Tuesday, January 20, 2015


Is this a volcano?

It certainly looks like one to me.  It is in the Bradshaw Mountains foothills just to the south of StoneRidge in Prescott Valley, where I live.

It pokes it's head up above the other hills around here.  Here's a photo to show how close it is to the surrounding development.

If it is (or was) an active volcano I suspect it is long extinct.  Just the other direction is Glassford Hill, the landmark of Prescott Valley and a proven extinct volcano.

Photographed from these angles it doesn't really look like a volcano to me.  No cone shape. But a little further around the side and you can see where the lava flew 10 to 14 million years ago.

They're not real good photos.  The entrance road to the property that I discovered was not closed off or posted but I decided not to get any closer.  By cropping my photo you can get a bit better view.

You may notice some towers up at the peak.  Those are various radio transmission towers that the town and the county administer. I'd love to get up there to the top at 6,177 feet but I believe it is restricted territory.  There's probably a locked gate somewhere up the road aways.

But if that other one, to the south, ever decides to come to life the residents of StoneRidge may be in for a rude awakening.


  1. Neat post. I'm not a volcanologist but I spent about a year with several while writing and directing a documentary on their science and the "ring of fire." The Glassford Hill looks like an old lava dome, or cap that was created by the upward flow and pooling of magma. It reminds me of Pu'ua O' O, the lava dome of Kilauea that collapsed in 2011. A few years earlier Donald Swanson, the head of the USGS team and I flew up to the rim of Pu'u O'O and stood there there looking into the lava cap when we experienced a gas piston tremor that shook the fragile and fissured ground and belched out a huge jet of sulfurous gas. Sounded like jet engine firing up. His gas chemist specialist read us the riot act when we got back to the lab because we were not wearing respirators. The inside of my nose was affected for a couple of months afterward.

    BTW-volcanic uplift as well as eruptions can create those pointed peaks. BUT-and this is a bit far out-when I was working with archeologists in Guatemala, Honduras and Belize I learned that pointed peaks with a particular symmetry were also frequently old Mayan Temples. Some that had been thought to be old volcanos later were discovered to have been temples covered by centuries of vegetation and decay. Is there any evidence of Mayan, Aztec, Incan or Monte Alban migration in that part of Arizona?

    1. No, Tom, I don't think so. We had a number of Native American peoples go through this area but I don't believe there were any pyramid builders. When we were in Mexico, though, we used to see small peaks that we suspected were former temples of an earlier race.

  2. I too am not a vulcanologist, but it would seem to me - at least from the viewpoint you have photographed it - that the structure is too clean and too symmetrical to be an extinct volcano. Surely weathering would have taken its toll. If it were active, I guess you would have some knowledge of the fact.

  3. Looks like an old volcano to me, I have to defer to Tom...he seems to know his stuff.

  4. Glassford Hill is known to be an extinct volcano. I rode my horse up to the top one time many years ago. I went up the east side and it was treacherous terrain. I had to get off and lead my horse the last bit through layers of volcanic rock. Once was enough. That road behind Home Depot wasn't there then. I don't know about the other peak but it sure looks like it could have been a volcano.

  5. If I were one of those home owners, I'd be hoping it was extinct. Here in Portland we're close to Mt. Hood, which many people think is extinct, but it isn't. I does rumble from time to time.