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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 55 records · Page 3Linked to original sources
USGS1986

Background hydrologic information in potential lignite mining areas in north-central Mississippi, August 1985

The U.S. Geological Survey, in cooperation with the Mississippi Department of Natural Resources, Bureau of Geology, is conducting a hydrologic data collection program in potential lignite-producing areas in the outcrops of the Wilcox Group in Mississippi. During August 1985, hydrologic data were collected at a total of 15 stream sites in Benton, Lafayette, Marshall, and Union Counties. Main channel widths ranged from approximately 30 feet to 115 feet. Stream depths during low-flow periods were shallow, generally less than 1.0 foot at most sites. Discharges ranged from 0.04 to 74.8 cubic feet per second. The specific conductance of stream water ranged from 28 to 78 microsiemens and dissolved-solids concentrations ranged from 24 to 59 milligrams per liter. Turbidity values were 20 units or less. Chromium and copper concentrations in bottom material samples ranged from below detection limits (1 microgram per gram) to 5 microgram per gram and mercury concentrations ranged from 0.01 to 0.08 microgram per gram. (USGS)

Open-File Report↗
USGS1996

Selected reports of the U.S. Geological Survey on Water Resources in Mississippi, 1990-96

Results of water-resources data-collection programs and interpretive hydrologic studies conducted by the U.S. Geological Survey (USGS) are published in reports and are made available to universities, State and local agencies, other Federal agencies, and the public. The following is a list of selected USGS reports on water resources in Mississippi published since 1990 and categorized according to the major emphasis of the report; these reports are available for inspection at the Mississippi District Office in Pearl, Mississippi.

Mississippi↗
USGS2010

Geomorphology and depositional subenvironments of Gulf Islands National Seashore, Mississippi

The U.S. Geological Survey (USGS) is studying coastal hazards and coastal change to improve our understanding of coastal ecosystems and to develop better capabilities of predicting future coastal change. One approach to understanding the dynamics of coastal systems is to monitor changes in barrier-island subenvironments through time. This involves examining morphological and topographic change at temporal scales ranging from millennia to years and spatial scales ranging from tens of kilometers to meters. Of particular interest are the processes that produce those changes and the determination of whether or not those processes are likely to persist into the future. In these analyses of hazards and change, both natural and anthropogenic influences are considered. Quantifying past magnitudes and rates of coastal change and knowing the principal factors that govern those changes are critical to predicting what changes are likely to occur under different scenarios, such as short-term impacts of extreme storms or long-term impacts of sea-level rise. Gulf Islands National Seashore was selected for detailed mapping of barrier-island morphology and topography because the islands offer a diversity of depositional subenvironments and the islands' areas and positions have changed substantially in historical time. The geomorphologic and subenvironmental maps emphasize the processes that formed the surficial features and also serve as a basis for documenting which subenvironments are relatively stable, such as the beach ridge complex, and those which are highly dynamic, such as the beach and active overwash zones. The primary mapping procedures used supervised functions within a Geographic Information System (GIS) that classified depositional subenvironments and features (map units) and delineated boundaries of the features (shapefiles). The GIS classified units on the basis of tonal patterns of a feature in contrast to adjacent features observed on georeferenced aerial photographs. Land elevations from recent lidar surveys served as supplementary data to assist in delineating the map-unit boundaries.

Mississippi↗
USGS1994

Lateral movement and stability of channel banks near four highway crossings in southwestern Mississippi

Channel meandering in alluvial streams has caused localized channel instability that has resulted in bridge failure and loss of human life in Mississippi. The U.S. Geological Survey, in coopera- tion with the Mississippi Department of Transpor- tation, conducted a study to develop a better methodology for defining and estimating channel meandering. For this report, river reaches near four bridge sites with current lateral movement of channel banks were selected for study. The lateral movement of channel banks was studied by mapping meanders from aerial photographs taken at various times, evaluating available discharge measurements, and measuring existing channel geometry and soil strength properties at these sites. Rapid, unre- stricted meander cuts and sandy banks are charac- teristic of the sites. Lateral movement was signi- ficant upstream from all four sites, and only one bridge site did not have significant lateral channel-bank movement during the study period. The development of cutbanks and localized channel-bank erosion have caused unstable conditions at three of the sites. Maps of tops of channel indicate significant lateral movement of channel banks upstream and downstream of all four sites and near the bridges at three of four sites. No significant movement occurred at the U.S. Highway 98 crossing of the Bogue Chitto near Tylertown from 1941 to 1991 despite large floods in 1983 and 1990. Slope stability analyses indicated this site to be marginally stable. The maximum lateral movement indicated from maps of tops of channel banks was 680 feet of northward movement of the right (north) bank of the Homochitto River near the State Highway 33 crossing at Rosetta from 1941 to 1983.

Mississippi↗
USGS2014

U.S. Geological Survey unconventional petroleum systems research in south Mississippi: Observations on burial history and thermal maturity in the Cretaceous

Shale hydrocarbon ‘resource’ plays have revolutionized the United States energy mix over the last 5 years. These plays are diverse in lithology and age but share the common feature of occurring in ‘tight’ formations which require hydraulic (hydro-) fracturing for economic flow rates. In general, economic success requires an organic-rich reservoir with a quartz- or carbonate-rich mineralogy that responds to artificial stimulation by fracturing. The U.S. Geological Survey (USGS) is tasked with estimating the quantity and quality of undiscovered hydrocarbons reservoired in shales. In support of that mission, we began an investigation of unconventional petroleum systems in the southern part of the Mississippi Salt Basin in 2012, building on earlier reconnaissance work that identified this area as potentially prospective for ‘shale’ gas (Enomoto et al., 2012). While our recent studies (Valentine et al., 2014a; Hackley et al., 2014) have suggested poor ‘shale’ gas prospectivity (due to low organic content, low porosity, high clay content, and significant depth), at least for the Aptian section, they also have generated a wealth of new information about thermal maturity in the Cretaceous of south Mississippi. In addition, our work to-date has set the stage for future USGS evaluation of unconventional hydrocarbons reservoired in the Upper Cretaceous Tuscaloosa Marine Shale (TMS). Here, we summarize recent USGS thermal maturity studies in the south Mississippi Salt Basin.

Mississippi↗
USGS2026

Magnitude and frequency of urban floods in Alabama and Mississippi using data through the 2024 water year

To improve flood-frequency estimates for urban streams in Alabama and Mississippi, the U.S Geological Survey, in cooperation with the Alabama and Mississippi Departments of Transportation, estimated streamflows corresponding to selected annual exceedance probabilities (AEPs) for 64 streamgages on urban streams in the two States—48 in Alabama and 16 in Mississippi. Using estimates from 42 of the 64 streamgages, regression equations were developed that can be used to predict streamflows corresponding to the selected AEPs at ungaged locations on urban streams. Annual peak-flow data through September 2024 were used in the at-site flood-frequency analyses. Drainage area and the percentage of developed land use in the drainage basins of the streamgages (from the 2011 National Land Cover Database) were identified as statistically significant explanatory variables. Pseudo coefficient of determination (pseudo-R2) values ranged from 81 percent for the 0.2-percent AEP (500-year flood) to 91 percent for the 4- and 2-percent AEPs (25- and 50-year floods, respectively). Standard errors of prediction ranged from 23.1 percent for the 4-percent AEP (25-year flood) to 36.1 percent for the 2-percent AEP (500-year flood).

Alabama, Mississippi↗
USGS1995

Changes in the volume of water in the Mississippi River alluvial aquifer in the Delta, northwestern Mississippi, 1980-94

The U.S. Geological Survey, in cooperation with the Mississippi Department of Environmental Quality, Office of Land and Water Resources, and the Natural Resources Conservation Service, estimated the volumetric changes of water in the Mississippi River alluvial aquifer in northwestern Mississippi from 1980 through 1994. Volumetric changes of water in the alluvial aquifer were estimated for the entire Delta and for five selected areas within the Delta. The volume of water per square mile in the alluvial aquifer in the Delta changed from 17,886 acre-feet during fall 1980 to 17,719 acre-feet during fall 1994, a decrease in volume per square mile of 167 acre-feet. The minimum volume of water per square mile in the alluvial aquifer in the Delta during 1980-94 was 17,640 acre-feet during fall 1988. Of five selected areas within the Delta, an area near Cleveland in Bolivar County had the greatest change in volume of water in the alluvial aquifer. During fall 1980 this area had 20,790 acre-feet of water per square mile in the aquifer; by fall 1994, the volume had decreased to 19,947 acre-feet of water per square mile. An area located in the vicinity of the Sunflower-Leflore County line has within its boundaries a large cone of depression in the potentiometric surface of the alluvial aquifer. The volume of water per square mile in this area decreased from 17,857 acre-feet during fall 1980 to 17,075 acre-feet during fall 1994.

Mississippi↗
USGS2024

Hypothetical CO2 leakage into, and hydrological plume management within, an underground source of drinking water at a proposed CO2 storage facility, Kemper County, Mississippi, USA

A large Geologic Carbon Sequestration (GCS) hub has been proposed in Kemper County, Mississippi. The target injection interval consists of numerous Cretaceous-aged deep saline aquifers overlain by a competent and extensive regional sealing layer. Above the seal, the deepest Underground Source of Drinking Water (USDW) at the site is the Eutaw aquifer of the Eutaw Group and McShan Formation, undifferentiated. To assess potential risks of leakage from the deep sequestration reservoir, a model of a portion of the Cretaceous Eutaw Group was constructed in this study. Simulations tested various permeabilities, hypothetical leakage rates, and plume mitigation strategies utilizing existing wells. Results suggest that, under the influence of regional groundwater flow fields, leaking CO 2 would effectively bypass the existing wells, and to influence this migration would require very large water extraction rates. Therefore, to ensure plume detection, monitoring for leakage at the injection wells themselves is very important.

Mississippi↗
USGS1998

Soil, environmental, and watershed measurements in support of carbon cycling studies in northwestern Mississippi

Measurements including soil respiration, soil moisture, soil temperature, and carbon export in suspended sediments from small watersheds were recorded at several field sites in northwestern Mississippi in support of hillslope process studies associated with the U.S. Geological Survey's Mississippi Basin Carbon Project (MBCP). These measurements were made to provide information about carbon cycling in agricultural and forest ecosystems to understand the potential role of erosion and deposition in the sequestration of soil organic carbon in upland soils. The question of whether soil erosion and burial constitutes an important net sink of atmospheric carbon dioxide is one hypothesis that the MBCP is evaluating to better understand carbon cycling and climate change. This report contains discussion of methods used and presents data for the period December 1996 through March 1998. Included in the report are ancillary data provided by the U.S. Department of Agriculture (USDA) ARS National Sedimentation Laboratory and U.S. Forest Service (USFS) Center for Bottomland Hardwoods Research on rainfall, runoff, sediment yield, forest biomass and grain yield. Together with the data collected by the USGS these data permit the construction of carbon budgets and the calibration of models of soil organic matter dynamics and sediment transport and deposition. The U.S. Geological Survey (USGS) has established cooperative agreements with the USDA and USFS to facilitate collaborative research at research sites in northwestern Mississippi.

Mississippi↗
USGS2004

Data compilation, synthesis, and calculations used for organic-carbon storage and inventory estimates for mineral soils of the Mississippi River Basin

U.S. Geological Survey investigations of environmental controls on carbon cycling in soils and sediments of the Mississippi River Basin (MRB), an area of 3.3 x 106 square kilometers (km2), have produced an assessment tool for estimating the storage and inventory of soil organic carbon (SOC) by using soil-characterization data from Federal, State, academic, and literature sources. The methodology is based on the linkage of site-specific SOC data (pedon data) to the soil-association map units of the U.S. Department of Agriculture State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) digital soil databases in a geographic information system. The collective pedon database assembled from individual sources presently contains 7,321 pedon records representing 2,581 soil series. SOC storage, in kilograms per square meter (kg/m2), is calculated for each pedon at standard depth intervals from 0 to 10, 10 to 20, 20 to 50, and 50 to 100 centimeters. The site-specific storage estimates are then regionalized to produce national-scale (STATSGO) and county-scale (SSURGO) maps of SOC to a specified depth. Based on this methodology, the mean SOC storage for the top meter of mineral soil in the MRB is approximately 10 kg/m2, and the total inventory is approximately 32.3 Pg (1 petagram = 109 metric tons). This inventory is from 2.5 to 3 percent of the estimated global mineral SOC pool.

Professional Paper↗
USGS2026

Applying a metapopulation model to compare native and invasive fish passage scenarios in the Upper Mississippi River

The U.S. Geological Survey assessed the ability of metapopulation models to evaluate population-level effects of fish passage projects in the Upper Mississippi River for six native species: Ictalurus furcatus (Valenciennes in Cuvier and Valenciennes, 1840; blue catfish), Ictiobus cyprinellus (Valenciennes in Cuvier and Valenciennes, 1844; bigmouth buffalo), Acipenser fulvescens (Rafinesque, 1817; lake sturgeon), Polyodon spathula (Walbaum, 1792; American paddlefish [paddlefish]), Ictiobus bubalus (Rafinesque, 1818; smallmouth buffalo), Scaphirhynchus platorynchus (Rafinesque, 1818; shovelnose sturgeon), and one invasive species: Hypophthalmichthys molitrix (Valenciennes in Cuvier and Valenciennes, 1844; silver carp). The study had four objectives: to (1) compile parameter values and identify gaps, (2) parameterize species-specific models, (3) apply the models to multiple scenarios, and (4) develop a point-and-click interface. The literature review revealed a paucity of data, for all species except silver carp and paddlefish; however, length–weight relations, female length–maturity curves, growth curves, spawning and recruitment estimates, and movement data among pools were identified. These data allowed the parameterization of native species metapopulation models, in addition to the use of an existing silver carp model. The models were applied to scenarios representing increased passage, decreased passage, combined passage and deterrents effects, and increased native passage with decreased invasive passage. Increased passage scenarios (depicting potential passage projects) produced greater movement and larger upriver populations. Decreased passage scenarios (depicting potential deterrent projects) yielded reduced movement. Similar population dynamic patterns were observed across species for each scenario because of a lack of species-specific empirical movement data. Simulations for longer lived, slow growing species required longer response times, including time to reach equilibria. A point-and-click model was created to allow others to use the model. Data availability for movement limited the ability of the model to be used to understand fish-movement biology and thereby inform management strategies. More fish-movement data could improve model projections of these scenarios.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗
USGS1982

Depositional history of Louisiana-Mississippi outer continental shelf

A geological study was undertaken in 1981 in the Louisiana-Mississippi outer continental shelf for the Bureau of Land Management. The study included a high-resolution seismic reflection survey, surficial sediment sampling and surface current drifter sampling. Approximately 7100 sq km of the Louisiana-Mississippi shelf and upper slope were surveyed. The sea floor of the entire area is relatively smooth except for occasional areas of uplift produced by diapiric intrusion along the upper slope. Characteristics of the topography and subsurface shelf sediments are the result of depositional sequences due to delta outbuilding over transgressive sediments with intervening periods of erosion during low sea level stands. Little evidence of structural deformation such as faults, diapirs, and shallow gas is present on the shelf and only a few minor faults and scarps are found on the slope. Minisparker seismic records in combination with air gun (40 and 5 cu in) and 3.5-kHz subbottom profile records reveal that seven major stages of shelf development have occurred since the middle Pleistocene. The shelf development has been controlled by the rise and fall of sea level. These stages are defined by four major unconformities, several depositions of transgressive sediments, sequences of river channeling and progradational delta deposits. Surficial sediment sample and seismic records indicate tat the last major depositional event was the progradation of the St. Bernard Delta lobe. This delta lobe covered the northwestern and central regions. Surficial sediments in most of the study area are the product of the reworking of the San Bernard Delta lobe and previous progradations.

Open-File Report↗
USGS2014

Mississippi Valley-type lead-zinc deposits through geological time: Implications from recent age-dating research

Remarkable advances in age dating Mississippi Valley-type (MVT) lead-zinc deposits provide a new opportunity to understand how and where these deposits form in the Earth's crust. These dates are summarized and examined in a framework of global tectonics, paleogeography, fluid migration, and paleoclimate. Nineteen districts have been dated by paleomagnetic and/or radiometric methods. Of the districts that have both paleomagnetic and radiometric dates, only the Pine Point and East Tennessee districts have significant disagreements. This broad agreement between paleomagnetic and radiometric dates provides added confidence in the dating techniques used. The new dates confirm the direct connection between the genesis of MVT lead-zinc ores with global-scale tectonic events. The dates show that MVT deposits formed mainly during large contractional tectonic events at restricted times in the history of the Earth. Only the deposits in the Lennard Shelf of Australia and Nanisivik in Canada have dates that correspond to extensional tectonic events. The most important period for MVT genesis was the Devonian to Permian time, which corresponds to a series of intense tectonic events during the assimilation of Pangea. The second most important period for MVT genesis was Cretaceous to Tertiary time when microplate assimilation affected the western margin of North America and Africa-Eurasia. There is a notable paucity of MVT lead-zinc ore formation following the breakup of Rodinia and Pangea. Of the five MVT deposits hosted in Proterozoic rocks, only the Nanisivik deposit has been dated as Proterozoic. The contrast in abundance between SEDEX and MVT lead-zinc deposits in the Proterozoic questions the frequently suggested notion that the two types of ores share similar genetic paths. The ages of MVT deposits, when viewed with respect to the orogenic cycle in the adjacent orogen suggest that no single hydrologic model can be universally applied to the migration of the ore fluids. However, topographically driven models best explain most MVT districts. The migration of MVT ore fluids is not a natural consequence of basin evolution; rather, MVT districts formed mainly where platform carbonates had some hydrological connection to orogenic belts. There may be a connection between paleoclimate and the formation of some MVT deposits. This possible relationship is suggested by the dominance of evaporated seawater in fluid inclusions in MVT ores, by hydrological considerations that include the need for multiple-basin volumes of ore fluid to form most MVT districts, and the need for adequate precipitation to provide sufficient topographic head for topographically-driven fluid migration. Paleoclimatic conditions that lead to formation of evaporite conditions but yet have adequate precipitation to form large hydrological systems are most commonly present in low latitudes. For the MVT deposits and districts that have been dated, more than 75% of the combined metal produced are from deposits that have dates that correspond to assembly of Pangea in Devonian through Permian time. The exceptional endowment of Pangea and especially, North America with MVT lead-zinc deposits may be explained by the following: (1) Laurentia, which formed the core of North America, stayed in low latitudes during the Paleozoic, which allowed the development of vast carbonate platforms; (2) intense orogenic activity during the assembly of Pangea created ground preparation for many MVT districts through far-field deformation of the craton; (3) uplifted orogenic belts along Pangean suture zones established large-scale migration of basin fluids; and (4) the location of Pangea in low latitudes with paleoclimates with high evaporation rates led to the formation of brines by the evaporation of seawater and infiltration of these brines into deep basin aquifers during Pangean orogenic events.

Mineralium Deposita↗
USGS2007

Geologic Assessment of Undiscovered Oil and Gas Resources of the Black Warrior Basin Province, Alabama and Mississippi

Introduction The purpose of the U.S. Geological Survey's (USGS) National Oil and Gas Assessment is to develop geologically based hypotheses regarding the potential for additions to oil and gas reserves in priority areas of the United States. The USGS recently completed an assessment of undiscovered oil and gas potential of the Cambrian-Ordovician carbonate rocks, the Chattanooga and Floyd Shales, and the Pottsville Formation coals in the Black Warrior Basin Province in northeastern Mississippi and northwestern Alabama in the Gulf Coast Region. The Cambrian-Ordovician carbonate rocks, the Chattanooga and Floyd Shales, and the Pottsville Formation coals are important because of their potential for natural gas resources. This assessment is based on geologic principles and uses the total petroleum system concept. The geologic elements of a total petroleum system include hydrocarbon source rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy and petrophysical properties), and hydrocarbon traps (trap formation and timing). The USGS used this geologic framework to define two total petroleum systems and three assessment units. All three assessment units were quantitatively assessed for undiscovered oil and gas resources.

Data Series↗
USGS1995

Detailed lithologic log of the Dow Chemical #1 B.L. Garrigan Drill Hole, Mississippi County, Arkansas

The geology and tectonic setting of the New Madrid region in southeastern Missouri has received considerable attention because of the area's high seismic activity. The largest recorded earthquakes in this area occurred in the winter of 1811-1812. These earthquakes has estimated magnitudes as large as 8.0 on the Richter scale (Johnsonton and Kanter, 1990) and affected an area of about 1 million square miles (Fuller, 1912). Today, an area of continuously high seismic activity defines the New Madrid seismic zone, which extends from northeastern Arkansas into southeastern Missouri and northwestern Tennessee. Seismicity is locally concentrated along two subsurface archers--the Blytheville and Pascola (Hildenbrand and others, 1977; Crone and others, 1985; Hildenbrand, 1985; McKeown, 1988). The Padcola arch is not pertinent to this study and, therefore will not be discusses further. The Blytheville arch is located in and is subparallel to the axis of the northeast-southwest-trending Reelfoot structural basin, which formed during early Paleozoic rifting (Ervin and McGinnis, 1975; fig. 1). The Reelfoot basin is filled with Cambrian and Ordovician sedimentary rocks (Grohskopf, 1955; Howe, 1984; Houseknevht, 1989; Collins and others, 1992) that are uncomfortably overlain by Cretacaous and Tertiary sedimentary rocks and underlain by crystalline rocks of the eastern granite-rhyolite province (see Bickford and others, 1986). The presence of some Late Proterozoic sedimentary rocks in the Reelfoot basin currently cannot be ruled out. The Dow Chemical #1 B.L. Garrigan drill hole (hereafter, Garrigan) penetrated Paleozoic rocks on the Blytheville arch. The Garrigan is locted in the Reelfoot basin in the NW1/4, NW1/4 sec. 28, T. 15 N., R. 10 E., Mississippi County, Arkansas (fig. 1) and was completed to a total depth of 12,038 ft from a ground elevation of 239 ft on April 11, 1982 (Swolfs, 1991). The Garrigan is the only reported drill hole that penetrates the subsurface Blytheville arch and is an important source of core from the Reelfoot basin (Collins and others, 1992). Therefore, this drill hole is important for understanding structure and Paleozoic stratigraphy in a basin where stratigraphic and structural data are sparse. Rocks in the Garrigan were originally logged and described by J.R. Howe (personal communication to D.S. Collins, 1990) and published as a composite stratigraphic section along with the rock description for the Dow Chemical #1 Wilson drill hole (Howe, 1984). F.A. McKeown later relogged the rocks in the Garrigan and presented a generalized log in McKeown and others (1990). Swolfs (1991) presented another version of the Garrigan drill-hole geologic section (fig. 2). Aided by new biostratigraphic information, Taylor and others (1991) corrected major errors in the characterization and correlation of rocks in the Garrigan (fig. 2). Collins (1991) described the insoluble residues from the cuttings of the Garrigan, but could not correlate them with the insoluble resides from rocks of the carbonate platform west of the basin. However Taylor and others (1991), Collins and others (1992), and Collins and Bohm (1993) did correlate fossils from the Garrigan to other drill holes in the Reelfoot basin and adjacent areas. Using these correlated data, Collins and Bohm (1993) provided information on the structural relief across a part of the Reelfoot basin. Collins and others (1992) also interpreted the depositional setting for the Paleozoic rocks of the Garrigan. This report presents a detailed lithologic log of the Paleozoic rocks penetrated by the Garrigan that differs from the lithologic logs of previous workers (Howe, 1984; McKeown and others, 1990; see also Dart, 1992, p. 18-19). The lithologic descriptions of the Garrigan are derived from observations of well cuttings and core. Cored intervals used were 11,426-11,402 ft, 10,229-10,200 ft, and 8,002-7,979 ft. These intervals were the only intervals cored during the Garrigan drill project. Detailed analyses of the core will be described in a subsequent report.

Arkansas↗
USGS1990

Perspectives on earthquake hazards in the New Madrid seismic zone, Missouri

A sequence of three great earthquakes struck the Central United States during the winter of 1811-1812 in the area of New Madrid, Missouri. they are considered to be the greatest earthquakes in the conterminous U.S because they were felt and caused damage at far greater distances than any other earthquakes in U.S history. The large population currently living within the damage area of these earthquakes means that widespread destruction and loss of life is likely if the sequence were repeated. In contrast to California, where the earthquakes are felt frequently, the damaging earthquakes that have occurred in the Easter U.S-in 155 (Cape Ann, Mass.), 1811-12 (New Madrid, Mo.), 1886 (Charleston S.C) ,and 1897 (Giles County, Va.- are generally regarded as only historical phenomena (fig. 1). The social memory of these earthquakes no longer exists. A fundamental problem in the Eastern U.S, therefore, is that the earthquake hazard is not generally considered today in land-use and civic planning. This article offers perspectives on the earthquake hazard of the New Madrid seismic zone through discussions of the geology of the Mississippi Embayment, the historical earthquakes that have occurred there, the earthquake risk, and the "tools" that geoscientists have to study the region. The so-called earthquake hazard is defined by the characterization of the physical attributes of the geological structures that cause earthquakes, the estimation of the recurrence times of the earthquakes, the estimation of the recurrence times of the earthquakes, their potential size, and the expected ground motions. the term "earthquake risk," on the other hand, refers to aspects of the expected damage to manmade strctures and to lifelines as a result of the earthquake hazard.

New Madrid seismic zone↗