Etna, California . Etna, California Etna is a city in the Scott Valley area of Siskiyou County, California, United States. The population was 737 at the 2010 census, down from 781 at the 2000 census. Originally named Rough and Ready, it was changed by statute in 1874 to Etna after the local flour mill (spelled Ætna/Aetna after Mount Ætna in Sicily). Etna is located at (41.457350, -122.896875). Etna is in Northern California near the Oregon border, located in Scott Valley near the CDP of Greenview, the city of Fort Jones, and the unincorporated community of Callahan. Etna is located at the foot
Mount Etna volcanic edifice, forming a stratovolcano in alternating explosive and effusive eruptions. The growth of the mountain was occasionally interrupted by major eruptions, leading to the collapse of the summit to form calderas. From about 35,000 to 15,000 years ago, Etna experienced some highly explosive eruptions, generating large pyroclastic flows, which left extensive ignimbrite deposits. Ash from these eruptions has been found as far away as south of Rome's border, to the north. Thousands of years ago, the eastern flank of the mountain experienced a catastrophic collapse, generating an enormous landslide in an event similar to that seen in the 1980