Neotectonics in Earthquake Evaluation

Here is a new, state-of-the-art guide for assessing earthquake sources throughout the contiguous United States. Because the relevant literature on the geological aspects of earthquake assessment has become so extensive in recent years, scientists should welcome this timely and compact group of new, useful syntheses of current knowledge addressing recent developments in the principal seismically active regions of the United States: the Pacific Coast; the western mountain area; the New Madrid area; New England; and the southeastern United States, including Charleston, South Carolina. Among the contributors are researchers who have made notable contributions to the art in their own right, making this an especially valuable new tool.
Seismic-hazard assessment in the central United States
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Published:January 01, 1990
Abstract
Problems with and approaches to seismic-hazard estimation in the midcontinent of the United States are evaluated by using recent data on stress regime, crustal age and structure, and seismicity of other stable continental regions. Evaluating earthquake hazard in the central U.S. is difficult because of the lack of identifiable seismogenic faults and because of the low rate of seismic activity. Furthermore, the recurrence intervals of large earthquakes are poorly known, in part because of the short historical record that spans only a fraction of the repeat times of these quakes. The seismotectonic regime of the central U.S. is dominated by the Reelfoot rift complex and the associated New Madrid, Missouri, seismic zone. However, there are other major tectonic structures in the region such as the Nemaha ridge, the Midcontinent rift system, and the Wichita-Ouachita orogenic belt; earthquakes generating damaging ground motion (approximately magnitude 5.0 or greater) have occurred in the states of Ohio, Illinois, Oklahoma, Texas, Kansas, Nebraska, Kentucky, Alabama, and Arkansas, as well as Missouri. Opinions vary widely about the best way to delineate seismic source zones in such a diffuse and varied seismotectonic environment. Moreover, detailed paleoseismic or neo-tectonic data that could improve hazard assessments are extremely sparse in the central United States. The Meers fault scarp in southwestern Oklahoma, with its evidence for Holocene displacement and its lack of background seismicity, highlights a new set of assessment problems. Development of site-specific probabilistic hazard curves are further hampered by the lack of strong ground-motion data and high-resolution attenuation data. We address aspects of the overall seismic-hazard assessment problem for which neotectonic information provides constraints. These include a seismic source zonation for the central U.S. and estimates of maximum possible earthquakes for these zones, especially for the New Madrid region.
- crust
- displacements
- earthquakes
- engineering geology
- geologic hazards
- ground motion
- magnitude
- Midcontinent
- Mississippi Valley
- neotectonics
- New Madrid region
- Reelfoot Rift
- seismic zoning
- seismicity
- seismotectonics
- stress
- tectonics
- United States
- central United States
- Meers fault scarp
- Wichita-Ouachita orogenic belt