Describe observations that tell us the Cascadia subduction zone has (a) had large earthquakes in the past and (b) is building towards an earthquake.
The measurements of the Earth’s crust movements show that a strain is building up beneath Oregon. The geologists proved that large-scale earthquakes occurred in the Cascadia area every 244 years (Oregon Field Guide, 2015). Now there have been no big earthquakes for 300 years already, which means that they can strike at any moment.
What lessons could Oregon learn about earthquake/tsunami hazards and building resilience from the 2011 Japan event?
After the earthquake of 2011, Japan recovered relatively quickly because it was well-prepared. Oregon could prepare for such a situation using earthquake-proof construction technologies and training people. The main lesson is that an earthquake is not an apocalypse, and people should be ready to face it.
Describe at least three (3) of the specific, major vulnerabilities to a large earthquake identified in Oregon.
First of all, bridges, buildings, and many other infrastructure elements were not prepared for the earthquake. All of the Cascadia areas is geologically unstable, whereas there are many old brick buildings in the area. In case of an earthquake, these buildings will fall quickly. Second, Oregon has only one fuel depot that can be damaged during an emergency. Third, the soil in Oregon is watery, which increases the risk of an earthquake, whereas all the tank farms are based on this soil. Besides, the city has no evacuation shelters in the most vulnerable zones.
What could be done to mitigate the vulnerabilities you described?
The soil can be strengthened by adding ground and putting stone columns into it. The buildings can be built with base isolation, a technology that has been successfully applied for the buildings in tsunami zones in Japan. Seismic retrofitting can be applied to the buildings that already exist in dangerous areas. Different facilities, such as schools and hospitals, can be moved to the highlands. People can make personal water and food stores in order to be ready for the earthquake and be self-reliable.
What are some of the reasons that these improvements are not implemented?
The laws of the country do not allow putting the columns in the foundation of the fuel tanks. None of the companies owing the tanks agreed to take measures against the earthquake. Besides, local officials do not listen to seismologists and continue to use old planning. Seismic retrofitting is not required in Oregon, and few volunteers are ready to spend money on it.
After watching the whole documentary, if you had to prioritize one (1) earthquake mitigation measure for Oregon, what would you choose and why?
It is possible to prepare the area for the disaster, but the officials create obstacles. For this reason, I would choose to actively inform them about the need for seismic retrofitting and following the new plan during construction. Perhaps, it could be possible to inform higher instances that could provide financial support to the region.
Reference
Oregon Field Guide (2015). Unprepared: An Oregon field guide special [Video]. Public Broadcasting Service. Web.