Geophysical elements in identification of seismic source zones, Eastern United States

1985 ◽  
Author(s):  
James G. McWhorter ◽  
Robert B. Herrmann
Keyword(s):  
United States ◽  
Seismic Source ◽  
Eastern United States ◽  
Source Zones

Earthquake Hazard in the Eastern United States: Consequences of Alternative Seismic Source Zones

1987 ◽  
Vol 3 (2) ◽  
pp. 227-261 ◽  
Author(s):  
P. C. Thenhaus ◽  
D. M. Perkins ◽  
S. T. Algermissen ◽  
S. L. Hanson
Keyword(s):  
United States ◽  
South Carolina ◽  
Ground Motion ◽  
Seismic Source ◽  
Source Zone ◽  
Zone Model ◽  
Maximum Magnitude ◽  
Eastern United States ◽  
Thrust Tectonics ◽  
Source Zones

The regional variability in expected ground motion associated with six different characterizations of seismic source zones for probabilistic ground motion assessment is examined for the eastern United States. Three of the seismic source zone models are based on types of geologic structure: (1) regions characterized by late-Precambrian faulting; (2) middle-to-late Paleozoic thrust tectonics; and (3) early-to-middle Mesozoic extensional features. Two other seismic source zone configurations considered are based on data related to vertical crustal movements, and the final source zone model investigated is that of Algermissen and others (1982). Maintaining the same maximum magnitude among all zones and for all source zone configurations, a comparison of results indicates a factor of 3 difference among source zone models for calculated acceleration levels in eastern Massachusetts, southeastern Maine, and the Cape Fear arch of eastern North Carolina; a factor of about 2 or greater difference for most other eastern seaboard areas; and a factor of 1.5 or less for much of the Appalachian region extending from New Brunswick to the Gulf Coast. Results show that certain source zone models based exclusively on speculative geologic hypotheses result in considerably lower ground-motion hazard than otherwise implied by accepting historical seismicity as a guide to future hazard. Significantly, variation in the seismic hazard estimates at probability levels of 1 in 500 due to uncertain earthquake causal structures or processes is considerably higher in the heavily populated northeast region than in the Charleston, South Carolina, area.

scholarly journals Seismic Hazard in the Nation's Breadbasket

2015 ◽  
Vol 31 (1_suppl) ◽  
pp. S109-S130 ◽  
Author(s):  
Oliver Boyd ◽  
Kathleen Haller ◽  
Nico Luco ◽  
Morgan Moschetti ◽  
Charles Mueller ◽  
...  
Keyword(s):  
United States ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Nearest Neighbor ◽  
Seismic Source ◽  
Eastern United States ◽  
Source Characterization ◽  
Nuclear Facilities ◽  
Motion Models ◽  
Ground Motion Models

The USGS National Seismic Hazard Maps were updated in 2014 and included several important changes for the central United States (CUS). Background seismicity sources were improved using a new moment-magnitude-based catalog; a new adaptive, nearest-neighbor smoothing kernel was implemented; and maximum magnitudes for background sources were updated. Areal source zones developed by the Central and Eastern United States Seismic Source Characterization for Nuclear Facilities project were simplified and adopted. The weighting scheme for ground motion models was updated, giving more weight to models with a faster attenuation with distance compared to the previous maps. Overall, hazard changes (2% probability of exceedance in 50 years, across a range of ground-motion frequencies) were smaller than 10% in most of the CUS relative to the 2008 USGS maps despite new ground motion models and their assigned logic tree weights that reduced the probabilistic ground motions by 5–20%.

scholarly journals Central and Eastern United States (CEUS) Seismic Source Characterization (SSC) for Nuclear Facilities Project

2012 ◽  
Author(s):  
Kevin J. Coppersmith ◽  
Lawrence A. Salomone ◽  
Chris W. Fuller ◽  
Laura L. Glaser ◽  
Kathryn L. Hanson ◽  
...  
Keyword(s):  
United States ◽  
Seismic Source ◽  
Eastern United States ◽  
Source Characterization ◽  
Nuclear Facilities
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