Benson Murals

The animals and birds roaming these rocks look like they’re ready to walk or fly off the wall, but the real focal points are the strange rock formations – precariously balanced rocks called PBRs. The story behind these rocks isn’t completely understood, but scientists trace the history to a volcanic eruption between 25 and 50 million years ago. The eruption spread ash over a vast area, and the ash particles fused together to form a type of rock known as rhyolite. Uplifting and other geologic forces later created joints and cracks in the rocks. Then, over the eons, the erosive forces of water, wind and ice slowly sculpted the rock into the formations seen today.

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PBRs are proving to be life-saving natural ornaments in seismically active regions. The presence of PBRs is evidence that an area has not experienced large earthquake-induced ground motions since the formation of the precarious rocks. Otherwise, the PBRs would likely have toppled by the shaking of the earthquake.