Publications

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...

This report is an update to the presentation by Schulz (1989) introducing potential users to the creepmeter data collected between the publication of Schulz’s report and mid-2020. The creepmeter network monitors aseismic, surface slip at various locations on the Hayward, Calaveras, and San Andreas Faults in northern and central California. There are different designs of creepmeters and...

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...

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...

Martian gullies resemble water-carved gullies on Earth, yet their present-day activity cannot be explained by water-driven processes. The sublimation of CO2 has been proposed as an alternative driver for sediment transport, but how this mechanism works remains unknown. Here we combine laboratory experiments of CO2-driven granular flows under Martian atmospheric pressure with 1D climate...

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...

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...

Executive SummaryThe U.S. Geological Survey has a long history of contributions to the understanding and resolution of various scientific questions related to earthquakes associated with human activities, referred to as induced seismicity. Work started with the Rocky Mountain Arsenal studies in the 1960’s (Healy and others, 1968) when it was first discovered that fluid waste-disposal...

Earthquakes pose substantial threats to communities worldwide. Understanding how people respond to the fast-changing environment during earthquakes is crucial for reducing risks and saving lives. This study aims to study people’s protective action decision-making in earthquakes by leveraging explainable machine learning and video data. Specifically, this study first collected real-world...

The objective of the study is to assess when liquefaction is triggered in a suite of ground motions following simplified approaches and measure the remaining post-triggering energy content of those ground motions. For liquefaction-induced deformations, current simplified analysis procedures do not directly incorporate temporal effects and rely on peak transient intensity measurements...

The conceptual risk framework, previously developed by the U.S. Geological Survey, for uranium mining was updated to include indigenous knowledge components informed by the Havasupai Tribe perspective. This General Information Product was designed to show the contaminant exposure framework from the Havasupai perspective in the Havasupai language.

Comet 67P/Churyumov-Gerasimenko displays a pronounced hemispherical dichotomy in surface morphology, where the southern hemisphere exhibits more erosional features than the northern hemisphere due to receiving much greater solar radiation. Consequently, it is generally assumed that particles are ejected from the southern hemisphere through sublimation and a significant fraction...