Shaking in the Southeastern United States: Examining Earthquakes and Blasts in the Central Georgia–South Carolina Seismic Region

2021 ◽  
Author(s):  
Rachel E. Marzen ◽  
James B. Gaherty ◽  
Donna J. Shillington ◽  
Won-Young Kim
Keyword(s):  
United States ◽  
South Carolina ◽  
Southeastern United States ◽  
Horizontal Stress ◽  
Water Levels ◽  
Spectral Amplitude ◽  
Seismic Zone ◽  
Seismic Region ◽  
Temporal Cluster ◽  
Maximum Horizontal Stress

Abstract Seismicity in the southeastern United States is relatively poorly characterized and thus not well understood. Structures and heterogeneities from multiple stages of Appalachian orogenesis, continental rifting, and magmatism as well as rivers and reservoirs may be influencing seismic activity in the region, but previous constraints are limited. The addition of seismic stations from the U.S. Transportable Array and the Southeastern Suture of the Appalachian Margin Experiment Array in 2012–2014 provide an opportunity to characterize seismicity in the central Georgia–South Carolina region. We develop a seismic catalog of >1000 events from March 2012 to May 2014 within or near the instrument array boundaries 30.1°–35.2°N, 80.9°– 85.7°W. Many of the events detected were industrial blasts, so multiple strategies were tested to discriminate between earthquakes and blasts based on event locations, timing, and spectral amplitude of the P and S arrivals. Based on this analysis, ∼10% of the events in the catalog were classified as earthquakes. Most earthquakes southeast of the eastern Tennessee seismic zone are located in the Carolina terrane, particularly where the Carolina terrane intersects major rivers or reservoirs. One prominent region of seismicity along the Savannah River near Thurmond Lake corresponds with an ∼4.5  m rise in water levels in 2013. A temporal cluster of earthquakes in April 2013 was followed by increased levels of ambient seismicity preceding the nearby Mw 4.1 earthquake in 2014. Focal mechanisms based on first-motion polarities indicate strike-slip to oblique-thrust motion on structures trending approximately north–south or east–west, and a maximum horizontal stress orientation consistent with the regional trend of ∼N60°E, implying that seismicity may reactivate more optimally oriented structures in the Carolina terrane that are oblique to the trend of the Appalachians. Seismicity in central Georgia appears to be controlled by a complex interaction between preexisting crustal structure and hydrologic variability.

Seismicity of the southeastern United States

1973 ◽  
Vol 63 (5) ◽  
pp. 1785-1808
Author(s):  
G. A. Bollinger
Keyword(s):  
United States ◽  
South Carolina ◽  
Southeastern United States ◽  
Vertical Component ◽  
Seismic Zone ◽  
Local Magnitude ◽  
Short Period ◽  
Central United States ◽  
Order Of Magnitude ◽  
Attenuation Characteristics

abstract Review and analysis of the existing data base for southeastern United States earthquakes indicate that the spatial pattern of energy release can be interpreted to occur in zones both parallel (southern Appalachian seismic zone) and transverse (central Virginia and South Carolina-Georgia seismic zones) to the regional Appalachian structural trend. The temporal pattern, for events V ≦ Io ≦ VIII, can be expressed by the recursion relationship, log N = 3.01 − 0.59 Io. Felt areas are, in general, one order of magnitude greater than for similar west coast events. Their configuration is elliptical and aligned with regional structure, except in central Virginia and Alabama and in coastal South Carolina. These latter areas have circular or lobate felt areas that may be caused by differences in focal depths and/or focal mechanisms. A tentative local magnitude formula is developed that employs the vertical component of the short-period Lg phase. It appears that the regional attenuation characteristics of this phase are similar to those found by Nuttli (1973a) in the central United States.

Shell Mounds in the Southeast: Middens, Monuments, Temple Mounds, Rings, or Works?

2010 ◽  
Vol 75 (3) ◽  
pp. 551-570 ◽  
Author(s):  
William H. Marquardt
Keyword(s):  
United States ◽  
South Carolina ◽  
Climate Changes ◽  
Southeastern United States ◽  
Short Term ◽  
Mound Construction ◽  
Architectural Features ◽  
Shell Mounds ◽  
Shell Rings ◽  
Oriented Approach

Focusing on the southeastern United States, I provide some alternative perspectives on shell mounds previously interpreted as architectural features, temple mounds, and feasting sites. The same pattern of deposition often inferred to indicate mound construction—darker-colored, highly organic strata alternating with lighter-colored, shell-rich strata—can be accounted for by domestic midden accumulation and disposal of refuse away from living areas. Observed abundances of particular shell species can result from local or regional ecological conditions. Site complexes interpreted as architectural may have evolved largely in response to short-term climate changes. Shell rings on the Georgia and South Carolina coasts probably functioned to conserve and store unconfined water. To understand ancient shell mounds, we need a sediment-oriented approach to the study of mound deposits and more attention to the environmental contexts in which shell mounds accumulated.

scholarly journals Fungicide Rotation Programs for Managing Phytophthora Fruit Rot of Watermelon in Southeastern United States

2017 ◽  
Vol 18 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Chandrasekar (Shaker) S. Kousik ◽  
Pingsheng Ji ◽  
Daniel S. Egel ◽  
Lina M. Quesada-Ocampo
Keyword(s):  
United States ◽  
South Carolina ◽  
Phytophthora Capsici ◽  
Southeastern United States ◽  
Heavy Rain ◽  
Integrated Approach ◽  
The United States ◽  
Fruit Rot ◽  
Management Options ◽  
Before And After

About 50% of the watermelons in the United States are produced in the southeastern states, where optimal conditions for development of Phytophthora fruit rot prevail. Phytophthora fruit rot significantly limits watermelon production by causing serious yield losses before and after fruit harvest. Efficacy of fungicide rotation programs and Melcast-scheduled sprays for managing Phytophthora fruit rot was determined by conducting experiments in Phytophthora capsici-infested fields at three locations in southeastern United States (North Carolina, South Carolina, and Georgia). The mini seedless cultivar Wonder and seeded cultivar Mickey Lee (pollenizer) were used. Five weekly applications of fungicides were made at all locations. Significant fruit rot (53 to 91%, mean 68%) was observed in the nontreated control plots in all three years (2013 to 2015) and across locations. All fungicide rotation programs significantly reduced Phytophthora fruit rot compared with nontreated controls. Overall, the rotation of Zampro alternated with Orondis was highly effective across three locations and two years. Rotations of Actigard followed by Ranman+Ridomil Gold, Presidio, V-10208, and Orondis, or rotation of Revus alternated with Presidio were similarly effective. Use of Melcast, a melon disease-forecasting tool, may occasionally enable savings of one spray application without significantly impacting control. Although many fungicides are available for use in rotations, under very heavy rain and pathogen pressure, the fungicides alone may not offer adequate protection; therefore, an integrated approach should be used with other management options including well-drained fields.

Recent Research Concerning the Freezing Point Value of Milk Produced in the Southeastern United States

1963 ◽  
Vol 46 (4) ◽  
pp. 732-736
Author(s):  
R W Henningson
Keyword(s):  
United States ◽  
South Carolina ◽  
Freezing Point ◽  
Southeastern United States ◽  
Fat Content ◽  
Extensive Survey ◽  
Milk Solids

Abstract In 1953 Dahlberg, et al. published the first information indicating that the freezing point value of milk produced in the Southeastern United States might be higher than commonly accepted values. An extensive survey of retail milk marketed in South Carolina during 1957 produced an unweighted average freezing point value of –0.529°C, and disclosed that the unweighted average milk solids-not-fat content of retail milk marketed in South Carolina was 8.88%. Other surveys revealed such freezing point values as –0.537, –0.540, –-0.533, –0.528, and –0.532°C. Custer and Cardwell found freezing point depressions averaging 0.025—0.030°C less for reconstituted non-fat milks of southern origin than for similar milks of northern origin. The lactose and chloride contents of these milks were lower than those of the northern milks. Problems created by high freezing point values which are intensified by the effects of vacuum pasteurization, common in the Southeastern United States, on freezing point values will be discussed.

scholarly journals Seasonal Hydrological Forecasts for Watersheds over the Southeastern United States for the Boreal Summer and Fall Seasons

2013 ◽  
Vol 17 (25) ◽  
pp. 1-22 ◽  
Author(s):  
Satish Bastola ◽  
Vasubandhu Misra ◽  
Haiqin Li
Keyword(s):  
United States ◽  
South Carolina ◽  
Climate Model ◽  
Southeastern United States ◽  
Boreal Summer ◽  
Hydrological Models ◽  
State University ◽  
Streamflow Prediction ◽  
Seasonal Climate ◽  
Hydrological Prediction

Abstract The authors evaluate the skill of a suite of seasonal hydrological prediction experiments over 28 watersheds throughout the southeastern United States (SEUS), including Florida, Georgia, Alabama, South Carolina, and North Carolina. The seasonal climate retrospective forecasts [the Florida Climate Institute–Florida State University Seasonal Hindcasts at 50-km resolution (FISH50)] is initialized in June and integrated through November of each year from 1982 through 2001. Each seasonal climate forecast has six ensemble members. An earlier study showed that FISH50 represents state-of-the-art seasonal climate prediction skill for the summer and fall seasons, especially in the subtropical and higher latitudes. The retrospective prediction of streamflow is based on multiple calibrated rainfall–runoff models. The hydrological models are forced with rainfall from FISH50, (quantile based) bias-corrected FISH50 rainfall (FISH50_BC), and resampled historical rainfall observations based on matching observed analogs of forecasted quartile seasonal rainfall anomalies (FISH50_Resamp). The results show that direct use of output from the climate model (FISH50) results in huge biases in predicted streamflow, which is significantly reduced with bias correction (FISH50_BC) or by FISH50_Resamp. On a discouraging note, the authors find that the deterministic skill of retrospective streamflow prediction as measured by the normalized root-mean-square error is poor compared to the climatological forecast irrespective of how FISH50 (e.g., FISH50_BC, FISH50_Resamp) is used to force the hydrological models. However, our analysis of probabilistic skill from the same suite of retrospective prediction experiments reveals that, over the majority of the 28 watersheds in the SEUS, significantly higher probabilistic skill than climatological forecast of streamflow can be harvested for the wet/dry seasonal anomalies (i.e., extreme quartiles) using FISH50_Resamp as the forcing. The authors contend that, given the nature of the relatively low climate predictability over the SEUS, high deterministic hydrological prediction skills will be elusive. Therefore, probabilistic hydrological prediction for the SEUS watersheds is very appealing, especially with the current capability of generating a comparatively huge ensemble of seasonal hydrological predictions for each watershed and for each season, which offers a robust estimate of associated forecast uncertainty.

scholarly journals Quantitative Aspects of the Spread of Asian Soybean Rust in the Southeastern United States, 2005 to 2006

2007 ◽  
Vol 97 (11) ◽  
pp. 1428-1433 ◽  
Author(s):  
R. S. C. Christiano ◽  
H. Scherm
Keyword(s):  
United States ◽  
South Carolina ◽  
Average Rate ◽  
Southeastern United States ◽  
Monitoring Program ◽  
Early Summer ◽  
Soybean Rust ◽  
Initial Inoculum ◽  
Disease Progress ◽  
Short Period

The regional dynamics of soybean rust, caused by Phakopsora pachyrhizi, in six southeastern states (Florida, Georgia, Alabama, South Carolina, North Carolina, and Virginia) in 2005 and 2006 were analyzed based on disease records collected as part of U.S. Department of Agriculture's soybean rust surveillance and monitoring program. The season-long rate of temporal disease progress averaged ≈0.5 new cases day–1 and was higher in nonsentinel soybean (Glycine max) plots than in sentinel soybean plots and kudzu (Pueraria lobata) plots. Despite the early detection of rust on kudzu in January and/or February each year (representing the final phase of the previous year's epidemic), the disease developed slowly during the spring and early summer on this host species and did not enter its exponential phase until late August, more than 1 month after it did so on soybean. On soybean, cases occurred very sporadically before the beginning of July, after which their number increased rapidly. Thus, while kudzu likely provides the initial inoculum for epidemics on soybean, the rapid increase in disease prevalence on kudzu toward the end of the season appears to be driven by inoculum produced on soybean. Of 112 soybean cases with growth stage data, only one occurred during vegetative crop development while ≈75% occurred at stage R6 (full seed) or higher. The median nearest-neighbor distance of spread among cases was ≈70 km in both years, with 10% of the distances each being below ≈30 km and above ≈200 km. Considering only the epidemic on soybean, the disease expanded at an average rate of 8.8 and 10.4 km day–1 in 2005 and 2006, respectively. These rates are at the lower range of those reported for the annual spread of tobacco blue mold from the Caribbean Basin through the southeastern United States. Regional spread of soybean rust may be limited by the slow disease progress on kudzu during the first half of the year combined with the short period available for disease establishment on soybean during the vulnerable phase of host reproductive development, although low inoculum availability in 2005 and dry conditions in 2006 also may have reduced epidemic potential.

Distribution of an Invasive Weevil, Pseudocneorhinus bifasciatus Roelofs, in the Southeastern United States

2005 ◽  
Vol 40 (1) ◽  
pp. 25-30 ◽  
Author(s):  
A. G. Wheeler ◽  
David W. Boyd
Keyword(s):  
United States ◽  
North Carolina ◽  
South Carolina ◽  
North America ◽  
Southeastern United States ◽  
Ornamental Plants ◽  
Review Of The Literature ◽  
Northeastern United States

The twobanded Japanese weevil, Pseudocneorhinus bifasciatus Roelofs, first found in North America near Philadelphia, PA, in 1914, is better known in the northeastern United States than in the Southeast. Based on examination of specimens in 11 museums, fieldwork, and review of the literature, we document the presence of this pest of ornamental plants in Alabama (3 counties), Georgia (12), North Carolina (16), and South Carolina (19). The southeastern distribution is mapped, and locality and date are provided for the first collection in each state: North Carolina, 1955; Georgia, 1956; South Carolina, 1966; and Alabama, 1970.

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