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Debris-flow entrainment modelling under climate change: Considering antecedent moisture conditions along the flow path

Debris-flow volumes can increase along their flow path by entraining sediment stored in the channel bed and banks, thus also increasing hazard potential. Theoretical considerations, laboratory experiments and field investigations all indicate that the saturation conditions of the sediment along the flow path can greatly influence the amount of sediment entrained. However, this process is usually n
Anna Könz, Jacob Hirschberg, Brian McArdell, Benjamin B. Mirus, Tjalling de Haas, Perry Bartelt, Peter Molnar

Assessing locations susceptible to shallow landslide initiation during prolonged intense rainfall in the Lares, Utuado, and Naranjito municipalities of Puerto Rico

Hurricane Maria induced about 70 000 landslides throughout Puerto Rico, USA, including thousands each in three municipalities situated in Puerto Rico's rugged Cordillera Central range. By combining a nonlinear soil-depth model, presumed wettest-case pore pressures, and quasi-three-dimensional (3D) slope-stability analysis, we developed a landslide susceptibility map that has very good performance
Rex L. Baum, Dianne L. Brien, Mark E. Reid, William Schulz, Matthew J. Tello

Evaluation of debris-flow building damage forecasts

Reliable forecasts of building damage due to debris flows may provide situational awareness and guide land and emergency management decisions. Application of debris-flow runout models to generate such forecasts requires combining hazard intensity predictions with fragility functions that link hazard intensity with building damage. In this study, we evaluated the performance of building damage fore
Katherine R. Barnhart, Christopher R. Miller, Francis K. Rengers, Jason W. Kean

Forecasting the long-term spatial distribution of earthquakes for the 2023 US National Seismic Hazard Model using gridded seismicity

Probabilistic seismic hazard analyses such as the U.S. National Seismic Hazard Model (NSHM) typically rely on declustering and spatially smoothing an earthquake catalog to estimate a long‐term time‐independent (background) seismicity rate to forecast future seismicity. In support of the U.S. Geological Survey’s (USGS) 2023 update to the NSHM, we update the methods used to develop this background o
Andrea L. Llenos, Andrew J. Michael, Allison Shumway, Justin Rubinstein, Kirstie Lafon Haynie, Morgan P. Moschetti, Jason M. Altekruse, Kevin R. Milner

Empirical ground-motion basin response in the California Great Valley, Reno, Nevada, and Portland, Oregon

We assess how well the Next-Generation Attenuation-West 2 (NGA-West2) ground-motion models (GMMs), which are used in the US Geological Survey’s (USGS) National Seismic Hazard Model (NSHM) for crustal faults in the western United States, predict the observed basin response in the Great Valley of California, the Reno basin in Nevada, and Portland and Tualatin basins in Oregon. These GMMs rely on sit
Sean Kamran Ahdi, Brad T. Aagaard, Morgan P. Moschetti, Grace Alexandra Parker, Oliver S. Boyd, William J. Stephenson

Apparent non-double-couple components as artifacts of moment tensor inversion

Compilations of earthquake moment tensors from global and regional catalogs find pervasive non-double-couple (NDC) components with a mean deviation from a double-couple (DC) source of around 20%. Their distributions vary only slightly with magnitude, faulting mechanism, or geologic environments. This consistency suggests that for most earthquakes, especially smaller ones whose rupture processes ar
Boris Rösler, Seth Stein, Adam T. Ringler, Jiří Vackár

Post-wildfire debris flows

Post-wildfire debris flows pose severe hazards to communities and infrastructure near and within recently burned mountainous terrain. Intense heat of wildfires changes the runoff characteristics of a watershed by combusting the vegetative canopy, litter, and duff, introducing ash into the soil and creating water repellant soils. Following wildfire, rainfall on bare ground is less able to infiltrat
Joseph Gartner, Jason W. Kean, Francis K. Rengers, Scott W. McCoy, Nina S. Oakley, Gary J. Sheridan

Noise constraints on global body‐wave measurement thresholds

Intermediate sized earthquakes (≈M4–6.5) are often measured using the teleseismic body‐wave magnitude (⁠mb⁠). mb measurements are especially critical at the lower end of this range when teleseismic waveform modeling techniques (i.e., moment tensor analysis) are difficult. The U.S. Geological Survey National Earthquake Information Center (NEIC) determines the location and magnitude of all M 5 and g
Adam T. Ringler, David C. Wilson, Paul S. Earle, William L. Yeck, David B. Mason, Justin T. Wilgus

Distinct yet adjacent earthquake sequences near the Mendocino Triple Junction: 20 December 2021 Mw 6.1 and 6.0 Petrolia, and 20 December 2022 Mw 6.4 Ferndale

Two earthquake sequences occurred a year apart at the Mendocino Triple Junction in northern California: first the 20 December 2021 �w 6.1 and 6.0 Petrolia sequence, then the 20 December 2022 �w 6.4 Ferndale sequence. To delineate active faults and understand the relationship between these sequences, we applied an automated deep‐learning workflow to create enhanced and relocated earthquake catalogs
Clara Yoon, David R. Shelly

Data-driven adjustments for combined use of NGA-East hard-rock ground motion and site amplification models

Model development in the Next Generation Attenuation-East (NGA-East) project included two components developed concurrently and independently: (1) earthquake ground-motion models (GMMs) that predict the median and aleatory variability of various intensity measures conditioned on magnitude and distance, derived for a reference hard-rock site condition with an average shear-wave velocity in the uppe
Maria E. Ramos-Sepulveda, Jonathan P. Stewart, Grace Alexandra Parker, Morgan P. Moschetti, Eric M. Thompson, Scott J. Brandenberg, Youssef M A Hashash, Ellen M. Rathje

The influence of anthropogenic regulation and evaporite dissolution on earthquake-triggered ground failure

Remote sensing observations of Searles Lake following the 2019 moment magnitude 7.1 Ridgecrest, California, earthquake reveal an area where surface ejecta is arranged in a repeating hexagonal pattern that is collocated with a solution-mining operation. By analyzing geologic and geotechnical data, here we show that the hexagonal surface ejecta is likely not a result of liquefaction. Instead, we pro
Paula Madeline Burgi, Eric M. Thompson, Kate E. Allstadt, Kyle Dennis Murray, Henry (Ben) Mason, Sean Kamran Ahdi, Devin Katzenstein

Background seismic noise levels among the Caribbean network and the role of station proximity to coastline

The amplitude and frequency content of background seismic noise is highly variable with geographic location. Understanding the characteristics and behavior of background seismic noise as a function of location can inform approaches to improve network performance and in turn increase earthquake detection capabilities. Here, we calculate power spectral density estimates in one‐hour windows for over
Justin T. Wilgus, Adam T. Ringler, Brandon Schmandt, David C. Wilson, Robert E. Anthony