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SCEC Community Workshop: Stress Drop Validation—Planning and Preliminary Results

Applications Due: October 18, 2021
Participants: 125 maximum

Date: November 4, 2021 (online)
Time: 09:00-15:00 PDT (UTC-7)

Conveners: Annemarie Baltay (USGS ESC) and Rachel Abercrombie (Boston University)
Dates: November 4, 2021 (online)
SCEC Award: 21114

SUMMARY: The motivation for the SCEC Technical Activity Group (TAG) for Community Stress Drop Validation Study is focused on understanding the nature and causes of discrepancies in earthquake stress drop, as well as where random and physical variability arises. We observe differences in stress drop estimates from different researchers, even when applying the same underlying method. We also observe differences between methods and data selections, even when applied by the same researcher. These differences are often larger than the calculated uncertainties, making it hard and confusing to use these measurements for ground motion prediction and to study earthquake source physics.

In this context, the main goals for the TAG are to use a common data set of records from the 2019 Ridgecrest earthquake sequence (consisting of over 12,000 events of M1 to M7.1) to address the questions: 

  • How do differing methods and model assumptions affect stress drop estimates? How do different researchers approach similar methods? 
  • How do data quantity, quality, selection and processing affect stress drop estimates? 
  • How do physical source (mechanism, depth, radiation pattern, directivity), path (geometrical spreading, attenuation), and site (soil conditions, site attenuation) features affect the estimates?
  • What measurements, and uncertainties, would be most useful for the broader community?

For more details, visit the SCEC Community Stress Drop Validation Study TAG website.

The workshop will be held as a Zoom meeting on November 4, 2021. Anyone currently working on, or interested in, the science questions noted above and/or learning about Ridgecrest earthquake studies is encouraged to apply to participate, especially researchers and young investigators. The workshop agenda includes plenty of time for discussions as a large group, as well as smaller breakouts.

All times below are Pacific Daylight Time (PDT or UTC-7).

09:00 - 10:30 Session 1: Introductions and Comparisons of Initial Results  
09:00 - 09:30 Welcome and Overview of Workshop, Dataset and Initial Results  
09:30 - 10:15 Introduction to Methods by Various Research Groups  
10:15 - 10:30 Group Discussion and Participant Introductions  
10:30 -11:00 Break  
11:00 - 12:30 Session 2: Method Comparisons—Breakouts and Discussion  
11:00 - 11:15 Keynote Science Talk, Comparative Studies  
11:15 - 11:35 Breakout Discussion #1  
11:35 - 11:55 Breakout Discussion #2  
11:55 - 12:15 Breakout Discussion #3  
12:15 - 12:30 Group Discussion  
12:30 - 13:30 Break  
13:30 - 15:00 Session 3: User Needs and Looking Forward  
13:30 - 13:45 Stress Drop in Ground Motion  
13:45 - 14:00 Stress Drop in Simulations and Source Physics  
14:00 - 14:15 Static Stress Drop  
14:15 - 14:30 Breakout Discussion #4  
14:30 - 15:00 Group Discussion: Looking Forward  
15:00 Adjourn  


Rachel Abercrombie (Boston Univ)
Florent Aden (MIT)
Mohadese Ajami
Pablo Ampuero (Geoazur, IRD/UCA)
Pablo Aravena (Saint Louis Univ)
Ralph Archuleta (UCSB)
Marcelo Assumpção (Univ São Paulo)
Annemarie Baltay (USGS)
Michael Barall (USGS)
Luis Bazán Flores (Memphis, CERI)
Yehuda Ben-Zion (SCEC/USC)
Allison Bent (Natural Res Canada)
Susan Bilek (New Mexico Tech)
Dino Bindi (GFZ Potsdam)
Aglaja Blanke (GFZ Potsdam)
Carolyn Boulton (Victoria Univ)
Oliver Boyd (USGS)
Giovanna Calderoni (INGV)
Raul Castro (CICESE)
Hilary Chang (MIT)
Xiang Chen (Chinese Univ of HK)
Xiaowei Chen (Univ of Oklahoma)
Shanna Chu (Brown)
Elizabeth Cochran (USGS )
Leonardo Colavitti (INGV)
Emma Devin (USGS)
Douglas Dreger (UC Berkeley)
Ahmed Elbanna (UIUC)
Bill Ellsworth (Stanford)
Wenyuan Fan (SIO/UCSD)
Carmen Garfias (Victoria Univ)
Abhijit Ghosh (UC Riverside)
Thomas Goebel (Memphis, CERI)
Christine Goulet (SCEC/USC)
Catherine Hanagan (Univ of Arizona)
Tom Hanks (USGS)
Jeanne Hardebeck (USGS)
Rebecca Harrington (Ruhr Univ)
Ruth Harris (USGS)
Behzad Hassani (BC Hydro)
Egill Hauksson (Caltech)
Joanna Holmgren (Univ of Bristol)
Susan Hough (USGS)
Yihe Huang (UMich)
Tran Huynh (USC/SCEC)
Nadine Igonin (UT Austin)
Chen JI (UCSB)
Junle Jiang (Univ of Oklahoma)
Yoshi Kaneko (Kyoto Univ)
Kilian Kemna (Ruhr Univ Bochum)
Navid Kheirdast (IIEES)
Debi Kilb (SIO/UCSD)
Olga-Joan Ktenidou (Nat'l Obs Athens)
Christos Kyriakopoulos (U Memphis)
Valere Lambert (UCSB)
Giovanni Lanzano (INGV)
Nadia Lapusta (Caltech)
Bo Li (LMU)
Duo Li (Munich)
Guoqing Lin (Univ of Miami)
Meichen Liu (UMich)
Julian Lozos (CSUN)
Semechah Lui (Univ of Toronto)
Björn Lund (Uppsala Univ)
Kuo-Fong Ma (Academia Sinica)
Jose A Magana (UC Berkeley)
Martin Mai (KAUST)
Luca Malagnini (INGV)
David Marsan (ISTerre)
Claudia Mascandola (INGV)
Eric Matzel (LLNL)
Kevin Mayeda (AFTAC)
Andrew Michael (USGS)
Ken Miyakoshi (GEOR)
Paola Morasca (INGV)
Jim Mori (Kyoto Univ)
Francesco Mosconi (Univ Sapienza)
Pamela Moyer (New Hampshire)
Irene Munafò (INGV)
Khadija Nadimi (Memphis, CERI)
James Neely (Northwestern)
Arjun Neupane (Univ of Tulsa)
Chukwuebuka Nweke (USC)
David Oglesby (UC Riverside)
Joses Omojola (LSU)
Roberto Ortega (CICESE)
Adrien Oth (ECGS)
Kiran Pandey (Memphis, CERI)
Grace Parker (USGS)
Anupam Patel (SDSU)
Edric Pauk (USC/SCEC)
Colin Pennington (USGS)
German Prieto (Uni Nac Colombia)
Christine Ruhl (Univ of Tulsa)
Natalie Schaal (CSUN)
Sara Sgobba (INGV)
Daya Shanker (Indian Inst Tech)
David Shelly (USGS)
Shuzhong Sheng (E China Univ Tech)
Kazuhiro Somei (GEOR)
Minkyung Son (KIGAM)
Mariano Supino (ERI)
Michelle Sutherland (Group Delta)
Taka'aki Taira (UC Berkeley)
Navin Thapa (Memphis, CERI)
Elisa Tinti (Università La Sapienza)
Sagar Tripathy (Tata Projects Ltd)
Daniel Trugman (UT Austin)
Ayako Tsuchiyama (MIT)
Jay Tung (UW Madison)
Takahiko Uchide (GSJ, AIST)
Ian Vandevert (UCSD)
Frank Vernon (UCSD)
Wei Wang (USC)
Yongfei Wang (SCEC/USC)
Emily Warren-Smith (GNS Science)
Katherine Whidden (Univ of Utah)
Baoning Wu (UC Riverside)
Changjiang Wu (Nuc Reg Auth, Japan)
Qimin Wu (Lettis)
Jiakang Xie (Array Info Tech)
Alan Yong (USGS)
Clara Yoon (USGS)
Nana Yoshimitsu (Kyoto Univ)

The Southern California Earthquake Center is committed to providing a safe, productive, and welcoming environment for all participants. We take pride in fostering a diverse and inclusive SCEC community, and therefore expect all participants to abide by the SCEC Activities Code of Conduct.