August 26, 2015 | David F. Coppedge

Balanced Rocks Challenge Dating Methods

A person could almost push over some balanced rocks. Have they really been standing for 10,000 years through earthquakes and all?

There are about 1,200 known Precariously Balanced Rocks (PBRs) in California’s earthquake country, Live Science says, leading off with a photo of a remarkable example in western Nevada. Major quakes occur every 200 to 300 years, scientists say, yet these rocks have not fallen over. What’s the explanation?

One possibility is that the ones we see are the lucky remnants of a larger population that did fall. It’s less likely that earthquakes toppled them into position. Somehow, they survive despite severe shaking.

PBRs originate, the article says, from granite boulders pushed upward through the earth, loaded with cracks. Weathering chisels them down to the forms we see today (see globe-shaped rock in the Sierra Nevada). Found all over the world, PBRs require thousands or tens of thousands of years to form, the article claims.  It’s interesting that they are not said to be hundreds of thousands or millions of years old.

PBRs near the San Andreas and San Jacinto faults are also puzzling because the rocks are roughly 10,000 years old and earthquakes there typically occur every 200 to 300 years, Lozos said.

The California PBRs must have stayed balanced through the 1812 and 1857 quakes on the San Andreas Fault. If they are really 10,000 years old, they should have survived 33 to 50 earthquakes, some of them major. How they survive large quakes calls for explanation. Does this freeway analogy work?

The presence of PBRs close to the San Andreas Fault suggests that nearby earthquakes didn’t happen very often, or happened with little energy, Lozos said.

A ruptured fault can either continue on the same fault, or “jump” to another one nearby, Lozos said. It’s “like the rupture taking a different freeway exit,” he added. Maybe the rupture is “charging down the San Andreas and decides to keep going or decides to take the exit onto the San Jacinto.”

It would be hard advance that idea beyond a suggestion. The longer the rocks are assumed to have stood there, the more improbable it is that they would survive so long. The shaking adds up over time.

When dealing with historical inferences, natural scientists can only apply probabilities with known causes that might have produced current observations. PBRs are not objects of intelligent design because the probability natural causes can produce them is high; there is no information content or irreducible complexity. But the older one assumes they are, the more improbable the date becomes.

Biblical creationists only allow for about 4,500 years since the Flood. While still remarkable there are so many PBRs in existence, it’s not as improbable as believing the rocks have stood 5,500 years longer through dozens more earthquakes. Another consequence of the creation view is that quakes were stronger and more frequent after the Flood, when the boulders were first weathering, but have tapered off since, along with declining volcanism and tectonism (see Steven Austin article on ICR).

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