Publications
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Measuring settling velocity in a strongly tidal estuary
Predicting sediment transport in estuarine systems requires understanding sediment settling velocity, its range of fluctuations, and the shortcomings of the tools to measure it. Previous studies have used Laser In-Situ Scattering and Transmissometry (LISST) instruments to measure particle size and Acoustic Doppler Velocimeters (ADV) to return estimates of settling velocity. We deployed both instru
Authors
Rachel Allen, Jessica R. Lacy, Evan A Variano
Controls on sediment transport over coral reefs off southwest Puerto Rico: Seasonal patterns and Hurricane Maria
Guánica Bay in southwest Puerto Rico is highly turbid and has some of the highest PCB concentrations in the USA. To investigate how and to what extent the bay waters influence coral reef ecosystem health along the coastline, 6 months of hydrodynamic data were collected at 8 sites on the insular shelf. Bed shear stresses were primarily driven by waves and were weakest at the site closest to La Parg
Authors
Olivia Cheriton, Curt D. Storlazzi, Kurt J. Rosenberger, Clark Sherman
A physical model of the high-frequency seismic signal generated by debris flows
We propose a physical model for the high‐frequency (>1 Hz) spectral distribution of seismic power generated by debris flows. The modeled debris flow is assumed to have four regions where the impact rate and impulses are controlled by different mechanisms: the flow body, a coarser‐grained snout, a snout lip where particles fall from the snout on the bed, and a dilute front composed of saltating par
Authors
Maxime Farin, Victor C. Tsai, Michael P. Lamb, Kate E. Allstadt
Ground-motion residuals, path effects, and crustal properties: A pilot study in southern California
To improve models of ground motion estimation and probabilistic seismic hazard analyses, the engineering seismology field is moving toward developing fully nonergodic ground motion models, models specific for individual source‐to‐site paths. Previous work on this topic has examined systematic variations in ground‐motion along particular paths (from either recorded or simulated earthquake data) and
Authors
Valerie J. Sahakian, Annemarie S. Baltay, Thomas C. Hanks, Janine Bueler, Frank Vernon, Deborah L. Kilb, Norm A. Abrahamson
Constraining parameter uncertainty in modeling debris-flow initiation during the September 2013 Colorado Front Range storm
The occurrence of debris flows during the September 2013 northern Colorado floods took the emergency management community by surprise. The September 2013 debris flows in the Colorado Front Range initiated from shallow landslides in colluvium. Most occurred on south- and east-facing slopes on the walls of steep canyons in crystalline rocks and on sedimentary hogbacks. Previous studies showed that m
Authors
Rex L. Baum, C.R. Scheevel, Eric S. Jones
Bayesian analysis of the impact of rainfall data product on simulated slope failure for North Carolina locations
In the past decades, many different approaches have been developed in the literature to quantify the load-carrying capacity and geotechnical stability (or the Factor of Safety, F_s) of variably saturated hillslopes. Much of this work has focused on a deterministic characterization of hillslope stability. Yet, simulated F_s values are subject to considerable uncertainty due to our inability to char
Authors
Soni Yatheendradas, Dalia Kirschbaum, Grey Nearing, Jasper A. Vrugt, Rex L. Baum, Rick Wooten, Ning Lu, Jonathan W. Godt
Earthquake-induced chains of geologic hazards: Patterns, mechanisms, and impacts
Large earthquakes initiate chains of surface processes that last much longer than the brief moments of strong shaking. Most moderate- and large-magnitude earthquakes trigger landslides, ranging from small failures in the soil cover to massive, devastating rock avalanches. Some landslides dam rivers and impound lakes, which can collapse days to centuries later, and flood mountain valleys for hundre
Authors
Xuanmei Fan, Gianvito Scaringi, Oliver Korup, A. Joshua West, Cees J. van Westen, Hakan Tanyas, Niels Hovius, Tristram C Hales, Randall W. Jibson, Kate E. Allstadt, Limin Zhang, Stephen G. Evans, Chong Xu, Gen Li, Xiangjun Pei, Qiang Xu, Runqiu Huang
Characterizing seismogenic fault structures in Oklahoma using a relocated template matched catalog
Oklahoma is one of the most seismically active places in the United States as a result of industry activities. In order to characterize the fault networks responsible for these earthquakes in Oklahoma, we relocated a large-scale template matching catalog between 2010-2016 using the GrowClust algorithm . This relocated catalog is currently the most complete statewide catalog for Oklahoma during thi
Authors
Robert Skoumal, Joern Kaven, Jake Water
Active boulder movement at high Martian latitudes
Lobate stony landforms occur on steep slopes at high latitudes on Mars. We demonstrate active boulder movement at seven such sites. Sub-meter-scale boulders frequently move distances of a few meters. The movement is concentrated in the vicinity of the lobate landforms but also occurs on other slopes. This provides evidence for a new, common style of activity on Mars, which may play an important ro
Authors
Colin M. Dundas, Michael T. Mellon, Susan J. Conway, Renaldo Gastineau
Evidence for frequent, large tsunamis spanning locked and creeping parts of the Aleutian megathrust
At the eastern end of the 1957 Andreanof Islands magnitude-8.6 earthquake rupture, Driftwood Bay (Umnak Island) and Stardust Bay (Sedanka Island) lie along presently locked and creeping parts of the Aleutian megathrust, respectively, based on satellite geodesy onshore. Both bays, located 200-km apart, face the Aleutian trench and harbor coastal evidence for tsunami inundation in 1957. Here we desc
Authors
Robert C. Witter, Richard W. Briggs, Simon E. Engelhart, Guy R. Gelfenbaum, Richard D Koehler, Alan R. Nelson, SeanPaul La Selle, Reide Corbett, Kristi L. Wallace
Estimation of ground motion variability in the CEUS using simulations
We estimate earthquake ground-motion variability in the central and eastern U.S. (CEUS) by varying the model parameters of a deterministic physics-based and a stochastic site-based simulation method. Utilizing a moderate-magnitude database of recordings, we simulate ground motions for larger-magnitude scenarios M6.0, 6.5, 7.0, 7.5, and 8.0. For the physics-based method, we vary the faulting mechan
Authors
Xiaodan Sun, Sanaz Rezaeian, Brandon Clayton, Stephen H. Hartzell
Probabilistic seismic hazard analysis using stochastic simulated ground motions
: In recent years, ground motion models used in probabilistic seismic hazard analyses (PSHA) have evolved from the traditional approach of using ground motion prediction equations (GMPEs) to using ground motion time series models. The purpose of this paper is to develop an approach to perform a probabilistic seismic hazard analysis using stochastic site-based simulation techniques. These technique
Authors
Sarah Azar, Mayssa Dabaghi, Sanaz Rezaeian