Earthquake Investigations at the Dickey-Lincoln School Damsites, Maine

The Dickey-Lincoln School damsites are less than 50 miles from an area along the St. Lawrence River which has experienced some of the most severe earthquakes in North America. A geological and seismological investigation was made of the region in order to determine the hazards from earthquakes at the damsites. No active faults were found in the general area of the damsites. The source area of potentially severe earthquakes was found to be restricted to a narrow band that follows the St. Lawrence River. This band was designated as Zone A. The boundary of Zone A is located U5 miles from the damsites. Zone B, with less seismic risk, borders Zone A and is Uo miles from the damsites. The damsites are situated in Zone C, which has the least seismic risk in the region. Zone D, with a level of seismic risk between that of Zones B and C, occurs 75 miles southeast of the damsites. The most severe ground motion at the damsites was interpreted to be from an earthquake in Zone A attenuated over a distance of 45 miles. Such movement is interpreted to have a peak acceleration of 0.35 g, a peak velocity of 65 cm/sec, and a peak displacement of 22 cm. The duration of shaking is estimated at 18 sec. Accelerographs are recommended for scaling in order to develop time histories of bedrock ground motion for dynamic analyses

Some Physical and Chemical Properties of Loess Deposits in the Lower Mississippi Valley.

This study presents a general picture of loess in the Lower Mississippi Valley. Loess is recognized as unstratified, calcareous, slightly plastic, porous loam with an average grain size distribution between 0.05 and 0.01mm. diameter. Materials meeting this definition but lacking in calcium carbonate are termed leached loess when in association with loess and brown loam when not in association with loess. Loess has been found to occur chiefly as pseudo-anticlinal caps on hills. It is mapped as occurring within an area averaging 10 to 15 miles in width extending from southern Illinois southward along the eastern walls of the Lower Mississippi River Alluvial Valley to near Bayou Sara in Louisiana. Deposits are found also on Crowley’s Ridge and Sicily Island. The loess is thickest at the bluffs facing the Mississippi River flood plain and thins progressively away from these bluffs. The rate of thinning is estimated at 0.3 feet per mile. There is no correlation between thickness of loess and age of terraces on which it occurs. These loess capped hills have a northeast-southwest and northwest-southeast orientation and alluvial fans of loess intermixed with terrace materials extend out onto the flood-plain. Eastward the loess merges with brown loam. Chemical analyses of loess indicate a great uniformity of composition except for calcium carbonate which is highly variable. Loess is predominantly composed of Si02 (56.79 to 66.43%) together with Al2O3 (7.33 to 11.16%), CaO (7.74 to 11.72%), MgO (3.11 to 5.09%), and Fe203 (2.99 to 3.70%). Mechanical analyses show a great uniformity of grain size distributions over large areas. Leached loess has essentially the same grain size distribution as does loess but brown loam may be slightly finer grained. The range of variation of grain size distributions in loess is much less than in modern floodplain sediments. Carbonates in loess of the Lower Mississippi Valley are almost entirely secondary, chiefly in the form of precipitates around grass roots. Nodular concretions and tree root fillings are also abundant. These carbonates add to the strength of the loess when it is in a dry state but furnish very little strength when it is wet. This contrast is such that a slope of equilibrium on an exposed surface is nearly vertical. Terrestrial pulmonates are plentiful in loess. These are of species still living in the area. Evidences of colluviation and faulting of loess are plentiful

Seismic risk assessment for developing countries : Pakistan as a case study

Modern Earthquake Risk Assessment (ERA) methods usually require seismo-tectonic information for Probabilistic Seismic Hazard Assessment (PSHA) that may not be readily available in developing countries. To bypass this drawback, this paper presents a practical event-based PSHA method that uses instrumental seismicity, available historical seismicity, as well as limited information on geology and tectonic setting. Historical seismicity is integrated with instrumental seismicity to determine the long-term hazard. The tectonic setting is included by assigning seismic source zones associated with known major faults. Monte Carlo simulations are used to generate earthquake catalogues with randomized key hazard parameters. A case study region in Pakistan is selected to demonstrate the effectiveness of the method. The results indicate that the proposed method produces seismic hazard maps consistent with previous studies, thus being suitable for generating such maps in regions where limited data are available. The PSHA procedure is developed as an integral part of an ERA framework named EQRAM. The framework is also used to determine seismic risk in terms of annual losses for the study region

U.S. Waterways Experiment Station Reports

This report describes the results of a series of tests on soil borings taken in Atchafalaya Test Section VI, a 2000-ft-long portion of the Atchafalaya Basin Protection Levee System in south-central Louisiana. The samples were tested to interpret the depositional layers in the foundations soils and to determine various engineering properties

U.S. Waterways Experiment Station Reports

Abstract: "A set of 12 charts are presented that relate Modified Mercalli intensity units to peak horizontal acceleration, velocity and duration for near field and far field locations, hard and soft sites, and sizes of earthquakes. Also shown is the mean, mean plus one standard deviation, mean plus two standard deviations, and the highest observed values. Ratios are provided of vertical to horizontal motions and predominant periods. These charts are for use with known fault sources and for floating earthquakes in zones where there are no identifiable causative faults. The procedure provides parameters for shaping time histories to be used for dynamic analyses.

U.S. Waterways Experiment Station Reports

Summary: "This report provides data on the alluvial aquifer of the Lower Mississippi Valley in the area between Cape Girardeau, Missouri, and Port Gibson, Mississippi. Maps are presented of the Tertiary surface on which the alluvial aquifer rests as well as the geology of this surface and the areas where hydrologic recharge to the alluvial aquifer may occur. A set of piezometric-surface maps, together with hydrographs of observation wells, river stages, precipitation rates, and data on the hydrologic properties of the alluvium, makes it possible to calculate changes which take place in the aquifer. Further data are presented on the chemical quality of groundwater. The relevance of these data to engineering problems is discussed" (p. ix)

Prediction of the 1972 Managua Nicaragua, earthquake from groundwater changes; : inferred probability of earthquakes in the city of Managua, Nicaragua, during the summer of 1973, /

Translation of Probabilidad de ocurrencia de temblores en la ciudad de Managua durante el verano de 1973."May 1973."Includes bibliographical references (p. 16).Mode of access: Internet

Methodology and concepts for the design of surface storage fills at the Anvil Points Oil Shale Retort Facility

Primary obtectives in design of surface disposal fills for processed and raw oil shales are: (a) to insure long-term physical stability, and (b) to prevent surface runoff, surface erosion, and possible subsurface seepage from degrading the water quality of streams and ground water, it was concluded that the analysis and design of spent shale disposal fills should be based on sound geotechnical engineeering principles, considerable experience, and good judgment. An understanding of the source of variability of spent shale materials and its effect on engineering properties is a first step in developing fill design. A second important step is the assessment of long-term changes in the properties of spent shale within a disposal fill. This assessment requires consideration of possible thermal, hydrochemical, and physical interactions within the fill and between the fill and site environment. The site environment is site-specific and depends on the geological, surface and subsurface hydrological, and geotechnical characteristics of the site. The variability of spent shale materials is a direct function of variations in mineral and chemical composition of the raw shale and of the processes applied. Current technology for the design and construction of spent shale disposal fills has not been proven by experience. A major problem is the large quantities of spent shale generated for surface disposal and the lack of available sites other than large gulches in the oil shale country of the western United States. Conceptual research fill designs developed in this study should be refined and constructed to provide needed information on in situ properties and long-term performance. Research fills planned by others should be augmented to obtain needed information, especially for codisposal of spent shales with treated waste water, raw shale fines, and process dust

U.S. Waterways Experiment Station Reports

Final report discussing a facility built to test californium-252 in research on moisture, density, and other properties of soil and rock in relation to engineering characteristics