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Cascadia Subduction Zone - Crossref

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Last Updated: 10 January 2023

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Tectonics and Geodynamics of the Cascadia Subduction Zone

The Juan de Fuca plate sinks below western North America's young and thin oceanic Juan de Fuca plate, which falls below northern North America, is a thermally hot endmember of global subduction systems.

Source link: https://doi.org/10.2138/gselements.18.4.226


Spatial variations of the effective elastic thickness and internal load fraction in the Cascadia subduction zone

SUMMARY The effective elastic thickness of a subducting plate to overlying plate can reveal lateral shift in rheological properties from subducting plate to overlying plate, as well as aid in determining the relationship between geodynamic evolution and regional tectonic reaction to increasing forces by plate convergence. Here we present high-resolution maps of Te and F in the Cascadia subduction zone by examining the coherence between gravity anomaly and topography using a fan wavelet technique. The different Te pattern along the forearc zone off the coast of North America indicates different mechanical coupling states of the slabs in the northern and southern parts of the country. Due to a group of subducted seamounts, the central subducting plate has been decoupled from the overlying plate. A fluid/melt upwelling in the volcanic arc area may also be a good indicator of a fluid/melt upwelling. plates can be affected or even monitor plate temporal fluctuations during multiple seismic cycles because of the long-term mechanical stability of lithosphere.

Source link: https://doi.org/10.1093/gji/ggab495


Minimal stratigraphic evidence for coseismic coastal subsidence during 2000 yr of megathrust earthquakes at the central Cascadia subduction zone

The lower of several foraminiferal transfer function reconstructions of coseismic subsidence across the contact ranges are the most reliable, according to MINImal changes in diatom assemblages from below the contact to above its likely tsunami deposit. The more granular area and minimal changes in lithology, foraminifera, and diatom assemblages among the other 11 peat-mud contacts are insufficient to distinguish them from contacts established through small, gradual, or localized changes in tide levels during river floods, storm surges, and gradual sea level rise. Although no reports prevent any contacts from being synchronous with a megathrust earthquake, the results are equally consistent, with all contacts recording relative sea-level changes below the u223C0. 5 m detection threshold for distinguishing coseismic from nonseismic changes.

Source link: https://doi.org/10.1130/ges02254.1


Cascadia low frequency earthquakes at the base of an overpressured subduction shear zone

Low frequency earthquakes occur immediately below both the landward dipping area of high Poisson's ratio and a 6 km thick shear zone shown by seismic findings. The plate boundary here either corresponds to the low frequency earthquakes or to the irregular elastic properties in the lower 3u20135 km of the shear zone immediately above them.

Source link: https://doi.org/10.1038/s41467-020-17609-3


Ensemble ShakeMaps for Magnitude 9 Earthquakes on the Cascadia Subduction Zone

Abstract We produce ensemble ShakeMaps for several magnitude 9 earthquakes on the Cascadia megathrust, based on student data. In addition, we use empirical ground-motion simulations to extend the ground shaking estimates beyond Frankel et al's original model area. We provide ensemble ShakeMaps for the median, 2nd, 16th, 84th, and 98th percentile ground-motion intensity measures using this updated collection of 30 M 9 Cascadia earthquake scenarios. Whereas traditional ShakeMaps are based on a single hypothetical earthquake failure, our team ShakeMaps takes advantage of a logic-tree approach to estimating ground motions from multiple earthquake rupture scenarios. In addition, 3D earthquake simulations in the Pacific Northwestu2019s sedimentary basins are missing in the empirical GMMs that compose traditional scenario ShakeMaps, and strong ground-motion amplification are not present in the traditional scenario ShakeMaps' empirical GMMs.

Source link: https://doi.org/10.1785/0220200240


Mapping tectonic stress at subduction zones with earthquake focal mechanisms: application to Cascadia, Japan, Nankai, Mexico, and northern Chile

The Earthquake focal mechanisms have contributed significantly to our understanding of modern tectonic stress regimes, perhaps more than any other data source. Stress patterns in a region are generally grouped by epicentral location in order to investigate changes in stress. Similarly, by dividing the focal mechanism catalog in northern Japan into those before and those after the 2011 Mw 9. 1 Tohoku-Oki earthquake, we're able to produce detailed 3D maps of stress rotation, which is near to 90 degrees in the areas of highest slip. Southern Cascadia and Nankai seem to have major stress discontinuities at 20 km depth, and northern Cascadia may have a similar discontinuity at 30 km depth, and northern Cascadia may have similar discontinuities at 30 km depth. These stress boundaries may refer to rheological inequiar voids in the forearc, and could help us figure out how subduction zone composition influences subduction zone behavior and seismic hazard.

Source link: https://doi.org/10.4095/330943


The Cascadia Subduction Zone earthquake: Will emergency managers be willing and able to report to work?

This report explores the reasons that may influence emergency planners' willingness and ability to report to work after a catastrophic event using the Cascadia Subduction Zone earthquake threat as an example. The six-step concept mapping process is a structured and integrated multi-method approach that gathers participants' ideas and concepts from both qualitative and quantitative methods, then produces a visual representation of these findings and concepts using multivariate statistical methods.

Source link: https://doi.org/10.1007/s11069-020-04005-9


Impacts of Simulated M9 Cascadia Subduction Zone Motions on Idealized Systems

Ground motions for a magnitude 9 Cascadia Subduction Zone earthquake have been created, and it will impact the Puget Lowland area, including cities that have been underlain by the Seattle, Everett, and Tacoma sedimentary basins. For deformation determinants and collapse probability for four sets of single-degree-of-freedom systems that were similar to the MCE R intensity's average, the corresponding values for periods of 1 s or longer were higher. The likelihood of collapse during an M9 earthquake averaged 13% and 18% at 1. 0 s and 2. 0 s times, respectively, for high-strength, low-ductility systems located above deep basins.

Source link: https://doi.org/10.1193/052418eqs123m


Slope failures within and upstream of Lake Quinault, Washington, as uneven responses to Holocene earthquakes along the Cascadia subduction zone

Detailed investigation of Lake Quinault in western Washington, which includes a reflection seismic survey, analysis of piston cores, and preliminary mapping in the lake's rugged, landslide-prone Quinault River catchment upstream of the lake, reveals evidence for three episodes of earthquake activity in the last 3000 yr. The ages of the three Lake Quinault disturbance events are similar to those of coseismically submerged, coastal marsh soils nearby in southwest Washington that are believed to show Cascadia megathrust ruptures.

Source link: https://doi.org/10.1017/qua.2017.96


Comparing felt intensity patterns for crustal earthquakes in the Cascadia and Chilean subduction zones, offshore British Columbia, United States, and Chile

In this report, we use the U. S. Geological Survey citizen science earthquake felt intensity data to determine whether, crustal earthquakes in the Chilean Subduction Zone have similar, "felt intensity" distributions to events of the same magnitude and depths within the Cascadia Subduction Zone. Building on the success of the intraslab companion article, this comparison will determine whether felt intensity data from many recent major subduction earthquakes in Chile can be applied to Cascadia. We used 20 years of cataloged Did-You-Feel-It citizen science data from the U. S. Geological Survey's earthquake online catalog, the ANSS Comprehensive Earthquake Catalog Documentation, for this study. We investigated and compared intensity profiles for fourteen magnitudes from 30 earthquakes in Cascadia to the intensity patterns from 114 earthquakes in Chile, with the same magnitudes as the Cascadia events.

Source link: https://doi.org/10.4095/330475

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions