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TitleAn assessment of array types and processing algorithms for microtremor observations, via the COSMOS blind trials
 
AuthorAsten, M W; Yong, A; Foti, S; Hayashi, K; Martin, A J; Stephensen, W J; Cassidy, J FORCID logo; Coleman, J S
SourceAmerican Geophysical Union Annual Fall Meeting, 2018, abstracts; 2018 p. 1 Open Access logo Open Access
LinksOnline - En ligne
Image
Year2018
Alt SeriesNatural Resources Canada, Contribution Series 20180180
PublisherAmerican Geophysical Union
Meeting2018 American Geophysical Union Annual Fall Meeting; Washington, DC; US; December 10-14, 2018
DocumentWeb site
Lang.English
Mediapaper; on-line; digital
File formathtml; pdf (Adobe® Reader®)
Subjectsgeophysics; Science and Technology; seismology; earthquakes; array seismology; in-field instrumentation; drillholes; Consortium of Organizations for Strong Motion Observation Systems (COSMOS); Methodology; Assessment
ProgramPublic Safety Geoscience Assessing Earthquake Geohazards
Released2018 12 01
AbstractThe blind trial studies conducted for the 2006 3rd International Symposium on the Effects of Surface Geology (Grenoble, France) and the 2015 Inter-comparison of methods for site PArameter and veloCIty proFIle charaCterization (InterPACIFIC) Workshop (Turin, Italy) evaluated the utility of microtremor array methods for characterizing seismic site conditions. These studies used a multiplicity of arrays but left an open question as to whether (and under what) conditions might sparse (low-cost) arrays be technically sufficient for the task.
In this study, the Consortium of Organizations for Strong Motion Observation Systems (COSMOS) blind trials used microtremor array data from four sites with geology ranging from deep alluvial valleys to an alpine valley. Data were incrementally released to approximately a dozen analysts in four phases: (1) 2-station linear arrays; (2) sparse triangular arrays; (3) complex nested triangular or circular arrays; (4) all available geological control including drill-hole data. While data from one site consisted of recordings from 3-component sensors, the other three sites consisted of data from vertical-component sensors only. The sites covered a range of noise source distributions, ranging from one site with a highly directional microtremor wave field, to others with distributed or omni-directional wave fields.
Here, we review the results based on the different processing algorithms (e.g., beam-forming, spatial autocorrelation, seismic interferometry) as applied by the analysts to the incrementally released data, and then compare the effectiveness between the differing wave-field distributions. The results of the study will aid in building an evidence-based consensus on preferred cost-effective arrays and processing methodology for future site-effect studies.
Summary(Plain Language Summary, not published)
This invited paper reviews the "blind-test" results where many groups from around the world use common datasets (for a wide variety of geological settings) and common processing techniques to determine the shear-wave velocity at the test sites. We then compare the results from different groups to see if the results are similar, or what is common (or different), in an effort to determine best data collection and processing practises for determining earthquake site response. The results of the study will aid in building an evidence-based consensus on preferred cost-effective arrays and processing methodology for future site-effect studies for direct application to earthquake hazard studies.
GEOSCAN ID311132

 
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