Publications

In October 2019, California became the first state in the United States to fully activate a public earthquake early warning system—ShakeAlert®—managed by the U.S. Geological Survey. The system was subsequently rolled out in March 2021 in Oregon and May 2021 in Washington. Earthquake early warning (EEW) systems can provide seconds of notice to people and technological systems that shaking...

Executive Summary Landslide hazards are present in all 50 States and most U.S. territories, and they affect lives, property, infrastructure, and the environment. Landslides are the downslope move­ment of earth materials under the force of gravity. They can occur without any obvious trigger. Widespread or severe land­slide events are often driven by such hazards as hurricanes, earthquakes...

No abstract available.

Prior studies have repeatedly shown that probabilistic seismic hazard maps from several different countries predict higher shaking than that observed. Previous map assessments have not, however, considered the influence of site response on hazard. Seismologists have long acknowledged the influence of near-surface geology, in particular low-impedance sediment layers, on earthquake ground...

Inversion of low-frequency regional seismic records to solve for a time series of bulk forces exerted on the earth by a landslide (a force-time function) is increasingly being used to infer volumes and dynamics of large, highly energetic landslides, such as rock avalanches and flowslides, and to provide calibration information on event dynamics and volumes for numerical landslide runout...

We test the behavior of the United States (US) West Coast ShakeAlert earthquake early warning (EEW) system during temporally close earthquake pairs to understand current performance and limitations. We consider performance metrics based on source parameter and ground‐motion forecast accuracy, as well as on alerting timeliness. We generate ground‐motion times series for synthesized...

The U.S. Geological Survey (USGS) National Seismic Hazard Model (NSHM) is used in construction codes, such as the National Earthquake Hazard Reduction Program (NEHRP) Provisions, to develop ground motions for structural and geotechnical design. When the NSHM is updated (e.g. changes to its earthquake rupture forecast or ground motion models), or the manner in which it is implemented in

A variety of models exist for characterizing earthquake-induced ground failures, but application of these models towards regional seismic performance assessments of buried pipelines remains challenging. One challenge is that ground failures often occur at localized geospatial scales while buried pipelines are spatially distributed over long distances. In this study, we propose a...

We develop an empirical, spatially continuous model for the single-station within-event (ϕSS) component of earthquake ground motion variability in the Los Angeles area. ϕSS represents event-to-event variability in site response or remaining variability due to path effects not captured by ground motion models. Site-specific values of ϕSS at permanent seismic network stations were...

We investigate bias in ground motions predicted for Central and Eastern North America (CENA) using ground motion models (GMMs) combined with site amplification models developed in the NGA-East project. Bias is anticipated because of de-coupled procedures used in the development of the GMMs and site amplification models. The NGA-East GMMs were mainly calibrated by adjusting CENA data to a...

This paper presents a summary of the applicability of the NGA-West2 damping scaling factors to ground motions recorded in France. In developing ground motion models for response spectra, generally, the damping of the oscillator is set to a reference value of five percent of the critical damping. Damping scaling factors (DSF) are used to translate the predictions of 5%-damped ground...

Earthquake scenarios are generally selected to serve a wide variety of local and regional needs ranging from testing a community’s ability to respond to earthquakes to developing proactive targeted mitigation strategies for minimizing impending risk. These deterministic scenarios can also be used to communicate seismic hazard and risk to audiences who are not well versed in more complex...