Publications
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Rapid water quality change in the Elwha River estuary complex during dam removal Rapid water quality change in the Elwha River estuary complex during dam removal
Dam removal in the United States is increasing as a result of structural concerns, sedimentation of reservoirs, and declining riverine ecosystem conditions. The removal of the 32 m Elwha and 64 m Glines Canyon dams from the Elwha River in Washington, U.S.A., was the largest dam removal project in North American history. During the 3 yr of dam removal—from September 2011 to August 2014...
Authors
Melissa M. Foley, Jeffrey J. Duda, Matthew M. Beirne, Rebecca Paradis, Andrew Ritchie, Jonathan A. Warrick
Southern San Andreas Fault seismicity is consistent with the Gutenberg-Richter magnitude-frequency distribution Southern San Andreas Fault seismicity is consistent with the Gutenberg-Richter magnitude-frequency distribution
The magnitudes of any collection of earthquakes nucleating in a region are generally observed to follow the Gutenberg-Richter (G-R) distribution. On some major faults, however, paleoseismic rates are higher than a G-R extrapolation from the modern rate of small earthquakes would predict. This, along with other observations, led to formulation of the characteristic earthquake hypothesis...
Authors
Morgan T. Page, Karen Felzer
Slope activity in Gale crater, Mars Slope activity in Gale crater, Mars
High-resolution repeat imaging of Aeolis Mons, the central mound in Gale crater, reveals active slope processes within tens of kilometers of the Curiosity rover. At one location near the base of northeastern Aeolis Mons, dozens of transient narrow lineae were observed, resembling features (Recurring Slope Lineae) that are potentially due to liquid water. However, the lineae faded and...
Authors
Colin M. Dundas, Alfred S. McEwen
Temperature profile around a basaltic sill intruded into wet sediments Temperature profile around a basaltic sill intruded into wet sediments
The transfer of heat into wet sediments from magmatic intrusions or lava flows is not well constrained from field data. Such field constraints on numerical models of heat transfer could significantly improve our understanding of water–lava interactions. We use experimentally calibrated pollen darkening to measure the temperature profile around a basaltic sill emplaced into wet lakebed...
Authors
Leslie Baker, Andrew Bernard, William C. Rember, Moses P. Milazzo, Colin M. Dundas, Oleg Abramov, Laszlo P. Keszthelyi
Trench logs, terrestrial lidar system imagery, and radiocarbon data from the kilometer-62 site on the Greenville Fault, southeastern Alameda County, California, 2014 Trench logs, terrestrial lidar system imagery, and radiocarbon data from the kilometer-62 site on the Greenville Fault, southeastern Alameda County, California, 2014
In 2014, we investigated an abrupt 8.5-meter (m), right-laterally deflected stream channel located near the Greenville Fault in southeastern Alameda County, California (-121.56224° E, 37.53430° N) that we discovered using 0.5-m resolution, 2011 aerial lidar imagery flown along the active fault trace. Prior to trenching we surveyed the site using a terrestrial lidar system (TLS) to...
Authors
James J. Lienkaemper, Stephen B. DeLong, Nikita N. Avdievitch, Alexandra J. Pickering, Thomas P. Guilderson
Tsunami recurrence in the eastern Alaska-Aleutian arc: A Holocene stratigraphic record from Chirikof Island, Alaska Tsunami recurrence in the eastern Alaska-Aleutian arc: A Holocene stratigraphic record from Chirikof Island, Alaska
Despite the role of the Alaska-Aleutian megathrust as the source of some of the largest earthquakes and tsunamis, the history of its pre–twentieth century tsunamis is largely unknown west of the rupture zone of the great (magnitude, M 9.2) 1964 earthquake. Stratigraphy in core transects at two boggy lowland sites on Chirikof Island’s southwest coast preserves tsunami deposits dating from...
Authors
Alan R. Nelson, Richard W. Briggs, Tina Dura, Simon E. Engelhart, Guy Gelfenbaum, Lee-Ann Bradley, S.L. Forman, Christopher H. Vane, K.A. Kelley
Global volcanic hazards and risk Global volcanic hazards and risk
An estimated 800 million people live within 100 km of an active volcano in 86 countries and additional overseas territories worldwide [see Chapter 4 and Appendix B]1. Volcanoes are compelling evidence that the Earth is a dynamic planet characterised by endless change and renewal. Humans have always found volcanic activity fascinating and have often chosen to live close to volcanoes...
Authors
S. K. Brown, S. C. Loughlin, R. S. J. Sparks, C. Vye-Brown, J. Barclay, E. Calder, E. Cottrell, G. Jolly, J.C. Komorowski, Charlie Mandeville, C. Newhall, J. Palma, S. Potter, G. Valentine
Objective definition of rainfall intensity-duration thresholds for post-fire flash floods and debris flows in the area burned by the Waldo Canyon fire, Colorado, USA Objective definition of rainfall intensity-duration thresholds for post-fire flash floods and debris flows in the area burned by the Waldo Canyon fire, Colorado, USA
We present an objectively defined rainfall intensity-duration (I-D) threshold for the initiation of flash floods and debris flows for basins recently burned in the 2012 Waldo Canyon fire near Colorado Springs, Colorado, USA. Our results are based on 453 rainfall records which include 8 instances of hazardous flooding and debris flow from 10 July 2012 to 14 August 2013. We objectively...
Authors
Dennis M. Staley, Joseph E. Gartner, Jason W. Kean
NGA-West 2 GMPE average site coefficients for use in earthquake-resistant design NGA-West 2 GMPE average site coefficients for use in earthquake-resistant design
Site coefficients corresponding to those in tables 11.4–1 and 11.4–2 of Minimum Design Loads for Buildings and Other Structures published by the American Society of Civil Engineers (Standard ASCE/SEI 7-10) are derived from four of the Next Generation Attenuation West2 (NGA-W2) Ground-Motion Prediction Equations (GMPEs). The resulting coefficients are compared with those derived by other
Authors
Roger D. Borcherdt
Chance findings about early holocene tidal marshes of Grays Harbor, Washington, in relation to rapidly rising seas and great subduction earthquakes Chance findings about early holocene tidal marshes of Grays Harbor, Washington, in relation to rapidly rising seas and great subduction earthquakes
Tidal marshes commonly build upward apace with gradual rise in the level of the sea. It is expected, however, that few tidal marshes will keep up with accelerated sea-level rise later in this century. Tidal marshes have been drowned, moreover, after subsiding during earthquakes. This report tells of ancient marshes that endured rapid sea-level rise in a region that subsides during...
Authors
James B. Phipps, Eileen Hemphill-Haley, Brian F. Atwater
Curiosity’s robotic arm-mounted Mars Hand Lens Imager (MAHLI): Characterization and calibration status Curiosity’s robotic arm-mounted Mars Hand Lens Imager (MAHLI): Characterization and calibration status
MAHLI (Mars Hand Lens Imager) is a 2-megapixel, Bayer pattern color CCD camera with a macro lens mounted on a rotatable turret at the end of the 2-meters-long robotic arm aboard the Mars Science Laboratory rover, Curiosity. The camera includes white and longwave ultraviolet LEDs to illuminate targets at night. Onboard data processing services include focus stack merging and data...
Authors
Kenneth S. Edgett, Michael A. Caplinger, Justin N. Maki, Michael A. Ravine, F. Tony Ghaemi, Sean McNair, Kenneth E. Herkenhoff, Brian M. Duston, Reg G. Wilson, R. Aileen Yingst, Megan R. Kennedy, Michelle E. Minitti, Aaron J. Sengstacken, Kimberley D. Supulver, Leslie J. Lipkaman, Gillian M. Krezoski, Marie J. McBride, Tessa L. Jones, Brian E. Nixon, Jason K. Van Beek, Daniel J. Krysak, Randolph L. Kirk
Cascadia subducting plate fluids channelled to fore-arc mantle corner: ETS and silica deposition Cascadia subducting plate fluids channelled to fore-arc mantle corner: ETS and silica deposition
In this study we first summarize the constraints that on the Cascadia subduction thrust, there is a 70 km gap downdip between the megathrust seismogenic zone and the Episodic Tremor and Slip (ETS) that lies further landward; there is not a continuous transition from unstable to conditionally stable sliding. Seismic rupture occurs mainly offshore for this hot subduction zone. ETS lies...
Authors
Roy D. Hyndman, Patricia A. McCrory, Aaron Wech, Han Kao, Jay Ague