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R. E. Kayen

Publications and source records attributed to R. E. Kayen.

34 records · Page 2Linked to original sources
USGS2002

Influence of the Portuguese Bend landslide on the character of the effluent-affected sediment deposit, Palos Verdes margin, southern California

Historic accretion of sediment on the Palos Verdes margin off Los Angeles County, CA, is dominated by two sources, effluent from Whites Point outfall and sediment eroded from the toe of Portuguese Bend landslide. In this paper, we document the recent history of sedimentation from these non-marine sources from 1937 until the late 1990s, and attempt to estimate the amount of material preserved on the shelf. Toward that end, we characterized offshore sediment by physical and geotechnical testing, using non-destructive gamma-ray whole-core logging techniques and conventional geotechnical strength tests, and X-ray diffraction. Results are reported within a geographic information system framework that allows for: (1) the evaluation of the spatial variability of the measured properties, and (2) assessment of the influence of these properties on processes affecting the effluent-affected Sediment layer. In the inner shelf, material eroded by wave action from the toe of the Portuguese Bend landslide since 1956 has contributed 5.7-9.4 million metric tons (Mmt) of sediment, from a total eroded mass of 12.1 Mmt. A lesser fraction (???2.7Mmt) of sediment is incorporated into the mid- and outer-shelf effluent-affected sediment layer. Evidence from X-ray diffractograms clearly indicates that landslide material has mixed with the mid- and outer-shelf effluent. From 1937-1987, it is estimated that 3.8 Mmt of solid anthropogenic effluent was discharged into the water column and onto the Palos Verdes Shelf.

Continental Shelf Research↗
USGS2002

Comments on potential geologic and seismic hazards affecting Mare Island, Solano County, California

This report was prepared in response to a written request from the City of Vallejo, California, to the U.S. Geological Survey (USGS). By letter of October 4, 2002, the City requested that the USGS "provide advice to the City’s LNG Health and Safety Committee on its review of a potential liquid natural gas project" on the southern portion of Mare Island. The City specifically requested that the USGS advise the committee on potential hazards including fault rupture, earthquake ground motion, soil failure during earthquakes, tsunami and seiche, and landslides. The City requested that the USGS: (1) comment on these hazards, (2) describe its degree of confidence in its opinions, and (3) describe the scope of additional studies that will be needed if the City enters into an agreement with project sponsors. Advice was also requested on the selection of the safe shutdown and operating basis earthquakes as specified in the NFPA 59A standard (NFPA, 2001). This review of published reports and other publicly available information indicates that all of the hazards on which the USGS was asked to comment should be considered for the proposed project on the southern portion of Mare Island. Available information differs greatly for each of these potential hazards, and adequate understanding for design will require detailed site-specific investigations.

California↗
USGS1999

Nondestructive laboratory measurement of geotechnical and geoacoustic properties through intact core-liner

High-resolution automated measurement of the geotechnical and geoacoustic properties of soil at the U.S. Geological Survey (USGS) is performed with a state-of-the-art multi-sensor whole-core logging device. The device takes measurements, directly through intact sample-tube wall, of p-wave acoustic velocity, of soil wet bulk density, and magnetic susceptibility. This paper summarizes our methodology for determining soil-sound speed and wet-bulk density for material encased in an unsplit liner. Our methodology for nondestructive measurement allows for rapid, accurate, and high-resolution (1 cm-spaced) mapping of the mass physical properties of soil prior to sample extrusion.

ASTM Special Technical Publication↗
USGS1997

Arias intensity assessment of liquefaction test sites on the east side of San Francisco Bay affected by the Loma Prieta, California, earthquake of 17 October 1989

Uncompacted artificial-fill deposits on the east side of San Francisco Bay suffered severe levels of soil liquefaction during the Loma Prieta earthquake of 17 October 1989. Damaged areas included maritime-port facilities, office buildings, and shoreline transportation arteries, ranging from 65 to 85 km from the north end of the Loma Prieta rupture zone. Typical of all these sites, which represent occurrences of liquefaction-induced damage farthest from the rupture zone, are low cone penetration test and Standard Penetration Test resistances in zones of cohesionless silty and sandy hydraulic fill, and underlying soft cohesive Holocene and Pleistocene sediment that strongly amplified ground motions. Postearthquake investigations at five study sites using standard penetration tests and cone penetration tests provide a basis for evaluation of the Arias intensity-based methodology for assessment of liquefaction susceptibility.

California↗
USGS1997

Assessment of liquefaction potential during earthquakes by Arias intensity

An Arias intensity approach to assess the liquefaction potential of soil deposits during earthquakes is proposed, using an energy-based measure of the severity of earthquake-shaking recorded on seismograms of the two horizontal components of ground motion. Values representing the severity of strong motion at depth in the soil column are associated with the liquefaction resistance of that layer, as measured by in situ penetration testing (SPT, CPT). This association results in a magnitude-independent boundary that envelopes initial liquefaction of soil in Arias intensity-normalized penetration resistance space. The Arias intensity approach is simple to apply and has proven to be highly reliable in assessing liquefaction potential. The advantages of using Arias intensity as a measure of earthquake-shaking severity in liquefaction assessment are: Arias intensity is derived from integration of the entire seismogram wave form, incorporating both the amplitude and duration elements of ground motion; all frequencies of recorded motion are considered; and Arias intensity is an appropriate measure to use when evaluating field penetration test methodologies that are inherently energy-based. Predictor equations describing the attenuation of Arias intensity as a function of earthquake magnitude and source distance are presented for rock, deep-stiff alluvium, and soft soil sites.

Journal of Geotechnical and Geoenvironmental Engin↗
USGS1996

Misinterpretation of lateral acoustic variations on high-resolution seismic reflection profiles as fault offsets of Holocene bay mud beneath the southern part of San Francisco Bay, California

We collected high-resolution seismic reflection profiles in the southern part of San Francisco Bay in 1992 and 1993 to investigate possible Holocene faulting along postulated transbay bedrock fault zones. The initial analog records show apparent offsets of reflection packages along sharp vertical boundaries. These records were originally interpreted as showing a complex series of faults along closely spaced, sharp vertical boundaries in the upper 10 m (0.013 s two-way travel time) of Holocene bay mud. A subsequent survey in 1994 was run with a different seismic reflection system, which utilized a higher power source. This second system generated records with deeper penetration (max. 20 m, 0.026 s two-way travel time) and demonstrated that the reflections originally interpreted as fault offsets by faulting were actually laterally continuous reflection horizons. The pitfall in the original interpretations was caused by lateral variations in the amplitude brightness of reflection events, coupled with a long (greater than 15 ms) source signature of the low-power system. These effects combined to show apparent offsets of reflection packages along sharp vertical boundaries. These boundaries, as shown by the second system, in fact occur where the reflection amplitude diminishes abruptly on laterally continuous reflection events. This striking lateral variation in reflection amplitude is attributable to the localized presence of biogenic(?) gas.

Marine and Petroleum Geology↗
USGS1991

Pleistocene slope instability of gas hydrate-laden sediment on the Beaufort Sea margin

In oceanic areas underlain by sediment with gas hydrate, reduction of sea level initiates disassociation along the base of the gas hydrate, which, in turn, causes the release of large volumes of gas into the sediment and creates excess pore-fluid pressures and reduced slope stability. Fluid diffusion properties dominate the disassociation process in fine-grained marine sediment. Slope failure appears likely for this sediment type on moderate slopes unless pressures can be adequately vented away from the gas hydrate base. Pleistocene eustatic-sea level regressions, likely triggered seafloor landslides on the continental slope of the Beaufort Sea and other margins where gas hydrate is present in seafloor sediment. -from Authors

Marine Geotechnology↗
USGS1991

Quantitative controls on submarine slope failure morphology

The concept of the steady-state of deformation can be applied to predicting the ultimate form a landslide will take. The steady-state condition, defined by a line in void ratio-effective stress space, exists at large levels of strain and remolding. Conceptually, if sediment initially exists with void ratio-effective stress conditions above the steady-state line, the sediment shear strength will decrease during a transient loading event, such as an earthquake or storm. If the reduced shear strength existing at the steady state is less than the downslope shear stress induced by gravity, then large-scale internal deformation, disintegration, and flow will occur. -from Authors

Marine Geotechnology↗
USGS1990

Geotechnical characteristics and slope stability on the Ebro margin, western Mediterranean

Sedimentological and geotechnical analyses of core samples from the Ebro continental slope define two distinct areas on the basis of sediment type, physical properties and geotechnical behavior. The first area is the upper slope area (water depths of 200–500 m), which consists of upper Pleistocene prodeltaic silty clay with a low water content (34% dry weight average), low plasticity, and high overconsolidation near the seafloor. The second area, the middle and lower slope (water depths greater than 500 m), contains clay- and silt-size hemipelagic deposits with a high water content (90% average), high plasticity, and a low to moderate degree of overconsolidation near the sediment surface. Results from geotechnical tests show that the upper slope has a relatively high degree of stability under relatively rapid (undrained) static loading conditions, compared with the middle and lower slopes, which have a higher degree of stability under long-term (drained) static loading conditions. Under cyclic loading, which occurs during earthquakes, the upper slope has a higher degree of stability than the middle and lower slopes. For the surface of the seafloor, calculated critical earthquake accelerations that can trigger slope failures range from 0.73 g on the upper slope to 0.23 g on the lower slope. Sediment buried well below the seafloor may have a critical acceleration as low as 0.09 g on the upper slope and 0.17 g on the lower slope. Seismically induced instability of most of the Ebro slope seems unlikely given that an earthquake shaking of at least intensity VI would be needed, and such strong intensities have never been recorded in the last 70 years. Other cyclic loading events, such as storms or internal waves, do not appear to be direct causes of instability at present. Infrequent, particularly strong earthquakes could cause landslides on the Ebro margin slope. The Columbretes slide on the southwestern Ebro margin may have been caused by intense earthquake shaking associated with volcanic emplacement of the Columbretes Islands. Localized sediment slides on steep canyon and levee slopes could have been caused by less intense shaking. In general, the slope is stable under present environmental loading conditions and is fundamentally constructional. Nevertheless, rapid progradation caused by high sedimentation rates and other processes acting during low sea-level periods, such as more intense wave loading near the shelfbreak, may have caused major instability in the past.

Marine Geology↗
USGS1989

Morphology of sea-floor landslides on Horizon Guyot: application of steady-state geotechnical analysis

Mass movement and erosion have been identified on the pelagic sediment cap of Horizon Guyot, a seamount in the Mid-Pacific Mountains. Trends in the size, shape and preservation of bedforms and sediment textural trends on the pelagic cap indicate that bottom-current-generated sediment transport direction is upslope. Slumping of the sediment cap occurred on and that the net bedload transport direction is upslope. Slumping of the sediment cap occurred on the northwest side of the guyot on a 1.6?? to 2.0?? slope in the zone of enhanced bottom-current activity. Submersible investigations of these slump blocks show them to be discrete and to have a relief of 6-15 m, with nodular chert beds cropping out along the headwall of individual rotated blocks. An evaluation of the stability of the sediment cap suggests that the combination of the current-induced beveling of the sea floor and infrequent earthquake loading accompanied by cyclic strength reduction is responsible for the initiation of slumps. The sediment in the area of slumping moved short distances in relatively coherent masses, whereas sediment that has moved beyond the summit cap perimeter has fully mobilized into sediment gravity flows and traveled large distances. A steady-state geotechnical analysis of Horizon Guyot sediment indicates the predisposition of deeply buried sediment towards disintegrative flow failure on appropriately steep slopes. Thus, slope failure in this deeper zone would include large amounts of internal deformation. However, gravitational stress in the near-surface sediment of the summit cap (sub-bottom depth < 14 m) is insufficient to maintain downslope movement after initial failure occurs. The predicted morphology of coherent slump blocks displaced and rafted upon a weakened zone at depth corresponds well with seismic-reflection data and submersible observations. ?? 1990.

Deep Sea Research Part A, Oceanographic Research P↗
USGS1988

Erosion and slope instability on Horizon Guyot, Mid-Pacific Mountains

Seismic-reflection profiles, sediment cores, and current velocities were assessed to study the impact of erosion and sediment redistribution on the pelagic sediment cap of Horizon Guyot, a flat-topped submarine volcanic ridge in the Mid-Pacific Mountains. These processes seem to concentrate their effect around the rim of the sediment cap. Sediment slumping occurs on the northwest perimeter of the guyot's sediment cap. Slope stability analysis suggests that if overconsolidation on Horizon Guyot is the result of current reworking or if local undercutting by bottom currents steepens the sea floor declivity, the sediment cap may be unstable during infrequent earthquake loading, transporting sediment from the guyot summit to the abyssal sea floor. ?? 1988 Springer-Verlag New York Inc.

Geo-Marine Letters↗