00000nam 2200000zi 4500 9.915991 CaOODSP 20251031142448 m o d f cr mn||||||||| 221006t20222022onca ob f000 0 eng d 9780660457369 CaOODSP eng rda CaOODSP M183-2/8925E-PDF Plourde, A. P. (Alexandre P.) author. Mapping tectonic stress at subduction zones with earthquake focal mechanisms : application to Cascadia, Japan, Nankai, Mexico, and northern Chile / A.P. Plourde and J.F. Cassidy. [Ottawa] : Geological Survey of Canada, 2022. ©2022 1 online resource (35 pages) : colour illustrations. text txt rdacontent computer c rdamedia online resource cr rdacarrier Open file, 2816-7155 ; 8925 Includes bibliographical references (pages 32-35). "Earthquake focal mechanisms have contributed substantially to our understanding of modern tectonic stress regimes, perhaps more than any other data source. Studies generally group focal mechanisms by epicentral location to examine variations in stress across a region. However, stress variations with depth have rarely been considered, either due to data limitations or because they were believed to be negligible. This study presents 3D grids of tectonic stress tensors using existing focal mechanism catalogs from several subduction zones, including Cascadia, Japan, Nankai, Mexico, and northern Chile. We bin data into 50 x 50 x 10 km cells (north, east, vertical), with 50% overlap in all three directions. This resulted in 181380 stress inversions, with 90% of these in Japan (including Nankai). To the best of our knowledge, this is the first examination of stress changes with depth in several of these regions. The resulting maps and cross-sections of stress can help distinguish locked and creeping segments of the plate interface. Similarly, by dividing the focal mechanism catalog in northern Japan into those before and those >6 months after the 2011 Mw 9.1 Tohoku-Oki earthquake, we are able to produce detailed 3D maps of stress rotation, which is close to 90° near the areas of highest slip. These results could inform geodynamic rupture models of future megathrust earthquakes in order to more accurately estimate slip, shaking, and seismic hazard"--Abstract, page 4. Earthquakes. Seismology. Subduction zones. Three-dimensional imaging in geology. Tremblements de terre. Sismologie. Zones de subduction. Imagerie tridimensionnelle en géologie. Geological Survey of Canada, issuing body. Open file (Geological Survey of Canada) 8925. (CaOODSP)9.506878 PDF 4.34 MB https://publications.gc.ca/collections/collection_2023/rncan-nrcan/m183-2/M183-2-8925-eng.pdf (report) HTML N/A https://doi.org/10.4095/330943 (complete dataset)