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Late Quaternary evolution of channel and lobe complexes of Monterey Fan Late Quaternary evolution of channel and lobe complexes of Monterey Fan

The modern Monterey submarine fan, one of the largest deep-water deposits off the western US, is composed of two major turbidite systems: the Neogene Lower Turbidite System (LTS) and the late Quarternary Upper Turbidite System (UTS). The areally extensive LTS is a distal deposit with low-relief, poorly defined channels, overbank, and lower-fan elements. The younger UTS comprises almost...
Authors
Andrea Fildani, William R. Normark

Strain accumulation across the Coast Ranges at the latitude of San Francisco, 1994-2000 Strain accumulation across the Coast Ranges at the latitude of San Francisco, 1994-2000

A 66-monument geodetic array spanning the Coast Ranges near San Francisco has been surveyed more than eight times by GIPS between late 1993 and early 2001. The measured horizontal velocities of the monuments are well represented by uniform, right-lateral, simple shear parallel to N29°W. (The local strike of the San Andreas Fault is ∼N34°W.) The observed areal dilatation rate of 6.9 ± 10...
Authors
J.C. Savage, Weijun Gan, W.H. Prescott, J. L. Svarc

Magmatic precursors to the 18 May 1980 eruption of Mount St. Helens, USA Magmatic precursors to the 18 May 1980 eruption of Mount St. Helens, USA

Perhaps the most difficult task facing volcanologists today is that of distinguishing between low-level volcanic restlessness and activity that presages a full-scale eruption. We illustrate these difficulties by reexamining the sequence of events that led to the 18 May 1980 eruption of Mount St. Helens, activity that is often presented as a classic example of early phreatic explosions...
Authors
K. V. Cashman, R. Hoblitt

Coastal vulnerability assessment of Assateague Island National Seashore (ASIS) to sea-level rise Coastal vulnerability assessment of Assateague Island National Seashore (ASIS) to sea-level rise

A coastal vulnerability index (CVI, http://pubs.usgs.gov/of/2004/1020/html/cvi.htm) was used to map relative vulnerability of the coast to future sea-level rise within Assateague Island National Seashore (ASIS) in Maryland and Virginia. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate...
Authors
Elizabeth A. Pendleton, S. Jeffress Williams, E. Robert Thieler

Landslides triggered by the 2002 Denali fault, Alaska, earthquake and the inferred nature of the strong shaking Landslides triggered by the 2002 Denali fault, Alaska, earthquake and the inferred nature of the strong shaking

The 2002 M7.9 Denali fault, Alaska, earthquake triggered thousands of landslides, primarily rock falls and rock slides, that ranged in volume from rock falls of a few cubic meters to rock avalanches having volumes as great as 15 ?? 106 m3. The pattern of landsliding was unusual; the number of slides was less than expected for an earthquake of this magnitude, and the landslides were...
Authors
R.W. Jibson, E. L. Harp, W. Schulz, D. K. Keefer

Ultra-high chlorine in submarine Kı̄lauea glasses: Evidence for direct assimilation of brine by magma Ultra-high chlorine in submarine Kı̄lauea glasses: Evidence for direct assimilation of brine by magma

Basaltic glass grains from the submarine south flank of Kı̄lauea, Hawai′i, have Cl concentrations of 0.01–1.68 wt%, the latter being the highest Cl content yet recorded for a Hawaiian glass. The high-Cl glass grains are products of brine assimilation by tholeiite magma. The glasses are grains in a sandstone clast from bedded breccias draping the southwestern margin of Kı̄lauea’s...
Authors
Michelle L. Coombs, Thomas W. Sisson, Jun-Ichi Kimura

Shear wave velocity, seismic attenuation, and thermal structure of the continental upper mantle Shear wave velocity, seismic attenuation, and thermal structure of the continental upper mantle

Seismic velocity and attenuation anomalies in the mantle are commonly interpreted in terms of temperature variations on the basis of laboratory studies of elastic and anelastic properties of rocks. In order to evaluate the relative contributions of thermal and non-thermal effects on anomalies of attenuation of seismic shear waves, Q−1s, and seismic velocity, Vs, we compare global maps of...
Authors
I.M. Artemieva, M. Billien, J.-J. Leveque, Walter D. Mooney

Localization and physical properties experiments conducted by Spirit at Gusev crater Localization and physical properties experiments conducted by Spirit at Gusev crater

The precise location and relative elevation of Spirit during its traverses from the Columbia Memorial station to Bonneville crater were determined with bundle-adjusted retrievals from rover wheel turns, suspension and tilt angles, and overlapping images. Physical properties experiments show a decrease of 0.2% per Mars solar day in solar cell output resulting from deposition of airborne...
Authors
R. E. Arvidson, R. C. Anderson, P. Bartlett, J.F. Bell, D. Blaney, P. R. Christensen, P. Chu, L. Crumpler, K. Davis, B.L. Ehlmann, R. Fergason, M.P. Golombek, S. Gorevan, J. A. Grant, R. Greeley, E.A. Guinness, A. F. C. Haldemann, Kenneth E. Herkenhoff, J. Johnson, G. Landis, R. Li, R. Lindemann, H. McSween, D. W. Ming, T. Myrick, L. Richter, F.P. Seelos, S. W. Squyres, R.J. Sullivan, A. Wang, Jim Wilson

Evidence for liquefaction identified in peeled slices of Holocene deposits along the Lower Columbia River, Washington Evidence for liquefaction identified in peeled slices of Holocene deposits along the Lower Columbia River, Washington

Peels made from 10 geoslices beneath a riverbank at Washington's Hunting Island, 45 km inland from the Pacific coast, aid in identifying sand that liquefied during prehistoric earthquakes of estimated magnitude 8-9 at the Cascadia subduction zone. Each slice was obtained by driving sheetpile and a shutter plate to depths of 6-8 m. The resulting sample, as long as 8 m, had a trapezoidal...
Authors
K. Takada, B.F. Atwater

Geochemical constraints on possible subduction components in lavas of Mayon and Taal Volcanoes, Southern Luzon, Philippines Geochemical constraints on possible subduction components in lavas of Mayon and Taal Volcanoes, Southern Luzon, Philippines

Mayon is the most active volcano along the east margin of southern Luzon, Philippines. Petrographic and major element data indicate that Mayon has produced a basaltic to andesitic lava series by fractional crystallization and magma mixing. Trace element data indicate that the parental basalts came from a heterogeneous mantle source. The unmodified composition of the mantle wedge is...
Authors
P.R. Castillo, C. G. Newhall

Stress field variations in the Swiss Alps and the northern Alpine foreland derived from inversion of fault plane solutions Stress field variations in the Swiss Alps and the northern Alpine foreland derived from inversion of fault plane solutions

This study is devoted to a systematic analysis of the state of stress of the central European Alps and northern Alpine foreland in Switzerland based on focal mechanisms of 138 earthquakes with magnitudes between 1 and 5. The most robust feature of the results is that the azimuth of the minimum compressive stress, S3, is generally well constrained for all data subsets and always lies in...
Authors
U. Kastrup, M.L. Zoback, N. Deichmann, Kenneth F. Evans, D. Giardini, A.J. Michael
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