Publications
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A Miocene river in northern Arizona and its implications for the Colorado River and Grand Canyon
The southwesterly course of the pre–late Miocene Crooked Ridge River can be traced continuously for 48 km and discontinuously for 91 km in northern Arizona. It is visible today in inverted relief. Pebbles in the river gravel came from at least as far northeast as the San Juan Mountains. The river valley was carved out of easily eroded Jurassic and Cretaceous rocks, whose debris overloaded the rive
Authors
Ivo Lucchitta, Richard F. Holm, Baerbel K. Lucchitta
East Antarctic rifting triggers uplift of the Gamburtsev Mountains
The Gamburtsev Subglacial Mountains are the least understood tectonic feature on Earth, because they are completely hidden beneath the East Antarctic Ice Sheet. Their high elevation and youthful Alpine topography, combined with their location on the East Antarctic craton, creates a paradox that has puzzled researchers since the mountains were discovered in 1958. The preservation of Alpine topograp
Authors
Fausto Ferraccioli, Carol A. Finn, Tom A. Jordan, Robin E. Bell, Lester M. Anderson, Detlef Damaske
Specifying initial stress for dynamic heterogeneous earthquake source models
Dynamic rupture calculations using heterogeneous stress drop that is random and self-similar with a power-law spatial spectrum have great promise of producing realistic ground-motion predictions. We present procedures to specify initial stress for random events with a target rupture length and target magnitude. The stress function is modified in the depth dimension to account for the brittle-ducti
Authors
D. J. Andrews, M. Barall
Landslide inventories: The essential part of seismic landslide hazard analyses
A detailed and accurate landslide inventory is an essential part of seismic landslide hazard analysis. An ideal inventory would cover the entire area affected by an earthquake and include all of the landslides that are possible to detect down to sizes of 1–5 m in length. The landslides must also be located accurately and mapped as polygons depicting their true shapes. Such mapped landslide distrib
Authors
E. L. Harp, D. K. Keefer, H.P. Sato, H. Yagi
History of plains resurfacing in the Scandia region of Mars
We present a preliminary photogeologic map of the Scandia region of Mars with the objective of reconstructing its resurfacing history. The Scandia region includes the lower section of the regional lowland slope of Vastitas Borealis extending about 500–1800 km away from Alba Mons into the Scandia sub-basin below −4800 m elevation. Twenty mapped geologic units express the diverse stratigraphy of the
Authors
Kenneth L. Tanaka, Corey M. Fortezzo, Rosalyn K. Hayward, J. Alexis P. Rodriguez, James A. Skinner
Spectral heterogeneity on Phobos and Deimos: HiRISE observations and comparisons to Mars Pathfinder results
The High-Resolution Imaging Science Experiment (HiRISE) onboard Mars Reconnaissance Orbiter (MRO) has been used to observe Phobos and Deimos at spatial scales of around 6 and 20 m/px, respectively. HiRISE (McEwen et al.; JGR, 112, CiteID E05S02, DOI: 10.1029/2005JE002605, 2007) has provided, for the first time, high-resolution colour images of the surfaces of the Martian moons. When processed, by
Authors
N. Thomas, R. Stelter, A. Ivanov, N.T. Bridges, Kenneth E. Herkenhoff, A. S. McEwen
Controls on large landslide distribution and implications for the geomorphic evolution of the southern interior Columbia River basin
Large landslides (>0.1 km2) are important agents of geomorphic change. While most common in rugged mountain ranges, large landslides can also be widespread in relatively low-relief (several 100 m) terrain, where their distribution has been relatively little studied. A fuller understanding of the role of large landslides in landscape evolution requires addressing this gap, since the distribution of
Authors
E.B. Safran, S.W. Anderson, M. Mills-Novoa, P.K. House, L. Ely
The role of dyking and fault control in the rapid onset of eruption at Chaitén Volcano, Chile
Rhyolite is the most viscous of liquid magmas, so it was surprising that on 2 May 2008 at Chaitén Volcano, located in Chile’s southern Andean volcanic zone, rhyolitic magma migrated from more than 5 km depth in less than 4 hours and erupted explosively with only two days of detected precursory seismic activity. The last major rhyolite eruption before that at Chaitén was the largest volcanic erupti
Authors
Charles Wicks, Llera De La, L.E. Lara, J. Lowenstern
Mars: the evolutionary history of the northern lowlands based on crater counting and geologic mapping
The geologic history of planetary surfaces is most effectively determined by joining geologic mapping and crater counting which provides an iterative, qualitative and quantitative method for defining relative ages and absolute model ages. Based on this approach, we present spatial and temporal details regarding the evolution of the Martian northern plains and surrounding regions.
The highland–low
Authors
S.C. Werner, K. L. Tanaka, J.A. Skinner
Rock fall simulation at Timpanogos Cave National Monument, American Fork Canyon, Utah, USA
Rock fall from limestone cliffs at Timpanogos Cave National Monument in American Fork Canyon east of Provo, Utah, is a common occurrence. The cave is located in limestone cliffs high on the southern side of the canyon. One fatality in 1933 led to the construction of rock fall shelters at the cave entrance and exit in 1976. Numerous rock fall incidents, including a near miss in 2000 in the vicinity
Authors
Edwin Harp, Richard L. Dart, P. Reichenbach
Rainfall intensity-duration thresholds for postfire debris-flow emergency-response planning
Following wildfires, emergency-response and public-safety agencies can be faced with evacuation and resource-deployment decisions well in advance of coming winter storms and during storms themselves. Information critical to these decisions is provided for recently burned areas in the San Gabriel Mountains of southern California. A compilation of information on the hydrologic response to winter sto
Authors
S.H. Cannon, E.M. Boldt, J.L. Laber, J. W. Kean, D.M. Staley
Widespread inclination shallowing in Permian and Triassic paleomagnetic data from Laurentia: Support from new paleomagnetic data from Middle Permian shallow intrusions in southern Illinois (USA) and virtual geomagnetic pole distributions
Recent paleomagnetic work has highlighted a common and shallow inclination bias in continental redbeds. The Permian and Triassic paleomagnetic records from Laurentia are almost entirely derived from such sedimentary rocks, so a pervasive inclination error will expectedly bias the apparent polar wander path of Laurentia in a significant way. The long-standing discrepancy between the apparent polar
Authors
M. Domeier, R. Van Der Voo, F.B. Denny