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EERI Seminar on Next Generation Attenuation Models
Updated MCER & MCEG Ground Motions in 2015 NEHRP Provisions
(& ASCE/SEI 7-16)
2016 ASCE Geotechnical & Structural Engineering Congress
Nicolas Luco Research Structural Engineer, USGS (Golden, CO)
BSSC PUC Design Mapping Issue Team (“IT-11”) (Bachman, Crouse, Harris, Hooper, Kircher, Caldwell)
EERI Seminar on Next Generation Attenuation Models
ASCE/SEI 7-10
“Recent Changes to Peak Ground Accelerations in the ASCE/SEI 7 Standard,” N. Luco (USGS) February 15, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
ASCE/SEI 7-10
“Recent Changes to Peak Ground Accelerations in the ASCE/SEI 7 Standard,” N. Luco (USGS) February 15, 2016
FIGURE 22-7 MAXIMUM CONSIDERED EARTHQUAKE GEOMETRIC MEAN (MCEG) PGA …, SITE CLASS B …
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
Outline of this presentation
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
• Updates to MCER (& MCEG) maps for conterminous US for 2015 NEHRP Provisions (and ASCE 7-16)
• Comparisons with values from ASCE 7-10
• Comparisons with previous editions of ASCE 7-05 and ASCE 7-02/7-98
• Impacts on Seismic Design Categories
• Updates to MCER (& MCEG) maps for Guam, the Northern Mariana Islands, and American Samoa
• Summary
EERI Seminar on Next Generation Attenuation Models
2) Fragility curve β = 0.8 β = 0.6, for consistency with the site-specific ground motion chapter (Ch. 21) of ASCE 7-10
Reasons for Updated Design Maps
1) 2014 USGS National Seismic Hazard Model (including NGA-West2, UCERF3, CEUS-SSC)
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
10-1
100
101
0
0.1
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0.6
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0.8
0.9
1
Spectral Acceleration (1.0 sec), a [g]
P [
Col
laps
e | S
A =
a ]
β = 0.8β = 0.6
EERI Seminar on Next Generation Attenuation Models
USGS Hazard Model Updates
“Proposed seismic maps for the conterminous United States,” N. Luco, USGS et al September 17, 2015
American Society of Civil Engineers 7-16 Standard (ASCE 7-16) Main Committee Webinar
•
• Others listed in Chapter 22 Commentary and explained in December 2015 Special Issue of Earthquake Spectra journal
Project Name Lead(s) Duration Sponsors Central & Eastern US Seismic Source Characterization for Nuclear Facilities (CEUS-SSC)
Consultants 2008-2011
US DOE, EPRI, US NRC
Uniform California Earthquake Rupture Forecast, Version 3 (UCERF3)
USGS, CGS, SCEC (WGCEP)
2010-2013
CEA
Next Generation Attenuation Relations for Western US, Version 2 (NGA-West2)
PEER 2010-2013
CEA, Caltrans, PG&E
EERI Seminar on Next Generation Attenuation Models
Fragility β=0.8 β=0.6 Update
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
• For 2009 NEHRP Provisions MCER ground motions & site-specific ground motion chapter (Ch. 21), the BSSC Seismic Design Procedures Reassessment Group settled on β = 0.8
• For 2010 ASCE 7 Standard Ch. 21 (but not MCER maps), the Seismic Subcommittee (SSC) Ad-Hoc Ground Motion Committee updated to β = 0.6, based on …
EERI Seminar on Next Generation Attenuation Models
Changes at 34 High-Risk Locations
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
Name Latitude Longitude Name Population
Los Angeles 34.05 -118.25Century City 34.05 -118.40Northridge 34.20 -118.55Long Beach 33.80 -118.20Irvine 33.65 -117.80 Orange 3,002,048Riverside 33.95 -117.40 Riverside 2,026,803San Bernardino 34.10 -117.30 San Bernardino 1,999,332San Luis Obispo 35.30 -120.65 San Luis Obispo 257,005San Diego 32.70 -117.15 San Diego 2,941,454Santa Barbara 34.45 -119.70 Santa Barbara 400,335Ventura 34.30 -119.30 Ventura 799,720
22,349,098 Population - 8 Counties 21,374,778Oakland 37.80 -122.25 Alameda 1,502,759Concord 37.95 -122.00 Contra Costa 955,810Monterey 36.60 -121.90 Monterey 421,333Sacramento 38.60 -121.50 Sacramento 1,233,449San Francisco 37.75 -122.40 San Francisco 776,733San Mateo 37.55 -122.30 San Mateo 741,444San Jose 37.35 -121.90 Santa Clara 1,802,328Santa Cruz 36.95 -122.05 Santa Cruz 275,359Vallejo 38.10 -122.25 Solano 423,473Santa Rosa 38.45 -122.70 Sonoma 489,290
14,108,451 Population - 10 Counties 8,621,978
Total Population - S. California
RegionCity and Location of Site County or Metropolitan Statistical Area
9,948,081Los AngelesN
orth
ern
Cal
iforn
iaSo
uthe
rn C
alifo
rnia
Total Population - N. California …
EERI Seminar on Next Generation Attenuation Models
Changes at 34 High-Risk Locations
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
Name Latitude Longitude Name Population
RegionCity and Location of Site County or Metropolitan Statistical Area
Seattle 47.60 -122.30 King WA 1,826,732Tacoma 47.25 -122.45 Pierce WA 766,878Everett 48.00 -122.20 Snohomish WA 669,887Portland 45.50 -122.65 Portland Metro OR (3) 1,523,690
10,096,556 Population - 6 Counties 4,787,187Salt Lake City 40.75 -111.90 Salt Lake UT 978,701Boise 43.60 -116.20 Ada/Canyon ID (2) 532,337Reno 39.55 -119.80 Washoe NV 396,428Las Vegas 36.20 -115.15 Clarke NV 1,777,539
6,512,057 Population - 5 Counties 3,685,005St. Louis 38.60 -90.20 St. Louis MSA (16) 2,786,728Memphis 35.15 -90.05 Memphis MSA (8) 1,269,108Charleston 32.80 -79.95 Charleston MSA (3) 603,178Chicago 41.85 -87.65 Chicago MSA (7) 9,505,748New York 40.75 -74.00 New York MSA (23) 18,747,320
48,340,918 Population - 57 Counties 32,912,082
Total Population - ID/UT/NV
Total Population - MO/TN/SC/IL/NY
CEU
SO
ther
WU
SPa
cific
N
orth
wes
t
Total Population - OR and WA
…
EERI Seminar on Next Generation Attenuation Models
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
34 City Locations from 2009 Provisions
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1718 19 20 21 22 23 24 25 2627 28 29 30 31 32 33 340.6
0.7
0.8
0.9
1
1.1
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City Location #
Prop
osed
÷ A
SCE
7-1
0 G
roun
d M
otio
n
Southern California Northern California PacNW IMW CEUS
SS (MCER)
S1 (MCER)
PGA (MCEG)
Changes in MCER & MCEG Values
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
San
ta B
arba
ra
Las
Vega
s
Irvin
e
San
Die
go
Cha
rlest
on
EERI Seminar on Next Generation Attenuation Models
Underlying Components of SS and S1
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
• As laid out in the 2009 NEHRP Provisions (& Ch. 21) … …
SS = min( CRS SSUH, SSD )
S1 = min( CR1 S1UH, S1D )
EERI Seminar on Next Generation Attenuation Models
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1718 19 20 21 22 23 24 25 2627 28 29 30 31 32 33 340.6
0.7
0.8
0.9
1
1.1
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1.7
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City Location #
Prop
osed
÷ A
SCE
7-1
0 G
roun
d M
otio
n
Southern California Northern California PacNW IMW CEUS
SSUHS1UH"PGAUH"
Changes in USGS Uniform-Hazard Values
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
Las
Vega
s
San
ta B
arba
ra
San
Die
go
EERI Seminar on Next Generation Attenuation Models
Changes at Las Vegas Location
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
• In ASCE 7-10 maps, rate of earthquakes on Eglington fault is ~1/14,000yrs.
• Based on recent publications (references in dePolo et al, 2013), …
• Nevada Bureau of Mines & Geology recommended, in effect, a rate of ~1/600yrs.
• Through additional communication with USGS, all agreed on ~1/2,100yrs.
EERI Seminar on Next Generation Attenuation Models
Changes at Santa Barbara Location
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
• ASCE 7-10 maps are based on UCERF2 in California.
• UCERF3 includes more multi-fault earthquakes (like 2011 M7.2 El Mayor-Cucapah), in part to remove UCERF2 over-prediction of M6.5-7 earthquakes.
• This, in effect, lowers rate of earthquakes that dominate hazard in Santa Barbara.
• ASCE 7-10 maps are based on NGA-West1 for Western U.S. crustal earthquakes.
• NGA-West2 includes recent data from 2009 M6.3 L’Aquila, 2008 M7.9 Wenchuan & 5 other earthquakes on dipping faults, as well as 130,000 ground motion simulations.
• The effect was to decrease best estimates of ground motions over reverse faults near Santa Barbara.
EERI Seminar on Next Generation Attenuation Models
Commentary on Additional Changes
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1718 19 20 21 22 23 24 25 2627 28 29 30 31 32 33 340.6
0.7
0.8
0.9
1
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City Location #
Prop
osed
÷ A
SCE
7-1
0 R
isk C
oeffi
cien
t
Southern California Northern California PacNW IMW CEUS
CRS
CR1
Changes in Risk Coefficients
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
Changes in Deterministic Values
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1718 19 20 21 22 23 24 25 2627 28 29 30 31 32 33 340.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
City Location #
Prop
osed
÷ A
SCE
7-1
0 G
roun
d M
otio
n
Southern California Northern California PacNW IMW CEUS
SSDS1D"PGAD"
EERI Seminar on Next Generation Attenuation Models
• UCERF3 includes multi-fault ruptures (M8+), in part to remove UCERF2 overprediction of M6.5-7 earthquakes.
Deterministic Earthquakes
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
• UCERF3 also includes low-activity-rate faults, e.g., …
Deterministic Earthquakes
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
From ASCE 7-10 site-specific ground motion chapter (Ch. 21):
Deterministic Earthquakes
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
• For 2015 NEHRP Provisions, characteristic earthquakes from UCERF2 (& ASCE 7-10) have been updated and used in lieu of UCERF3 multi-fault ruptures, and …
• “Active” faults have been defined as those with Holocene (last ~12K years) displacement/slip, or with slip rate > 0.1 mm/year. All other faults have been excluded.
EERI Seminar on Next Generation Attenuation Models
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1718 19 20 21 22 23 24 25 2627 28 29 30 31 32 33 340.6
0.7
0.8
0.9
1
1.1
1.2
1.3
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City Location #
Gro
und
Mot
ion
Rat
io
Southern California Northern California PacNW IMW CEUS
ASCE 7-10 ÷ ASCE 7-05 , SS
ASCE 7-10 ÷ ASCE 7-05 , S1
ASCE 7-05 ÷ ASCE 7-98 , SS
ASCE 7-05 ÷ ASCE 7-98 , S1
Previous Changes in MCE(R) Values
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
Precision vs. Uncertainty
ASCE 7 Edition
2000 2005 2010 2015
Spe
ctra
l Res
pons
e A
ccel
erat
ion,
g
0.5
1
1.5
2
2.5
Santa Barbara
SS
S1
ASCE 7 Edition
2000 2005 2010 2015S
pect
ral R
espo
nse
Acc
eler
atio
n,
g
0.5
1
1.5
2
2.5
Ventura
SS
S1
EERI Seminar on Next Generation Attenuation Models
Changes in Seismic Design Categories
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
Default Site Class
Seismic DesignCategory (SDC)
A
B
C
D
E
EERI Seminar on Next Generation Attenuation Models
SDC changes
B → C
C → B
Changes in Seismic Design Categories
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
Default Site Class
EERI Seminar on Next Generation Attenuation Models
Changes in Seismic Design Categories
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
Default Site Class
SDC changes
D → E
E → D
EERI Seminar on Next Generation Attenuation Models
Deeper Explanations of Changes
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
Guam & Tutuila in ASCE 7-10
“New Design Ground Motions in 2015 NEHRP Provisions …,” N. Luco (USGS) & IT-11 November 13, 2015
2015 COSMOS Technical Session: Current Ground-Motion Design Value Maps – Issues & Proposed Solutions
EERI Seminar on Next Generation Attenuation Models
USGS Hazard Model for Guam
“New Design Ground Motions in 2015 NEHRP Provisions …,” N. Luco (USGS) & IT-11 November 13, 2015
2015 COSMOS Technical Session: Current Ground-Motion Design Value Maps – Issues & Proposed Solutions
EERI Seminar on Next Generation Attenuation Models
USGS Hazard Model for Tutuila
“New Design Ground Motions in 2015 NEHRP Provisions …,” N. Luco (USGS) & IT-11 November 13, 2015
2015 COSMOS Technical Session: Current Ground-Motion Design Value Maps – Issues & Proposed Solutions
EERI Seminar on Next Generation Attenuation Models
MCER Maps for 2015 Provisions
“New Design Ground Motions in 2015 NEHRP Provisions …,” N. Luco (USGS) & IT-11 November 13, 2015
2015 COSMOS Technical Session: Current Ground-Motion Design Value Maps – Issues & Proposed Solutions
13°
14°
15°
16°
13°
14°
15°
16°
Northern Mariana Islands
Guam
200
150
125
100908070
6070 80
100
125
150
90
200
200.2
250.6
288.6
243.9
13°
14°
15°
16°
13°
14°
15°
16°
Northern Mariana Islands
Guam 2530
4050
60
72.3
1.0 Second Spectral Response Acceleration(5% of Critical Damping)
0.2 Second Spectral Response Acceleration(5% of Critical Damping)
100 0 100 200 Miles
100 0 100 200 Kilometers
. SS = 287%g
. SS = 176%g
. S1 = 72%g
. S1 = 44%g
EERI Seminar on Next Generation Attenuation Models
MCER Maps for 2015 Provisions
“New Design Ground Motions in 2015 NEHRP Provisions …,” N. Luco (USGS) & IT-11 November 13, 2015
2015 COSMOS Technical Session: Current Ground-Motion Design Value Maps – Issues & Proposed Solutions
OfuOlosega
Ta'u
Tutuila
Aunu'u
SwainsIsland
RoseAtoll
AmericanSamoa
172° 171° 170° 169° 168°
15°
14°
13°
12°
11°
15°
14°
13°
12°
11°
125
10090
8070
6050
40
35
30
60
50
40
2520
15
10
5
0.2 Second Spectral Response Acceleration (5% of Critical Damping)
OfuOlosega
Ta'u
Tutuila
Aunu'u
SwainsIsland
RoseAtoll
AmericanSamoa
172° 171° 170° 169° 168°
15°
14°
13°
12°
11°
5°
4°
3°
2°
1°
50
40
3025
20
15
10
8
6
415
2
15
1.0 Second Spectral Response Acceleration (5% of Critical Damping)
. SS = 40%g . S1 = 15%g
EERI Seminar on Next Generation Attenuation Models
2015 Provisions Ch. 22 Commentary
“New Design Ground Motions in 2015 NEHRP Provisions …,” N. Luco (USGS) & IT-11 November 13, 2015
2015 COSMOS Technical Session: Current Ground-Motion Design Value Maps – Issues & Proposed Solutions
… In comparing the MCER ground motion maps derived from these USGS hazard models to the geographically-constant values stipulated for Guam and American Samoa (Tutuila) in the 2010 and previous editions of ASCE/SEI 7, it is important to bear in mind that the latter were not computed via seismic hazard modeling. According to the commentary of the 1997 Provisions, the geographically-constant values were merely conversions, via rough approximations, from values on the 1994 Provisions maps that had been in use for nearly 20 years. As such, they did not take into account the 1993 Guam earthquake that was the largest ever recorded in the region and caused considerable damage, the 2009 earthquake near American Samoa that caused a tsunami, nor the 2008 “Next Generation Attenuation (NGA)” and another 2006 empirical ground motion prediction equation that have now been used for both Guam/NMI and American Samoa. …
EERI Seminar on Next Generation Attenuation Models
Summary
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
• Conterminous US updates include (i) 2014 USGS NSHM, (ii) β=0.6, and (iii) definition of “active faults” for deterministic ground motions.
• Amongst 34 high-risk locations, 9/10-ths of design map changes are within +/-20%, 2/3-rds are within +/-10%.
• Most of the >20% changes are due to significant USGS hazard model updates.
• Seismic Design Categories change in relatively small areas, mostly at relatively low-risk locations.
• Uncertainty in design ground motions desired for perspective.
EERI Seminar on Next Generation Attenuation Models
Updated Design Maps Web Tool
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
http://earthquake.usgs.gov/designmaps/beta/us/
EERI Seminar on Next Generation Attenuation Models
Risk-Targeted Ground Motion Calculator
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
Bonus Slides …
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
Changes in Seismic Design Categories
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
EERI Seminar on Next Generation Attenuation Models
Changes in Seismic Design Categories
“Updated MCER and MCEG Ground Motions in 2015 NEHRP Provisions,” N. Luco (USGS) et al February 14, 2016
2016 ASCE Geotechnical & Structural Engineering Congress: Course on “… 2015 NEHRP Provisions”
Site Class B
SDC changes
B → C
C → B