Shannon Othus
10/22/04
ENVS 220
Molitor

Earthquake Potential for Walla Walla

My Internship for this semester deals with the potential for an Earthquake in the city of Walla Walla . I am an intern for the Walla Walla County Emergency Management Department (EMD). The Walla Walla EMD is the department of the county that identifies the potential for natural disasters and potential damage that could be created because of these disasters. The information that the EMD discovers is then relayed to the public on the Internet or through official documentation. The work that I did for the first part of the internship regarded public information about the likelihood of an Earthquake in our area, the magnitude of said earthquake and the damage that could be incurred. This work was easily done using the knowledge that I had received in Environmental Geology and also became applicable to the next project, a potential earthquake scenario.

It was my job to relay to the public the implications of this fault and what damages could occur. My work was to create an updated version of the information in the form of an HIVA (Hazard Identification and Vulnerability Analysis) that is already available on the EMD website. The previously created document was confusing because it was somewhat dense in that it did not explain what an Earthquake really is, what will happen along the fault we are close to, and what potential damages could occur. For the first part of the internship I updated this document in hopes that it will be easier for the public to easily understand what the likely damages could be for citizens of Walla Walla .

Afterward the HIVA was completely updated, my job changes to include a probable earthquake scenario to be used in the estimation of what would happen in the highest magnitude of earthquake along our closest fault. To write the potential earthquake scenario had to learn about the fault zones in the area and the hazards associated with an earthquake located on those fault zones and the geologic structures in the region. The two faults located very near Walla Walla County are the OWL, or the Olympic-Wallowa Lineament, and the Hite Fault System. The OWL is a series of faults that run from the Blue Mountains across the state of Washington to the Olympic Mountains in Oregon and runs in a north-northeast direction. The Hite Fault System stretches in a north-northwest fashion from Pendleton , Oregon to 150 miles to the north, to Pomeroy , Washington . An earthquake will most likely occur on the Wallula Fault System because the Hite Fault was once active but has decreased in activity suggesting that it is becoming inactive. There is a "medium" chance that an Earthquake will occur at some point in the future. This does not suggest that we may or may not have an earthquake because we will most certainly have an earthquake along this fault system in the future. Rather, it means that we have a medium chance of incurring great damages from an earthquake on one of the fault zones in our region.

The most likely scenario of a potential earthquake is one that has its epicenter on the Wallula Fault Zone. The greatest magnitude that we can expect is a 6.5 magnitude. This large of an earthquake will be extremely costly to public and private property. Due to the nature of the fault, any earthquake on the Wallula Fault Zone will have an extremely shallow depth up to 15km and will be very close to Walla Walla County at about 10km away. The hazards that could possibly occur in this area due to earthquakes are shaking, fault displacement (vertical or horizontal movement of ground along the fault), differential settling (structures resettling on their foundations at different rates due to energy waves), landslides, and seiches (oscillation of the surface of an enclosed body of water). With this information of hazards I was able to begin determining damage that could be caused to homes, businesses, and the infrastructure during an earthquake in the region. Also, I compared two older earthquakes in other regions that have similar fault systems to Walla Walla County . The two earthquakes that I compared to Walla Walla 's Wallula Fault Zone are 1994 Northridge earthquake in San Fernando Valley , California and the 2001 Nisqually earthquake 52km outside Seattle , Washington . Through the comparison of these two earthquakes I was able to see the type of damage created by fault systems like the Wallula Fault Zone.

The aforementioned information was used to aid in creating a report regarding a potential earthquake scenario in the area. With this report the county could possibly plan for the event. To complete this task I made an analysis of the possible damages ranging from death and injuries of humans and damages to the infrastructure of the city including damage to unreinforced masonry, the water treatment plant, and private homes and businesses. I also be addressed the non-structural damage to human property regarding such things as high storage of heavy items, computer damage, ect. (Attached to this final paper are both the HIVA and the potential earthquake scenario that I worked on for the semester).

During the semester I have learned less than I would have liked and have done very little work. This specific internship could have been more interesting and challenging to someone who is not an Environmental Studies—Geology major. The actual internship started out extremely slow. I had the task of updating a finished document. After I was finished with this document I was informed that the path of my internship had completely changed. I had originally been asked to learn about two coinciding programs, both GIS and the HAZUS programs. These programs are relatively new programs created for earthquake prediction. The programs have been tested in relation to California earthquakes and have proved to be very accurate regarding actual damage prediction. It would have been beneficial for me to learn these programs because they are applicable to my chosen field. However, I was left to do effortless work for the duration of my internship.

In addition to my problems regarding the actual tasks undertaken, my sponsor was a very hard man to reach. He was rarely in the office from the very beginning of the internship and was constantly out of town. At one point I had to call him to make sure that I was still participating in the internship and which is when he relayed to me that his ideas about my position had changed. Because of his absence and the lack of work provided reflections were very difficult. Also, the completely hands-off approach used by my sponsor created a stressful situation in which I had to figure out what work to do when and how it should be done. This was somewhat cleared up in the end, though I still rarely had direct information on how my work should be prepared. As a result, I would mostly do a large portion of the work all at one time and not work anything for prolonged periods of time. It seemed as though I was only writing a paper for another class. Suggestions concerning the future of this internship would be that perhaps the sponsors should know exactly what the proposed position entails. I have worked for the government before and know how busy it can be, and so if the time commitment that is relayed is too much for the sponsor, then they can decline the responsibility. In the end I tried to do as much as possible on my own.