Publications

The thermal thickness of Precambrian lithosphere is modeled and compared with estimates from seismic tomography and xenolith data. We use the steady state thermal conductivity equation with the same geothermal constraints for all of the Precambrian cratons (except Antarctica) to calculate the temperature distribution in the stable continental lithosphere. The modeling is based on the...

The Mars Global Surveyor thermal emission spectrometer has made observations of Mars' north polar region for nearly a full martian year. Measurements of bolometric emission and reflectance, as well as brightness temperatures in specific bands synthesized from thermal radiance spectra, are used to track the behavior of surface and atmospheric temperatures, the distribution of condensed...

In the 1970s, Mariner and Viking spacecraft observations of the north polar region of Mars revealed polar brightness temperatures that were significantly below the expected kinetic temperatures for CO2 sublimation. For the past few decades, the scientific community has speculated as to the nature of these Martian polar cold spots. Thermal Emission Spectrometer (TES) thermal spectral data...

No abstract available.

Karst and similar landscapes are found in a wide range of biogeographic classes. In the U.S. for example, Everglades, Mammoth Cave, and Hawaii Volcanoes National Parks have little in common - except karst or pseudokarst, and a cultural past (even though these are very different). This diversity of geologic settings makes karst difficult to categorize and work with when designing a...

We use the energy-to-moment ratio, as introduced by Newman and Okal [1998] to examine the source characteristics of normal-faulting intraslab earthquakes, compared to nearby interplate thrust events, based on recent case studies in central Chile and southeastern Mexico. In Chile, we find that the 1997 intraslab event had an exceptionally large E/M0 ratio, 30 times greater than the nearby

No abstract available.

The Los Angeles Region Seismic Experiment (LARSE) is a joint project of the U.S. Geological Survey (USGS) and the Southern California Earthquake Center (SCEC). The purpose of this project is to produce seismic images of the subsurface of the Los Angeles region down to the depths at which earthquakes occur, and deeper, in order to remedy a deficit in our knowledge of the deep structure of...

No abstract available.

We examine the various methods and parameters in common use for quantifying and reporting surface topographic "roughness." It is shown that scale-dependent roughness parameters are almost always required, though not widely used. We suggest a method of standardizing the parameters that are computed and reported so that topographic data gathered by different workers using different field...

We have examined the local base of the south polar layered deposits (SPLD) exposed in the bounding scarp near 72°–74°S, 215°–230°W where there is a clear unconformable contact with older units. Sections of layering up to a kilometer thick were examined along the bounding scarp, permitting an estimate of the thinnest individual layers yet reported in the SPLD. Rhythmic layering is also...

HypoDD is a Fortran computer program package for relocating earthquakes with the double-difference algorithm of Waldhauser and Ellsworth (2000). This document provides a brief introduction into how to run and use the programs ph2dt and hypoDD to compute double-difference (DD) hypocenter locations. It gives a short overview of the DD technique, discusses the data preprocessing using ph2dt...