Publications

We have developed and tested (calibration, linearity, and cross-axis errors) a new six-degree-of-freedom mechanical seismic sensor for collocated measurements of three translational and three rotational ground motion velocity components. The device consists of standard geophones arranged in parallel pairs to detect spatial gradients. The instrument operates in a high-frequency range...

[1] Analysis is made of the geomagnetic-activityaaindex covering solar cycle 11 to the beginning of 24, 1868–2011. Autocorrelation shows 27.0-d recurrent geomagnetic activity that is well-known to be prominent during solar-cycle minima; some minima also exhibit a smaller amount of 13.5-d recurrence. Previous work has shown that the recent solar minimum 23–24 exhibited 9.0 and 6.7-d...

The 23 August 2011 Mineral, Virginia, earthquake (Mw 5.8) was the largest to strike the eastern U.S. since 1897 and was felt over an extraordinarily large area. Although no large landslides occurred, the shaking did trigger many rock and soil falls from steep river banks and natural cliffs in the epicentral area and from steep road cuts along, and northwest of, the Blue Ridge Parkway. We...

We use a database of approximately 200,000 modified Mercalli intensity (MMI) observations of California earthquakes collected from USGS "Did You Feel It?" (DYFI) reports, along with a comparable number of peak ground-motion amplitudes from California seismic networks, to develop probabilistic relationships between MMI and peak ground velocity (PGV), peak ground acceleration (PGA), and 0...

Demand surge is understood to be a socio-economic phenomenon where repair costs for the same damage are higher after large- versus small-scale natural disasters. It has reportedly increased monetary losses by 20 to 50%. In previous work, a model for the increased costs of reconstruction labor and materials was developed for hurricanes in the Southeast United States. The model showed that...

The moment magnitude 7.8 earthquake that struck offshore the Mentawai islands in western Indonesia on 25 October 2010 created a locally large tsunami that caused more than 400 human causalities. We identify this earthquake as a rare slow‐source tsunami earthquake based on: 1) disproportionately large tsunami waves; 2) excessive rupture duration near 125 s; 3) predominantly shallow, near...

The eastern margin of the Australia plate is one of the most seismically active areas of the world due to high rates of convergence between the Australia and Pacific plates. In the region of New Zealand, the 3,000 km long Australia-Pacific plate boundary extends from south of Macquarie Island to the southern Kermadec Island chain. It includes an oceanic transform (the Macquarie Ridge)...

There have been 22 M7.5+ earthquakes recorded in the New Guinea region since 1900. The dominant earthquake mechanisms are thrust and strike slip, associated with the arc-continent collision and the relative motions between numerous local microplates. The largest earthquake in the region was a M8.2 shallow thrust fault event in the northern Papua province of Indonesia that killed 166...

This map shows details of the Australia plate and vicinity not presented in Tarr and others (2010). The boundary of the Australia plate includes all fundamental plate boundary components: mid-ocean ridges, subduction zones, arc-continent collisions, and large-offset transform faults. Along the southern edge of the plate the mid-ocean ridge separates the Australia and Antarctica plates...

In response to the June 15, 2010 request from the Polish Geological Institute (PGI) to the U.S. Geological Survey (USGS) for assistance and advice regarding real-time landslide monitoring, landslide specialists from the USGS Landslide Hazard Program visited PGI headquarters and field sites in September 2010. During our visit we became familiar with characteristics of landslides in the...

Four independent ground-motion simulation codes are used to model the strong ground motion for three earthquakes: 1994 Mw 6.7 Northridge, 1989 Mw 6.9 Loma Prieta, and 1999 Mw 7.5 Izmit. These 12 sets of synthetics are used to make estimates of the variability in ground-motion predictions. In addition, ground-motion predictions over a grid of sites are used to estimate parametric...

The Global Seismographic Network (GSN) (Figure 1) plays a key role in providing seismic data for global earthquake monitoring (e.g., Benz et al. 2005), earthquake science (e.g., Tsai et al. 2005), and studies of Earth structure (e.g., Dalton et al. 2008). One of the key GSN design goals is to "provide high fidelity digital recordings of all teleseismic ground motions (adequate to resolve...