Hamblin-Cleopatra Volcano

Painting of the Hamblin-Cleopatra Volcano seen from the water.

Along the north shore of Lake Mead exists an ancient volcano, long dormant but very intriguing. The Hamblin-Cleopatra Volcano (HCV) was once a large stratovolcano and now has split into three large sections due to earthquake faults in the area.

The volcano formed in the late Miocene time and through the years slowly split in half, and then parts of the Cleopatra section split again, separating the original volcano complex by twelve miles. The original volcano was more than 3,000 feet high and had a circular width of approximately eight miles. It’s formation was rapid.


Area Map

Map showing the location of the volcano, in the northwest section of Lake Mead.

What is a Stratovolcano

3D representation showing the inside of a stratovolcano.

Illustration by Anthony Ross


History of Hamblin-Cleopatra

Graphic showing Hamblin Mountain and the Cleopatra lobe as they were 13 million years ago.

13 Million Years Ago

Around 13 million years ago, Hamblin-Cleopatra were one large stratovolcano. The volcano sat on the Hamblin Bay Fault which ran right through the middle of the mountain, splitting it in two. For clarity the Hamblin Mountain portion is in light red, the Cleopatra portion in light green, and the Cleopatra split-off is colored grey..
Graphic showing Hamblin and the Cleopatra lobe splitting 1 million years ago.

~1 Million Years Ago

Over the millions of years since the volcano has been active the movement of the Hamblin Bay Fault moved the Hamblin portion to the southwest and the Cleopatra terrain to the northeast. Another fault formed that split the Cleopatra lobe in two.
Graphic showing Hamblin Mountain and the Cleopatra lobe apart from each other as they are today.


Currently the Cleopatra lobe is around 12 miles from the Hamblin Mountain lobe. You can see in the color coded USGS map below the distinct locations of the three parts of the Hamblin-Cleopatra Volcano as it is today (Dark Magenta color)
A color-coded topographical map of a section of Lake Mead.
Thematic Geology Map of Hamblin-Cleopatra area.

Courtesy of USGS




Geologic Map by United States Geological Survey https://ngmdb.usgs.gov/Prodesc/proddesc_81106.htm

DOI Paper, Large-Magnitude Late Tertiary Strike-Slip Faulting North Lake Mead, R Ernest Anderson. 1973

Last updated: December 14, 2022

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