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Russell H. Campbell

Publications and source records attributed to Russell H. Campbell.

At least 19 recordsLinked to original sources
USGS2007

The Miocene Topanga group of southern California — A 100-year history of changes in stratigraphic nomenclature

A review of selected literature summarizes the origin and chronology of changes in usage of 'Topanga' in the Miocene stratigraphic nomenclature of the Los Angeles Basin and adjacent areas in southern California. The review was done to summarize and reconcile some differences in Miocene stratigraphic nomenclature as applied to geologic map compilations of the Santa Ana (Morton, 2004), San Bernardino (Morton and Miller, 2003), Long Beach (Saucedo and others, 2003) and Los Angeles (Yerkes and Campbell, 2005) 30' x 60' quadrangles, all of which are products of the cooperative (California Geological Survey-U.S. Geological Survey) Southern California Areal Mapping Project (SCAMP). The deposition of the Topanga Group spans about 6 my (from as old as about 18 ma to as young as about 12 ma), and the sequence of included strata records changes in provenance and depositional environments that are contemporaneous with part of a major Miocene tectonic episode in southern California -- the 'basin-inception phase' in the evolution of the Neogene Los Angeles basin (Yerkes and others, 1965). The area of Topanga deposition extends to the southern, eastern, northern, and northwestern sides of the Los Angeles basin, as well as the southern part of the eastern Ventura Basin. Topanga beds are inferred to underlie the thick upper Miocene and Pliocene deposits of the central Los Angeles Basin and the southern part of the eastern Ventura Basin; however, they have been reached by drilling only in marginal areas, where the overlying deposits are relatively thin. Post-Topanga strata were deposited in more-restricted areas of rapid subsidence. Selected papers are summarized as they relate to the Topanga nomenclature, and are presented in chronological order.

California↗
USGS2005

Preliminary geologic map of the Los Angeles 30' x 60' quadrangle, Southern California

This data set maps and describes the geology of the Los Angeles 30? x 60? quadrangle, southern California. Compilation of the Los Angeles quadrangle is based upon published mapping at scales of 1:12,000 and smaller, unpublished mapping at scales of 1:12,000 and smaller, with reconnaissance mapping by the compilers to resolve some edge-matching problems. The Los Angeles 30' x 60' quadrangle covers approximately 5,000 km2 including some of the most densely populated urban and suburban areas of the southern California megalopolis. It extends about 90 km E-W and about 55 km N-S, from Fillmore and Thousand Oaks in the west to Vincent in the northeast and Montebello in the southeast, and includes urban San Gabriel Valley and San Gabriel Mountain foothill communities from Monrovia to Pasadena, as well as Glendale, downtown Los Angeles, Hollywood, Santa Monica, Malibu, in addition to all the communities in the San Fernando Valley, Simi Valley, and the upper Santa Clara River Valley. From the 2000 Census, the population of these urban and suburban areas totals approximately 5.6 million, and estimates of property value total hundreds of billions of dollars. Residents and transient visitors are subject to potential hazards from earthquakes, debris flows and other landslides, floods, wildfires, subsidence from ground water and petroleum withdrawal, and swelling soils; and coastal areas are exposed to flooding and erosion by storm and tsunami waves. Topographic relief ranges from about one hundred meters sub sea (in Santa Monica Bay) to more than 2,000 meters above sea level at Pacifico Mountain in the high San Gabriel Mountains. In addition to the populated area, the quadrangle includes significant areas of wilderness in the Angeles and Los Padres National Forests, in the Santa Monica Mountains National Recreation Area, and the Sespe Condor Sanctuary. The geologic map illustrates the general distribution of the rocks and surficial deposits in the area and their structural and stratigraphic relations to one another. The principal characteristics of the map units are described and are part of the database. The map provides a regional geologic framework as an aid to better evaluations of the potential for hazard from active earth processes. It synthesizes and combines studies by many earth scientists. Most of the source maps are at more detailed scales than 1:100,000, and we utilized the most detailed source materials available. We have not attempted to resolve all problems of stratigraphic correlation and nomenclature. In most areas we have retained the unit designations of source-map authors, but in some areas, particularly in the igneous-metamorphic complex of the San Gabriel Mountains, some unit designations have been changed. Hopefully, this map will stimulate further work to describe and correlate the many units within the scope of a more coherent, more accurate geologic history.

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USGS2003

Preliminary soil-slip susceptibility maps, southwestern California

This group of maps shows relative susceptibility of hill slopes to the initiation sites of rainfall-triggered soil slip-debris flows in southwestern California. As such, the maps offer a partial answer to one part of the three parts necessary to predict the soil-slip/debris-flow process. A complete prediction of the process would include assessments of “where”, “when”, and “how big”. These maps empirically show part of the “where” of prediction (i.e., relative susceptibility to sites of initiation of the soil slips) but do not attempt to show the extent of run out of the resultant debris flows. Some information pertinent to “when” the process might begin is developed. “When” is determined mostly by dynamic factors such as rainfall rate and duration, for which local variations are not amenable to long-term prediction. “When” information is not provided on the maps but is described later in this narrative. The prediction of “how big” is addressed indirectly by restricting the maps to a single type of landslide process—soil slip-debris flows. The susceptibility maps were created through an iterative process from two kinds of information. First, locations of sites of past soil slips were obtained from inventory maps of past events. Aerial photographs, taken during six rainy seasons that produced abundant soil slips, were used as the basis for soil slip-debris flow inventory. Second, digital elevation models (DEM) of the areas that were inventoried were used to analyze the spatial characteristics of soil slip locations. These data were supplemented by observations made on the ground. Certain physical attributes of the locations of the soil-slip debris flows were found to be important and others were not. The most important attribute was the mapped bedrock formation at the site of initiation of the soil slip. However, because the soil slips occur in surficial materials overlying the bedrocks units, the bedrock formation can only serve as a surrogate for the susceptibility of the overlying surficial materials. The maps of susceptibility were created from those physical attributes learned to be important from the inventories. The multiple inventories allow a model to be created from one set of inventory data and evaluated with others. The resultant maps of relative susceptibility represent the best estimate generated from available inventory and DEM data. Slope and aspect values used in the susceptibility analysis were 10-meter DEM cells at a scale of 1:24,000. For most of the area 10-meter DEMs were available; for those quadrangles that have only 30-meter DEMs, the 30-meter DEMS were resampled to 10-meters to maintain resolution of 10-meter cells. Geologic unit values used in the susceptibility analysis were five-meter cells. For convenience, the soil slip susceptibility values are assembled on 1:100,000-scale bases. Any area of the 1:100,000-scale maps can be transferred to 1:24,000-scale base without any loss of accuracy. Figure 32 is an example of part of a 1:100,000-scale susceptibility map transferred back to a 1:24,000-scale quadrangle.

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USGS1997

Debris-flow hazard map units from gridded probabilities

The common statistical practice of dividing a range of probabilities into equal probability intervals may not result in useful landslide-hazard map units for areas populated by equal-area cells, each of which has a unique probability. Most hazard map areas contain very large numbers of cells having low probability of failure, and as probability increases, the number of cells decreases in a non-linear fashion. Exploration of this distribution suggests that the spatial frequency of expected failures may be used to identify probability intervals that define map units. From a spatial database of gridded probabilities, map units that address the different objectives of land-use planners and emergency response officials can be defined.

Conference Paper↗
USGS1995

Preliminary geologic map of the Val Verde 7.5' quadrangle, southern California: A digital database

This Open-File report is a digital geologic map database. A pamphlet serves to introduce and describe the digital data. There is no paper map included in the Open-File report. This digital map database is compiled from previously published sources combined with some new mapping and modifications in nomenclature. The geologic map database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U. S. Geological Survey. For detailed descriptions of the units, their stratigraphic relations and sources of geologic mapping consult Yerkes and Campbell (1995). More specific information about the units may be available in the original sources.

California↗
USGS1995

Preliminary Geologic Map of the Thousand Oaks 7.5' Quadrangle, Southern California: A Digital Database

Thousand Oaks is located in Arroyo Conejo, a region spanning both southeastern Ventura County and extreme northwest Los Angeles County in southern California. It was discovered in 1542 by Spanish explorer Juan Rodriquez Cabrillo and eventually became part of the Spanish Rancho El Conejo land grant (conejo means 'rabbit' in Spanish, of which there are many in the area). It is located in the Santa Monica Mountains in the northwestern part of the greater Los Angeles area. The area is bordered by the San Fernando Valley and the city of Los Angeles to the east, Simi Hills to the north, Las Posas Hills and the Santa Rosa Valley to the northwest, Conejo Mountain (also known as Conejo Hills) and Oxnard Plain to the west, and the Santa Monica Mountains and Malibu to the southwest. The geology of the surrounding Santa Monica Mountains is dominated by a sequence of Tertiary sedimentary and volcanic rocks. These include the Tertiary Modelo Formation and the upper part of the Topanga Formation, other minor Tertiary rocks, and Miocene volcanic and intrusive rocks of the Conejo Formation. The basement units within the Santa Monica Mountains are a series of Jurassic and Cretaceous sedimentary rocks. The volcanic rocks of the Conejo Formation underlies much of the surrounding watersheds. The younger Tertiary sedimentary Modelo and Upper Topanga Formations flank the Conejo to the north and south. On the north slope of the Santa Monica Mountains where the Arroyo Conejo and Thousand Oaks are located, the Tertiary formations are gently folded. The south flank of the Santa Monica Mountains is structurally dominated by the Malibu Coast Fault that runs along the foot of the mountains. This fault, and associated structures, creates a complex geologic setting on the south flank of the Santa Monica Mountains. The active nature of the Malibu Coast fault and associated structures accounts for the steep and rugged coastal topography. The most widely exposed rock units in the area are the Plio-Pleistocene marine and nonmarine Pico and Saugus formations, which crop out on the southern flank of South Mountain-Oak Ridge and on the Las Posas uplands and Las Posas Hills. Locally, the Pico Formation consists of marine siltstone and silty shale with minor sandstone and pebbly sandstone. The Saugus Formation overlies and interfingers with the Pico Formation and is composed of interbedded shallow-marine to brackish water sandstone, siltstone, pebble-cobble conglomerate, and coquina beds that grade laterally and vertically into non-marine sandstone, siltstone, and conglomerate. A local member of the Saugus Formation is exposed in the southeast corner of the map area. It is predominantly a volcanic breccia conglomerate that resembles the Conejo Volcanics breccia, but is believed to represent remnants of landslide debris shed from the Conejo Formation into a local trough during Saugus time. Eroded from, and overlying, these bedrock formations are a series of recent alluvial units. These alluvial units include Quaternary alluvium comprised of alluvium, stream deposits, alluvial fan and floodplain deposits, beach deposits, dissected older alluvial deposits. Also present are Quaternary landslides and colluvium composed of landslide deposits and colluvium deposits. The colluvium represents relatively thick continuous deposits of soil and rock fragments that are common on the steep slopes of the coastal canyons, and generally feed the many landslides, soil slips, and debris flows.

Open-File Report↗
USGS1995

Preliminary geologic map of the Oat Mountain 7.5' quadrangle, southern California: A digital database

This database, identified as "Preliminary Geologic Map of the Oat Mountain 7.5' Quadrangle, southern California: A Digital Database," has been approved for release and publication by the Director of the USGS. Although this database has been reviewed and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. This database is released on condition that neither the USGS nor the U. S. Government may be held liable for any damages resulting from its use. This digital map database is compiled from previously published sources combined with some new mapping and modifications in nomenclature. The geologic map database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U. S. Geological Survey. For detailed descriptions of the units, their stratigraphic relations and sources of geologic mapping consult Yerkes and Campbell (1993). More specific information about the units may be available in the original sources.

California↗
USGS1978

Cyclic landsliding at Wrightwood, southern California: A preliminary report

Recurring landslide and mudflow events in the Wrightwood area of Southern California are parts of a composite cycle of landslide activity that includes three recognizable stages. The three stages are interdependent, occur in sequence, and are of different duration. Deposits of the first stage--the largest in size--are removed to positions further downstream by the activity of second- and third-stage landslides. First-stage landslides are represented by huge slumped masses derived from steep bedrock slopes in the canyon heads; the material moves down the principal stream drainage, which may be completely filled with debris. Second-stage activity develops as streams cut a network of branching channels into the massive first-stage deposit. The second-stage landslides are chiefly slumps from the older slide mass and from adjacent bedrock slopes. The movement of these slides generally is downslope toward actively eroding drainages. Third-stage activity includes mudflows that accompany the spring melting of snowpack. The debris moves down the stream channels to depositional reaches on major fans. Removal of sufficient amounts of the first-stage landslide mass to the fan by second- and third-stage events resets the bedrock slope of the main drainage for another first-stage event. The first-stage landslides in the Wrightwood area are of prehistoric origin, and their recurrence interval in any one canyon is probably several thousand years. The active duration of a first-stage landslide is one to several thousand years. Second-stage landslides last one to several years and are apparently preceded and triggered by a series of high-precipitation winters. The duration of observed third-stage (spring mudflow) sequences ranges from a few days to as much as six weeks; peak mudflow activity apparently results when a-heavy spring snowmelt occurs during a period of second-stage landslide activity.

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USGS1974

Preparation and use of isopleth maps of landslide deposits

Isopleth maps derived from landslide inventory maps generalize and quantify the areal distribution of landslide deposits in contour form and may be uniquely useful for some types of regional planning. The isopleth format permits incorporation of landslide information with other quantified map data in the preparation of slope stability maps. The isopleth map of landslide deposits in San Mateo County, California (scale 1:300,000), serves as an example of this technique.

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