The New Madrid earthquakes
Stephen F. Obermeier
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The New Madrid earthquakes
Published
1989
Publisher
U.S. G.P.O.
Pages
114
Description
Earthquake-induced sand blows and sand-filled fissures are present in a belt 40 to 60 km. wide that extends from near Charleston, Mo., southward to about 20 km. south of Marked Tree, Ark. This region of earthquake-induced sand blows and other liquefaction-related features is almost exclusively in the St. Francis Basin, an alluvial lowland that typically has a thin (2 to 8 m thick), clay-bearing topstratum underlain by about 30 to 60 m of unconsolidated sand (the substratum). Liquefaction of the substratum sands has made the sand blows. The sand blows and other liquefaction-related features on the ground surface in the St. Francis Basin are almost certainly results of the New Madrid earthquakes of 1811-12.^ In this report, geologic and engineering properties of the alluvium are used in combination with a map showing the bounds of the liquefaction-related features to locate approximately the epicentral zones for two of the major shocks: the earthquakes of December 16,1811, and February 7,1812. Properties used for the analysis included the Standard Penetration Resistance of the substratum sands, characteristics of the sand's grain size, thickness of the topstratum, and the thickness of the post-Tertiary alluvium. The method of analysis relies largely on the evaluation of the liquefaction potential of the sands. This is done by using the Standard Penetration Test blow counts and by devising a method that uses all possible combinations of liquefaction potential and a realistic relation between attenuation of earthquake accelerations and distance from the epicenter (or more correctly, energy-release center).^ Two interpreted 1811-12 energy-release centers generally agree well with zones of seismicity defined by modern, small earthquakes. Bounds on accelerations are placed at the limits of sand blows that were generated by the 1811-12 earthquakes in the St. Francis Basin. Conclusions show how the topstratum thickness, sand size of the substratum, and thickness of alluvium affected the distribution of sand blows in the St. Francis Basin.
Frequently Asked Questions
How many pages are in The New Madrid earthquakes?
This edition of The New Madrid earthquakes has approximately 114 pages. Please note, this is an estimate and the exact page count can vary between hardcover, paperback, and e-book versions.
How long does it take to read The New Madrid earthquakes?
For most readers, The New Madrid earthquakes typically takes between 2h 23m and 1h 35m to complete. This is based on the book's length of approximately 28,500 words and common reading speeds.
Here's a detailed breakdown: • Continuous reading at 250 WPM: approximately 1h 54m of focused reading • Casual reading (30 minutes/day): you could finish in roughly 4 days • Estimated word count: 28,500 words
Your individual reading time will vary based on your personal reading pace, the amount of daily reading time, and your familiarity with the subject matter.
What is the word count of The New Madrid earthquakes?
The estimated word count for The New Madrid earthquakes is approximately 28,500 words. This figure is calculated using industry-standard methods that consider genre-specific word density patterns, typical formatting and layout characteristics, and standard words-per-page ratios for published books.
This is an approximation — actual word count may vary based on font size, formatting, edition, and the presence of illustrations or charts.
Who is the author of The New Madrid earthquakes?
The New Madrid earthquakes was written by Stephen F. Obermeier.
When was The New Madrid earthquakes published?
The publication date for this specific edition is 1989. The original work may have been published on a different date.