I am going into my second year of the Master’s of Natural Resources program at Oregon State University. I graduated in 2020 with my Honors Bachelor’s of Physics at Oregon State as well where I competed a undergraduate thesis project under Anne Tréhu, one of the lead PIs on this project. My thesis projected consisted on data from the Cascadia Subduction Zone in 2012 that was collected in a similar matter to this project, just on a smaller scale. During my first year of grad school, I also completed a GIS graduate certificate that included the opportunity of an internship. For my internship, I made maps in ArcGIS for the Cascadia project. I plotted potential site locations and sifted through data that told us what little-known roads were available to drive on and what obstacles we might face, such as gates and 4-wheel-drive-only roads. I also got the opportunity to participate in the recovery phase for the nodes in the field.
I am a M.S. student at Oregon State University working with Anne Tréhu. I received my B.S. in Physics from the State University of New York at New Paltz in 2019. Currently, my research uses data from controlled source seismic experiments to examine the topography of the subducted Juan de Fuca plate beneath the central Oregon margin. Later this summer, I will begin looking at the data from this experiment. This was my first experience conducting fieldwork and I have enjoyed getting to know the other volunteers and exploring the beautiful coastal range of Oregon.
I’m from one of the most active subduction zones in the world, and I love earthquakes and landforms created by tectonic activity. I’m a Chilean Geologist living in Seattle, and I moved to the US to start my Ph.D. at the University of Washington (UW) in Fall 2020. I’m part of two research groups at UW: tectonic geomorphology and geodesy, and now I’m studying the landscape evolution of strike-slip faults in hyper-arid environments in Northern Chile. I’m trying to measure slip rates of these crustal structures using short-term data (GPS) and long-term records (geomorphology); test predictions of strike-slip models; understand the relationship between short and long-term deformation, and assess their seismic hazard. I found this project thanks to an email in my seismology class and I immediately started looking for information about it to apply as a volunteer. Knowing more about Cascadia is one of my goals during my Ph.D. I think that comparison is a great learning method for science and I want to apply my knowledge from Chile to Cascadia and about Cascadia to Chile when I get back there. There are so many things in common in these two areas! During fieldwork, my favorite part was driving through the macromorphologies: crossing from the valley at the east side, to the Coastal Range in the middle, and towards the west getting to the Coast. I enjoyed the great views at high altitudes that give you a big panoramic of the multiple geologic processes that had to happen to see the actual landscape of Oregon.
I am entering my 1st year for a PhD program at Georgia Institute of Technology, where I will be studying Planetary Geology. I recently graduated from Salem State University in Massachusetts with a Bachelor degree in Geological Sciences. I discovered the Cascadia2021 Project early in spring 2021 and decided it would be a wonderful opportunity to expand my experience. Being able to get out in the field alongside other great scientists and students was exhilarating. I made a lot of great connections, and I am happy that were able to accomplish so much in such a short time. The resulting data is sure to be even more rewarding!
The Cascadia Subduction Zone, or CSZ, runs from Northern Vancouver Island in BC, Canada to Cape Mendocino in California. A subduction zone is created when one tectonic plate sinks and slides, or subducts, below another tectonic plate. Usually, this occurs with a dense oceanic plate subducting below a less dense continental plate. In the case of the CSZ, the Juan de Fuca plate is sinking below the North American plate. The Juan de Fuca plate is located in between the Pacific plate and the North American plate, making up the ocean floor along the coastline. The Juan de Fuca plate is being pushed towards the North American plate by a mid-ocean ridge between itself and the Pacific plate. A mid-ocean ridge is where new material in the form of magma is being pushed to the surface, causing the ground on either side to spread. The Juan de Fuca plate is a remnant of a much larger plate that is gradually disappearing as subduction, which is driven primarily by gravity pulling down on the dense subducting plate, overtakes spreading from the ridge. Further south, the ridge has subducted entirely and the Pacific plate has come into contact with the North American plate, creating the San Andreas fault system.
Map of the Cascadia Subduction Zone outlining the plate motions, as well as the location of subduction zone earthquakes (Map graphic courtesy Wash. Dept. of Natural Resources).
When one plate slides beneath another, it’s not a smooth process. The weight of the overlying plate wedge generates a lot of friction, which will lock the plates together until the frictional forces are overcome. An earthquake occurs when plates overcome friction in a certain location, allowing stress to be released and the plates to slip past one another. These slips can be slow or fast, small or large. Subduction zone earthquakes are located along the line of subduction, where the most severe slipping can occur. Here, the plates are strongly locked by friction, building up stress until there is a large release in the form of a megathrust earthquake. Topography on the subducting plate, sediments and fluids trapped between the plates, and the geology of the upper plate all vary along and across the plate boundary and affect the frictional stress on the plate boundary. All of these factors make predicting earthquakes extremely difficult.
Earthquakes also occur deeper down within the subducting Juan de Fuca plate or shallower within the North American plate. At greater depth along the plate boundary is a transitional zone, where there are distinct episodes of slow slip accompanied by seismic tremor. During a slow slip event, the Juan de Fuca plate will move a few cm past the North American plate over a period of a few weeks. These motions are imperceptible to all but the most sensitive GPS instrumentation. However, they relieve stress between plates just like megathrust events. At still greater depth, the plates move past each other continuously because of the impact of high temperature and pressure on the plate boundary. Processes deep within the subduction zone are also responsible for the beautiful Cascade volcanoes.
Because stress builds up gradually over time, large earthquakes do not occur often. The last megathrust earthquake on the CSZ was in 1700. Based on geologic evidence, earthquakes like this have recurred every 400 to 600 years. This suggests that we are due for a megathrust event in the next hundred years or so. The timing and size of this expected earthquake, however, is impossible to predict with our current understanding. Observations from megathrust earthquakes around the globe suggest that at least some earthquakes had subtle precursors that were not previously recognized because of inadequate data. A better understanding of the mechanisms causing such precursors may eventually improve earthquake forecasts.
One of the goals of Cascadia2021 is to improve our imaging of the plate boundary using techniques analogous to those used to image within the human body. If we know what the interface between the Juan de Fuca plate and the North American plate looks like, we can better understand the forces at play and assess the risk of a large slip event in the near future. The more detailed images we obtain, the better our models of expected ground shaking will be for various earthquake scenarios.
I just finished my junior year at the University of Oregon majoring in physics. I recently added a minor in earth science, and I’m excited to learn more about geophysics. This has been my first experience with fieldwork and seismic data collection. I heard about the Cascadia2021 project from Emilie Hooft, whose lab I’ve been working in. I’ve really enjoyed meeting people in the geophysics community, learning about the local geology, and being part of such a major project!
At the “Willamette Stone” in the forest of the West Hills in Portland, OR
I am a recent Bachelor of Science graduate, and a returning post-baccalaureate student, majoring in Geology and Earth Science, from Portland State University in Oregon. As a former graduate, and U.S. Army veteran, I decided to go back to school to pursue my passion in Geology. I initially found out about the Cascadia2021, back when it had originally been called the Cascadia2020 project, which was postponed. Volcanoes and earthquakes in the Pacific Northwest are areas that continue to fascinate me, especially as they relate to the larger story of regional plate tectonics and crustal clockwise rotation. As newer data emerges, the scientific possibility of better forecasting future Cascadia Subduction Zone earthquakes hopefully will become a reality.
During field excursions to deploy the nodes, there are many roads that are overgrown with vegetation or may have lots of tall grass. This is always concerning, but it’s especially concerning during the fire season (summer and early fall, sometimes late spring) when it is drier and hotter. Small cars andSUVs that don’t have much ground clearance are a concern because they may spark forest fires. These sparks may come from the underside of the car and near the exhaust pipe. Due to this risk, all vehicles must carry shovels, fire extinguishers, and water in case a vehicle sparks a fire. Additionally, this is why we drive larger, taller trucks with lots of ground clearance to sites that are overgrown with grass or have lots of debris on the road. While driving along these roads during deployment and recovery of the nodes, it is extremely important to be very cautious and keep a watchful eye on your surroundings to make sure no fires are started by sparks from the vehicle. We also keep an eye out for wildfire occurring nearby. And, of course, NO SMOKING!
When taking a vehicle into the backcountry, four factors need to be carefully considered:
1) the driving terrain,
2) the capabilities of the vehicle
3) vehicle maintenance, and
4) the experience level of the driver.
In this short post, I will focus only on vehicle capabilities and maintenance.
All Wheel Drive (AWD) Vehicle
4×4 Vehicle
AWD vs 4×4, which is better? Well, that depends upon the application. AWD vehicles provide power to all four wheels through clutches and gearing that do not require the driver to provide any input. AWD vehicles are designed mainly to give traction on normal roads during inclement weather or light off-roads such as gravel. Conversely, 4×4 systems are designed to handle rugged terrain.
One misconception that drivers have when they select an AWD vehicle, is that they assume these vehicles can perform just as well as 4x4s on rough terrain. For most models of AWD vehicles, this is not the case. For AWD vehicles, traction is optimized, while for 4x4s traction is maximized. Also, AWD vehicles tend to have much less ground clearance than 4x4s. When negotiating trails with tree branches, rocks, large ruts, and washouts, clearance can be equally or more important than the type of drive system.
For 4x4s, both the size of the vehicle and the drive system can have drawbacks. It is rare to find a vehicle that is a full-time 4×4; therefore, the driver must learn to predict when it is necessary to switch between two-wheel drive, 4H, and 4L modes. Moreover, for many vehicles, it is necessary to come to a full stop before changing modes. On improved gravel trails one can generally get away with staying in two-wheel drive. Upon engaging the 4H or 4L mode, the differentials become locked and prevent the vehicle from negotiating tight corners smoothly. The inner wheel typically “skips” when it loses grip: this characteristic is especially noticeable when backing around a corner. When turning a 4×4 vehicle around in tight spaces, try to avoid using 4H/4L modes. Remember to execute turnarounds by using the maximum space available and taking advantage of a spotter.
Be sure to walk around the vehicle before heading into backcountry. Look for things such as worn-out tires, including a worn-out or poorly inflated spare. One spare tire will not replace four tires that are all ready to fail in quick succession! Know where the tire jack and lug nut wrenches are and how to use them. Check to make sure the vehicle sits level while on flat terrain; this will let you know if the suspension is damaged. Look for holes in the radiator grill that may indicate damage to the radiator. Lastly, fill up the fuel tank before heading out.
A lot of sites are in land managed by Suislaw or Siskiyou National Forest, the Bureau of Land Management, or different timber companies. Many signs of wildlife are present here, and it’s exciting when we get sightings of them! Sightings ranging from large to small (e.g. bears, coyotes, and cougars to rabbits, chipmunks, and small insects). Different teams came across different things, but there was a lot of overlap too. A few unique situations arose for my teams. Tamara and I saw a large gopher snake and a very large snake get carried away by a turkey vulture! On another field day with my partner Tara, we saw a couple-days-old bear track. The day prior to this, a BLM watchman stopped to give us a warning as we were installing a node: Seven different cougar individuals were spotted in the area where we were working – just up the road from us! Four of these individuals were young adult male cougars that were running around together as a group. This is unusual cougar behavior as they are usually solitary, but it has been documented among siblings that have not yet separated. With all of the tools and gear that we had, one or two may not have been as concerning, but seven – especially four of them together! – was a bit unnerving. We decided to install one last node and get out of there since it was approaching late afternoon – evening, which is when cougars are more active. Terrestrial or marine creatures that are more active at dusk and dawn are referred to as crepuscular animals. On one of our last days in the field during deployment, an owl flew right in front of us (about two feet from the windshield of our truck)! We also saw tons of deer, including a newborn, and some cows that may have been feral or grazing on National Forest land.
