Publications
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Hawaiian Volcano Observatory 1969 quarterly administrative Report Hawaiian Volcano Observatory 1969 quarterly administrative Report
INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined...
Authors
Jennifer S. Nakata
Surface-source downhole seismic analysis in R Surface-source downhole seismic analysis in R
This report discusses a method for interpreting a layered slowness or velocity model from surface-source downhole seismic data originally presented by Boore (2003). I have implemented this method in the statistical computing language R (R Development Core Team, 2007), so that it is freely and easily available to researchers and practitioners that may find it useful. I originally applied...
Authors
Eric M. Thompson
Landslide susceptibility revealed by LIDAR imagery and historical records, Seattle, Washington Landslide susceptibility revealed by LIDAR imagery and historical records, Seattle, Washington
Light detection and ranging (LIDAR) data were used to visually map landslides, headscarps, and denuded slopes in Seattle, Washington. Four times more landslides were mapped than by previous efforts that used aerial photographs. The mapped landforms (landslides, headscarps, and denuded slopes) were created by many individual landslides. The spatial distribution of mapped landforms and...
Authors
W.H. Schulz
Annual modulation of seismicity along the San Andreas Fault near Parkfield, CA Annual modulation of seismicity along the San Andreas Fault near Parkfield, CA
We analyze seismic data from the San Andreas Fault (SAF) near Parkfield, California, to test for annual modulation in seismicity rates. We use statistical analyses to show that seismicity is modulated with an annual period in the creeping section of the fault and a semiannual period in the locked section of the fault. Although the exact mechanism for seasonal triggering is undetermined...
Authors
L.B. Christiansen, Shaul Hurwitz, Steven E. Ingebritsen
U/Th series radionuclides as coastal groundwater tracers U/Th series radionuclides as coastal groundwater tracers
The study of coastal groundwater has recently surfaced as an active interdisciplinary area of research, driven foremost by its importance as a poorly quantified pathway for subsurface material transport into coastal ecosystems. Key issue in coastal groundwater research include a complete geochemical characterization of the groundwater(s); quantification of the kinetics of subsurface...
Authors
P.W. Swarzenski
Three-dimensional P-wave velocity structure derived from local earthquakes at the Katmai group of volcanoes, Alaska Three-dimensional P-wave velocity structure derived from local earthquakes at the Katmai group of volcanoes, Alaska
The three-dimensional P-wave velocity structure beneath the Katmai group of volcanoes is determined by inversion of more than 10,000 rays from over 1000 earthquakes recorded on a local 18 station short-period network between September 1996 and May 2001. The inversion is well constrained from sea level to about 6 km below sea level and encompasses all of the Katmai volcanoes; Martin...
Authors
A.D. Jolly, S.C. Moran, S.R. McNutt, D.B. Stone
Hydrothermal circulation at Mount St. Helens determined by self-potential measurements Hydrothermal circulation at Mount St. Helens determined by self-potential measurements
The distribution of hydrothermal circulation within active volcanoes is of importance in identifying regions of hydrothermal alteration which may in turn control explosivity, slope stability and sector collapse. Self-potential measurements, indicative of fluid circulation, were made within the crater of Mount St. Helens in 2000 and 2001. A strong dipolar anomaly in the self-potential...
Authors
Paul A. Bedrosian, Martyn J. Unsworth, Malcolm J. S. Johnston
Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper
The Cassini Titan Radar Mapper obtained Synthetic Aperture Radar images of Titan's surface during four fly-bys during the mission's first year. These images show that Titan's surface is very complex geologically, showing evidence of major planetary geologic processes, including cryovolcanism. This paper discusses the variety of cryovolcanic features identified from SAR images, their...
Authors
Rosaly Lopes, K. L. Mitchell, Ellen R. Stofan, Jonathan I. Lunine, Ralf D. Lorenz, F. Paganelli, Randolph L. Kirk, C. A. Wood, Stephen D. Wall, L.E. Robshaw, A.D. Fortes, Catherine D. Neish, Jani Radebaugh, E. Reffet, S.J. Ostro, Charles Elachi, M.D. Allison, Y. Anderson, R. Boehmer, G. Boubin, Philip S. Callahan, P. Encrenaz, E. Flamini, G. Francescetti, Y. Gim, G. Hamilton, S. Hensley, Michael A. Janssen, W.T.K. Johnson, K. Kelleher, D.O. Muhleman, G. Ori, R. Orosei, G. Picardi, F. Posa, L.E. Roth, R. Seu, S. Shaffer, Laurence A. Soderblom, B. Stiles, S. Vetrella, R.D. West, L. Wye, H. A. Zebker
Waveform inversion of volcano-seismic signals for an extended source Waveform inversion of volcano-seismic signals for an extended source
[1] We propose a method to investigate the dimensions and oscillation characteristics of the source of volcano-seismic signals based on waveform inversion for an extended source. An extended source is realized by a set of point sources distributed on a grid surrounding the centroid of the source in accordance with the source geometry and orientation. The source-time functions for all...
Authors
M. Nakano, Hiroyuki Kumagai, B. Chouet, P. Dawson
Three-dimensional geophysical mapping of rock alteration and water content at Mount Adams, Washington: Implications for lahar hazards Three-dimensional geophysical mapping of rock alteration and water content at Mount Adams, Washington: Implications for lahar hazards
[1] Hydrothermally altered rocks, particularly if water saturated, can weaken stratovolcanoes, thereby increasing the potential for catastrophic sector collapses that can lead to far-traveled, destructive debris flows. Evaluating the hazards associated with such alteration is difficult because alteration has been mapped on few active volcanoes and the distribution and intensity of...
Authors
C. A. Finn, M. Deszcz-Pan, E. D. Anderson, D. A. John
An efficient mode-splitting method for a curvilinear nearshore circulation model An efficient mode-splitting method for a curvilinear nearshore circulation model
A mode-splitting method is applied to the quasi-3D nearshore circulation equations in generalized curvilinear coordinates. The gravity wave mode and the vorticity wave mode of the equations are derived using the two-step projection method. Using an implicit algorithm for the gravity mode and an explicit algorithm for the vorticity mode, we combine the two modes to derive a mixed...
Authors
Fengyan Shi, James T. Kirby, Daniel M. Hanes
Spatial and temporal variability in oceanographic and meteorologic forcing along Central California and its implications on nearshore processes Spatial and temporal variability in oceanographic and meteorologic forcing along Central California and its implications on nearshore processes
In the past two decades, the understanding of the important large-scale phenomena (El Niño, upwelling, California current, etc) that drive physical, chemical, and biological processes along the US West Coast has greatly improved. However, the ability to predict the influence of annual and inter-annual events on a regional scale still remains limited. High-resolution hourly data from 6...
Authors
D.K. Wingfield, C. D. Storlazzi