Behind you to the east is a steep cliff called Abert Rim, made of many layers of hardened lava flows. This 30-mile-long, 2,500-foot-high, steep cliff is an example of a fault scarp, produced over millennia by great blocks of rock tilting and moving along faults in this region where the earth’s crust is thinning and stretching.

The fault that produced Abert Rim is one of many in the Basin and Range Province- a geologic region where rising blocks of crust (horsts) form mountain ranges, and sinking blocks of crust (grabens) create broad basins. The region spans about 300,000 square miles, including almost all of Nevada and parts of Oregon, Idaho, Utah, California, Arizona, and New Mexico.

• Geologists believe the crustal movements contributing to Abert Rim’s formation were probably accompanied by earthquakes of up to magnitude 6 to 6.5. They also believe the fault is still active.
• Lake Abert, in the basin below Abert Rim, covers 63 square miles-but it is only a remnant of Ice Age Lake Chewaucan, which once covered over 470 square miles. Lake Chewaucan’s shorelines can still be seen lining Abert Rim’s cliffs, far above the present shoreline.
• Archaeological evidence shows that Native Americans have been here for about 11,000 years, with the greatest use between 2,000 and 500 years ago. Most lived in pit house villages along Lake Abert’s shoreline. Artifacts suggest these early people were affiliated with ancestors of the modern Klamath and Modoc Indians, who now live to the west.

Location: On the west side of HWY 395 just south of intersection with 31.

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