Publications
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The discovery of columnar jointing on Mars The discovery of columnar jointing on Mars
We report on the discovery of columnar jointing in Marte Valles, Mars. These columnar lavas were discovered in the wall of a pristine, 16-km-diameter impact crater and exhibit the features of terrestrial columnar basalts. There are discontinuous outcrops along the entire crater wall, suggesting that the columnar rocks covered a surface area of at least 200 km2, assuming that the rocks...
Authors
Moses P. Milazzo, Laszlo P. Keszthelyi, Windy L. Jaeger, Mark R. Rosiek, Sarah Mattson, C. Verba, Ross A. Beyer, Paul E. Geissler, Alfred S. McEwen
Dielectric properties of lava flows west of Ascraeus Mons, Mars Dielectric properties of lava flows west of Ascraeus Mons, Mars
The SHARAD instrument on the Mars Reconnaissance Orbiter detects subsurface interfaces beneath lava flow fields northwest of Ascraeus Mons. The interfaces occur in two locations; a northern flow that originates south of Alba Patera, and a southern flow that originates at the rift zone between Ascraeus and Pavonis Montes. The northern flow has permittivity values, estimated from the time...
Authors
Lynn M. Carter, Bruce A. Campbell, John W. Holt, Roger J. Phillips, Nathaniel E. Putzig, Stefania Mattei, Roberto Seu, Chris H. Okubo, Anthony F. Egan
Probabilistic liquefaction hazard mapping Probabilistic liquefaction hazard mapping
Many investigators have applied the liquefaction potential index (LPI) to map regional liquefaction hazard. LPI, which integrates the liquefaction potential of susceptible soil elements at a specific location into a single value, has been used to assess both (1) spatial variability of liquefaction potential, and (2) liquefaction potential of surficial geologic units. A promising...
Authors
Thomas L. Holzer
Submarine landslide as the source for the October 11, 1918 Mona Passage tsunami: Observations and modeling Submarine landslide as the source for the October 11, 1918 Mona Passage tsunami: Observations and modeling
The October 11, 1918 ML 7.5 earthquake in the Mona Passage between Hispaniola and Puerto Rico generated a local tsunami that claimed approximately 100 lives along the western coast of Puerto Rico. The area affected by this tsunami is now significantly more populated. Newly acquired high-resolution bathymetry and seismic reflection lines in the Mona Passage show a fresh submarine...
Authors
A.M. López-Venegas, Uri S. ten Brink, Eric L. Geist
The coral reef of South Moloka'i, Hawai'i— Portrait of a sediment-threatened fringing reef The coral reef of South Moloka'i, Hawai'i— Portrait of a sediment-threatened fringing reef
Moloka‘i, with the most extensive coral reef in the main Hawaiian Islands, is especially sacred to Hina, the Goddess of the Moon. As Hinaalo, she is the Mother of the Hawaiian people; as Hinapuku‘a, she is the Goddess of Fishermen; and in the form Hina‘opuhalako‘a, she is the Goddess who gave birth to coral, coral reefs, and all spiny marine organisms. Interdependence between the reef’s...
Report on the Aseismic Slip, Tremor, and Earthquakes Workshop Report on the Aseismic Slip, Tremor, and Earthquakes Workshop
This report summarizes the discussions and information presented during the workshop on Aseismic Slip, Tremor, and Earthquakes. Workshop goals included improving coordination among those involved in conducting research related to these phenomena, assessing the implications for earthquake hazard assessment, and identifying ways to capitalize on the education and outreach opportunities...
Authors
Joan Gomberg, Evelyn Roeloffs, Anne Trehu, Herb Dragert, Charles Meertens
Origin of meter-size granite basins in the southern Sierra Nevada, California Origin of meter-size granite basins in the southern Sierra Nevada, California
Meter-size granite basins are found in a 180-km belt extending south from the South Fork of the Kings River to Lake Isabella on the west slope of the southern Sierra Nevada, California. Their origin has long been debated. A total of 1,033 basins have been inventoried at 221 sites. The basins occur on bedrock granitic outcrops at a median elevation of 1,950 m. Median basin diameter among...
Authors
James G. Moore, Mary A. Gorden, Joel E. Robinson, Barry C. Moring
Steady and intermittent slipping in a model of landslide motion regulated by pore-pressure feedback Steady and intermittent slipping in a model of landslide motion regulated by pore-pressure feedback
This paper studies a parsimonious model of landslide motion, which consists of the one-dimensional diffusion equation (for pore pressure) coupled through a boundary condition to a first-order ODE (Newton's second law). Velocity weakening of sliding friction gives rise to nonlinearity in the model. Analysis shows that solutions of the model equations exhibit a subcritical Hopf bifurcation...
Authors
David G. Schaeffer, Richard M. Iverson
Seismicity and deformation induced by magma accumulation at three basaltic volcanoes Seismicity and deformation induced by magma accumulation at three basaltic volcanoes
We analyzed the evolution of volcano‐tectonic (VT) seismicity and deformation at three basaltic volcanoes (Kilauea, Mauna Loa, Piton de la Fournaise) during phases of magma accumulation. We observed that the VT earthquake activity displays an accelerating evolution at the three studied volcanoes during the time of magma accumulation. At the same times, deformation rates recorded at the...
Authors
O. Lengline, David Marsan, J.-L. Got, Virginie Pinel, Valerie Ferrazzini, Paul G. Okubo
Strong tremor near Parkfield, CA, excited by the 2002 Denali Fault earthquake Strong tremor near Parkfield, CA, excited by the 2002 Denali Fault earthquake
We show clear evidence of non-volcanic tremor triggered by 2002 Mw7.8 Denali Fault earthquake near Parkfield. Triggered tremor is identified as bursts of high-frequency (∼2–8 Hz), non-impulsive seismic energy whose envelope is coherent among many stations and has the same periodicity as the passing surface waves. The tremor originates from at least three hypocenters near the San Andreas...
Authors
Zhigang Peng, John E. Vidale, Kenneth C. Creager, Justin L. Rubenstein, Joan S. Gomberg, Paul Bodin
Relative age of interior layered deposits in southwest Candor Chasma based on high-resolution structural mapping Relative age of interior layered deposits in southwest Candor Chasma based on high-resolution structural mapping
High‐resolution topography generated from stereo HiRISE (High‐Resolution Imaging Science Experiment) imagery reveals the meter‐scale structure of interior layered deposits (ILD) in southwest Candor Chasma. This study seeks to determine the age of the local ILD relative to any normal faults that can be attributed to chasma formation. The study area is located near the contact of these ILD...
Authors
Chris H. Okubo, Kevin W. Lewis, Alfred S. McEwen, Randolph L. Kirk
Surface processes recorded by rocks and soils on Meridiani Planum, Mars: Microscopic Imager observations during Opportunity's first three extended missions Surface processes recorded by rocks and soils on Meridiani Planum, Mars: Microscopic Imager observations during Opportunity's first three extended missions
The Microscopic Imager (MI) on the Mars Exploration Rover Opportunity has returned images of Mars with higher resolution than any previous camera system, allowing detailed petrographic and sedimentological studies of the rocks and soils at the Meridiani Planum landing site. Designed to simulate a geologist's hand lens, the MI is mounted on Opportunity's instrument arm and can resolve...
Authors
Kenneth E. Herkenhoff, John P. Grotzinger, Andrew H. Knoll, Scott M. McLennan, Catherine M. Weitz, Aileen Yingst, Robert Anderson, Brent A. Archinal, Raymond E. Arvidson, Janet M. Barrett, Kris J. Becker, James F. Bell, Charles Budney, Mary G. Chapman, Debbie Cook, Bethany L. Ehlmann, Brenda Franklin, Lisa R. Gaddis, Donna M. Galuszka, Patricia A. Garcia, Paul E. Geissler, Trent M. Hare, Elpitha Howington-Kraus, Jeffrey R. Johnson, Laszlo P. Keszthelyi, Randolph L. Kirk, Peter Lanagan, Ella M. Lee, Craig Leff, Justin N. Maki, Kevin F. Mullins, Timothy J. Parker, Bonnie L. Redding, Mark R. Rosiek, Michael H. Sims, Laurence A. Soderblom, Nicole Spanovich, Richard Springer, Steven W. Squyres, Daniel A. Stolper, Robert M. Sucharski, Tracie L. Sucharski, Robert Sullivan, James M. Torson