RETRODICTING CASCADIA SUBDUCTION ZONE GREAT EARTHQUAKE SOURCE CHARACTERISTICS FROM TSUNAMI INUNDATION ALONG THE OREGON COAST

2017 ◽  
Author(s):  
Andrew Meigs ◽  
◽  
Eric Kirby ◽  
H. Benjamin Mason ◽  
Greg Wilson ◽  
...  
1996 ◽  
Vol 61 (4) ◽  
pp. 772-781 ◽  
Author(s):  
Rick Minor ◽  
Wendy C. Grant

Fire hearths associated with prehistoric Native American occupation lie within the youngest buried lowland soil of the estuaries along the Salmon and Nehalem rivers on the northern Oregon coast. This buried soil is the result of sudden subsidence induced by a great earthquake about 300 years ago along the Cascadia subduction zone, which extends offshore along the North Pacific Coast from Vancouver Island to northern California. The earthquake 300 years ago was the latest in a series of subsidence events along the Cascadia subduction zone over the last several thousand years. Over the long term, subsidence and burial of prehistoric settlements as a result of Cascadia subduction zone earthquakes have almost certainly been an important factor contributing to the limited time depth of the archaeological record along this section of the North Pacific Coast.


2009 ◽  
Vol 54 (1) ◽  
pp. 27-73 ◽  
Author(s):  
George R. Priest ◽  
Chris Goldfinger ◽  
Kelin Wang ◽  
Robert C. Witter ◽  
Yinglong Zhang ◽  
...  

Author(s):  
Chen Chen ◽  
Alexandra Buylova ◽  
Cadell Chand ◽  
Haizhong Wang ◽  
Lori A. Cramer ◽  
...  

Earthquakes along the Cascadia subduction zone would generate a local tsunami that could arrive at coastlines within minutes. Few studies provide empirical evidence to understand the potential behaviors of local residents during this emergency. To fill this knowledge gap, this study examines residents’ perceptions and intended evacuation behaviors in response to an earthquake and tsunami, utilizing a survey sent to households in Seaside, OR. The results show that the majority of respondents can correctly identify whether their house is inside or outside a tsunami inundation zone. Older respondents are more likely to identify this correctly regardless of any previous disaster evacuation experience or community tenure. The majority of respondents (69%) say they would evacuate in the event of a tsunami. Factors influencing this choice include age, motor ability, access to transportation, and trust in infrastructure resiliency or traffic conditions. While the City of Seaside actively promotes evacuation by foot, 38% of respondents still state they would use a motor vehicle to evacuate. Females and older respondents are more likely to evacuate by foot. Respondents with both higher confidence in their knowledge of disaster evacuation and higher income are more likely to indicate less time needed to evacuate than others. Generally, respondents are more likely to lead rather than follow during an evacuation, especially respondents who report being more prepared for an evacuation and who have a higher perceived risk. This study showcases a unique effort at empirically analyzing human tsunami evacuation lead or follow choice behavior.


1992 ◽  
Vol 38 (1) ◽  
pp. 74-90 ◽  
Author(s):  
Alan R. Nelson

AbstractPeaty, tidal-marsh soils interbedded with estuarine mud in late Holocene stratigraphic sequences near Coos Bay, Oregon, may have been submerged and buried during great (M > 8) subduction earthquakes, smaller localized earthquakes, or by nontectonic processes. Radiocarbon dating might help distinguish among these alternatives by showing that soils at different sites were submerged at different times along this part of the Cascadia subduction zone. But comparison of conventional 14C ages for different materials from the same buried soils shows that they contain materials that differ in age by many hundreds of years. Errors in calibrated soil ages represent about the same length of time as recurrence times for submergence events (150–500 yr)—this similarity precludes using conventional 14C ages to distinguish buried soils along the southern Oregon coast. Accelerator mass spectrometer 14C ages of carefully selected macrofossils from the tops of peaty soils should provide more precise estimates of the times of submergence events.


2020 ◽  
Vol 6 (38) ◽  
pp. eaba6790
Author(s):  
S. R. LaHusen ◽  
A. R. Duvall ◽  
A. M. Booth ◽  
A. Grant ◽  
B. A. Mishkin ◽  
...  

The coastal Pacific Northwest USA hosts thousands of deep-seated landslides. Historic landslides have primarily been triggered by rainfall, but the region is also prone to large earthquakes on the 1100-km-long Cascadia Subduction Zone megathrust. Little is known about the number of landslides triggered by these earthquakes because the last magnitude 9 rupture occurred in 1700 CE. Here, we map 9938 deep-seated bedrock landslides in the Oregon Coast Range and use surface roughness dating to estimate that past earthquakes triggered fewer than half of the landslides in the past 1000 years. We find landslide frequency increases with mean annual precipitation but not with modeled peak ground acceleration or proximity to the megathrust. Our results agree with findings about other recent subduction zone earthquakes where relatively few deep-seated landslides were mapped and suggest that despite proximity to the megathrust, most deep-seated landslides in the Oregon Coast Range were triggered by rainfall.


2013 ◽  
Vol 103 (6) ◽  
pp. 3205-3221 ◽  
Author(s):  
R. Kulkarni ◽  
I. Wong ◽  
J. Zachariasen ◽  
C. Goldfinger ◽  
M. Lawrence

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