It’s a Landslide!

There has been talk of an electoral landslide in November, but what I’m referencing is an actual landslide. I stumbled across an article on the Arizona Geological Survey (AZGS) website about the Marcus Landslide on the northeast side of the McDowell Mountains away from Scottsdale’s McDowell Sonoran Preserve, and I noted some scary statistics.

Marcus Landslide, AZGS Brian F. Gootee.

The Marcus Landslide field is within what is now the Maricopa County McDowell Mountain Regional Park, north of Fountain Hills. Scientists estimate it occurred about a half-million years ago.

At that time, AZGS says,

Central Arizona’s climate then was wetter and cooler than today.  And the McDowell Mountains would have been home to indigenous dwarf conifer woodlands rising out of a grass-covered plain that supported mammoths, giant sloths, saber-tooth cats, camels, and horses.  It is likely that traces of former life [from the Pleistocene epoch] are still preserved in the Marcus Landslide, just waiting to be discovered.

These are the scary statistics:

  • 12 billion kilograms of rock
  • traveling at speeds up to 44 miles per hour
  • as much as 46 Tera-Joules of energy released (~11 kilo-tons of TNT)
  • approximately equivalent to the yield of each of the Fat Man and Little Boy bombs dropped on Japan toward the end of WWII.

The most scary?

The Marcus Landslide shows that large landslides are a real geologic hazard in the mountains of the Central Arizona. The proximity of the landslide to Scottsdale argues for a more careful analysis of landslide hazards in the McDowell Mountains, and all the ranges surrounding the Valley of the Sun.

Here’s a virtual tour of the Marcus Landslide, courtesy of ASU.

Here’s an interesting history of electoral landslides.

Another interesting side-note. In looking up the conversion factor between tera-joules and TNT yield, I noted that the US had at one time a backpackable, “man-portable” nuclear weapon called SADM. Just thought you might find that entertaining.

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