34.7

18.3 8.2

4.6

4.1

4.7

3.4

11.2

8.1

31.1

19.0

11.3

13.6

10.7

14.7

24.7

20.6

6.8

5.9

5.1

10.1

10.6

12.9

11.7

12.7

10.2

19.5

4.7

6.6

13.3

19.2

18.7

2.6 4.8

4.3

5.2

6.5

3.2 3.8

3.9

3.9

2.4

4.3

1.4

1.3

2.3

2.7

3.2

5.4

1.3

1.5

2.6 2.2

6.5

6.4

6.7

5.9

18.9

11.8

3.8

1.6

2.6

2.2

5.7

5.9

20.4

5.1

4.6

7.6

3.3

6.0

3.5

2.3

6.2

5.6

6.2

16.2

16.8

14.0

2

6

60

40

3

5

5

2

25

15

2

25

30

20

15

10

8

7

6

5

4

3

2

30

10

7

5

4

3

40

20

15

10

7

5

4

10

7

6

5

4

3

2

1

1

15

9

8

7

6

15

10

9

8

7

6

8

7

2

8

6

5

25

20

15

8

7

6

5

9

7

6

3

40

60

40

30

25

20

25

8

7

6

5

9

7

5

4

8

6

60

30

7

6

5

4

3

2

1

10

9

7

40

20

15

10

9

8

7

5

6

4

7

6

20

15

10

9

15

25

10

9

25

9

5

6

15

20

30

40

15

15

60

25

15

6

10

25

4

3

2

5

6

3

4

30

30

25

25

20

40

25

40

25

5

5

25

4

3

40

1

2

3

60

40

4

10

20

8

9

9

10

20

80

20

40

20

60

60

4

15

9

7

60

8

7

40

10

10

20

15

9

6

2

30

30

9

60

40

3

30

30

25

9

8

10

8

9

30

30

30 25

25

20

25

20

20

20

7

5

80

60

60

4

9

7

40

30

30

9

10

6

8

20

3

40

1

30

2

25

40

20

10

7

5

4

3

2

1

6

80

30

20

15

20

25

9

3

3

10

30

5

4

2

1

20

40

25

20

2

25

30

40

20

1

CANADA

MEXICO

 125° 120° 115° 110° 105° 100° 95° 90° 85° 80° 75° 70° 65°

 115° 110° 105° 100° 95° 90° 85° 80° 75°

 25°

 30°

 35°

 40°

 45° 45°

 40°

 35°

 30°

 25°

50°

 50°

Digital data prepared with ArcGIS 10.1 running under Windows 7

100 0 100 200 300 400 500 600 700 800 900 1000 MILES

100 0 100 200 300 400 500 600 700 800 900 1000 KILOMETERS

SCALE 1:7 000 000

Seismic-Hazard Maps for the Conterminous United States, 2014

Peak Horizontal Acceleration with 10 Percent Probability of Exceedance in 50 Years

By

Mark D. Petersen,1

 Morgan P. Moschetti,1 Peter M. Powers,

1

 Charles S. Mueller,1 Kathleen M. Haller,1Arthur D. Frankel,

1 Yuehua Zeng,1 Sanaz Rezaeian,1 

Stephen C. Harmsen,

1 Oliver S. Boyd,1 Edward H. Field,1 Rui Chen,2 Nicolas Luco,1

Russell L. Wheeler,

1 Robert A. Williams,1

 Anna H. Olsen,1 and Kenneth S. Rukstales1

2015

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. 

Government.

Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as 

noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

This database, identified as SIM 3325, has been approved for release and publication by the U.S. Geological Survey 

(USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS 

reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition 

that neither the USGS nor the U.S. Government may be held liable for any damages resulting from its authorized or 

unauthorized use.

Suggested citation: Petersen, M.D., Moschetti, M.P., Powers, P.M., Mueller, 

C.S., Haller, K.M., Frankel, A.D., Zeng, Yuehua, Rezaeian, Sanaz, Harmsen, 

S.C., Boyd, O.S., Field, E.H., Chen, Rui, Luco, Nicolas, Wheeler, R.L., 

Williams, R.A., Olsen, A.H., and Rukstales, K.S., 2015, Seismic-hazard maps 

for the conterminous United States, 2014: U.S. Geological Survey Scientific 

Investigations Map 3325, 6 sheets, scale 1: 7,000,000,

http://dx.doi.org/10.3133/sim3325.

 

ISSN 2329-132X (online)

http://dx.doi.org/10.3133/sim3325

This and other USGS information products are available at

http://store.usgs.gov/. 

U.S. Geological Survey

Box 25286, Denver Federal Center

Denver, CO 80225

To learn about the USGS and its information products visit

http://www.usgs.gov/. 

1-888-ASK-USGS

This report is available at:

http://pubs.usgs.gov/sim/3325/

1

U.S. Geological Survey

2

California Geological Survey, Sacramento, Calif.

Shaded relief base from Esri Inc., 2008, Data and Maps

All other base map data from Esri Inc., 1993, Digital Chart of the World

United States County base map from the U.S. Geological Survey National Atlas, available at http://nationalatlas.gov/

Projection: Albers equal-area conic

Standard parallels 29.5°N. and 45.5°N., central meridian 95°W 

For more information concerning this publication, contact:

Center Director, USGS Geologic Hazards Science Center 

Box 25046, Mail Stop 966

Denver, CO 80225

(303) 273-8579

Or visit the Geologic Hazards Science Center Web site at:

http://geohazards.cr.usgs.gov/. 

Publishing support provided by: 

Denver Publishing Service Center

Edit and digital layout by L.J. Binder

Manuscript approved for publication on April 6, 2015

Gulf of Mexico

ATLANTIC OCEAN

PACIFIC OCEAN

Gulf of

St. Lawrence

EXPLANATION

%g

≥100

80–100

60–80

40–60

30–40

25–30

20–25

15–20

10–15

9–10

Peak acceleration expressed as a percent

of gravity (%g)

8–9

7–8

6–7

5–6

4–5

3–4

2–3

1–2

≤1

Contours of peak acceleration expressed

as a percent of gravity (%g)

10 Onshore

10 Offshore

Point values of peak acceleration

expressed as a percent of gravity (%g)

6.5

Local maximum

2.4

Local minimum

4.3 Saddle point

DISCUSSION

The acceleration values contoured are the random horizontal component. Reference 

site condition is firm rock, defined as having an average shear-wave velocity of 760 m/s in the 

top 30 meters, corresponding to the boundary between NEHRP (National Earthquake Hazards 

Reduction Program) site classes B and C. Documentation, gridded values, interactive maps, 

and GIS data used to make the map are available online at

ttp://earthquake.usgs.gov/hazards or http://dx.doi.org/10.3133/sim3325.

ACKNOWLEDGMENTS

We would like the thank the hundreds of workshop participants who made valuable 

suggestions that significantly improved the quality of the maps. The California part of the 

maps was produced jointly with the California Geological Survey.

REFERENCES

Petersen, M.D., Moschetti, M.P., Powers, P.M., Mueller, C.S., Haller, K.M., Frankel, A.D., 

Zeng, Yuehua, Rezaeian, Sanaz, Harmsen, S.C., Boyd, O.S., Field, Ned, Chen, Rui, 

Rukstales, K.S., Luco, Nico, Wheeler, R.L., Williams, R.A., and Olsen, A.H., 2014, 

Documentation for the 2014 Update of the United States National Seismic Hazard Maps: 

U.S. Geological Survey Open-File Report 2014–1091, 243 p.,

http://dx.doi.org/10.3133/ofr20141091.

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 3325

Sheet 1 of 6