Edward A. Keller

University of California, Santa Barbara

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Duane E. DeVecchio

Arizona State University

T. Rockwell

San Diego State University

Donald L. Johnson

National Park Service

Nicholas Pinter

University of California, Davis

Larry D. Gurrola

Ventura College

Paul Alessio

University of California, Santa Barbara

W. N. Melhorn

Purdue University West Lafayette

Andrew Rich

University of California, Santa Barbara

Kristin Morell

University of California, Santa Barbara

T.L. Ku

University of Southern California

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United States Geological Survey

University of California, Berkeley

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Universidad de Granada

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University of California, Davis

University of California, Los Angeles

Entertainment Industries Council

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Areal Sorting of Bed-Load Material: The Hypothesis of Velocity Reversal: Reply

Geological Society of America Bulletin (1972)

Edward A. Keller

Research Article| March 01, 1972 Areal Sorting of Bed-Load Material: The Hypothesis of Velocity Reversal: Reply E. A KELLER E. A KELLER Department ofGeosciences, Purdue University, Lafayette, Indiana 47907 Search for other works by this author on: GSW Google Scholar Author and Article Information E. A KELLER Department ofGeosciences, Purdue University, Lafayette, Indiana 47907 Publisher: Geological Society of America Received: 24 Aug 1971 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1972, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1972) 83 (3): 915–918. https://doi.org/10.1130/0016-7606(1972)83[915:ASOBMT]2.0.CO;2 Article history Received: 24 Aug 1971 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation E. A KELLER; Areal Sorting of Bed-Load Material: The Hypothesis of Velocity Reversal: Reply. GSA Bulletin 1972;; 83 (3): 915–918. doi: https://doi.org/10.1130/0016-7606(1972)83[915:ASOBMT]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract No abstract available This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

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10.1130/0016-7606(1972)83[915:asobmt]2.0.co;2

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Citations (17)

Neotectonics in Southern California Guidebook: Roadlog 1

Robert S. Yeats Edward A. Keller K.R. Lajoie T. Rockwell Andrei M. Sarna‐Wojcicki

Neotectonics

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Why does institutional vulnerability matter? Perceptions of Community Members from the 2018 Montecito debris flows in California.

International Journal of Disaster Risk Reduction (2025)

Erica Akemi Goto Summer Gray Edward A. Keller

Vulnerability

10.1016/j.ijdrr.2025.105185

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Watershed Controls on the Geomorphology of Small Coastal Lagoons in an Active Tectonic Environment

Estuaries and Coasts (2011)

Andrew Rich Edward A. Keller

10.1007/s12237-011-9439-x

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Citations (6)

Sediment Recruitment and Redistribution in Mountain Channel Networks by Post‐Wildfire Debris Flows

Geophysical Research Letters (2021)

Kristin Morell Paul Alessio Thomas Dunne Edward A. Keller

Abstract We used lidar differencing and field observations to map volumes, and interpret the origins of, sediment mobilized from mountain canyons by large post‐wildfire debris flows near Montecito, CA, USA in 2018. The debris flows progressively entrained and partially redeposited 550,000 m 3 of previously stored channel sediments throughout the canyon networks. The observations that scour depths and volumes were highest where the largest volumes of bouldery colluvium and debris‐flow deposits had accumulated, and that scour persisted beyond the mountain front, indicates that debris‐flow volumes in this extreme event were ultimately controlled by the coarse sediment reservoir available for scour. Because the volumes of available stored sediment result from the stochastic interaction of colluvial mass wasting, the magnitude and frequency of previous debris flows, and the accommodation space provided by valley morphology, the study reinforces the importance of estimating stored sediment volumes when developing debris‐flow hazard assessments.

Debris flow

Mass wasting

Colluvium

Sedimentary budget

Hyperconcentrated flow

Rockfall

Ravine

10.1029/2021gl095549

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Citations (32)

HYDROLOGICAL RESPONSE OF SMALL WATERSHEDS FOLLOWING THE SOUTHERN CALIFORNIA PAINTED CAVE FIRE OF JUNE 1990

Hydrological Processes (1997)

Edward A. Keller D. W. Valentine Dennis R. Gibbs

Following the Painted Cave Fire of 25 June 1990 in Santa Barbara, California which burned 1214 ha, an emergency watershed protection plan was implemented consisting of stream clearing, grade stabilizers and construction of debris basins. Research was initiated focusing on hydrological response and channel morphology changes on two branches of Maria Ygnacio Creek, the main drainage of the burned area. Research results support the hypothesis that the response of small drainage basins in chaparral ecosystems to wildfire is complex and flushing of sediment by fluvial processes is more likely than by high magnitude debris flows. During the winter of 1990–1991, 35–66 cm of rainfall and intensities up to 10 cm per hour for a five-minute period were recorded with a seasonal total of 100% of average (normal) rainfall (average=63 cm/year). During the winter of 1991–1992, 48–74 cm of rainfall and intensities up to 8 cm per hour were recorded with a seasonal total of 115% of normal. Even though there was moderate rainfall on barren, saturated soils, no major debris flows occurred in burned areas. The winter of 1992–1993 recorded total precipitation of about 170% of normal, annual average intensities were relatively low and again no debris flows were observed. The response to winter storms in the first three years following the fire was a moderate but spectacular flushing of sediment, most of which was derived from the hillslopes upstream of the debris basins. The first significant storm and stream flow of the 1990–1991 winter was transport-limited resulting in large volumes of sediment being deposited in the channel of Maria Ygnacio Creek; the second storm and stream flow was sediment-limited and the channel scoured. Debris basins trapped about 23 000 m3, the majority coming from the storm of 17–20 March 1991. Sediment transported downstream during the three winters following the fire and not trapped in the debris basins was eventually flushed to the estuarine reaches of the creeks below the burn area, where approximately 108 000 m3 accumulated. Changes in stream morphology following the fire were dramatic as pools filled with sediment which greatly smoothed longitudinal and cross-sectional profiles. Major changes in channel morphology occur following a fire as sediment derived from the hillslope is temporarily stored in channels within the burned area. However, this sediment may quickly move downstream of the burned region, where it may accumulate reducing channel capacity and increasing the flood hazard. Ecological consequences of wildfire to the riparian zone of streams in the chaparral environment are virtually unknown, but must be significant as the majority of sediment (particularly gravel necessary for fish and other aquatic organisms) entering the system does so in response to fires. © 1997 John Wiley & Sons, Ltd.

Flushing

Debris flow

Chaparral

10.1002/(sici)1099-1085(19970330)11:4<401::aid-hyp447>3.0.co;2-p

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Citations (80)

Fluid‐pressure induced seismicity at regional scales

Geophysical Research Letters (1993)

Edward A. Keller Hugo A. Loáiciga

The role of high fluid pressure as a seismogenic agent has been the subject of intense study (Hubert and Rubey, 1959; Hanshaw and Bredehoeft, 1968; Healy and Rubey, 1968; Simpson, 1976; Walder and Nur, 1984; Sibson, 1990). Of particular interest is the so‐called fault‐valve mechanism (Sibson, 1976; Sibson, 1990) a hypothesis whereby fluid pressure rises (as a result of tectonic compression and pore volume reduction) until crustal failure occurs, triggering seismic activity and upward fluid discharge. Sealing and healing of the rock matrix (Richter and Simmons, 1977; Sprunt and Nur, 1979; Angevine et al, 1982) following coseismic stress drop facilitates reaccumulation of fluid pressure, initiating another loading cycle. The fault‐valve mechanism is entertained as a plausible explanation for present‐day seismic activity in the western Transverse Ranges of California. We provide a quantitative test of the fault‐valve hypothesis that uses geologic data and rates of active tectonics for a cross‐section through an active fold‐and‐thrust belt on the flank of a developing mountain range. Rates of fluid pressure buildup and average recurrence times of large earthquakes in the fold‐and‐thrust belt are estimated to be on the order of 10 4 Pa/yr and hundreds of years, respectively.

Fluid pressure

Thrust fault

10.1029/93gl01661

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Citations (12)

Oxygen-isotope correlation of marine terraces and uplift of the Mesa hills, Santa Barbara, California, USA

Geological Society London Special Publications (1999)

M. A. Trecker Larry D. Gurrola Edward A. Keller

Abstract Resolving the chronology of marine terrace sequences is critical for determining uplift rates along tectonically active coastlines. Unfortunately, lack of suitable dating materials often makes this difficult. We present here oxygen isotopic data from 21 shells of Olivella biplicata from four marine terraces in the Santa Barbara and Ventura area located in southern California, USA. Terraces U-series dated at 47 ± 0.5 ka BP at Isla Vista and 70 ± 2 ka BP at Santa Barbara City College (SBCC) provide age control for the isotopic data. Shells from the Isla Vista and SBCC terraces yield average values of 1.117‰ and 0.627‰. respectively, and shells from a non-U-series dated terrace at Punta Gorda and an undated terrace at Santa Barbara Point yield average values of 1.010‰ and 0.751‰, respectively. The data indicate that stable oxygen isotopic signatures preserved in marine terrace molluscs provide a useful tool for correlating undated terraces with those of known age. Furthermore, we are able to correlate samples collected from offset fragments of the Punta Gorda terrace on either side of the Red Mountain fault, demonstrating the utility of this method for correlating terraces across structural features. Using oxygen isotopic data coupled with the U-series dated wave-cut platform at SBCC we calculate a rate of uplift ranging from 0.62 ± 0.03 mm/year (where the elevation of the first emergent terrace is 41 m) to 0.54 ± 0.05 mm/year (where the elevation of the first emergent terrace is 36 m) for marine terrace flights preserved on the Mesa hills anticline located in the city of Santa Barbara, California.

Mesa

10.1144/gsl.sp.1999.146.01.04

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Citations (19)

Late Pleistocene structural evolution of the Camarillo fold belt: Implications for lateral fault growth and seismic hazard in Southern California

Lithosphere (2012)

Duane E. DeVecchio Edward A. Keller M. Fuchs Lewis A. Owen

The Camarillo fold belt in the Western Transverse Ranges poses a significant seismic hazard to nearly one million people living in Southern California, yet few published geologic or geochronological data from this fold belt exist. The Camarillo fold belt is composed of several south-verging, west-plunging anticlines that characterize the western extent of the Simi fault zone, which extends for 40 km through urbanized Ventura and Los Angeles Counties. Surface and subsurface geologic data are utilized to accurately construct five cross sections within discrete structural domains to assess the local style of deformation, and to quantify the magnitudes of fault slip, fault- and fold-related uplift, and percent shortening. Eight new optically stimulated luminescence (OSL) dates from three paleoseismic trenches and six numerical dates from a previous study were utilized to quantify the timing and rates of deformation on discrete faults and folds. The onset of deformation in the Camarillo fold belt is everywhere younger than ca. 125 ka and locally as young as ca. 25 ka. Quaternary deformation occurs on reactivated steeply dipping (70°) Miocene faults, with shortening being largely accommodated in a narrow zone (<2 km) of folding where fold-related uplift is typically twice as great as hanging-wall uplift in response to fault slip. A minimum fault slip rate between 0.8 mm/yr and 1.4 mm/yr, a recurrence interval of 715–1100 yr, and a maximum Mw 6.8 earthquake for faults within the Simi fault zone is estimated, which are comparable to other better-studied fold belts in Southern California. A model of punctuated lateral fault propagation is proposed to explain westward growth of the Simi fault, which occurs in discrete pulses that are separated by intervals of fault displacement accumulation and fold amplification during constant-fault-length conditions. Lateral fault growth is limited in space and time by an orthogonal north-striking fault set, which juxtaposes a series of west-plunging anticlines that decrease in structural relief and age toward the west.

Anticline

Paleoseismology

10.1130/l136.1

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Citations (13)

Paleoseismicity of the Southern End of the Cascadia Subduction Zone, Northwestern California

Bulletin of the Seismological Society of America (2012)

D. W. Valentine Edward A. Keller G. A. Carver W. H. Li C. Manhart

The southern end of the Cascadia subduction zone (CSZ) in northwestern California poses a high seismic hazard. This study uses the Quaternary stratigraphy of the bays and estuaries to reconstruct coseismic subsidence caused by strong to great earthquakes. We used lithology, macrofossils, and microfossils to estimate the amount of relative sea‐level change at contacts caused by coseismic subsidence. Our paleoseismic record contains evidence of four to six earthquakes over the past 2000 years. Using the pattern and magnitude of submergence and other paleoseismic information (trenches and other sites), we determine whether the earthquakes were local or regional. We found that the record contained evidence for both smaller strong to major earthquakes on local structures ( M w 6.5–7.2) and larger regional subduction‐zone‐related great earthquakes ( M w>8.2). We compared our record to other records from Oregon and Washington and found three earthquakes likely caused by the rupture of the entire CSZ around approximately 230–270 (the A.D. 1700 event), 1150–1400, and 1750–1900 cal B.P. In addition, two other local earthquakes likely occurred around 500–600, 1000–1250, and possibly 1500–1650 cal B.P. Online Material: Table of radiocarbon ages obtained in the study.

10.1785/0120110103

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Citations (16)