ALBERT

Description: Faults in complex tectonic environments interact in various ways, including triggered rupture of one fault by another, that may increase seismic hazard in the surrounding region. We model static and dynamic fault interactions between the strike-slip and thrust fault systems in southern California. We find that rupture of the Sierra Madre-Cucamonga thrust fault system is unlikely to trigger rupture of the San Andreas or San Jacinto strike-slip faults. However, a large northern San Jacinto fault earthquake could trigger a cascading rupture of the Sierra Madre-Cucamonga system, potentially causing a moment magnitude 7.5 to 7.8 earthquake on the edge of the Los Angeles metropolitan region.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Anderson, Greg -- Aagaard, Brad -- Hudnut, Ken -- New York, N.Y. -- Science. 2003 Dec 12;302(5652):1946-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉U.S. Geological Survey, 525 South Wilson Avenue, Pasadena, CA 91106-3212, USA. anderson@unavco.org〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14671298" target="_blank"〉PubMed〈/a〉

Description: The Landers earthquake, which had a moment magnitude (M(w)) of 7.3, was the largest earthquake to strike the contiguous United States in 40 years. This earthquake resulted from the rupture of five major and many minor right-lateral faults near the southern end of the eastern California shear zone, just north of the San Andreas fault. Its M(w) 6.1 preshock and M(w) 6.2 aftershock had their own aftershocks and foreshocks. Surficial geological observations are consistent with local and far-field seismologic observations of the earthquake. Large surficial offsets (as great as 6 meters) and a relatively short rupture length (85 kilometers) are consistent with seismological calculations of a high stress drop (200 bars), which is in turn consistent with an apparently long recurrence interval for these faults.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sieh, K -- Jones, L -- Hauksson, E -- Hudnut, K -- Eberhart-Phillips, D -- Heaton, T -- Hough, S -- Hutton, K -- Kanamori, H -- Lilje, A -- Lindvall, S -- McGill, S F -- Mori, J -- Rubin, C -- Spotila, J A -- Stock, J -- Thio, H K -- Treiman, J -- Wernicke, B -- Zachariasen, J -- New York, N.Y. -- Science. 1993 Apr 9;260(5105):171-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17807175" target="_blank"〉PubMed〈/a〉

Description: The Gorkha earthquake (magnitude 7.8) on 25 April 2015 and later aftershocks struck South Asia, killing ~9000 people and damaging a large region. Supported by a large campaign of responsive satellite data acquisitions over the earthquake disaster zone, our team undertook a satellite image survey of the earthquakes' induced geohazards in Nepal and China and an assessment of the geomorphic, tectonic, and lithologic controls on quake-induced landslides. Timely analysis and communication aided response and recovery and informed decision-makers. We mapped 4312 coseismic and postseismic landslides. We also surveyed 491 glacier lakes for earthquake damage but found only nine landslide-impacted lakes and no visible satellite evidence of outbursts. Landslide densities correlate with slope, peak ground acceleration, surface downdrop, and specific metamorphic lithologies and large plutonic intrusions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kargel, J S -- Leonard, G J -- Shugar, D H -- Haritashya, U K -- Bevington, A -- Fielding, E J -- Fujita, K -- Geertsema, M -- Miles, E S -- Steiner, J -- Anderson, E -- Bajracharya, S -- Bawden, G W -- Breashears, D F -- Byers, A -- Collins, B -- Dhital, M R -- Donnellan, A -- Evans, T L -- Geai, M L -- Glasscoe, M T -- Green, D -- Gurung, D R -- Heijenk, R -- Hilborn, A -- Hudnut, K -- Huyck, C -- Immerzeel, W W -- Liming, Jiang -- Jibson, R -- Kaab, A -- Khanal, N R -- Kirschbaum, D -- Kraaijenbrink, P D A -- Lamsal, D -- Shiyin, Liu -- Mingyang, Lv -- McKinney, D -- Nahirnick, N K -- Zhuotong, Nan -- Ojha, S -- Olsenholler, J -- Painter, T H -- Pleasants, M -- Pratima, K C -- Yuan, Q I -- Raup, B H -- Regmi, D -- Rounce, D R -- Sakai, A -- Donghui, Shangguan -- Shea, J M -- Shrestha, A B -- Shukla, A -- Stumm, D -- van der Kooij, M -- Voss, K -- Xin, Wang -- Weihs, B -- Wolfe, D -- Lizong, Wu -- Xiaojun, Yao -- Yoder, M R -- Young, N -- New York, N.Y. -- Science. 2016 Jan 8;351(6269):aac8353. doi: 10.1126/science.aac8353. Epub 2015 Dec 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ, USA. kargel@hwr.arizona.edu dshugar@uw.edu uharitashya1@udayton.edu. ; Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ, USA. ; School of Interdisciplinary Arts and Sciences, University of Washington Tacoma, Tacoma, WA, USA. kargel@hwr.arizona.edu dshugar@uw.edu uharitashya1@udayton.edu. ; Department of Geology, University of Dayton, Dayton, OH, USA. kargel@hwr.arizona.edu dshugar@uw.edu uharitashya1@udayton.edu. ; Ministry of Forests, Lands and Natural Resource Operations, Prince George, BC, Canada. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. ; Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan. ; Scott Polar Research Institute, University of Cambridge, Cambridge, UK. ; Institute of Environmental Engineering, Federal Institute of Technology-ETH, Zurich, Switzerland. ; NASA Marshall Space Flight Center, Huntsville, AL, USA. ; International Centre for Integrated Mountain Development, Kathmandu, Nepal. ; NASA Headquarters, Washington, DC, USA. ; GlacierWorks, Marblehead, MA, USA. ; The Mountain Institute, Elkins, WV, USA. ; U.S. Geological Survey, Menlo Park, CA, USA. ; Central Department of Geology, Tribhuvan University, Kirtipur, Kathmandu, Nepal. ; Department of Geography, University of Victoria, Victoria, BC, Canada. ; CVA Engineering, Suresnes, France. ; Earthquake Science Center, U.S. Geological Survey, Pasadena, CA, USA. ; ImageCat, Long Beach, CA, USA. ; Faculty of Geosciences, Utrecht University, Utrecht, Netherlands. ; State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, Hubei Province, China. ; U.S. Geological Survey, Golden, CO, USA. ; Department of Geosciences, University of Oslo, Blindern, Oslo, Norway. ; Hydrological Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA. ; Cold and Arid Regions of Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China. ; School of Earth Sciences and Engineering, Nanjing University, Nanjing, China. ; Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX, USA. ; School of Geography Science, Nanjing Normal University, Nanjing, China. ; Department of Geography, Texas A&M University, College Station, TX, USA. ; Department of Geology, University of Dayton, Dayton, OH, USA. ; Arizona Remote Sensing Center, School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA. ; National Snow and Ice Data Center, University of Colorado, Boulder, CO, USA. ; Himalayan Research Center, Kathmandu, Nepal. ; Environmental and Water Resources Engineering, University of Texas at Austin, Austin, TX, USA. ; Wadia Institute of Himalayan Geology, Dehradun, India. ; MacDonald Dettwiler and Associates-GSI, Ottawa, Ontario, Canada. ; Department of Geography, University of California, Santa Barbara, Santa Barbara, CA, USA. ; College of Architecture and Urban Planning, Hunan University of Science and Technology, Xiangtan, China. ; Geography Department, Kansas State University, Manhattan, KS, USA. ; Global Land Ice Measurements from Space (GLIMS) Steward, Alaska Region, Anchorage, AK, USA. ; College of Geographical Science and Environment, Northwest Normal University, China. ; Department of Physics, University of California, Davis, Davis, CA, USA. ; Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, TAS, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26676355" target="_blank"〉PubMed〈/a〉

Description: Earthquake-related fault slip in the upper hundreds of meters of Earth’s surface has remained largely unstudied because of challenges measuring deformation in the near field of a fault rupture. We analyze centimeter-scale accuracy mobile laser scanning (MLS) data of deformed vine rows within ±300 m of the principal surface expression of the M (magnitude) 6.0 2014 South Napa earthquake. Rather than assuming surface displacement equivalence to fault slip, we invert the near-field data with a model that allows for, but does not require, the fault to be buried below the surface. The inversion maps the position on a preexisting fault plane of a slip front that terminates ~3 to 25 m below the surface coseismically and within a few hours postseismically. The lack of surface-breaching fault slip is verified by two trenches. We estimate near-surface slip ranging from ~0.5 to 1.25 m. Surface displacement can underestimate fault slip by as much as 30%. This implies that similar biases could be present in short-term geologic slip rates used in seismic hazard analyses. Along strike and downdip, we find deficits in slip: The along-strike deficit is erased after ~1 month by afterslip. We find no evidence of off-fault deformation and conclude that the downdip shallow slip deficit for this event is likely an artifact. As near-field geodetic data rapidly proliferate and will become commonplace, we suggest that analyses of near-surface fault rupture should also use more sophisticated mechanical models and subsurface geomechanical tests.