Publications
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Stratigraphy of the north polar layered deposits of Mars from high-resolution topography Stratigraphy of the north polar layered deposits of Mars from high-resolution topography
The stratigraphy of the layered deposits of the polar regions of Mars is theorized to contain a record of recent climate change linked to insolation changes driven by variations in the planet's orbital and rotational parameters. In order to confidently link stratigraphic signals to insolation periodicities, a description of the stratigraphy is required based on quantities that directly...
Authors
Patricio Becerra, Shane Byrne, Michael M. Sori, Sarah Sutton, Kenneth E. Herkenhoff
Comparisons between vs30 and spectral response for 30 sites in Newcastle, Australia from collocated seismic cone penetrometer, active- and passive-source vs data Comparisons between vs30 and spectral response for 30 sites in Newcastle, Australia from collocated seismic cone penetrometer, active- and passive-source vs data
Although the time‐averaged shear‐wave velocity down to 30 m depth (VS30) can be a proxy for estimating earthquake ground‐motion amplification, significant controversy exists about its limitations when used as a single parameter for the prediction of amplification. To examine this question in absence of relevant strong‐motion records, we use a range of different methods to measure the...
Authors
Theodora Volti, David Burbidge, Clive Collins, Michael W. Asten, Jackson K. Odum, William J. Stephenson, Chris Pascal, Josef Holzschuh
Amplification of postwildfire peak flow by debris Amplification of postwildfire peak flow by debris
In burned steeplands, the peak depth and discharge of postwildfire runoff can substantially increase from the addition of debris. Yet methods to estimate the increase over water flow are lacking. We quantified the potential amplification of peak stage and discharge using video observations of postwildfire runoff, compiled data on postwildfire peak flow (Qp), and a physically based model
Authors
Jason W. Kean, Luke McGuire, Francis K. Rengers, Joel B. Smith, Dennis M. Staley
Responses of a tall building in Los Angeles, California as inferred from local and distant earthquakes Responses of a tall building in Los Angeles, California as inferred from local and distant earthquakes
Increasing inventory of tall buildings in the United States and elsewhere may be subjected to motions generated by near and far seismic sources that cause long-period effects. Multiple sets of records that exhibited such effects were retrieved from tall buildings in Tokyo and Osaka ~ 350 km and 770 km from the epicenter of the 2011 Tohoku earthquake. In California, very few tall...
Authors
Mehmet Çelebi, Hasan Ulusoy, Nori Nakata
Fortnightly modulation of San Andreas tremor and low-frequency earthquakes Fortnightly modulation of San Andreas tremor and low-frequency earthquakes
Earth tides modulate tremor and low-frequency earthquakes (LFEs) on faults in the vicinity of the brittle−ductile (seismic−aseismic) transition. The response to the tidal stress carries otherwise inaccessible information about fault strength and rheology. Here, we analyze the LFE response to the fortnightly tide, which modulates the amplitude of the daily tidal stress over a 14-d cycle...
Authors
Nicholas van der Elst, Andrew Delorey, David R. Shelly, Paul Johnson
Observations and modeling of fjord sedimentation during the 30 year retreat of Columbia Glacier, AK Observations and modeling of fjord sedimentation during the 30 year retreat of Columbia Glacier, AK
To explore links between glacier dynamics, sediment yields and the accumulation of glacial sediments in a temperate setting, we use extensive glaciological observations for Columbia Glacier, Alaska, and new oceanographic data from the fjord exposed during its retreat. High-resolution seismic data indicate that 3.2 × 108 m3 of sediment has accumulated in Columbia Fjord over the past three...
Authors
Katherine B Love, Bernard Hallet, Thomas L. Pratt, Shad O’Neel
The influence of vegetation cover on debris-flow density during an extreme rainfall in the northern Colorado Front Range The influence of vegetation cover on debris-flow density during an extreme rainfall in the northern Colorado Front Range
We explored regional influences on debris-flow initiation throughout the Colorado Front Range (Colorado, USA) by exploiting a unique data set of more than 1100 debris flows that initiated during a 5 day rainstorm in 2013. Using geospatial data, we examined the influence of rain, hillslope angle, hillslope aspect, and vegetation density on debris-flow initiation. In particular we used a...
Authors
Francis K. Rengers, Luke McGuire, Jeffrey A. Coe, Jason W. Kean, Rex L. Baum, Dennis M. Staley, Jonathan W. Godt
Coseismic slip and early afterslip of the 2015 Illapel, Chile, earthquake: Implications for frictional heterogeneity and coastal uplift Coseismic slip and early afterslip of the 2015 Illapel, Chile, earthquake: Implications for frictional heterogeneity and coastal uplift
Great subduction earthquakes are thought to rupture portions of the megathrust, where interseismic coupling is high and velocity-weakening frictional behavior is dominant, releasing elastic deformation accrued over a seismic cycle. Conversely, postseismic afterslip is assumed to occur primarily in regions of velocity-strengthening frictional characteristics that may correlate with lower
Authors
William D. Barnhart, Jessica R. Murray, Richard W. Briggs, Francisco Gomez, Charles P. J. Miles, Jerry L. Svarc, Sebástian Riquelme, Bryan J. Stressler
Complex explosive volcanic activity on the Moon within Oppenheimer crater Complex explosive volcanic activity on the Moon within Oppenheimer crater
Oppenheimer Crater is a floor-fractured crater located within the South Pole-Aitken basin on the Moon, and exhibits more than a dozen localized pyroclastic deposits associated with the fractures. Localized pyroclastic volcanism on the Moon is thought to form as a result of intermittently explosive Vulcanian eruptions under low effusion rates, in contrast to the higher-effusion rate...
Authors
Kristen A Bennett, Briony H. N. Horgan, Lisa R. Gaddis, Benjamin T Greenhagen, Carlton C. Allen, Paul O. Hayne, James F. Bell, David A. Paige
ChemCam activities and discoveries during the nominal mission of the Mars Science Laboratory in Gale crater, Mars ChemCam activities and discoveries during the nominal mission of the Mars Science Laboratory in Gale crater, Mars
At Gale crater, Mars, ChemCam acquired its first laser-induced breakdown spectroscopy (LIBS) target on Sol 13 of the landed portion of the mission (a Sol is a Mars day). Up to Sol 800, more than 188 000 LIBS spectra were acquired on more than 5800 points distributed over about 650 individual targets. We present a comprehensive review of ChemCam scientific accomplishments during that...
Authors
Sylvestre Maurice, Samuel M. Clegg, Roger C. Wiens, O. Gasnault, W. Rapin, O. Forni, Agnes Cousin, V. Sautter, Nicolas Mangold, L. Le Deit, Marion Nachon, Ryan B. Anderson, Nina Lanza, Cecile Fabre, Valerie Payre, Jeremie Lasue, Pierre-Yves Meslin, Richard A. LeVeille, Bruce Barraclough, Pierre Beck, Steven C. Bender, Gilles Berger, John C. Bridges, Nathan Bridges, Gilles Dromert, M. Darby Dyar, Raymond Francis, Jens Frydenvang, B. Gondet, Bethany L. Ehlmann, Kenneth E. Herkenhoff, Jeffrey R. Johnson, Yves Langevin, Madsen Morten B., N. Melikechi, J.-L. Lacour, Stephane Le Mouelic, Eric Lewin, Horton E. Newsom, Ann M. Ollila, Patrick Pinet, S. Schroder, Jean-Baptiste Sirven, Robert L. Tokar, M.J. Toplis, Claude d’Uston, David Vaniman, Ashwin R. Vasavada
Granitic boulder erosion caused by chaparral wildfire: Implications for cosmogenic radionuclide dating of bedrock surfaces Granitic boulder erosion caused by chaparral wildfire: Implications for cosmogenic radionuclide dating of bedrock surfaces
Rock surface erosion by wildfire is significant and widespread but has not been quantified in southern California or for chaparral ecosystems. Quantifying the surface erosion of bedrock outcrops and boulders is critical for determination of age using cosmogenic radionuclide techniques, as even modest surface erosion removes the accumulation of the cosmogenic radionuclides and causes...
Authors
Katherine J. Kendrick, Camille Partin, Robert C. Graham
The missing large impact craters on Ceres The missing large impact craters on Ceres
Asteroids provide fundamental clues to the formation and evolution of planetesimals. Collisional models based on the depletion of the primordial main belt of asteroids predict 10–15 craters >400 km should have formed on Ceres, the largest object between Mars and Jupiter, over the last 4.55 Gyr. Likewise, an extrapolation from the asteroid Vesta would require at least 6–7 such basins...
Authors
S. Marchi, A. Ermakov, C.A. Raymond, R.R. Fu, D.P. O’Brien, Michael T. Bland, E. Ammannito, De Sanctis, Tim Bowling, P. Schenk, J.E.C. Scully, D.L. Buczkowski, D.A. Williams, H. Hiesinger, C.T. Russell