Powell Working Group on Seismic Hazard Modelling Issues Mark S:rling, Ross Stein Seismic hazard debate GEM needs resolu:on of these issues 1.  Ross and Mark approached the John Wesley Powell Centre, Fort Collins CO for support to address PSHA issues “The Powell Center serves as a catalyst for innova5ve thinking in earth system science research by providing scien5sts from different backgrounds a place and 5me to focus on mul5-­‐faceted issues” (powellcenter.usgs.gov/
concept.php) 2.  Powell Centre supported our proposal to convene 4 working group mee:ngs to address issues 3.  2 subgroups: interplate and intraplate seismic hazard issues (2 mee:ngs each in period August 2012 -­‐ September 2013) Powell Groups: Harnessing the community /Co-­‐PI Ray Durrheim Southern Africa seismologist Ross Stein USGS/Co-­‐PI Oona Sco( European Haz Model Anke Friedrich Neotectonics expert Powell Groups: Harnessing the community Margaret BoeLcher, Marine tectonics Nicola Litchfield GNS/GEM FE /Co-­‐Pi Ross Stein USGS/Co-­‐Pi Working Group mee:ngs have been harmonious & produc:ve Emerging Powell projects 1.  Test predicted ground mo:ons from seismic hazard models against observed ground mo:ons (GFZ/GNS workshop early 2013) 2.  Create and test global earthquake model using smoothed seismicity and GEM strain rate (UCLA workshop planned for early 2013; Tes5ng & evalua5on of official US models at GFZ) 3.  Abandon ‘maximum earthquake magnitude’ assignments for scien:fically defensible alterna:ves e.g. Mp, Mc (UCLA/FMG research) 4.  Evaluate alterna:ves to ‘declustering’ (removing a[ershocks from) seismic catalogues (possible workshop first half of 2013) 5.  “Op:mal mi:ga:on”/how good do hazard assessments need to be? (Seth Stein) A possible way out of the ‘max mag’ quagmire? Yufang Rong (FM Global) & David Jackson (UCLA) Preliminary max probable magnitude as a func:on of :me CumulaNve Annual Rate of Occurence Gutenberg-­‐Richter (GR) Distribu:on Op:ons vs. data mp(100 yr) 1000 Tapered GR (mc=9.0) 100 Truncated GR (Mmax=9.2) 10 Historical Earthquakes 1 0.1 0.01 mp(250 yr) 0.001 0.0001 5.5 6.5 7.5 8.5 9.5 Magnitude Legend
Flinn-Engdahl region
mp(T)
< 8.2
8.2 - 8.5
8.5 - 8.8
8.8 - 9.0
≥9.0
mp(500 yr) How we are making it happen 1.  Powell Centre funding for mee:ng facilita:on 2.  Ins:tu:onal support for par:cipants 3.  GEM support 4.  NSF funding for extension to Powell Centre-­‐funded ac:vi:es Payback = Advice to GEM and others Acknowledgements 1.  Par:cipants 2.  Jill Baron 3.  Mar:n Goldhaber 4.  Lorie Hughes 5.  GEM