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2009 Annual Meeting: Dynamic Weakening Mechanisms Workshop

Dates: September 12-13, 2009
Organizers: Eric Dunham, Judi Chester
Location: Plaza Ballroom, Hilton Palm Springs Resort, Palm Springs, CA

Over the past several years there has been a surge of research on dynamic weakening mechanisms, i.e., processes by which fault strength is dramatically reduced during coseismic slip. Dynamic weakening offers a possible resolution of a number of outstanding issues in fault and rupture mechanics, including the heat flow paradox, the low stresses inferred to be acting on major faults, and why ruptures take the form of narrow slip pulses. A variety of weakening mechanisms have been proposed, including flash heating of asperity contacts, thermal pressurization of pore fluid, macroscopic melting, and thermal decomposition weakening. At this workshop, speakers will provide an overview of 1) the latest high velocity friction experiments; 2) theoretical predictions of fault strength as a function of slip rate, normal stress, and other variables; 3) consequences of dynamic weakening in spontaneous rupture models; and 4) field constraints. The objective of the workshop is to foster discussion between experimentalists, modelers, and geologists in order to determine which weakening mechanisms are active in natural earthquakes and how they influence rupture behavior.


  Introduction and Overview  
10:00-10:10 Introduction Eric Dunham, Judi Chester
10:10-10:40 Overview of Dynamic Weakening Mechanisms Jim Rice
  Session I: High Velocity Experiments and Understanding Weakening Mechanisms  
10:40-11:10 Experimental constraints on coseismic slip David Goldsby
11:10-11:40 Laboratory experiments to understand slip weakening due to flash heating at seismic slip rates Vikas Prakash
11:40-12:10 Fault plasticity at seismic slip rates: Experiments and theory Kevin Brown
12:15-13:45 Lunch  
13:45-14:15 Dynamic weakening by gouge lubrication: Experimental observations of granite friction at velocity range of 0.001-1.0 m/s Ze'ev Reches
14:15-14:45 High-speed friction of Punchbowl Fault ultracataclasite in rotary shear: Characterization of frictional heating, mechanical behavior, and microstructure evolution Hiroko Kitajima
14:45-15:30 Session I Discussion Terry Tullis
15:30-15:45 Break  
  Session II: Interpreting Observations and Integrating Dynamic Weakening into Rupture Models  
15:45-16:15 Flash weakening and the onset of melting Alan Rempel
16:15-16:45 3D earthquake-sequence simulations with thermal pressurization of pore fluids: Effect of heterogeneous fault properties on slip complexity and interseismic stress Nadia Lapusta
16:45-17:00 Wrap-Up Discussion  
18:30-20:00 Dinner  
  Session II: Continued  
08:30-09:00 3D earthquake-sequence simulations with thermal pressurization of pore fluids: Effect of heterogeneous fault properties on slip complexity and interseismic stress Giulio Di Toro
09:00-09:30 Semi-empirical constitutive relations for dynamic weakening based on high speed friction experiments Nick Beeler
09:30-09:45 Break  
09:45-10:15 What can ground motion in the Chi-chi earthquake tell us about dynamic weakening? Joe Andrews
10:15-11:30 Session II Discussion Nadia Lapusta
  Moving Forward - What earthquake physics science priorities should SCEC4 pursue?  
11:30-11:59 Open Discussion and Wrap-Up of Day 2 Eric Dunham, Judi Chester


Brad Aagaard (USGS)
Sara Alsbury (OSU)
Celso Alvizuri (UCSB)
Jean Paul Ampuero (Caltech)
Greg Anderson (NSF)
Joe Andrews (USGS)
Rasool Anooshehpoor (UNR)
Ralph Archuleta (UCSB)
Dafna Avraham (UCLA)
Yehuda Ben-Zion (USC)
Scott Bennett (UC Davis)
Greg Beroza (Stanford)
Harsha Bhat (USC / Caltech)
Mike Blanpied (USGS EQH)
Emily Brodsky (UCSC)
Danny Brothers (UCSD)
Kevin Brown (UCSD)
Jim Brune (UNR)
Brian Campbell (U of Missouri)
Jefferson Chang (Oklahoma)
Jiangzhi Chen (U of Oregon)
Linda Chernak (Brown)
Jean Chéry (CNRS)
Judith Chester (TAMU)
Kuo-En Ching (Indiana)
Ethan Coon (Columbia)
Eric Daub (LANL)
Steve Day (SDSU)
Nora DeDontney (Harvard)
Giulio Di Toro (INGV)
Renata Dmowska (Harvard)
Ben Duan (TAMU)
Eric Dunham (Stanford)
Ahmed Elbanna (Caltech)
Bill Ellsworth (USGS)
Geoffrey Ely (USC)
Brittany Erickson (UCSB)
Jim Evans (Utah State)
Amanda Fabian (South Carolina)
Yuri Fialko (SIO / UCSD)
Erik Frost (USC)
Alice Gabriel (ETHZ)
Vahe Gabuchian (Caltech)
Saul Garcia (ELAC)
David Goldsby (Brown)
Javier Gonzàlez-Garcìa (CICESE)
Jill Hardy (USC)
Ruth Harris (USGS)
Egill Hauksson (Caltech)
Tom Heaton (Caltech)
Don Helmberger (Caltech)
Greg Hirth (Brown)
Bill Holt (SUNY-Stony Brook)
D'Nita Howard (Wilberforce)
Tran Huynh (SCEC / USC)
Walter Imperatori (ETHZ)
Ravi Jakka (UCR)
Susanne Janecke (Utah State)
Chen Ji (UCSB)
Junle Jiang (Caltech)
Lizhen Jin (UCR)
Tom Jordan (USC)
Frank Jordan, Jr. (JRB Inc.)
Taka Kanaya (Hess Corp)
Yoshihiro Kaneko (Caltech)
Jingqian Kang (TAMU)
Chinaemerem Kanu (Indiana)
Ichiro Kawasaki (Kyoto U)
Hiroko Kitajima (TAMU)
Arjun Kohli (Brown)
Jeremy Kozdon (Stanford)
Nadia Lapusta (Caltech)
En-Jui Lee (Wyoming)
Xiangyu Li (UCSB)
Zaifeng Liu (TAMU)
Qiming Liu (UCSB)
David Lockner (USGS)
Julian Lozos (UCR)
Shuo Ma (SDSU)
Martin Mai (KAUST)
John McRaney (SCEC / USC)
Tim Melbourne (CWU)
Michael Mello (Caltech)
Bernard Minster (UCSD)
Erica Mitchell (UCSD)
Damiano Monelli (ETHZ)
Sarah Moreland (CSUSB)
Hiro Noda (Caltech)
David Oglesby (UCR)
Kim Olsen (SDSU)
Yaman Ozakin (USC)
Vikas Prakash (CWRU)
Leonardo Ramirez-Guzman (USGS)
Ze'ev Reches (Oklahoma)
Alan Rempel (Oregon)
Jim Rice (Harvard)
Vanessa Rodriguez (LMU)
Otilio Rojas (SDSU)
Daniel Roten (SDSU)
John Rudnicki (Northwestern)
Kenny Ryan (UCR)
Paul Segall (Stanford )
Guangfu Shao (UCSB)
Bruce Shaw (Columbia)
Zheqiang Shi (SDSU)
Norm Sleep (Stanford)
Teira Solis (UTEP)
Surendra Nadh Somala (Caltech)
Seok Goo Song (URS)
Paul Spudich (USGS)
Igor Stubailo (UCLA)
Nathan Toke (ASU)
Matthew Totten (Oklahoma)
Terry Tullis (Brown)
Wei Wang (USC)
Shimon Wdowinski (U of Miami)
Stephanie Weaver (Oregon)
Max Werner (ETHZ)
Guanshui Xu (UCR)
Shiqing Xu (USC)
Warren Yamashita (USC)
Tomoko Yano (UCSB)
Yuehua Zeng (USGS)
Dongzhou Zhang (Caltech)
Wenbo Zhang (CAS)
Jinquan Zhong (TAMU)
Olaf Zielke (ASU)

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