Post-flood measurement of a refilled scour hole at the Bulkeley Bridge in Hartford, Connecticut
No abstract available.
Geology topics
Publications and source records attributed to F.P. Haeni.
No abstract available.
This annotated bibliography compiles references about the theory and application of surface geophysical techniques to locate fractures or fracture zones within bedrock units. Forty-three publications are referenced, including journal articles, theses, conference proceedings, abstracts, translations, and reports prepared by private contractors and U.S. Government agencies. Thirty-one of the publications are annotated. The remainder are untranslated foreign language articles, which are listed only as bibliographic references. Most annotations summarize the location, geologic setting, surface geophysical technique used, and results of a study. A few highly relevant theoretical studies are annotated also. Publications that discuss only the use of borehole geophysical techniques to locate fractures are excluded from this bibliography. Also excluded are highly theoretical works that may have little or no known practical application.
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No abstract available.
No abstract available.
A short-pulse ground-penetrating radar system was used to determine the extent and thickness of organic-rich lake-bottom sediments in Silver Lake in south-central Connecticut. Four mi of ground-penetrating radar profiles were obtained along traverses of the frozen lake during March 1984. The radar waves penetrated 6 inches of snow, 1 ft of ice, an average of 4 to 5 ft of water, and 5 ft of soft organic and inorganic deposits. A large area of the lake bottom is underlain by soft sediment exceeding 5 ft in depth. No radar reflections were obtained from the hard subbottom in these areas because the overlying sediment probably contains large proportions of silt and clay that are relatively impervious to radar. Coring along two radar profile lines confirmed the depths of soft sediment calculated from the radar data. Boring logs around the perimeter of the lake indicate that the eastern side may be underlain by till or poorly-sorted sand and gravel, and that the rest of the lake is probably underlain by fine sands and silts with some discontinuous layers of sand and gravel. (USGS)
Choosing a seismic source for a shallow reflection survey can be the most pivotal decision for the engineering geophysicist. The intent of this paper is to present data that will assist in selection of a shallow seismic source best meeting the goals within the constraints of specific projects, particularly in areas where the water table is near the surface. The data were collected (and displayed as seismograms and amplitude spectra) for 15 different shallow seismic sources in October, 1985, at a single site in New Jersey; they show the different characteristics of each source. Considering the almost three orders of magnitude difference in total source energy between the largest and smallest source, we chose a display format that presented the data as objectively as possible, while still allowing direct source‐to‐source comparisons. Two strong reflections at about 100 and 130 ms probably mark the top and bottom of a clay unit 80 m below the surface at this site. Our previous work and that of our colleagues suggests that, given a specific set of site characteristics, any source could dominate the comparison categories addressed here.
Seismic refraction studies were conducted over unconfined glacial aquifers in New England to determine: 1) depth of the underlying bedrock; 2) depth of the water table; 3) saturated thickness of the aquifer in areas not accessible to heavy drilling equipment; 4) areas where thick, unsaturated sediments overlie thickly saturated parts of the aquifer; and 5) locations of test holes and type of drilling equipment needed. These data were used in groundwater models and provided parameter values that required few adjustments during calibration. -from Author
During the past 30 years, seismic-refraction methods have been used extensively in petroleum, mineral, and engineering investigations, and to some extent for hydrologic applications. Recent advances in equipment, sound sources, and computer interpretation techniques make seismic refraction a highly effective and economical means of obtaining subsurface data in hydrologic studies. Aquifers that can be defined by one or more high seismic-velocity surfaces, such as (1) alluvial or glacial deposits in consolidated rock valleys, (2) limestone or sandstone underlain by metamorphic or igneous rock, or (3) saturated unconsolidated deposits overlain by unsaturated unconsolidated deposits, are ideally suited for applying seismic-refraction methods. These methods allow the economical collection of subsurface data, provide the basis for more efficient collection of data by test drilling or aquifer tests, and result in improved hydrologic studies. This manual briefly reviews the basics of seismic-refraction theory and principles. It emphasizes the use of this technique in hydrologic investigations and describes the planning, equipment, field procedures, and intrepretation techniques needed for this type of study. Examples of the use of seismic-refraction techniques in a wide variety of hydrologic studies are presented.
No abstract available.
No abstract available.
On May 18, 1980, Mount St. Helens violently erupted, sending billions of cubic yards of mud, ash, rock fragments, and debris down the North and South Forks of the Toutle River, the Cowlitz and Columbia Rivers, and other streams. A total of 35.6 million cubic yards of mudflow material was deposited in the lower Cowlitz (downstream from the Union Pacific Railroad bridge) and Columbia Rivers. The arrival of this material at the Columbia River, during a period of the daily tidal cycle, when the flow was at a minimum or quite probably reversed and flowing upstream resulted in its deposition in an area 7 miles upstream and 2 miles downstream from the junction of the Cowlitz and Columbia Rivers. The thickness of the deposit was at a maximum near Coffin Rock, where a hole 140 feet deep was filled with 90 feet of sediment. Incomplete filling, compaction, and (or) erosion caused a 1Q-foot depression to form in the surface of the newly deposited material at this location. On May 23, 1980, the presence of two scour channels on each side of a tonguelike deposit (delta) of very fine sand and silt indicates that the coarse-grained sediment and water surge on the morning of May 19 initially scoured the lower 0.5 mile of the Cowlitz River bed. A minimum of 0.4 million cubic yard of material was scoured from the Cowlitz River bed and subsequently redeposited in the Columbia River before the 1.3-million-cubic-yard delta was formed.
A continuous marine seismic-reflection survey system was used to define the configuration of shallow sedimentary layers underlying the Charlotte Harbor and Venice areas, southwest Florida. Seismic profiling was conducted over a distance of about 57 miles of Charlotte Harbor, the Peace and Myakka Rivers, and the Intracoastal Waterway near Venice using a high resolution energy source capable of penetrating 200 feet of sediments with a resolution of 1 to 3 feet. Five stratigraphic units defined from the seismic records includes sediments to Holocene to early Miocene age. All seismic-profile records are presented, along with geologic sections constructed from the records. Seismic reflection amplitude, frequency, continuity, configuration, external form, and areal association were utilized to interpret facies and depositional environments of the stratigraphic units. The despositional framework of the units ranges from shallow shelf to prograded slope. The stratigraphic units are correlated with the surficial aquifer and intermediate artesian aquifers, and permeable zones of the aquifers are related to the seismic records. (USGS)
A hydrologic analysis of the stratified drift in Newtown, Conn., based on available data, test drilling, seismic refraction profiling, and the stream-aquifer connection was performed using a digital computer model. Simulated pumping indicates that a total of 4.0 million gallons of water per day (Mgal/d) can be withdrawn from the stream-aquifer system. A minimum of 2.5 Mgal/d is available for future development since Fairfield Hills Hospital is capable of withdrawing 1.5 Mgal/d. Induced recharge from the Pootatuck River supplies 65 percent, or 2.6 Mgal/d of the total pumpage, and captured ground-water outflow supplies the remaining 35 percent of 1.4 Mgal/d. The predicted yields are for long-term average hydrologic conditions; usually dry or extended drought periods would significantly reduce the water available from the aquifer. The quality of surface water in the valley as shown by seven samples from five sites, meets the Connecticut standards for public drinking water except for excessive coliform bacteria. Ground-water quality also meets these standards, as indicated by analyses of 20 samples from 14 wells and 1 spring, but high manganese (up to 15 mg/L) and iron (up to 1.7 mg/L) would require treatment prior to use. Trace metals from one surface-water and four ground-water samples are also within these standards, except for the high cadmium concentration of 26 micrograms per liter in water from one well. (Woodard-USGS)
No abstract available.
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