T12A:
Geometry, Connectivity, and Dynamics of Fault Intersections and Stepovers I


Session ID#: 10796

Session Description:
The recent occurrence of large (Mw >7) multifault earthquakes highlights the need to evaluate the potential for through-going ruptures at fault intersections and stepovers. Fault geometry and fault connectivity are important components of seismic hazard analysis because fault connectivity impacts the distribution of seismic sources, and because the three-dimensional geometry of faults affects the dynamics of fault rupture, slip, and ground motion. Details of 3D fault geometry at important intersections and stepovers is often lacking or poorly understood, limiting efforts to constrain the hazard in these areas. Our session intends to focus on geologic and geophysical studies of the 3D structure, mechanics, and dynamic modeling of fault intersections and stepovers with particular emphasis on seismic hazard implications. Special emphasis will be put on contributions that provide an integrated geologic and geophysical perspective along with a dynamic modeling component.
Primary Convener:  Janet Tilden Watt, USGS, Santa Cruz, CA, United States
Conveners:  Jeanne Hardebeck, U.S. Geological Survey, Earthquake Science Center, Moffett Field, United States, David Douglas Oglesby, University of California Riverside, Department of Earth and Planetary Sciences, Riverside, CA, United States and Michele L Cooke, University of Massachusetts Amherst, Earth, Geographic and Climate Sciences, Amherst, MA, United States
Chairs:  Janet Tilden Watt, USGS, Santa Cruz, CA, United States and Jeanne Hardebeck, USGS, Menlo Park, CA, United States
OSPA Liaison:  David Douglas Oglesby, University of California Riverside, Department of Earth and Planetary Sciences, Riverside, CA, United States
Index Terms:

7230 Seismicity and tectonics [SEISMOLOGY]
8107 Continental neotectonics [TECTONOPHYSICS]
8118 Dynamics and mechanics of faulting [TECTONOPHYSICS]
8175 Tectonics and landscape evolution [TECTONOPHYSICS]

Abstracts Submitted to this Session:

A New Kinematic Model for Polymodal Faulting: Implications for Fault Connectivity (77628)
David Healy, University of Aberdeen, School of Geosciences, Aberdeen, United Kingdom and Roberto Emanuele Rizzo, Utrecht University, Utrecht, Netherlands
Geometry of the southern San Andreas fault and its implications for seismic hazard (Invited) (58974)
Victoria E Langenheim, U.S. Geological Survey, Menlo Park, CA, United States, Rebecca J Dorsey, University of Oregon, Department of Earth Sciences, Eugene, OR, United States, Gary S Fuis, USGS, Earthquake Science Center, Menlo Park, CA, United States, Michele L Cooke, University of Massachusetts Amherst, Earth, Geographic and Climate Sciences, Amherst, MA, United States, Laura Fattaruso, Umass Amherst, Northampton, MA, United States and Shahar Barak, Stanford University-Geophysics, Stanford, CA, United States
A Case for Historic Joint Rupture of the San Andreas and San Jacinto Faults (Invited) (59188)
Julian Lozos, Stanford University, Stanford, CA, United States
Coseismic brecciation at fault stepovers and transient fluid pathways in a mid-crustal San Andreas analogue: The Pofadder Shear Zone, Namibia and South Africa (82467)
Benjamin Lee Melosh, U.S.G.S., Menlo Park, United States, Christie D Rowe, McGill University, Dept of Earth and Planetary Sciences, Montreal, QC, Canada and Christopher C Gerbi, University of Maine, School of Earth and Climate Sciences, Orono, ME, United States
Growth of a Structure Connecting the 2010 M 7.2 El Mayor – Cucapah Rupture with the Elsinore Faul (75792)
Andrea Donnellan, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, United States and Jay W Parker, NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
Maps of Secondary Slip Structures within Fault Steps & Mechanical Models of their Development and Influence on Multifault Earthquake Ruptures (Invited) (76556)
Elizabeth H Madden, Ludwig Maximilian University of Munich, Department of Earth and Environmental Sciences, Munich, Germany, Michele L Cooke, University of Massachusetts Amherst, Earth, Geographic and Climate Sciences, Amherst, MA, United States and Heather M Savage, Columbia University of New York, Palisades, NY, United States
Along-strike Variation in Fault Structural Maturity Dictates Location of Largest Earthquake Slip and Rupture Speed (64624)
Isabelle Manighetti1, Clément Perrin2, Jean Paul Ampuero3, Frederic Cappa1 and Yves Gaudemer4, (1)Géoazur - Université Nice Sophia Antipolis, Valbonne, France, (2)Nantes Université - Laboratoire de Planétologie et Geosciences (CNRS 6112) - Observatoire des Sciences de l'Univers Nantes Atlantique (CNRS 3281), Nantes, France, (3)California Institute of Technology, Pasadena, CA, United States, (4)IPGP, Paris, France
Zipper Faults (62745)
John P Platt, University of Southern California, Earth Sciences, Los Angeles, CA, United States and Cees W Passchier, Johannes Gutenberg University of Mainz, Mainz, Germany

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