Since You Asked: There's no chance Roxy Ann will blow her top

Dear Newsroom Folks Who Know Everything: According to a Web site, Roxy Ann Peak is a dormant volcano which is approximately 30 million years old. Is that true? If it is, what's the danger of living close to it?

— Jan T., Medford

Jan, you touched on one of our favorite — and most often addressed topics. Our cursory search through the dusty archives in the basement of Since You Asked International Headquarters came up with 42 SYA answers that involved Roxy Ann Peak, the 3,571-foot-tall peak that serves as Medford's eastern boundary.

Roxy Ann is indeed a volcano, or what's left of one. The best estimates are that it last blew its top 30 million years ago, give or take a day or two. What remains is the neck of the volcano and the ancient debris from its eruption that formed the hill above the valley floor.

According to reports we've read, Roxy Ann includes some of the oldest volcanic rocks of the western Cascades. They also told us that volcanic necks survive long after the rest of the volcano has eroded because the hardest rock forms inside the base of the volcano.

The ancient nature of Roxy Ann means you can relax, Jan, because our hometown volcano is considered extinct. There's no absolute definition of what time period qualifies a volcano as extinct — as opposed to dormant — but the explanations we've seen range from no eruptions in recorded time to 1 million years of no activity. At 30 million years, Roxy Ann is well on the safe side of those lines.

The reason a volcano goes extinct is because its supply of magma is cut off. When magma is still active in an area, it's often accompanied by minor earthquakes, and none have been recorded here that suggest any connection to Roxy Ann.

To forestall another episode in the Most-Often Asked Questions About Roxy Ann, the peak was named for Roxy Ann Bowen, who with her husband, John, settled at the base of the peak in the 1850s.

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