💧🌏 Greg CocksOct 15
Unravelling The Dance Of Earthquakes - Evidence Of Partial Synchronization Of The Northern San Andreas Fault And Cascadia Megathrust
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https://doi.org/10.1130/GES02857.1 <-- shared paper
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“Previous paleoseismic work has suggested a possible stress triggering relationship between the Cascadia subduction zone and the northern San Andreas fault based on similar event timings. Turbidite successions correlated to both systems may support this hypothesis. Historic earthquakes in 1980 and 1992 in the Cascadia subduction zone and the 1906 earthquake on the northern San Andreas fault left turbidite records that are temporally well constrained by bomb-carbon−supported age-depth models..."
#geology #USWest #Seattle #Washington #California #earthquake #engineeringeology #fault #faulting #SanAndreas #Cascadiasubductionzone #linked #Cascadia #research #sediment #sedimentology #Turbidite #paleoseismology #historic #spatial #spatialanalysis #spatiotemporal #model #modeling #stress #subduction #dating #radiocarbon #Holocene
💧🌏 Greg CocksOct 1, 2024
Algorithm Raises New Questions About Cascadia Earthquake Record
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https://phys.org/news/2024-08-algorithm-cascadia-earthquake.html <-- shared technical article
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https://doi.org/10.1130/B37343.1 <-- shared paper
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#GIS #spatial #mapping #sedimentology #geology #structuralgeology #platetectonics #CascadiaSubductionZone #PNW #PacificNorthwest #spatialanalysis #spatiotemporal #forests #tsunamis #earthquake #risk #hazard #timing #naturaldisasters #geomorphology #geomorphometry #turbidite #corrleation #causation #model #modeling #massmovement #landslides #algorithm #machinelearning #AI
Algorithm raises new questions about Cascadia earthquake record

The Cascadia subduction zone in the Pacific Northwest has a history of producing powerful and destructive earthquakes that have sunk forests and spawned tsunamis that reached all the way to the shores of Japan.

Phys.org
Chris WhiteSep 9, 2023

A small #outcrop of the #Squantum Member of the #Roxbury #Conglomerate

These #rocks are in the #BostonBay Group, which is currently dated to #Neoproterozoic. The Squantum Member was interpreted as a #tillite, possibly associated with the #Gaskiers #glaciation, although there a scant signs like scratched pebbles or faceted cobbles. It is currently commonly interpreted as a #debrite (debris flow). Details in captions.
#geology #glacier #turbidite #Quincy #Boston #Massachusetts #NewEngland

Chris WhiteJun 3, 2023

Anomalous pebble in layered #sedimentary #rock

An angular pebble is conformably surrounded by argillaceous and sandy layers in this #photograph of the #Neoproterozoic #Squantum Member of the #Roxbury Conglomerate. The wide range of clast sizes led to an interpretation as a #glacial #tillite thru the 1970s, but the Squantum Member is now mostly interpreted as a #debrisFlow (#debrite or #turbidite). My #photo.

#Boston #fieldTrip #UMassBoston

Chris WhiteJun 1, 2023

Deformed bedding in meta#sedimentary #rocks

The horizontal bedding of the #Squantum Member of the #Roxbury Conglomerate (#Neoproterozoic, #Boston Bay Group) has been disturbed locally.

In the #glacial #tillite interpretation of the Squantum (favored through at least the 1970s), the distortion might be caused by glaciotectonic drag at the ice base. The current interpretation as a #debrite or #turbidite would probably attribute the deformations to synsedimentary slumping. My #photo. #fieldTrip

Chris WhiteMay 29, 2023

The #glacier went that-a-way

The #striations on this face of the #Ediacaran (ca. 560 Ma) #Squantum Member of the #Roxbury #Conglomerate were probably left by the #Pleistocene #Laurentide ice sheet, which retreated ca. 12 ka. The striations have the right orientation, from northwest to southeast.

The Squantum Member was once interpreted as a (#glacial) #tillite. The most common contemporary model is a peri-#Gondwana #debrite (#turbidite).

My #photo. #Boston #geology #NewEngland #fieldTrip

John GarverDec 20, 2022

Turbidites above the Resurrection Peninsula Ophiolite, Alaska.

We now know that the turbidites on Fox Island, near Seward AK are part of the Paleocene Orca Group.

Spectacular in scale, and thickness.

#Alaska #Ophiolite #Turbidite #Paleocene #Chugach

Chris WhiteDec 18, 2022

Interbedded tuffaceous and fine grained siliciclastic layers in the Cambridge Argillite, a Neoproterozoic member of the Boston Bay Group, above the Roxbury Conglomerate. Usually interpreted as a turbidite distal to the Roxbury.

#turbidite #geology #turbidites #rocks