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Jay Patton described his new geodesy studies in southern Cascadia, which have illuminated differential motion across crustal faults.  His slides are attached (click the paperclip at the top of the page).

Brian Sherrod – Olympic Peninsula uplift

Tom Brocher 

The 2018 Corvallis workshop on building a new Cascadia 3D seismic model identified a need for review papers highlighting existing data and interpretations.  In this map Tom Brocher has summarized the locations of 34 individual controlled-source wide-angle seismic imaging experiments dating to the 1960s.  Together, they provide 40 million independent ray paths sampling the subsurface. There are important gaps in these surveys in northern and southern Oregon. The Corvallis workshop report is attached (click on paperclip at the top of the page).

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nameCascadia Wide Angle Seismic (1).pdf
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nameBrocher 1873 Crescent MMI.pdf
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1873 Crescent City earthquake:The location of this earthquake is very uncertain:  could it be a megathrust event?  Tom Brocher has been working in newspaper archives to uncover new accounts of the earthquake to update the ShakeMap for this earthquake.  There are few felt reports of the earthquake south of the southern edge of the Gorda slab and really no reports of aftershocks.  Tom thinks the best interpretation of these observations is that the earthquake occurred within the slab underneath the Oregon-Washington border.  Such inslab earthquakes produce few aftershocks and the slab provides an efficient waveguide for seismic waves.

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