Skip Links

USGS - science for a changing world

Open-File Report 2012-1015

Seismic Hazard Assessment for Guam and the Northern Mariana Islands

By Charles S. Mueller, Kathleen M. Haller, Nicholas Luco, Mark D. Petersen, and Arthur D. Frankel

Thumbnail of and link to report PDFAbstract

We present the results of a new probabilistic seismic hazard assessment for Guam and the Northern Mariana Islands. The Mariana island arc has formed in response to northwestward subduction of the Pacific plate beneath the Philippine Sea plate, and this process controls seismic activity in the region. Historical seismicity, the Mariana megathrust, and two crustal faults on Guam were modeled as seismic sources, and ground motions were estimated by using published relations for a firm-rock site condition. Maps of peak ground acceleration, 0.2-second spectral acceleration for 5 percent critical damping, and 1.0-second spectral acceleration for 5 percent critical damping were computed for exceedance probabilities of 2 percent and 10 percent in 50 years.

For 2 percent probability of exceedance in 50 years, probabilistic peak ground acceleration is 0.94 gravitational acceleration at Guam and 0.57 gravitational acceleration at Saipan, 0.2-second spectral acceleration is 2.86 gravitational acceleration at Guam and 1.75 gravitational acceleration at Saipan, and 1.0-second spectral acceleration is 0.61 gravitational acceleration at Guam and 0.37 gravitational acceleration at Saipan.

For 10 percent probability of exceedance in 50 years, probabilistic peak ground acceleration is 0.49 gravitational acceleration at Guam and 0.29 gravitational acceleration at Saipan, 0.2-second spectral acceleration is 1.43 gravitational acceleration at Guam and 0.83 gravitational acceleration at Saipan, and 1.0-second spectral acceleration is 0.30 gravitational acceleration at Guam and 0.18 gravitational acceleration at Saipan.

The dominant hazard source at the islands is upper Benioff-zone seismicity (depth 40–160 kilometers). The large probabilistic ground motions reflect the strong concentrations of this activity below the arc, especially near Guam.

First posted May 3, 2012

For additional information contact:

USGS Geologic Hazards Science Center
Box 25046, MS-966
Denver, CO 80225
geohazards.cr.usgs.gov/

This report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Mueller, C.S., Haller, K.M., Luco, Nicholas, Petersen, M.D., and Frankel, A.D., 2012, Seismic hazard assessment for Guam and the Northern Mariana Islands: U.S. Geological Survey Open-File Report 2012–1015, 52 p.



Contents

Abstract

Introduction

Seismic and Tectonic Setting of Guam and the Northern Mariana Islands

Methodology and Hazard Model

Results and Discussion

Acknowledgments

References Cited

Appendix. Supplementary Data Supporting Mariana Islands Seismic Hazard Analysis


Accessibility FOIA Privacy Policies and Notices

USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://pubs.usgs.gov/of/2012/1015/
Page Contact Information: GS Pubs Web Contact
Page Last Modified: Saturday, January 12, 2013, 03:13:10 PM