2017 One‐Year Seismic‐Hazard Forecast for the Central and Eastern United States from Induced and Natural Earthquakes

2017 ◽  
Vol 88 (3) ◽  
pp. 772-783 ◽  
Author(s):  
Mark D. Petersen ◽  
Charles S. Mueller ◽  
Morgan P. Moschetti ◽  
Susan M. Hoover ◽  
Allison M. Shumway ◽  
...  
Author(s):  
Mark D. Petersen ◽  
Charles S. Mueller ◽  
Morgan P. Moschetti ◽  
Susan M. Hoover ◽  
Andrea L. Llenos ◽  
...  

2018 ◽  
Vol 89 (3) ◽  
pp. 1049-1061 ◽  
Author(s):  
Mark D. Petersen ◽  
Charles S. Mueller ◽  
Morgan P. Moschetti ◽  
Susan M. Hoover ◽  
Kenneth S. Rukstales ◽  
...  

2018 ◽  
Author(s):  
Edward M. Brooks ◽  
◽  
Seth Stein ◽  
Bruce D. Spencer ◽  
Leah Salditch ◽  
...  

2019 ◽  
Vol 90 (3) ◽  
pp. 1155-1167 ◽  
Author(s):  
Edward M. Brooks ◽  
James Neely ◽  
Seth Stein ◽  
Bruce D. Spencer ◽  
Leah Salditch

2016 ◽  
Vol 87 (6) ◽  
pp. 1327-1341 ◽  
Author(s):  
Mark D. Petersen ◽  
Charles S. Mueller ◽  
Morgan P. Moschetti ◽  
Susan M. Hoover ◽  
Andrea L. Llenos ◽  
...  

2021 ◽  
Vol 37 (1_suppl) ◽  
pp. 1626-1651
Author(s):  
John E Lens M.EERI ◽  
Mandar M Dewoolkar ◽  
Eric M Hernandez M.EERI

This article describes the approach, methods, and findings of a quantitative analysis of the seismic vulnerability in low-to-moderate seismic hazard regions of the Central and Eastern United States for system-wide assessment of typical multiple span bridges built in the 1950s through the 1960s. There is no national database on the status of seismic vulnerability of bridges, and thus no means to estimate the system-wide damage and retrofit costs for bridges. The study involved 380 nonlinear analyses using actual time-history records matched to four representative low-to-medium hazard target spectra corresponding with peak ground accelerations from approximately 0.06 to 0.3 g. Ground motions were obtained from soft and stiff site seismic classification locations and applied to models of four typical multiple-girder with concrete bent bridges. Multiple-girder bridges are the largest single category, comprising 55% of all multiple span bridges in the United States. Aging and deterioration effects were accounted for using reduced cross-sections representing fully spalled conditions and compared with pristine condition results. The research results indicate that there is an overall low likelihood of significant seismic damage to these typical bridges in such regions, with the caveat that certain bridge features such as more extensive deterioration, large skews, and varied bent heights require bridge-specific analysis. The analysis also excludes potential damage resulting from liquefaction, flow-spreading, or abutment slumping due to weak foundation or abutment soils.


2020 ◽  
Vol 91 (6) ◽  
pp. 3483-3495
Author(s):  
Christine A. Powell ◽  
William A. Thomas ◽  
Robert D. Hatcher

Abstract Specifying the extent and location of rifted, crystalline Precambrian crust in the eastern United States is important for seismic hazard evaluation and for models that relate upper-mantle structure to ancient tectonic features and ongoing tectonism. As currently depicted in the National Seismic Hazard Maps (NSHM), the western limit of Iapetan rifted crust is beneath the Appalachian plateau physiographic province, west of the Valley and Ridge province. New estimates of crustal thickness using EarthScope Transportable Array and other data do not support the presence of rifted crust beneath the Blue Ridge, Valley and Ridge, and Appalachian plateau physiographic provinces. Crustal thicknesses exceed 45 km throughout most of this region. The crust thins to the southeast beneath the southeastern part of the Piedmont physiographic province and is only 36 km thick near the edge of the Atlantic coastal plain. We suggest that the western limit of Iapetan rift-extended crust is east of the Blue Ridge province and is associated with the prominent Appalachian gravity gradient. This location coincides with palinspastic reconstructions based on geologic data for the Iapetan rifted margin. Recognition of thick crust beneath the Blue Ridge and Valley and Ridge provinces, unextended by Iapetan rifting, will support more robust modeling of the effects of mantle structure (such as delamination and abrupt changes in lithospheric thickness) on ongoing tectonism and earthquake activity in the eastern United States and will provide more accurate seismotectonic zonation in the NSHM.


2020 ◽  
Vol 18 (14) ◽  
pp. 6119-6148
Author(s):  
Graeme Weatherill ◽  
Fabrice Cotton

Abstract Regions of low seismicity present a particular challenge for probabilistic seismic hazard analysis when identifying suitable ground motion models (GMMs) and quantifying their epistemic uncertainty. The 2020 European Seismic Hazard Model adopts a scaled backbone approach to characterise this uncertainty for shallow seismicity in Europe, incorporating region-to-region source and attenuation variability based on European strong motion data. This approach, however, may not be suited to stable cratonic region of northeastern Europe (encompassing Finland, Sweden and the Baltic countries), where exploration of various global geophysical datasets reveals that its crustal properties are distinctly different from the rest of Europe, and are instead more closely represented by those of the Central and Eastern United States. Building upon the suite of models developed by the recent NGA East project, we construct a new scaled backbone ground motion model and calibrate its corresponding epistemic uncertainties. The resulting logic tree is shown to provide comparable hazard outcomes to the epistemic uncertainty modelling strategy adopted for the Eastern United States, despite the different approaches taken. Comparison with previous GMM selections for northeastern Europe, however, highlights key differences in short period accelerations resulting from new assumptions regarding the characteristics of the reference rock and its influence on site amplification.


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