Sunset Crater Volcano
Sunday, July 12, 2026 1:40 PM
Southeast of Grand Canyon National Park & north of Flagstaff, Arizona is a region called the San
Francisco Volcanic Field
- It includes several hundred volcanic features, volcanoes, lava flows & other volcanic features.
The largest of them all is the San Francisco Volcano. The San Francisco Volcanic Field show a
pattern of formation (a chain) that indicates a weak, hot spot deep underground, which
breaks through every now & then to form another volcano (like the Hawaiian Islands, but its
within continental crust). Sunset Crater is likely extinct, but there's a definite possibility of
further volcanic activity here
- These peaks are remnants of a huge volcano that blew its top off in an explosion similar to
Mount St. Helens eruption of May 1980. All six are more than 11,000 feet high, the center-
right peak, w/ the white cap, is called Humphreys Peak. Its summit, Humphrey's Peak, is the
highest point in Arizona at 12,633 ft above sea level. The best estimate says the original peak
of the volcano was about 16,000ft above sea level, about a mile higher than Humphreys Peak
○ Sunset Crater lies within this volcano field. It’s an example of a cinder cone & one of the
tallest at about a thousand feet high. It last erupted about 1,000 yrs ago, b/c it had
rained on the black volcanic rock, it began to oxidize & gave the volcano the orange hue,
like the sun is setting on it perpetually
- Not only does the volcano have a central vent, but like most, there are side (flank) vents as
well. There are other cracks, adjacent to the cinder cone through which lava rises &
flows Another feature adjacent to Sunset Crater is a "squeeze-up." These are formed as lava
rises upward through a crack, hardens, and then more lava rises up and causes the hardened
surface to crack open. The new lava hardens in its place
○ The nearby agricultural settlement of the Wupatki Indians, about 22 miles away, had
great soil fertility after the eruption of Sunset Crater. Ashes & cinders coated the surface
w/ new rock, rich in minerals. It also blanket the surface & helped retain soil moisture
below, which enriched agricultural potential
Sunday, July 12, 2026 1:40 PM
Southeast of Grand Canyon National Park & north of Flagstaff, Arizona is a region called the San
Francisco Volcanic Field
- It includes several hundred volcanic features, volcanoes, lava flows & other volcanic features.
The largest of them all is the San Francisco Volcano. The San Francisco Volcanic Field show a
pattern of formation (a chain) that indicates a weak, hot spot deep underground, which
breaks through every now & then to form another volcano (like the Hawaiian Islands, but its
within continental crust). Sunset Crater is likely extinct, but there's a definite possibility of
further volcanic activity here
- These peaks are remnants of a huge volcano that blew its top off in an explosion similar to
Mount St. Helens eruption of May 1980. All six are more than 11,000 feet high, the center-
right peak, w/ the white cap, is called Humphreys Peak. Its summit, Humphrey's Peak, is the
highest point in Arizona at 12,633 ft above sea level. The best estimate says the original peak
of the volcano was about 16,000ft above sea level, about a mile higher than Humphreys Peak
○ Sunset Crater lies within this volcano field. It’s an example of a cinder cone & one of the
tallest at about a thousand feet high. It last erupted about 1,000 yrs ago, b/c it had
rained on the black volcanic rock, it began to oxidize & gave the volcano the orange hue,
like the sun is setting on it perpetually
- Not only does the volcano have a central vent, but like most, there are side (flank) vents as
well. There are other cracks, adjacent to the cinder cone through which lava rises &
flows Another feature adjacent to Sunset Crater is a "squeeze-up." These are formed as lava
rises upward through a crack, hardens, and then more lava rises up and causes the hardened
surface to crack open. The new lava hardens in its place
○ The nearby agricultural settlement of the Wupatki Indians, about 22 miles away, had
great soil fertility after the eruption of Sunset Crater. Ashes & cinders coated the surface
w/ new rock, rich in minerals. It also blanket the surface & helped retain soil moisture
below, which enriched agricultural potential
