David Hill (Former Employee)

Hill (2008) and Hill (2010) contain two technical errors: (1) a missing factor of 2 for computed Love‐wave amplitudes, and (2) a sign error in the off‐diagonal elements in the Euler rotation matrix.

The residents of coastal North Carolina are occasionally treated to sequences of booming sounds of unknown origin. The sounds are often energetic enough to rattle windows and doors. A recent sequence occurred in early January 2011 during clear weather with no evidence of local thunder storms. Queries by a local reporter (Colin Hackman of the NBC affiliate WETC in Wilmington, North...

The passage of radiating seismic waves generates transient stresses in the Earth’s crust that can trigger slip on faults far away from the original earthquake source. The triggered fault slip is detectable in the form of earthquakes and seismic tremor. However, the significance of these triggered events remains controversial, in part because they often occur with some delay, long after...

We examine remotely triggered microearthquakes and tectonic tremor in central California following the 2010 Mw 8.8 Chile earthquake. Several microearthquakes near the Coso Geothermal Field were apparently triggered, with the largest earthquake (Ml 3.5) occurring during the large-amplitude Love surface waves. The Chile mainshock also triggered numerous tremor bursts near the Parkfield...

No abstract available.

The ~300-year-old lava on Paoha Island in Mono Lake was produced by the most recent eruption in the Long Valley Caldera area in east-central California. The Long Valley Caldera was formed by a massive volcanic eruption 760,000 years ago. The region is monitored by the Long Valley Observatory (LVO), one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for...

This guidebook includes papers on various aspects of resource evaluation, exploration, petrophysics, reservoir potential, well deliverability and drilling and completion technology. As new shale plays are explored for and developed, it is important to learn from analogs and case histories, including those from outside the Rocky Mountain region. While the emphasis is on natural gas, we...

No abstract available.

No abstract available.

A GPS survey of leveling benchmarks done in Long Valley Caldera in 1999 showed that the application of the National Geodetic Survey (NGS) geoid model GEOID99 to tie GPS heights to historical leveling measurements would significantly underestimate the caldera ground deformation (known from other geodetic measurements). The NGS geoid model was able to correctly reproduce the shape of the...

Dynamic stresses associated with crustal surface waves with 15-30-sec periods and peak amplitudes 1 MPa are capable of triggering seismicity at sites remote from the generating mainshock under appropriate conditions. Coulomb failure models based on a frictional strength threshold offer one explanation for instances of rapid-onset triggered seismicity that develop during the surface-wave...

Long Valley Caldera and the Mono-Inyo Domes volcanic field in eastern California lie in a left-stepping offset along the eastern escarpment of the Sierra Nevada, at the northern end of the Owens Valley and the western margin of the Basin and Range Province. Over the last 4 Ma, this volcanic field has produced multiple volcanic eruptions, including the caldera-forming eruption at 760 000...