Publications
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Event detection performance of the PLUM earthquake early warning algorithm in southern California
We test the Japanese ground‐motion‐based earthquake early warning (EEW) algorithm, propagation of local undamped motion (PLUM), in southern California with application to the U.S. ShakeAlert system. In late 2018, ShakeAlert began limited public alerting in Los Angeles to areas of expected modified Mercalli intensity (IMMI) 4.0+ for magnitude 5.0+ earthquakes. Most EEW systems, including ShakeAle
Authors
Elizabeth S. Cochran, Julian Bunn, Sarah E. Minson, Annemarie S. Baltay, Deborah L. Kilb, Y. Kodera, Mitsuyuki Hoshiba
Source-dependent amplification of earthquake ground motions in deep sedimentary basins
Deep sedimentary basins amplify long-period shaking from seismic waves, increasing the seismic hazard for cities within such basins. We perform 3-D simulations of point source earthquakes distributed around the Seattle and Tacoma basins in Washington State, to examine the dependence of basin amplification on source azimuth, depth, and earthquake type. For periods between 1-10 s, the pattern of amp
Authors
Erin Wirth, John E. Vidale, Arthur Frankel, Thomas L. Pratt
A 4000-year history of debris flows in north-central Washington State, U.S.A.: Preliminary results from trenching and surficial geologic mapping at the Pope Creek fan
Long-term records of the magnitude and frequency of debris flows on fans are rare, but such records provide critical information needed for debris-flow hazard and risk assessments. This study explores the history of debris flows on a fan with seasonally inhabited cabins at Pope Creek along the Entiat River about 48 km upstream from the town of Entiat, Washington. Motivation for this study was prov
Authors
Jeffrey A. Coe, Erin Bessette-Kirton, Stephen Slaughter, Francis K. Rengers, Trevor A. Contreras, Katherin A Michelson, Emily Taylor, Jason W. Kean, Kara Jacobacci, Molly A Hanson
Exploring controls on debris-flow surge velocity and peak discharge at Chalk Cliffs, Colorado, USA
We present a series of debris-flow events and use combined sensor and video data to explore how sediment concentration and triggering rainfall intensity affect the velocity and discharge of debris-flow surges generated by surface-water runoff. We analyze an initial data set of 49 surges from four debris-flow events recorded by a monitoring system at Chalk Cliffs, Colorado and compare measurements
Authors
Joel B. Smith, Jason W. Kean, Jeffrey A. Coe
An evaluation of debris-flow runout model accuracy and complexity in Montecito, CA: Towards a framework for regional inundation-hazard forecasting
Numerous debris-flow inundation models have been applied retroactively to noteworthy events around the world. While such studies can be useful in identifying controlling factors, calibrating model parameters, and assessing future hazards in specific study areas, model parameters tailored to individual events can be difficult to apply regionally. The advancement of debris-flow modeling applications
Authors
Erin Bessette-Kirton, Jason W. Kean, Jeffrey A. Coe, Francis K. Rengers, Dennis M. Staley
Thin-layer sediment addition to an existing salt marsh to combat sea-level rise and improve endangered species habitat in California, USA
Current tidal marsh elevations and their accretion rates are important predictors of vulnerability to sea-level rise. When tidal marshes are at risk, adaptation measures, such as sediment addition to increase elevations, can be implemented to prevent degradation and loss. In 2016, wildlife managers prescribed a thin-layer sediment addition of locally sourced dredged material from Anaheim Bay to mi
Authors
Karen M. Thorne, Chase M. Freeman, Jordan A. Rosencranz, Neil K. Ganju, Glenn R. Guntenspergen
Real-time monitoring of debris-flow velocity and mass deformation from field experiments with high sample rate lidar and video
Debris flows evolve in both time and space in complex ways, commonly starting as coherent failures but then quickly developing structures such as roll waves and surges. This process is readily observed, but difficult to study or quantify because of the speed at which it occurs. Many methods for studying debris flows consist of point measurements (e.g., of flow height or basal stresses), which are
Authors
Francis K. Rengers, Thomas Rapstine, Kate E. Allstadt, Michael Olsen, Michael Bunn, Richard M. Iverson, Jason W. Kean, Ben Leshchinsky, Matthew Logan, Mahyar Sharifi-Mood, Maciej Obryk, Joel B. Smith
Looking through the window of disturbance at post-wildfire debris-flow hazards
The extreme heat from wildfire alters soil properties and incinerates vegetation, leading to changes in infiltration capacity, ground cover, soil erodibility, and rainfall interception. These changes promote increases in runoff and sediment transport that increase the likelihood of runoff-generated debris flows. Over a period of several years, referred to as the window of disturbance, the landscap
Authors
Luke McGuire, Francis K. Rengers, Jason W. Kean, Dennis M. Staley, Hui Tang, Ann Youberg
Topographic change detection at Chalk Cliffs, Colorado, USA, using Airborne LiDAR and UAS-based Structure-from-Motion photogrammetry
The Chalk Cliffs debris-flow site is a small headwater catchment incised into highly fractured and hydrothermally altered quartz monzonite in a semi-arid climate. Over half of the extremely steep basin is exposed bedrock. Debris flows occur multiple times per year in response to rainstorm events, typically during the summer monsoon season. The frequency of debris flows, and the uniformity of the u
Authors
Katherine R Barnhart, Francis K. Rengers, Ghent Jessica N, Gregory E. Tucker, Jeffrey A. Coe, Jason W. Kean, Joel B. Smith, Dennis M. Staley, William Kleiber, Ashton M Wiens
Data Report: Permeability, porosity, and frictional strength of core samples from IODP Expedition 366 in the Mariana forearc
Core samples from the International Ocean Discovery Program (IODP) Expedition 366 were tested in the laboratory to determine permeability, porosity, density, and frictional strength and their relation to mineralogy as part of an effort to understand hydro-mechanical processes at convergent plate margins. Seven samples were tested from a depth range of 19.6 to 197.9 m below the sea floor. The sampl
Authors
Carolyn A. Morrow, Diane E. Moore, David A. Lockner, Barbara A. Bekins
Changes in hydrodynamics and wave energy as a result of seagrass decline along the shoreline of a microtidal back-barrier estuary
Seagrasses are marine flowering plants that provide key ecological services. In recent decades, multiple stressors have caused a worldwide decline in seagrass beds. Changes in bottom friction associated with seagrass loss are expected to influence the ability of estuarine systems to trap sediment inputs through local and regional changes in hydrodynamics. Herein, we conduct a numerical study using
Authors
Carmine Donatelli, Neil Kamal Ganju, Tarandeep S. Kalra, S Fagherazzi, Nicoletta Leonardi
The roles of flow acceleration and deceleration in sediment suspension in the surf zone
Prediction of sediment suspension in the surf zone remains elusive. We explore how suspended sediment concentration at 19 cm above the bed in the mid-surf zone during a storm is influenced by flow acceleration and deceleration. There is a tendency for higher suspended sediment concentrations during onshore flow, with decelerating onshore flows having higher concentrations than steady, accelerating
Authors
Bruce E. Jaffe, SeanPaul La Selle