Publications

Debris flows typically occur when intense rainfall or snowmelt triggers landslides or extensive erosion on steep, debris-mantled slopes. The flows can then grow dramatically in size and speed as they entrain material from their beds and banks, but the mechanism of this growth is unclear. Indeed, momentum conservation implies that entrainment of static material should retard the motion of...

An empirical model of the quiet daily geomagnetic field variation has been constructed based on geomagnetic data obtained from 21 stations along the 210 Magnetic Meridian of the Circum‐pan Pacific Magnetometer Network (CPMN) from 1996 to 2007. Using the least squares fitting method for geomagnetically quiet days (Kp ≤ 2+), the quiet daily geomagnetic field variation at each station was...

The key to advancing the predictability of rainfall-triggered landslides is to use physically based slope-stability models that simulate the transient dynamical response of the subsurface moisture to spatiotemporal variability of rainfall in complex terrains. TRIGRS (transient rainfall infiltration and grid-based regional slope-stability analysis) is a USGS landslide prediction model...

This study demonstrates the novel application of genetic programming to evolve nonlinear post-fire debris-flow volume equations from variables associated with a data-driven conceptual model of the western United States. The search space is constrained using a multi-component objective function that simultaneously minimizes root-mean squared and unit errors for the evolution of fittest...

The M 9.0 11 March 2011 Tohoku, Japan, earthquake and associated tsunami near the east coast of the island of Honshu caused tens of thousands of deaths and potentially over one trillion dollars in damage, resulting in one of the worst natural disasters ever recorded. The U.S. Geological Survey National Earthquake Information Center (USGS NEIC), through its responsibility to respond to...

The USGS National Seismic Hazard Maps are updated about every six years by incorporating newly vetted science on earthquakes and ground motions. The 2008 hazard maps for the central and eastern United States region (CEUS) were updated by using revised New Madrid and Charleston source models, an updated seismicity catalog and an estimate of magnitude uncertainties, a distribution of...

The Johnson Creek Landslide is a translational slide in seaward-dipping Miocene siltstone and sandstone (Astoria Formation) and an overlying Quaternary marine terrace deposit. The basal slide plane slopes sub-parallel to the dip of the Miocene rocks, except beneath the back-tilted toe block, where it slopes inland. Rainfall events raise pore-water pressure in the basal shear zone in the...

We apply a recently developed and validated numerical model of tsunami propagation and runup to study the inundation of Resurrection Bay and the town of Seward by the 1964 Alaska tsunami. Seward was hit by both tectonic and landslide-generated tsunami waves during the MWMW 9.2 1964 megathrust earthquake. The earthquake triggered a series of submarine mass failures around the fjord, which...

Magnetic storms result from the dynamic interaction of the solar wind with the coupled magnetospheric-ionospheric system. Large storms represent a potential hazard for the activities and infrastructure of a modern, technologically based society [Baker et al., 2008]; they can cause the loss of radio communications, reduce the accuracy of global positioning systems, damage satellite...

Unfavorable groundwater conditions are often the determining factor in triggering landslides. Whereas regional hydrogeology typically determines overall groundwater conditions, surficial rainfall infiltration into slopes also drives potential instability.

A series of earthquakes hit the New Madrid seismic zone of southeastern Missouri, northeastern Arkansas, and adjacent parts of Tennessee and Kentucky, in December 1811 to February 1812. Three earthquakes had a magnitude of 7.0 or greater. The first earthquake occurred December 16, 1811, at 2:15 a.m.; the second 9 a.m. on January 23, 1812; and the third on February 7, 1812, at 3:45 a.m...

A late Wisconsin volcano erupted onto the JurassicCretaceous sedimentary bedrock of Augustine Island in lower Cook Inlet in Alaska. Olivine basalt interacting with water erupted explosively. Rhyolitic eruptive debris then swept down the south volcano flank while late Wisconsin glaciers from mountains on western mainland surrounded the island. Early to middle Holocene deposits probably...