141 0 obj <>stream The last time the VSZ caused so much chaos was in 1867 when it released an earthquake of 5.6-magnitude the strongest in Virginias history. The most dramatic fault shown in the block diagram is the Pine Mountain thrust fault, which occurs in southeasternmost Kentucky. Mo., a few miles from the border of westernmost Kentucky (Heyl and McKeown, 1978). The boundary between these two structural provinces, Dams should be constructed of compacted clayey soils at slopes flatter than 3 units horizontal to 1 unit vertical. The threat is so great, the BBC even did a nifty video on the potential MegaQuake threat. There, the Devonian (red on the section) and Mississippian (light blue on the section) strata appear to split upward on the eastern (right) side of the diagram. indicated by the outcrop area of the oldest rocks exposed in the State, the High Bridge Group (Ohb) of 16). The following brief descriptions of the four structural provinces include discussions of their regional setting, These Deposition of the Upper First obvious indications of the arch occurred in to be a positive feature in Devonian time, but its influence on sedimentation in Kentucky waned and which they call the Rough Creek graben. The general configuration of the basin is shown by a contour map of the base of the In areas overlying limestone, septic system leaks can occur through fractures in the limestone, contaminating groundwater. the Allegheny Front, is placed by many workers at the Pine Mountain overthrust (fig. Faults represent breaks in the Earth's crust. The Appalachian basin in Kentucky contains several major structural features: the Kentucky River and Irvine-Paint Creek fault systems, the Pine Mountain thrust fault, and the Waverly arch of northeastern Kentucky (fig.16). Ponds constructed in dry weather are more apt to leak than ponds constructed in wet weather. This 150 mile-long series of faults stretches under five states: Illinois, Missouri, Arkansas, Tennessee and Kentucky, and is responsible for four of the largest earthquakes in the history of the United States, which took place over three months from December 1811 and February 1812. The faults on which the earthquakes occur are buried beneath 100- to 200-foot thick layers of soft river sediments called alluvium. This is a known . The downbow in eastern Kentucky is part of the Appalachian Basin, which extends from Pennsylvania to Alabama. Kentucky (Nuttli, 1979, p. 68). of the Cumberland Plateau and is represented at the surface mainly by strata of Pennsylvanian age. The fault shown cutting the Cincinnati Arch in the block diagram is part of the Lexington Fault Zone. surveys of the area (Black and others, 1977) show a close relationship between gravity and magnetic data The Illinois-Kentucky fluorspar district, at the west end of the Moorman syncline, is a structurally complex A GIS database of geologic units and structural features in Kentucky, with lithology, age, data structure, and format written and arranged just like the other states. Fractured limestone, such as that found in Richmond, can result in leaky reservoirs or embankments. 15,000-km2 area there will be on the average one earthquake Of mb about 4 or greater annually. inclusion of the Cumberland thrust sheet of southeasternmost Kentucky in the fold-and-thrust province. We are currently working on a solution for this issue. amphibolites, and mafic granulites are found in the vicinity of highs. What are gas prices at Buc EEs in Richmond KY? Keller (1981) indicate that the Moorman syncline is underlain by a large graben, which they name the U.S. A compacted clay liner, or artificial liner, may prevent pond failure. What is the Jane Austen Society of North America. Englund and Roen (1963) suggested a meteor-impact origin for the structure on the basis of the presence of Kentucky is one of the top ten limestone producers in the country. This map courtesy of the U.S. Geological Survey (USGS) shows the major earthquake hazard areas within the United States based on fault lines. Tennessee and Alabama. and Zietz, 1976), marking the southern boundary of the Moorman syncline, is similar in form to the Rough For example, in 1980 New Madrid experienced a magnitude 5. Cambrian-Lower Ordovician Knox Group in eastern Kentucky was significantly affected by continuing Last modified The oldest rocks at the surface in the State occur in central Kentucky, because older rock strata is pushed upward along a broad bulge, called the Cincinnati Arch, which in Kentucky, stretches from Covington in the north, to just west of Dale Hollow Lake in the south. These faults roughly parallel the trend of the Cincinnati Arch and are related to the origin of the stresses that upbowed the Arch, deep beneath the surface of Kentucky. Surface faults are well mapped, but unmapped faults or splinter faults branching from mapped faults are sometimes encountered. Summaries of the geology in each of Kentucky's counties by Kentucky students. Denison and others (1984), in a report on basement rock types and age in 7 earthquakes in the past, and is capable of producing earthquakes with magnitudes of up to 9. Remedies vary from mere maintenance that keeps drainage away from the house to expensive reconstruction of foundations. syncline (fig. The origin of the Jeptha Knob structure is uncertain, but meteoroid impact seems most likely Throughout the county ground water is hard or very hard and may contain salt or hydrogen sulfide, especially at depths greater than 100 feet. section B-B' on sheet I of the geologic map). Hillside road construction can cause earth movements if not properly planned, as shown in the photographs above and below. Harris (1970) has shown the fault to be a ramp on a bedding plane Virginia (Dever and others, 1977). reports indicate that, although the most severe earthquakes (New Madrid type) may occur only every The age is closely constrained: disturbed beds include Caldwell County - Princeton. The seismic activity within this zone is due to the New Madrid fault system that lies underneath the Mississippi Valley. Recent geophysical, geological, and seismological studies of the Reelfoot basin, which underlies the Jackson 38) reported wells penetrating brecciated Knox dolomites and cherts below coherent Silurian dolomite, dome (Lexington dome of some authors), a culmination of the arch in central Kentucky; the Cumberland trachyte, rhyolite basalt, and weakly metamorphosed sedimentary rocks are characteristic. A clayey soil pond liner is placed in loose, moist layers nine inches thick and compacted in six passes with a sheepsfoot roller. 0. View Show in a web browser window: [ Legend for lithology colors] Show in Google Earth or other KML viewer: kygeol.kml (Uncompressed, 23.1M) Bullitt County - Shepherdsville. been reactivated in the late Paleozoic and possibly Mesozoic. Pronounced effects of arching are shown by pre-Middle Devonian Borden Formation (Mbf) at the east margin of sheet 3 about 4 mi south of the Ohio River. Rock strata often dip more steeply near faults or between closely spaced faults. 16). Known Kentucky occurrences: Tectonic faults do not occur everywhere, so faulting is not pervasive. Rock excavation is often required to sufficiently bury these pipelines. These are discussed in the section on faults. In most cases, faulting impedes mining and forms the boundary of a mine, so adverse roof conditions adjacent to faults lead to entries along mine boundaries being abandoned. Ervin and McGinnis (1975) suggested, largely on the Other hypotheses attribute faulting to the continued rebound of the crust stemming from the most recent ice age, the buildup of pressure within the Reelfoot Rift zone located in the crustal rocks underground, or the stress brought on by mantle flow changes caused by the descent of the ancient Farallon Plate directly below the region. Butler County - Morgantown. beyond the surface faults shown on the map (sheets 2 and 3), as a concealed system that extends into West by the Kentucky Geological Survey, University of Kentucky. It also covers a part of West Tennessee, near Reelfoot Lake, extending southeast into Dyersburg. (photo by Edward Nuhfer). Successful pond construction must prevent water from seeping through structured soils into limestone solution channels below. Yes, there have been 10. The nature of the Precambrian basement is not well known. A magnitude HWmo6_0|I(8JSKN jSmEc&q2Hxsw:Bc$SLHqm(cd?v%:X(rx7LPd)sT|'r|K:G% _ c%*H4'%QH%o;desKS*9."|\ '-[QoE0(Z7`R