Publications

Two recent earthquakes left their mark on Santiago de Chile and Tokyo, well beyond the rupture zones, raising questions about the future vulnerability of these and other cities that lie in seismically active regions. Though spared strong shaking, the megacities nevertheless lit up in small quakes, perhaps signaling an abrupt change in the condition for failure on the faults beneath the...

In this study, we quantify the seismic and tsunami hazard in the Lesser Antilles subduction zone, focusing on the plate interface offshore of Guadeloupe. We compare potential strain accumulated via GPS-derived plate motions to strain release due to earthquakes that have occurred over the past 110 yr, and compute the resulting moment deficit. Our results suggest that enough strain is...

On December 12, 2004, an earthquake of magnitude 2.2, located in the TauTona Gold Mine at a depth of about 3.65 km in the ancient Pretorius fault zone, was recorded by the in-mine borehole seismic network, yielding an excellent set of ground motion data recorded at hypocentral distances of several km. From these data, the seismic moment tensor, indicating mostly normal faulting with a...

A new database of volcanic fatalities is presented and analysed, covering the period 1600 to 2010 AD. Data are from four sources: the Smithsonian Institution, Witham (2005), CRED EM-DAT and Munich RE. The data were combined and formatted, with a weighted average fatality figure used where more than one source reports an event; the former two databases were weighted twice as strongly as...

The most commonly used intensity measure in ground-motion prediction equations is the pseudo-absolute response spectral acceleration (PSA), for response periods from 0.01 to 10 s (or frequencies from 0.1 to 100 Hz). PSAs are often derived from recorded ground motions, and these motions are usually filtered to remove high and low frequencies before the PSAs are computed. In this article...

The Charlevoix, Quebec, earthquake of 20 October 1870 caused damage to several towns in Quebec and was felt throughout much of southeastern Canada and along the U.S. Atlantic seaboard from Maine to Maryland. Site‐specific damage and felt reports from Canadian and U.S. cities and towns were used in analyses of the location and magnitude of the earthquake. The macroseismic center of the...

To better understand what controls fault slip along plate boundaries, we have exploited the abundance of seismic and geodetic data available from the richly varied tectonic environments composing Alaska. A search for tremor triggered by 11 large earthquakes throughout all of seismically monitored Alaska reveals two tremor “sweet spots”—regions where large-amplitude seismic waves...

No abstract available.

The use of seismic noise interferometry to retrieve Green's functions and the analysis of volcanic tremor are both useful in studying volcano dynamics. Whereas seismic noise interferometry allows long-range extraction of interpretable signals from a relatively weak noise wavefield, the characterization of volcanic tremor often requires a dense seismic array close to the source. We here...

Wildfire is a unique natural hazard because it poses immediate threats to life and property as well as creating conditions that can lead to subsequent debris flows. In recent years, the immediate destructive force of wildfires has been decreased through better understanding of fire behavior. Lightning detection networks now identify the number and locations of this common ignition source

Impact bombardment in the first billion years of solar system history determined in large part the initial physical and chemical states of the inner planets and their potential to host biospheres. The range of physical states and thermal consequences of the impact epoch, however, are not well quantified. Here, we assess these effects on the young Earth's crust as well as the likelihood...

The analysis of historical earthquakes in the northeastern Caribbean by ten Brink et al. [2011, hereafter TB11] addresses the occurrence of large and destructive historical earthquakes associated with the North American-Caribbean plate boundary. One conclusion presented in TB11 is that the recurrence interval for large earthquakes on the left-lateral, strike-slip Septentrional Fault (SF)...