Archive for September, 2011

Remembering the Scotts Mills Quake of ‘93

With the (sort of) recent earthquake in Virginia, I was reminded of our last significant shaker here in Oregon, the Scotts Mills (or “Spring Break”) quake of March 25th, 1993 with a registered magnitude of 5.6. It was my junior year of college and our school observed spring break a week before most schools. I happened to be extremely sick at the time, so when the rumbling started in the early hours (5:34 AM to be exact), I remained in bed. Really, the shaking didn’t last all that long — I’m guessing just 10 seconds. It sounded like a freight train was passing by my window though. I had one of those cheap chipboard shelves in my dorm room and had a TV sitting it. It really freaked me out to see it swaying dangerously back and forth. Overall, the quake did little damage and there were no serious injuries. In Salem, the State Capitol building needed repairs due to some cracks in the wall of the rotunda. There was a bridge in McMinnville that was damaged and an elementary school that had to be condemned. In total, FEMA reported 16 residences and 54 businesses sustained major damage. There are no known faults in the Scott Mills area; however the Mt. Angel fault is not far away. As a side note, while I was researching a history project in college I came across an article from the late 1890s about strange geological occurrences in Scotts Mills — something like liquefied sand spurting from the ground. Not sure if this might be related to a fault line in the area, but it made me wonder about the unknown dangers lurking under that part of the Willamette Valley.

The only other time I experienced a significant earthquake was in 2001, when the office building I was working in shook pretty hard from a quake in Washington. That quake was probably more like the one experienced out on the East Coast.

Add comment September 14th, 2011

Visiting the Former West Coast OTH-B Radar


On a recent trip to central Oregon I made a detour to Christmas Valley to visit the former Over-the-Horizon Backscatter (OTH-B) radar site — one of the last Cold War installations in Oregon. This first required permission from the US Bureau of Land Management and the Oregon Military Department, who were kind enough to allow me to explore the site. Most Oregonians have probably never heard about the AN/FPS-118 (the official Air Force designation) radar installation in Christmas Valley. The system actually had three components: the transmitter site here in Oregon, a receiver site in Tule Lake California, and an operations center at Mountain Home Air Force Base in Idaho. All three sites were connected by satellite. A similar OTH-B radar existed in Maine to serve the East Coast. At the Oregon site, there are really three separate radar installations arranged in a sort of half-moon pattern facing west. Each has wood fencing surrounding the massive 460 acre perimeter and cyclone fencing around a power station, water tank, and the lone pole-barn style building. The operation center in Mountain Home processed all the data from the three West Coast radars. If something looked suspicious on the radar returns, interceptor aircraft would be dispatched to in investigate.


Funding for the West Coast site was authorized by Congress between 1986 and 1988. Construction was completed in December of 1990 at a cost of over $300 million. In 1991, plans were on track to turn the West Coast site over to the Air Force’s Tactical Air Command for official operation. However, with the ending of the Cold War, the Air Force decided to end activities at both the East and West Coast OTH-B radar sites and both were placed into caretaker status. In the mid ‘90s, the National Oceanic and Atmospheric Administration (NOAA) began using data from the Navy’s smaller and portable OTH-B radar system (AN/TPS-71). The Air Force operated the West Coast site system briefly around this time for scientific and counter narcotics purposes, but this activity stopped in 1997 due to high operating costs. Again, the system was mothballed.


So how is OTH-B radar different from conventional radar? Well, conventional radar has always been limited in range due to the curvature of the earth. OTH-B radar gets around this problem by bouncing radio signals off the ionosphere. A small part of the signal is then reflects back to the receiver, which is called “backscatter”. The range of the OTH-B radar is anywhere from 500 to 1,800 nautical miles, much further than the conventional 250 mile maximum range of a rotating radar. The one major disadvantage of both the West and East Coast sites was the fixed 60 degree coverage. In contrast, a conventional rotating radar provides a 360 degree coverage. The Soviets also had their own OTH-B radar about a decade earlier than ours and was nicknamed the “Russian Woodpecker” by shortwave radio operators. It was shut-down around 1989, possibly because it interfered with civilian radio transmissions. Currently, the only large-scale fixed OTH-B radar site is in Australia.


The Oregon site sat unused from 1997 to 2007. Thieves took their toll as the price for metals soared during the economic boom years. In 2007 an Oregon State Trooper pulled over Peter and Andry Sharipoff of Mount Angel who were carrying 1,500 of copper wire stolen from the site. Both, not surprisingly, were also charged with meth possession. The Air Force dismantled the massive radar arrays shortly thereafter. In 2008, Lake County began exploring ways to use the site for alternative energy production. Since power transmission lines still exist at the site, the thinking was it would be easy to install solar arrays and push power out from the three sites. As of 2011, there has been no alternative energy development at the site. The Oregon Air National Guard now uses the installation for training purposes, but there doesn’t seem to be any long term game plan for the 2,500 acres of land.


I didn’t see any activity when I visited this summer — although there were a few exterior lights on. The power station was buzzing, so juice is still flowing to the site. Overall, the buildings and fencing look to be in good shape. Of course the radar arrays are long gone, but you can still see the cement footings. I should be clear though; this is still a military site and should not be entered without permission from the Oregon Military Office and the Bureau of Land Management. I suspect there are still security systems in place around the remaining buildings, so trespassing would be a bad idea. If you would like to see the site, my suggestion is to view it from the well maintained gravel roads that ring the three installations. But there really isn’t that much to see, so I’m not sure it’s worth making a trek out to Christmas Valley unless you’re a hard-core fan of Cold War infrastructure.

Add comment September 10th, 2011


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