Annemarie Baltay

I study how physical measures of earthquakes and the earth control ground motions measured at distance, and how ground motion observations can be used to gain insight on the earthquake source and path. I am particularly interested in earthquake stress drop: how it is measured, what is the variability, and how that all relates to ground motion data and models. I am also focused on physical components and uncertainty of ground-motion prediction equations (GMPEs), a critical building block in hazard maps. Reducing the variability and uncertainty in GMPEs is imperative to building better hazard maps, as well as for performing more accurate site-specific hazard studies for critical facilities. Currently, I am working towards physical explanations for variability in the source, site, and path components in ground motions. Ultimately we will develop models for predicting those effects from geophysical observables, such as stress drop (for source), site velocity profiles and attenuation (for site), and whole-path attenuation (for path). I am also involved in the USGS-led ShakeAlert earthquake early warning project, which aims to alert the U.S. West coast for earthquake ground motion before it arrives at a user's location; as part of that project, I work on the best ways to model ground motion and associated uncertainty in early warning, as well as chair the Ground Motion Working Group and collaborate on the PLUM algorithm development.