Publications
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Positive feedback and momentum growth during debris-flow entrainment of wet bed sediment Positive feedback and momentum growth during debris-flow entrainment of wet bed sediment
Debris flows typically occur when intense rainfall or snowmelt triggers landslides or extensive erosion on steep, debris-mantled slopes. The flows can then grow dramatically in size and speed as they entrain material from their beds and banks, but the mechanism of this growth is unclear. Indeed, momentum conservation implies that entrainment of static material should retard the motion of...
Authors
Richard M. Iverson, Mark E. Reid, Matthew Logan, Richard G. Lahusen, Jonathan W. Godt, Julia P. Griswold
Pore-fluid migration and the timing of the 2005 M8.7 Nias earthquake Pore-fluid migration and the timing of the 2005 M8.7 Nias earthquake
Two great earthquakes have occurred recently along the Sunda Trench, the 2004 M9.2 Sumatra-Andaman earthquake and the 2005 M8.7 Nias earthquake. These earthquakes ruptured over 1600 km of adjacent crust within 3 mo of each other. We quantitatively present poroelastic deformation analyses suggesting that postseismic fluid flow and recovery induced by the Sumatra-Andaman earthquake...
Authors
K.L.H. Hughes, Timothy Masterlark, Walter D. Mooney
Seasonal erosion and restoration of Mars' northern polar dunes Seasonal erosion and restoration of Mars' northern polar dunes
Despite radically different environmental conditions, terrestrial and martian dunes bear a strong resemblance, indicating that the basic processes of saltation and grainfall (sand avalanching down the dune slipface) operate on both worlds. Here, we show that martian dunes are subject to an additional modification process not found on Earth: springtime sublimation of Mars' CO 2 seasonal...
Authors
C.J. Hansen, M. Bourke, Nathan T. Bridges, Shane Byrne, C. Colon, S. Diniega, Colin M. Dundas, Kenneth E. Herkenhoff, A. McEwen, M. Mellon, Ganna Portyankina, N. Thomas
Structure of the San Fernando Valley region, California: implications for seismic hazard and tectonic history Structure of the San Fernando Valley region, California: implications for seismic hazard and tectonic history
Industry seismic reflection data, oil test well data, interpretation of gravity and magnetic data, and seismic refraction deep-crustal profiles provide new perspectives on the subsurface geology of San Fernando Valley, home of two of the most recent damaging earthquakes in southern California. Seismic reflection data provide depths to Miocene–Quaternary horizons; beneath the base of the...
Authors
V.E. Langenheim, T. L. Wright, D. A. Okaya, R.S. Yeats, G. S. Fuis, K. Thygesen, H. Thybo
Spatiotemporal earthquake clusters along the North Anatolian fault zone offshore Istanbul Spatiotemporal earthquake clusters along the North Anatolian fault zone offshore Istanbul
We investigate earthquakes with similar waveforms in order to characterize spatiotemporal microseismicity clusters within the North Anatolian fault zone (NAFZ) in northwest Turkey along the transition between the 1999 İzmit rupture zone and the Marmara Sea seismic gap. Earthquakes within distinct activity clusters are relocated with cross-correlation derived relative travel times using...
Authors
Fatih Bulut, William L. Ellsworth, Marco Bohnhoff, Mustafa Aktar, Georg Dresen
Whole-edifice ice volume change A.D. 1970 to 2007/2008 at Mount Rainier, Washington, based on LiDAR surveying Whole-edifice ice volume change A.D. 1970 to 2007/2008 at Mount Rainier, Washington, based on LiDAR surveying
Net changes in thickness and volume of glacial ice and perennial snow at Mount Rainier, Washington State, have been mapped over the entire edifice by differencing between a highresolution LiDAR (light detection and ranging) topographic survey of September-October 2007/2008 and the 10 m lateral resolution U.S. Geological Survey digital elevation model derived from September 1970 aerial...
Authors
T. W. Sisson, J.E. Robinson, D.D. Swinney
Epistemic uncertainty in the location and magnitude of earthquakes in Italy from Macroseismic data Epistemic uncertainty in the location and magnitude of earthquakes in Italy from Macroseismic data
Three independent techniques (Bakun and Wentworth, 1997; Boxer from Gasperini et al., 1999; and Macroseismic Estimation of Earthquake Parameters [MEEP; see Data and Resources section, deliverable D3] from R.M.W. Musson and M.J. Jimenez) have been proposed for estimating an earthquake location and magnitude from intensity data alone. The locations and magnitudes obtained for a given set...
Authors
W. H. Bakun, Capera A. Gomez, M. Stucchi
Extreme volcanism on Io: Latest insights at the end of Galileo era Extreme volcanism on Io: Latest insights at the end of Galileo era
Galileo has now completed 7 years exploring Jupiter. The spacecraft obtained breathtaking views of the four major satellites, and studied Jupiter's clouds and atmospheric composition, rings, small satellites, and magnetic field. It had five successful close flybys and many distant observations of Io. Scientists already knew from Voyager and Earth‐based astronomy that Io is by far the...
Authors
Jeffrey S. Kargel, Robert R. Carlson, Ashley G. Davies, Bruce Fegley, Alan R. Gillespie, Ronald Greeley, Robert G. Howells, Kandis Lea Jessup, Lucas Kamp, Laszlo P. Keszthelyi, Rosaly Lopes, Timothy MacIntyre, Franck Marchis, Alfred McEwen, Moses P. Milazzo, Jason Perry, Jani Radebaugh, Laura Schaefer, Nicholas Schmerr, William Smythe, John M. Spencer, David A. Williams, Ju Zhang, Mikhail Zolotov
On the contribution of reconstruction labor wages and material prices to demand surge On the contribution of reconstruction labor wages and material prices to demand surge
Demand surge is understood to be a socio-economic phenomenon of large-scale natural disasters, most commonly explained by higher repair costs (after a large- versus small-scale disaster) resulting from higher material prices and labor wages. This study tests this explanation by developing quantitative models for the cost change of sets, or "baskets," of repairs to damage caused by...
Authors
Anna H. Olsen, Keith A. Porter
Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 2, changes in surface morphometry from terrestrial laser scanning in the summer of 2009 Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 2, changes in surface morphometry from terrestrial laser scanning in the summer of 2009
High resolution topographic data that quantify changes in channel form caused by sequential debris flows in natural channels are rare at the reach scale. Terrestrial laser scanning (TLS) techniques are utilized to capture morphological changes brought about by a high-frequency of debris-flow events at Chalk Cliffs, Colorado. The purpose of this paper is to compare and contrast the...
Authors
Dennis M. Staley, Thad A. Wasklewicz, Jeffrey A. Coe, Jason W. Kean, Scott W. McCoy, Greg E. Tucker
Assessment of topographic and drainage network controls on debris-flow travel distance along the west coast of the United States Assessment of topographic and drainage network controls on debris-flow travel distance along the west coast of the United States
To better understand controls on debris-flow entrainment and travel distance, we examined topographic and drainage network characteristics of initiation locations in two separate debris-flow prone areas located 700 km apart along the west coast of the U.S. One area was located in northern California, the other in southern Oregon. In both areas, debris flows mobilized from slides during...
Authors
Jeffrey A. Coe, Mark E. Reid, Dainne L. Brien, John A. Michael
Studying geodesy and earthquake hazard in and around the New Madrid Seismic Zone Studying geodesy and earthquake hazard in and around the New Madrid Seismic Zone
Workshop on New Madrid Geodesy and the Challenges of Understanding Intraplate Earthquakes; Norwood, Massachusetts, 4 March 2011 Twenty-six researchers gathered for a workshop sponsored by the U.S. Geological Survey (USGS) and FM Global to discuss geodesy in and around the New Madrid seismic zone (NMSZ) and its relation to earthquake hazards. The group addressed the challenge of...
Authors
Oliver Salz Boyd, Harold Magistrale