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Geology topics

John R. Ege

Publications and source records attributed to John R. Ege.

15 recordsLinked to original sources
USGS1983

Mitigation of hazards from future lahars from Mount Merapi in the Krasak River channel near Yogyakarta, central Java

Procedures for reducing hazards from future lahars and debris flows in the Krasak River channel near Yogyakarta, Central Java, Indonesia, include (1) determining the history of the location, size, and effects of previous lahars and debris flows, and (2) decreasing flow velocities. The first may be accomplished by geologic field mapping along with acquiring information by interviewing local residents, and the second by increasing the cross sectional area of the river channel and constructing barriers in the flow path.

Open-File Report↗
USGS1983

Landslide investigations, southern Cianjur Regency, West Java Province, Indonesia; a progress report

Two landslide-monitoring sites have been established for a minimum 2-year investigation near the villages of Pasirpari and Cibacang in southern Cianjur Regency, West Java, Indonesia. Surveyed-in lines will measure amounts of surface movement and tilt, borings that produced exploratory cores now serve as slip-surface detectors and open-pipe piezometers, and rain gages will record rainfall at both sites. Exploratory cores and field observations located upper slip surfaces ranging in depth between 4 and 14 m. Rises of borehole-water levels of as much as 63 cm during drilling suggest that pore pressures exist at the inferred-slip surfaces. Sliding along slip surfaces and slope failures occurred during the rainy season between November 1980 and April 1981.

Open-File Report↗
USGS1979

Selected bibliography on subsidence processes and related engineering problems in carbonate rocks

The Solution Subsidence and Collapse project is a U.S. Geological Survey research activity funded by the Reactor Hazards Research program. The objective of the study is to determine the geologic and hydrologic controls and mechanisms of ground subsidence in soluble rock terranes caused by natural processes and man's activities. The results of the research will be used for the general geologic characterization of proposed and existing nuclear reactor sites in regions underlain by soluble rocks. In addition, the knowledge gained from the study will be applied to defining potential geologic hazards in soluble rock areas where ground subsidence or collapse can occur. The Solution Subsidence and Collapse project is divided into two study units, one looking at subsidence in evaporitic terranes, the other in carbonate terranes. Each of the two geologic environments has its own unique set of conditions that lead to subsidence and, therefore, each warrants its own special study. As part of the subsidence study a selected bibliography covering various topics on ground subsidence in carbonate karst terranes was compiled and is presented here. The entries in the bibliography are placed in five categories: (1) General; (2) Geology, Geomorphology, Hydrology; (3) Caves, Solution Channels; (4) Subsidence, Sinkholes; and (5) Engineering, Land Use, Detection. A separate bibliography on ground subsidence caused by dissolution and removal of salt and other soluble evaporites has been published as a companion reference to this report (Ege, 1979).

Open-File Report↗
USGS1970

Schmidt hammer test method for field determination of physical properties of zeolitized tuff

The L-type Schmidt hammer is a hand-carried impact instrument that was originally designed and developed to test the compressive strength of concrete. When properly impacted against a stiff material the device measures the amount of rebound of a spring-loaded hammer, with the rebound of the hammer being directly proportional to the strength of the material tested. Application of this instrument to rock, specifically water-saturated zeolitized tuff, is demonstrated through a set of correlation diagrams that relate Schmidt hammer rebound values, obtained from core samples and from the sites where samples were taken, to physical properties measured on rock samples in the laboratory. The properties include compressive strength, compressional and shear velocities, and dynamic and static Young's shear and bulk moduli. The correlation diagrams apply only to zeolitized tuff of the type found at the Nevada Test Site in its natural state (freshly excavated). These diagrams enable the user of the L-type Schmidt hammer to immediately obtain values of physical properties of such rocks in place, a convenience desirable where conventional sampling is not feasible or is impossible, and when results are required on short notice. The charts apply to L-type hammers that are calibrated to a nominal rebound value of 74. Calibration is made on a 35-pound-(16-kg-) test anvil with a steel-hardened test surface of Brinell hardness = 500 kg/mm 2 .

Open-File Report↗
USGS1969

Evaluation of core data, physical properties, and oil yield USBM/AEC Colorado Core Hole no. 3 (Bronco BR-1)

USBM/AEC Colorado Core Hole No. 3 (Bronco BR-1) is located in the SW1/4SW1/4SW1/4 sec. 14, T. 1 N., R. 98 W., Rio Blanco County, Colorado. The collar is at a ground elevation of 6,356 feet. The hole was core drilled between depths of 964 and 3,325 feet with a total depth of 3,797 feet. The hole was drilled to investigate geologic, geophysical and hydrological conditions at a possible in situ oil-shale retorting experiment site. The drill hole passed through 1,157 feet of alluvium and the Evacuation Creek Member of the Green River Formation, 1,603 feet of the Parachute Creek Member and penetrated into the Garden Gulch Member of the Green River Formation. In-bole density log/oil yield ratio interpretation indicates that two oil-shale zones exist which yield more than 20 gallons of shale oil per ton of rock; an upper zone lying between 1,271 and 1,750 feet in depth and a lower zone lying between 1,900 and 2,964 feet. Halite (sodium chloride salt) is found between 2,140 and 2,185 feet and nahcolite (sodium bicarbonate salt) between 2,195 and 2,700 feet. Nahcolite was present at one time above 2,195 feet but has been subsequently dissolved out by ground water. The core can be divided into six structural units based upon degree of fracturing. A highly fractured interval is found between 1,646 and 1,899 feet, which coincides with the dissolution or leached nahcolite zone. Physical property tests made on core samples between 1,356 and 3,253 feet give average values of 11,988 psi for uniaxial compressive strength, 1.38 X 10[superscript]6[superscript] psi for static Young's modulus and 11,809 fps for compressional velocity.

Open-File Report↗