Publications

Geologic mapping combined with the tephrochronology of spatially isolated sedimentary sections along the western Black Mountains piedmont adjacent the Death Valley fault zone (DVFZ) improves the late Cenozoic stratigraphy from relative age to correlated age. Pliocene tephra layers identified in Funeral Formation conglomerates at Artist Drive and Copper Canyon include a “Nomlaki-like”...

Yucca Mountain straddles the west boundary of the Nevada Test Site in an arid, remote, and thinly populated region of southwestern Nevada. It is the potential site of a monitored geologic repository for the Nation’s commercial and military spent nuclear fuel, high-level radioactive waste derived from reprocessing of uranium and plutonium, surplus plutonium, and other nuclear-weapons...

The Los Angeles region is underlain by a network of active faults, including many that are deep and do not break the Earth's surface. These hidden faults include the previously unknown one responsible for the devastating January 1994 Northridge earthquake, the costliest quake in U.S. history. So that structures can be built or strengthened to withstand the quakes that are certain in the...

The San Francisco Bay region sits astride a dangerous “earthquake machine,” the tectonic boundary between the Pacific and North American Plates. The region has experienced major and destructive earthquakes in 1838, 1868, 1906, and 1989, and future large earthquakes are a certainty. The ability to prepare for large earthquakes is critical to saving lives and reducing damage to property...

The 1994 Northridge, Calif., earthquake caused widespread permanent ground deformation on the gently sloping alluvial fan surface of the San Fernando Valley. The ground cracks and distributed deformation damaged both pipelines and surface structures. To evaluate the mechanism of soil failure, detailed subsurface investigations were conducted at four sites. Three sites are underlain by...

To help answer the question of how much solid CO2 exists in the Martian south polar cap, we performed a series of laboratory triaxial deformation experiments at constant displacement rate in compression on jacketed cylinders of pure, polycrystalline CO2. Test conditions were temperatures 150 T 190 K, hydrostatic confining pressures 5≤ P ≤40 MPa, and strain rates 4.5×10−8 ≤ ε ≤4.3×10−4 s...

El McVCO es un generador de frecuencias basado en un microcontrolador que reemplaza al oscilador controlado por voltaje (VCO) utilizado en telemetría analógica de datos sísmicas. Acepta señales de baja potencia desde un sismómetro y produce una señal subportadora modulada en frecuencia adecuada para enlaces telefónicos o vía radio a un lugar remoto de recolección de datos. La frecuencia...

A physically-motivated model for earthquake recurrence based on the Brownian relaxation oscillator is introduced. The renewal process defining this point process model can be described by the steady rise of a state variable from the ground state to failure threshold as modulated by Brownian motion. Failure times in this model follow the Brownian passage time (BPT) distribution, which is...

Displacements derived from the accelerogram recordings of the 1999 Chi-Chi, Taiwan earthquake at stations TCU078 and TCU129 show drifts when only a simple baseline derived from the pre-event portion of the record is removed from the records. The appearance of the velocity and displacement records suggests that changes in the zero-level of the acceleration are responsible for these drifts...

Eaton (1975), Bakun and Dratler (1976), Eaton (1977), Healy and O’Neil (1977), Asten (1977), Stewart and O'Neill (1980), Liu and Peselnick (1986), Eaton (1991), Rodgers et al. (1995), and many others (see Asten (1977) for a list of earlier references) have presented formulae for calculating the damped generator constant (or motor constant), and the damping constant (or fractional damping...

The focus of the Southern California Earthquake Hazards project is to identify the landslide and earthquake hazards and related ground-deformation processes occurring in the offshore areas that have significant potential to impact the inhabitants of the Southern California coastal region. The project activity is supported through the Coastal and Marine Geology Program of the Geologic...

McVCO is a microcontroller-based frequency generator that replaces the voltage controlled oscillator (VCO) used in the analog telemetry of seismic data. It accepts low-level signals from a seismometer and produces a frequency modulated subcarrier suitable for radio or telephone links to a data collection site. McVCO was designed for the purpose of improving the analog telemetry of...