0 500 1000 1500 20000
10
20
30
40
50
60 Vs (m/s)
Dep
th (
m)
2
Alluvial
Residual
Weathered Rock
Investigation of Subsurface Geology
38.84
38.88
39.00
38.96
38.92
-76.97
-77.05
-77.13
-77.09
-77.01Longitud
e
Lati
tud
e
Subsurface profiles from about 600 geotechnical investigations
Shear wave velocity profiles from 122 investigations
Artificial neural network (ANN) analysis of the geological profile in the area