Publications

Recent research provides clear geologic evidence that floods even larger than the lethal floods of 1972 have occurred repeatedly over recent millennia in the Black Hills of South Dakota. This information is vitally important for planning for flash flood events in this area.

Statistical analysis is made of rare, extreme geophysical events recorded in historical data -- counting the number of events $k$ with sizes that exceed chosen thresholds during specific durations of time $\tau$. Under transformations that stabilize data and model-parameter variances, the most likely Poisson-event occurrence rate, $k/\tau$, applies for frequentist inference and, also...

Estimates of the probability that an ML 4.8 earthquake, which occurred near the southern end of the San Andreas fault on 24 March 2009, would be followed by an M 7 mainshock over the following three days vary from 0.0009 using a Gutenberg–Richter model of aftershock statistics (Reasenberg and Jones, 1989) to 0.04 using a statistical model of foreshock behavior and long‐term estimates of...

Synthetic seismicity simulations have been explored by the Southern California Earthquake Center (SCEC) Earthquake Simulators Group in order to guide long‐term forecasting efforts related to the Unified California Earthquake Rupture Forecast (Tullis et al., 2012a). In this study I describe the viscoelastic earthquake simulator (ViscoSim) of Pollitz, 2009. Recapitulating to a large extent...

The 11 March 2011 M 9.0 Great East Japan earthquake generated significant long-duration shaking that propagated hundreds of kilometers from the epicenter and affected urban areas throughout much of Honshu. Recorded responses of a tall building at 770 km from the epicenter of the mainshock and other related or unrelated events show how structures sensitive to long-period motions can be...

The Mars Exploration Rover Opportunity has investigated bedrock outcrops exposed in several craters at Meridiani Planum, Mars, in an effort to better understand the role of surface processes in its geologic history. Opportunity has recently completed its observations of Victoria crater, which is 750 m in diameter and exposes cliffs up to ~15 m high. The plains surrounding Victoria crater...

Data on the specific timing of post-fire flash floods and debris flows are very limited. We describe a method to measure the response times of small burned watersheds to rainfall using a low-cost pressure transducer, which can be installed quickly after a fire. Although the pressure transducer is not designed for sustained sampling at the fast rates ({less than or equal to}2 sec) used at...

The rover Opportunity has investigated the rim of Endeavour Crater, a large ancient impact crater on Mars. Basaltic breccias produced by the impact form the rim deposits, with stratigraphy similar to that observed at similar-sized craters on Earth. Highly localized zinc enrichments in some breccia materials suggest hydrothermal alteration of rim deposits. Gypsum-rich veins cut...

The propagation of the rupture of the Mw7.9 Denali fault earthquake from the central Denali fault onto the Totschunda fault has provided a basis for dynamic models of fault branching in which the angle of the regional or local prestress relative to the orientation of the main fault and branch plays a principal role in determining which fault branch is taken. GeoEarthScope LiDAR and...

Landslides are caused by a failure of the mechanical balance within hillslopes. This balance is governed by two coupled physical processes: hydrological or subsurface flow and stress. The stabilizing strength of hillslope materials depends on effective stress, which is diminished by rainfall. This book presents a cutting-edge quantitative approach to understanding hydro-mechanical...

No abstract available.

In order to quantify earthquake risk of any selected region or a country of the world within the Global Earthquake Model (GEM) framework (www.globalquakemodel.org/), a systematic compilation of building inventory and population exposure is indispensable. Through the consortium of leading institutions and by engaging the domain-experts from multiple countries, the GED4GEM project has been...