Insights Into Tectonic Regionalisation in Seismic Hazard Analysis and Computational Methods for Delineation
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The document discusses advancements in tectonic regionalization for seismic hazard analysis, emphasizing the need for a quantitative, objective methodology using global data. It critiques current approaches based on subjective judgments and proposes a fuzzy framework to enhance decision-making. Key datasets and models, such as seismic moment rate and shear wave velocity, are explored to better delineate seismic zones.
Insights Into Tectonic Regionalisation in Seismic Hazard Analysis and Computational Methods for Delineation
- 1. Insights Into Tectonic Regionalisation in Seismic Hazard Analysis and Computational Methods for Delineation Yen-Shin Chen1, Graeme Weatherill2, Marco Pagani3, GEM Working Group on Tectonic Regionalisation 1PhD Student, Understand & Managing Extremes School, Pavia, Italy 2GEM Hazard Scientist, Pavia, Italy 3GEM Hazard Coordinator, Pavia, Italy 26th, August, 2014 2ECEES Istanbul, Turkey
- 2. Precedents for Tectonic Regionalisation Jordan (1981) USGS (1997) Douglas (2007) Kagan et al. (2010)
- 3. Tectonic Regionalisation in Seismic Hazard Analysis GMPEs • Active shallow crust • Subduction Interface/Intra-slab • Stable Continent Region • Volcanic • Non-subduction deep focus • Oceanic Travel Path • Q, attenuation • κappa Magnitude Scaling Relations • Active shallow/subduction/SCR • Crustal age/structural maturity • Orogenic? • High/low stress drop Tectonic Proxies • MMAX (e.g. EPRI, 1994) or Corner Magnitude • Recurrence (e.g. Truncated | Tapered G-R) • Seismogenic depth distribution?
- 4. Tectonic Regionalisation: Basic Objective Questions, Comments Current Regionalisation methods are mainly performed by subjective judgements – basis for delineation of zones remains unclear Our goal is to design an quantitative and objective definition of a regionalisation scheme/methodology – a global data driven and transparent, scalable, replicable approach
- 5. Possible Relevant Datasets for Seismic Hazard Regionalisation Seismic Moment Rate QLG Global Composite (from Brian Mitchell, personal comm.) Shear Wave Velocity Variation at Depth of 175 km (Mooney, 2012) Global Continent Crust Age Map(modified from CCGM)
- 6. Softening the Decisions: Implementation in a Fuzzy Framework not Active Active 10-9 Ex: strain Rate Definitely Definitely not • Crisp Classification
- 7. Softening the Decisions: Implementation in a Fuzzy Framework not Active Active 10-9 Ex: strain Rate Definitely Definitely not •Fuzzy Classification Softening the boundary 10-9 Ex: strain Rate degree of belief Definitely Definitely not Based on knowledge … ex: If Strain rate is high, then high chance to be Active • Crisp Classification
- 8. Example of Fuzzy Framework Smoothed Seismic Moment Rate Exploratory Data Analysis Log10(Mo)(N-myr-1-km-2) Log10(Mo)(N-myr-1-km-2) Normalized recording number Stable Active Log Mo(N-m yr-1 km-2) Stable Continent Regions by Johnson, 1994
- 9. Example of Fuzzy Framework Smoothed Seismic Moment Rate Fuzzy Framework: If moment rate is high, and S velocity var. is low Deg. of “Active” is high Log Mo(N-m yr-1 km-2) Shear Wave Velocity Variation Shear wave velocity var.(%) (Mooney, 2012) Stable Active Shear wave velocity variation Normalized recording number Exploratory Data Analysis
- 10. Result - Degree of Being Active SCR regions defined by Johnson, 1994 Degree of being “Active”
- 11. Defuzzication– Active/ Stable Delineation Stable Active SCR regions defined by Johnson, 1994
- 12. Tectonic Regionalisation Model Drive From our Study Stable Continent Region, Non-Craton Stable Continent Region, Craton Subduction Active Continent Shallow Region Stable Oceanic Region Active Oceanic Region
- 13. Please attribute to the GEM Foundation with a link to - www.globalearthquakemodel.org Except where otherwise noted, this work is licensed under: creativecommons.org/licenses/by-nc-nd/4.0/
Editor's Notes
- #2: When we
- #3: the ergodic process is often a necessary component of a seismic hazard analysis in any given location , where local data in sufficient to characterisitc fully the source and attenuation characteristics it becomes necessary to draw from regions of tectonic similarity.
- #5: Regionalisation by judgement – basis for delineation of zones remains unclear It’s necessary to define a classification process that is objective, or at the very least, replicable across the globe. formalisation the delineation procedure. available to plug in the new available dataset which is relevent in tectonic regionalisaiton.
- #9: Fuzzy Framework: If moment rate is higher, and S velocity var. is lower Deg. of “Active” is higher
- #10: Fuzzy Framework: If moment rate is higher, and S velocity var. is lower Deg. of “Active” is higher
- #12: North China craton