Historic earthquake sequences on subduction zones that are similar to the Cascadia subduction zone are used to hypothesize the nature of shallow subduction earthquakes that might occur in the northwestern United States. Based on systematic comparisons of several physical characteristics, including physiography and seismicity, subduction zones that are deemed most similar to the Cascadia subduct...

[1] On 23 June 2001, a Mw = 8.4 underthrusting earthquake occurred in the southern Peru subduction zone, followed by several large aftershocks, including 26 June (Mw = 6.7) and 7 July (Mw = 7.5). Broadband analyses of seismic data for the largest of these earthquakes show southeastward rupture of 180 km along the portion of the subduction zone previously ruptured in 1868 (Mw 8.8–9). Moment rele...

Large subduction earthquakes on the Cascadia subduction zone pose a potential seismic hazard. Very young oceanic lithosphere (10 million years old) is being subducted beneath North America at a rate of approximately 4 centimeters per year. The Cascadia subduction zone shares many characteristics with subduction zones in southern Chile, southwestern Japan, and Colombia, where comparably young oc...

Climate trends on timescales of 10s to 100s of millions of years are controlled by changes in solar luminosity, continent distribution, and atmosphere composition. Plate tectonics affect geography, but also atmosphere composition through volcanic degassing of CO2 at subduction zones and midocean ridges. So far, such degassing estimates were based on reconstructions of ocean floor production for...

Despite good evidence of present-day convergence of the Juan de Fuca and North American plates, there has been remarkably little historical seismic activity along the shallow part of the Juan de Fuca subduction zone. Although we cannot completely rule out the possibility that the plate motion is being accommodated by aseismic creep, we find that the Juan de Fuca subduction zone shares many feat...

Rheological flow laws can be obtained from studies using multi-anvil high-pressure systems with synchrotron-based piezometers and strain metrics. The high flux X-ray source provides minute-scale time resolution with accurate measurement of diffraction patterns and direct sample images. Measurements of length changes with an accuracy of one part in 104 are being developed and will provide a new ...

Despite good evidence of present-day convergence of the Juan de Fuca and North American plates, there has been remarkably little historical seismic activity along the shallow part of the Juan de Fuca subduction zone. Although we cannot completely rule out the possibility that the plate motion is being accommodated by aseismic creep, we find that the Juan de Fuca subduction zone shares many feat...

Several lines of evidence suggest that simple subduction with one downgoing and one overriding plate is an insufficient model of the Cascadia Subduction Zone. Instead, the subduction zone and arc are segmented, exhibiting variations in multiple characteristics along strike. One line of evidence comes from the analysis of seismicity. The subduction zone is atypical everywhere in that the Wadati-...

-Seismic energy release is dominated by the underthrusting earthquakes in subduction zones, and this energy release is further concentrated in a few subduction zones. While some subduction zones are characterized by the occurrence of great earthquakes, others are relatively aseismic. This variation in maximum earthquake size between subduction zones is one of the most important features of glob...

[1] Nearly half of all active subduction zones initiated during the Cenozoic. All subduction zones associated with active back arc extension have initiated since the Eocene, hinting that back arc extension may be intimately associated with an interval (several tens of Myr) following subduction initiation. That such a large proportion of subduction zones are young indicates that subduction initi...