[huron]

This looks like it was recently eroded from the center of a Tiger Mountain trail not far from the Issaquah shooting range. Its about 3cm diameter. Red rubber/plastic or shiny paint. Looks like a tube or stake going down into the soil. Marked with "P.E.D. Control" in faded black letters. What is it? Found a Wikipedia entry for cave radio system of some sort.

[Joey]

A corner on a land survey is typically marked by driving a length of rebar into the ground and placing a plastic cap on top. The cap will have the surveyor's registered ID number that was assigned by the state. Maybe something along those lines.

[texasbb]

Land mine.

[thunderhead]

Performance enhancing drugs? Any russian olympic officials around?

[huron]

Found the answer. It appears to be the control interface point where a signal can be sent to a low frequency antenna that propagates through rock. This can enable a "personal emergency beacon", remote text messaging or initiate remote blasting from surface to mine/cave. Still curious about what signal is being sent or received there.

[hatchetation]

[moonspots]

[huron]

Found another up the trail a way. This one was also dead center on the path. Joey is correct. A simple survey stake. It was raised 3 inches or so enough to see the rebar. The caps on these things don't look like they will be around for long and I would hate to think that trail runners will be impaling themselves on a 1/2 inch rebar spike. That was my concern.

[RodF]

[Joey]

Covering them as RodF suggested is fine. Surveyors have metal detectors that are 'tuned' to find vertical rebar and they will know approximately where to look if they need to recover (surveyor-speak for "find") those stakes.

[cdestroyer]

I was once stationed at rocky point naval transmitter facility NAS whidbey a long long long time ago. The VLF transmitters in the area at that time were near arlington. they were 1.5 million watts and sent signals to subs at sea thru the water and later a very large one was built in upper wisconsin that sent the signals thru the earth..

[DIYSteve]

Yeah, as Joey says and Huron confirms, it's a survey marker. Do NOT attempt to move it or alter it. "Disturbing" a survey marker with intent is a gross misdemeanor in WA. See RCW 58.04.015 Yeah, you can cover it up with dirt or rocks, or place rocks around to warn others of its position.

[Malachai Constant]

We had a potential dispute with a neighbor and I had the property line surveyed. The surveyor put in a number of flagged wood stakes. I later drove in metal fence posts below the surface next to each stake for future reference on advice of the surveyor. Standard operating procedure.

[DIYSteve]

[Malachai Constant]

I am well aware of all that. One of my first jobs out of high school was as an assistant to a surveyor and when in general practice I did several boundary disputes. I know where all the original markers are. Unfortunately the leagal description is meets and bounds. The neighbor was an early MS employee whose wife wanted to raise sheep and he wanted to clear cut the adjacent property on a steep slope all the way to the property line which he claimed was marked by a used diaper in a tree. At that time Issaquah tree cutting restrictions were lax (now you need a permit for anything over 6"). Rather than continue arguing I paid a couple hundred for the survey. The neighbor finally gave up and sold the property but I wanted the boundary clear for the future. Long irrelevant story but fun to tell.