Publications
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Seismic attenuation monitoring of a critically stressed San Andreas fault
We show that seismic attenuation ( ) along the San Andreas fault (SAF) at Parkfield correlates with the occurrence of moderate‐to‐large earthquakes at local and regional distances. Earthquake‐related anomalies are likely caused by changes in permeability from dilatant static stress changes, damage by strong shaking from local sources, and pore unclogging/clogging from mobilization of colloids by
Authors
Luca Malagnini, Thomas E. Parsons
Ensemble ShakeMaps for magnitude 9 earthquakes on the Cascadia Subduction Zone
We develop ensemble ShakeMaps for various magnitude 9 (MM 9) earthquakes on the Cascadia megathrust. Ground‐shaking estimates are based on 30 MM 9 Cascadia earthquake scenarios, which were selected using a logic‐tree approach that varied the hypocenter location, down‐dip rupture limit, slip distribution, and location of strong‐motion‐generating subevents. In a previous work, Frankel et al. (2018)
Authors
Erin Wirth, Alex R. R. Grant, Nasser A. Marafi, Arthur Frankel
Sediment dynamics of a divergent bay–marsh complex
Bay–marsh systems, composed of an embayment surrounded by fringing marsh incised by tidal channels, are widely distributed coastal environments. External sediment availability, marsh-edge erosion, and sea-level rise acting on such bay–marsh complexes may drive diverse sediment-flux regimes. These factors reinforce the ephemeral and dynamic nature of fringing marshes: material released by marsh-edg
Authors
Daniel J. Nowacki, Neil K. Ganju
Generalizing the inversion‐based PSHA source model for an interconnected fault system
This article represents a step toward generalizing and simplifying the procedure for constructing an inversion‐based seismic hazard source model for an interconnected fault system, including the specification of adjustable segmentation constraints. A very simple example is used to maximize understandability and to counter the notion that an inversion approach is only applicable when an abundance o
Authors
Edward H. Field, Kevin R. Milner, Morgan T. Page
Spectral inversion for seismic site response in central Oklahoma: Low-frequency resonances from the Great Unconformity
We investigate seismic site response by inverting seismic ground‐motion spectra for site and source spectral properties, in a region of central Oklahoma, where previous ground‐motion studies have indicated discrepancies between observations and ground‐motion models (GMMs). The inversion is constrained by a source spectral model, which we computed from regional seismic records, using aftershocks as
Authors
Morgan P. Moschetti, Stephen H. Hartzell
Earthquake early warning in Aotearoa New Zealand: A survey of public perspectives to guide warning system development
Earthquake early warning (EEW) can be used to detect earthquakes and provide advanced notification of strong shaking, allowing pre-emptive actions to be taken that not only benefit infrastructure but reduce injuries and fatalities. Currently Aotearoa New Zealand does not have a nationwide EEW system, so a survey of the public was undertaken to understand whether EEW was considered useful and accep
Authors
Julia S. Becker, Sally H. Potter, Lauren Vinnel, Kazuya Nakayachi, Sara McBride, David A. Johnston
More fault connectivity Is needed in seismic hazard analysis
Did the third Uniform California Earthquake Rupture Forecast (UCERF3) go overboard with multifault ruptures? Schwartz (2018) argues that there are too many long ruptures in the model. Here, I address his concern and show that the UCERF3 rupture‐length distribution matches empirical data. I also present evidence that, if anything, the UCERF3 model could be improved by adding more connectivity to th
Authors
Morgan T. Page
Damping values derived from surface-source, downhole-receiver measurements at 22 sites in the San Francisco Bay Area of central California and the San Fernando Valley of southern California
A method discussed in Gibbs, Boore, et al. (1994) was applied to surface‐source, downhole‐receiver recordings at 22 boreholes, in the San Francisco Bay area in central California and the San Fernando Valley of southern California, to determine the average damping ratio of shear waves over depth intervals ranging from about 10 m to as much as 245 m (at one site), with most maximum depths being betw
Authors
David Boore, James F. Gibbs, William B. Joyner
Focused fluid flow and methane venting along the Queen Charlotte fault, offshore Alaska (USA) and British Columbia (Canada)
Fluid seepage along obliquely deforming plate boundaries can be an important indicator of crustal permeability and influence on fault-zone mechanics and hydrocarbon migration. The ~850-km-long Queen Charlotte fault (QCF) is the dominant structure along the right-lateral transform boundary that separates the Pacific and North American tectonic plates offshore southeastern Alaska (USA) and western B
Authors
Nancy G. Prouty, Daniel S. Brothers, Jared W. Kluesner, J. Vaughn Barrie, Brian D. Andrews, Rachel Lauer, Gary Greene, James E. Conrad, Thomas Lorenson, Michael D. Law, Diana Sahy, Kim Conway, Mary McGann, Peter Dartnell
Wildfire and landscape change
Wildfire is a worldwide phenomenon that is expected to increase in extent and severity in the future, due to fuel accumulations, shifting land management practices, and climate change. It immediately affects the landscape by removing vegetation, depositing ash, influencing water-repellent soil formation, and physically weathering boulders and bedrock. These changes typically lead to increased eros
Authors
Paul M. Santi, Francis K. Rengers
Wildfire and Earth surface processes
Wildfire is a worldwide phenomenon that is expected to increase in extent and severity in the future, due to fuel accumulations, shifting land management practices, and climate change. It immediately affects the landscape by removing vegetation, depositing ash, influencing water-repellent soil formation, and physically weathering boulders and bedrock. These changes typically lead to increased eros
Authors
Paul M Santi, Francis K. Rengers
A generic soil velocity model that accounts for near-surface conditions and deeper geologic structure
Near-surface soil conditions can significantly alter the amplitude and frequency content of incoming ground motions – often with profound consequences for the built environment – and are thus important inputs to any ground-motion prediction. Previous soil-velocity models (SVM) have predicted shear-wave velocity profiles based on the time-averaged shear-wave velocity in the upper 30 m (VS30). This
Authors
Nasser A. Marafi, Alex R. R. Grant, Brett W. Maurer, Gunjan Rateria, Marc O Eberhard, Jeff W Berman