Mysterious ‘cookie cutter’ sod displacements result from triggered shallow fault slips

Evidence

In Norway and other places in the world, there are records of mysterious, clean-cut, geometric-shaped portions of sod a meter or more on a side. These chunks of sod fly some meters and land cleanly next to the hole they left behind. It is as if a giant cookie cutter did the work. Little is written about the phenomenon, but some information can be found through an Internet search for cookie cutter mystery. A 3-ton piece of sod 10 feet by 7 by 2 feet thick was found 73 feet away from the hole it left in Washington State in 1987. There had been minor earthquakes recorded 20 miles away just before the discovery of the sod displacement, but certainly this was too far away to cause such localized damage. Much more likely is the triggering of a sudden but minor slipping event a few tens or hundreds of meters below the surface of the “cookie.” The energy involved would be small compared to the original quake—not noticed as a separate event perhaps. Triggering of shallow secondary faults by a main quake and resulting large localized surface accelerations have been seen in seismograph records and were considered theoretically by seismologists Norman H. Sleep and Shuo Ma at Stanford University in 2008, published in Geochemistry Geophysics Geosystems. — Eric J. Heller, Why You Hear What You Hear- An…, 707

Categorization

Category: Causal Relationships

• QUESTION: Cookie cutter mystery — an obscure phenomenon worth investigating; why so underdocumented?
• SEED: Cookie-cutter sod displacement as a case study in how modern scientists classify and explain folk phenomena.

Broader Connections

• Shear displacement is a right-angle force causing one material part to slip past another #expands (0.80) — David Howard, Jamie Angus, coustics and Psychoacoustics, 96