Project Update- August 6th 2007

By the end of last week, we were able to run waves ranging in height from 10cm to 60cm. For each height wave we ran three trials and collected data from the pressure sensors mounted on the blue commercial buildings. The data for the 10, 20, 30, and 50cm waves was sent from the pressure transducer to the computer where it was recorded using LabView and transfered into Excel for analysis. Here, we could sort, convert, and plot our data so that we may draw some conclusions for our study. We are still in the process of analyzing the data we've gathered, but we can already see that we may come to some interesting and unexpected conclusions.

On Thursday of last week we had the opportunity to travel up to Seaside, Oregon to check out the city we had modeled. It was very humbling to see the city in person especially after subjecting our version of the town with waves throughout the week. After seeing what a wave in the lab looks like in relation to our model it was a bit scary to see how high the water would be in relation to the coastal infrastructure in real life. Also, during our trip we planned to walk the tsunami evacuation route to see what it would be like (very roughly) to travel the path. The plan was to follow the designated tsunami evacuation signage and pretend that we were tourists who didn't know which way to go to get to higher ground. We began just a block off Broadway and about two blocks from the seawall. The tsunami evacuation route signs were very small and difficult to follow, as we eventually lost them and ended up in a neighborhood and not at Seaside Heights Elementary School like we expected. The signs were hard to see and often contradicted one another. If anything comes from our study, it would be encouraged that these signs be improved to facilitate evacuation in case of an emergency. Our brisk walk took us, three able-bodied young people, about 25 minutes and though we rushed we traveled under the most calm, uneventful circumstances. We did not encounter any destruction or obstacles that would most likely be present in an actual emergency situation and we still would have barely made it to safety in time. Obviously in an actual crisis adrenaline would be working on our side, but we were able to see that the evacuation route would be very difficult to traverse if one was not in fairly good physical condition.

Project Update- July 30th 2007

We have data!!! On Friday we were able to collect data from the waves run for another project. The data we collected was on 10 and 30cm waves. This translates to 5 and 15 m waves respectively. The graphs looked good, the data was repeatable and it is going to help us draw conclusions about our study. Soon we'd like to post some of the graphs or data on the blog. This week we will continue to take data from the waves run for the other project at 50 and 60cm, and time permitting at 20 and 40cm. The other project will be completed after Friday, at which point we can continue to work on our project with the specific wave heights we want. Our goal for the week is to collect and begin analyzing more data, begin to look at ADV (velocity) data, mount grid and observe bore height for various wave heights, and adjust cameras to capture helpful angles in order to study inundation patterns in the model. All in all, we are making good progress and collecting good-looking data that is like what we expected and is consistent.

Seaside Tsunami Run - First Wave

This is a video clip from the first tsunami wave run on our Seaside model. We didn't take data, but it was important for us to get a feel for the path of the inundation. On the right side of the screen, the area without any structures is the control area. The path, velocity, and depth make an interesting comparison between the model area and the control area.

Project Update- July 25th 2007

More progress was made one the Seaside model today, which just about wraps up the set-up and construction phase of the project. At the end of last week we bolted down the red concrete pavers. Gravity wasn't quite enough to keep them in place and large waves for the other project pushed the pavers close to the seawall around a bit. So, those were bolted down in the same manner as the houses and hotels.

Yesterday an ADV was placed in the model near the seawall. The placement of the ADV (which will measure flow velocity) will catch the velocity of the flow as it is channeled down a street with buildings on either side.

This morning, we mounted pressure sensors onto the large u-shaped hotel near the Turnaround and a smaller custom commercial building in the model. Two pressure sensors were placed on the inside of the u-shaped hotel as close to ground level as possible, one in the center and one in the corner. One more pressure sensor was placed on the front face of another building. These sensors will allow us to compare the pressure (and through calculations, the force) experienced by the buildings during various height waves.

We should be running waves tomorrow and collecting data as we go. It should be interesting and we've been waiting a long time to do this, so it ought to be fun!

The Pressure Sensor is the round metal piece
mounted in a metal bracket that resembles
a light switch plate.

The ADV placed so it will capture velocity as
the tsunami flows down a street.

Project Update- July 16th 2007

This morning, camera crews from across campus came in to document the inundation of Seaside. It was the first time we were able to see a tsunami hit Seaside with the accurate water level.


The first model we showed was normal waves. These are similar to the everyday waves that a person on the beach anywhere along the coast would see.



Next, we simulated a 10 centimeter wave which is equivalent to a 5 meter wave. It was relatively small, but did hit the seawall and splash over.



The next wave we ran was 20 centimeters which would be equivalent to 10 meter wave. This was noticeably larger as the wave created a large splash and run up as it hit the sea wall and inundated the coast.

The last wave we ran was 30 centimeters, or a 15 foot wave. This is the size of the wave that is predicted to hit the coast when the Cascadia Fault fails. This is the wave shown in the video above. As you can see the entire city was completely inundated in a matter of seconds.

Project Update- July 12th 2007

It has been a busy week! A small window of opportunity presented itself and we worked long and hard to install Seaside in 2 days. After we initially laid out the model, measurements were taken to accurately place the buildings.

Houses:
The dimension of each house is 6x9 inches. They were constructed in two parts, the rectangular base and the roof. Each base had two holes drilled in for bolts.


We drilled 1.5 inches into the concrete basin floor. Anchors were dropped into the holes and secured. The houses were placed carefully over the holes and bolted down.














After all the houses were securely bolted to the floor, we put the roofs on. The roof was placed on the base and screwed in.


Pavers:
Next, all 75 pavers were placed in the model to be bolted down later.

Hotels:
The hotels were all placed according to the model. Holes were drilled through the support beams within the hotel structure. From here, the hotels were mounted in the same way as the houses. Once the hotels were bolted down, the roofs were screwed into place.


Putting in each structure was a team effort requiring a lot of communication and cooperation.

















The last part of construction was touching up the houses with paint to cover any nail holes or scratches the buildings encountered during installation.

Seaside, Oregon on a 1:50 scale. Thank you so much to everyone who helped us!

Special thanks to Jason Killian, AJ, Alan, Barb, Jason Miles, and Trevor.

The Physical Model

We are currently in the process of building a 1:50 scale model of the city of Seaside, Oregon. The houses, commercial buildings, hotels and parking structures will be represented by various model elements. Houses will be represented by yellow wooden blocks bolted to the floor of the wave basin. Concrete pavers represent the idealized commercial buildings like restaurants and shops. Custom commercial buildings are represented by blue wooden boxes. These buildings are of particular interest to our research because of their size (especially height) and their proximity to the shoreline. ADVs and force transducers will be used to measure flow velocity, height, and wave force both in the flow field (the model area) and in a control area free from structures, for comparative purposes. Visible scales may be added to the sides of the custom commercial buildings in order to visualize inundation and calibrate the cameras and other instrumentation. Concrete 3 inches thick was poured on top of the floor of the wave basin to have the same effect as the real-life seawall upon which many of the hotels, the famous turnaround, and the boardwalk, or Promenade, sits. The model will consist of 125 idealized homes, 75 idealized commercial buildings, and 13 custom commercial buildings. Streets have been plotted based on coordinates picked from satellite images of Seaside. The location of the Necanicum River, to the east of the tourist center of Seaside, was plotted in this manner as well. The streets and river were painted onto the floor of the wave basin with an enamel paint for visibility and durability underwater.

Plotting and Preliminary Layout

This is the satellite image of Seaside with the model layout.

Jennifer and Brittany are plotting the Necanicum River in Seaside. Using a satellite image, they were able to pick coordinates to plot on the basin floor.

Using the same coordinate system as the river, we also plotted the streets in the downtown Seaside. After taping the edges, we applied several layers of black enamel paint to the streets.

In order to secure the houses to the concrete, pilot holes were drilled. Then, anchors were set into the drilled holes. The houses were places over the holes and bolted down.

The yellow blocks represent houses. There are about 125 of these idealized homes that will be places in our physical model. The concrete blocks represent idealized commercial structures like restaurants and shops. There will be 75 pavers. The blue boxes represent large custom commercial buildings such as hotels and parking structures. There will be 13 of these placed in the basin. These are of special interest to our research.

This is the preliminary layout of our model.

Current Evacuation Routes for Seaside, OR

The city of Seaside, like other coastal towns, has an evacuation plan and system of approved routes to be taken in the event of a tsunami. This link is the current tsunami evacuation map available on the City of Seaside's website.

http://www.cityofseaside.us/pdfforms/SeasideTMap.pdf

As seen on the evacuation map, a major issue in vacating the (yellow) tsunami hazard zone is the Necanicum River. The river flows parallel to the Pacific Ocean creating a natural barrier between the popular tourist center of Seaside and the beach, and the (green) safe zone. There are only three bridges that span the Necanicum in a direct path between the Turnaround and Promenade (at the center of the tourist center of Seaside and the safe zone. In the event of a tsunami, there are only about 20 minutes warning before the first wave reaches the shore. It could be extremely difficult to evacuate from the beach across one of these three bridges to the safe zone approximately 1 mile away.

The Team

Dan Cox is the director at the wave lab. Dr. Cox's research focuses on coastal processes, particularly nearshore hydrodynamics, sediment transport, surf zone turbulence and boundary layer processes. He also has an interest in the design and performance of coastal structures. He teaches junior level fluid mechanics and coastal and ocean engineering at the graduate and undergraduate levels.

Chris Bradner is a graduate student at Oregon State University. He received an undergraduate degree from the Naval Academy in Ocean Engineering. He is currently doing research on wave forces on structures.

Brittany Snyder is a Sophomore at Oregon State University. She is majoring in Civil Engineering and minoring in Spanish. Brittany is working on the Seaside Project as an intern along side other REU (Research Experience for Undergraduates) students at the Wave Lab.

Jennifer Krebs is a senior at Edgewood College in Madison, Wisconsin. She is a Natural Science major with a concentration in Geology. Jennifer is working at the wave basin as an REU, or Research Experience for Undergraduates student. Working here this summer is giving her an opportunity to experience life as a graduate student.

The Project- Seaside, Oregon

There is a 1 in 10 chance that the Cascadia Fault will fail in the next 50 years. This would trigger a tsunami that would be comparable to the tsunami observed in the Indian Ocean in 2004. By 2010, 60% of the United State's population will live within 50 miles of the coast. Since earthquakes are entirely unpredictable, the need for a more efficient evacuation plan is urgent.

A group at Oregon State University is researching the effects of an earthquake generated tsunami on coastal structures. If an earthquake triggered tsunami were to occur, residents would have 20-30 minutes to seek shelter in the predetermined evacuation shelters marked as blue boxes on the map below. For some, this is not a realistic option.Using a 1: 50 scale model of Seaside, Oregon, the researchers plan on exploring the idea of "vertical evacuation," seeking shelter from a tsunami wave by going up and not inland.

Cascadia Subduction Zone

The Cascadia Subduction Zone (CSZ) is a 680 mile fault located just 50 miles off the Pacific Northwest Coast. It runs from northern California up to Vancouver Island. As dense oceanic crust collides with the continental crust, the oceanic crust is thrust under the continental to create a subduction zone. The fault is evident by the long line of active volcanoes along the pacific northwest.

Along with active volcanoes, faults pose a high potential for earthquakes. As stress builds at the plate boundaries, the potential for earthquakes increases. Eventually, the plates will snap causing an earthquake. An earthquake with its epicenter located in the ocean would generate a tsunami.