Publications

Debris flows represent one of the most dangerous types of mass movements, because of their high velocities, large impact forces and long runout distances. This review describes the available debris-flow monitoring techniques and proposes recommendations to inform the design of future monitoring and warning/alarm systems. The selection and application of these techniques is highly...

Elevated soil moisture and heavy precipitation contribute to landslides worldwide. These environmental variables are now being resolved with satellites at spatiotemporal scales that could offer new perspectives on the development of landslide warning systems. However, the application of these data to hydro-meteorological thresholds (which account for antecedent soil moisture and rainfall...

This presentation summarizes the proposed updates to earthquake design ground motions for the 2020 edition of the NEHRP Recommended Seismic Provisions, expected to be incorporated into the ASCE 7-22 Standard. The implications of these updates on the values of design ground motions for example locations in both conterminous and nonconterminous U.S. cities are shown and discussed.

Geoelectric field time series can be estimated by convolving estimates of Earth‐surface impedance, such as those obtained from magnetotelluric survey measurements, with historical records of geomagnetic variation obtained at magnetic observatories. This straightforward procedure permits the mapping of geoelectric field variation during magnetic storms. Statistical analysis of the time...

Estimation of ground level geoelectric fields has been identified by the National Space Weather Action Plan as a key component of assessment and mitigation of space weather impacts on critical infrastructure. Estimates of spatially and temporally variable electric fields are used to generate statistically based hazard maps and show promise toward monitoring and responding to geomagnetic

Whether large and very large earthquakes are distinguishable from each other early on in the rupture process has been a subject often debated over the past several decades. Studies have shown that the frequency content of radiated seismic energy in the first few seconds of an earthquake scales with the final magnitude of the event, implying determinism. Other studies have shown that the...

The U.S. Geological Survey National Earthquake Information Center leads real-time efforts to provide rapid and accurate assessments of the impacts of global earthquakes, including estimates of ground shaking, ground failure, and the resulting human impacts. These efforts primarily rely on analysis of the seismic wavefield to characterize the source of the earthquake, which in turn...

On the 4th and 5th of March 2005, about 100 rainfall-induced landslides occurred along volcanic slopes of Camaldoli Hill in Naples, Italy. These started as soil slips in the upper substratum of incoherent and welded volcaniclastic deposits, then evolved downslope according to debris avalanche and debris flow mechanisms. This specific case of slope instability on complex volcaniclastic...

Executive Summary Damaging earthquakes occur regularly around the world; since the turn of the 20th century, hundreds of earthquakes have caused significant loss of life and (or) millions of dollars or more in economic losses. While most of these did not directly affect the United States and its Territories, by studying worldwide seismicity we can better understand how to mitigate the...

No abstract available.

In this paper we show that ML-MC is a viable and regionally portable depth discriminant and therefore may contribute in nuclear test ban treaty verification. A recent study found that the difference between local magnitude (ML) and coda duration magnitude (MC) discriminates shallow seismic events (mining blasts, mining-induced earthquakes, and shallow tectonic earthquakes) from deeper...

We invert the shear-wave displacement spectra obtained from 30 three-component, broadband waveforms recorded within 300 km of the 6 November 2011 Mw 5.7 Prague, Oklahoma earthquake to recover the site-response contribution using an inversion method that simultaneously inverts for source, path, and site effects. Site-response functions identify resonant frequencies within a range of 0.1...