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Alaska Hazard Maps, 1999

This page contains probabilistic seismic hazard maps for Alaska and accompanying documentation. Eight maps are presented: peak ground acceleration and 5-HZ, 3-HZ and 1-HZ spectral acceleration (5% damping), each at 10%-and 2%-in-fifty-years probability of exceedance.

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MAPS [Documentation] [Gridded Values] [ GIS maps, data, and metadata]

Spectral Acceleration (%g) Probability of Exceedance in 50 Years
2% 10%
Peak Ground Acceleration [GIFss | GIF | PDF | PS] [GIFss | GIF | PDF | PS]
0.2 Second [GIFss | GIF | PDF | PS] [GIFss | GIF | PDF | PS]
0.3 Second [GIFss | GIF | PDF | PS] [GIFss | GIF | PDF | PS]
1.0 Second [GIFss | GIF | PDF | PS] [GIFss | GIF | PDF | PS]

DOCUMENTATION [Maps] [ Gridded Values] [ GIS maps, data, and metadata]
Probabilistic Seismic Hazard Maps of Alaska by Robert L. Wesson, Arthur D. Frankel, Charles S. Mueller, and Stephen C. Harmsen, Open-File Report 99-36. PDF, HTML

Figure 1 Instrumental seismicity of Alaska and the Aleutian Islands from the consolidated catalogs. Earthquakes show have magnitudes, Mw>=5.5 and dates ranging from 1880 to 1996. (Mueller et al., 1998). [GIF | PDF | PS]
Figure 2 Rupture areas of large earthquakes in the Alaska Aleutian region during this century (Plafker et al., 1993). Note that virtually the entire boundary between the Pacific and North American Plates has ruptured during this period with the exceptions of 1) the western most Aleutians (~168°E), 2) the Shumagin gap (~160°W), and 3) the Yakataga gap (~142°W). See text for discussion. [GIF | PDF]
Figure 3 Hazard Model for Alaska. [PDF]
Figure 4 Segmentation Model I for the Alaska-Aleutian Megathrust [GIF | PDF | PS]
Figure 5 Segmentation Model II for the Alaska-Aleutian Megathrust [GIF | PDF | PS]
Figure 6 Active Crustal faults identified in Alaska (Plafker et al., 1993). [GIF | PDF]
Figure 7a Peak ground acceleration (%g) with 10% probability of exceedance in 50 years. [GIF | PDF | PS]
Figure 7b Peak ground acceleration (%g) with 2% probability of exceedance in 50 years. [GIF | PDF | PS]
Figure 8a 5 Hz acceleration (%g) with 10% probability of exceedance in 50 years. [GIF | PDF | PS]
Figure 8b 5 Hz acceleration (%g) with 2% probability of exceedance in 50 years. [GIF | PDF | PS]
Figure 9a 3.3 Hz acceleration (%g) with 10% probability of exceedance in 50 years. [GIF | PDF | PS]
Figure 9b 3.3 Hz acceleration (%g) with 2% probability of exceedance in 50 years. [GIF | PDF | PS]
Figure 10a 1 Hz acceleration (%g) with 10% probability of exceedance in 50 years. [GIF | PDF | PS]
Figure 10b 1 Hz acceleration (%g) with 2% probability of exceedance in 50 years. [GIF | PDF | PS]
Figure 11a Disaggregation of hazard at Anchorage for peak ground acceleration at 2%-in-50 year probability. [GIF | PDF | PS]
Figure 11b Disaggregation of hazard at Anchorage for 5 Hz ground acceleration at 2%-in-50 year probability. [GIF | PDF | PS]
Figure 11c Disaggregation of hazard at Anchorage for 1 Hz ground acceleration at 2%-in-50 year probability. [GIF | PDF | PS]
Figure 12a Disaggregation of hazard at Fairbanks for peak ground acceleration at 2%-in-50 year probability. [GIF | PDF | PS]
Figure 12b Disaggregation of hazard at Fairbanks for 5 Hz ground acceleration at 2%-in-50 year probability. [GIF | PDF | PS]
Figure 12c Disaggregation of hazard at Fairbanks for 1 Hz ground acceleration at 2%-in-50 year probability. [GIF | PDF | PS]
Figure 13a Disaggregation of hazard at Juneau for peak ground acceleration at 2%-in-50 year probability. [GIF | PDF | PS]
Figure 13b Disaggregation of hazard at Juneau for 5 Hz ground acceleration at 2%-in-50 year probability. [GIF | PDF | PS]
Figure 13c Disaggregation of hazard at Juneau for 1 Hz ground acceleration at 2%-in-50 year probability. [GIF | PDF | PS]
Table 1, Characteristics of active faults assumed for hazard analysis. PDF, HTML
Table 2, Attenuation models assumed for various seismic sources assumed for hazard analysis. PDF, HTML
Table 3, Comparison of peak ground acceleration for selected locations in Alaska between the current maps and those prepared by Thenhaus et al. (1985). PDF, HTML

GRIDDED VALUES [Maps] [ Documentation] [ GIS maps, data, and metadata]

These data are also available via ftp -
see GENERAL:Anonymous FTP
ASCII files of gridded points used to make maps - lon, lat, value
(%g)
(PE = probability of exceedance,
PGA = peak ground acceleration,
SA = spectral acceleration)
File sizes = approximately 8 Mb each
PGA with 10% PE in 50 yrs 0.3 sec SA with 10% PE in 50 yrs
PGA with 2% PE in 50 yrs 0.3 sec SA with 2% PE in 50 yrs
0.2 sec SA with 10% PE in 50 yrs 1.0 sec SA with 10% PE in 50 yrs
0.2 sec SA with 2% PE in 50 yrs 1.0 sec SA with 2% PE in 50 yrs

Although these maps and data have been used by the U.S. Geological Survey, no warranty, expressed or implied is made by the USGS as to the accuracy of the maps and related material nor shall the fact of distribution constitute any such warranty, and no responsibility is assumed by the USGS in connection therewith.