Point is, I wonder if this was the sound of Badwater Basin (lowest point in North America) getting a little bit lower...
Point is, I wonder if this was the sound of Badwater Basin (lowest point in North America) getting a little bit lower...
Today's earthquake was a strike-slip earthquake, where two parts of the crust slide laterally by each other on a fault plane inclined close to vertically in the crust. The fault is probably oriented NW-SE [1], parallel to the San Andreas fault, although from the pattern of energy release from the earthquake (known as the focal mechanism[2] or moment tensor[3]) it also could be on a NE-SW oriented fault, with the direction of shear being the opposite. Because this was a strike-slip earthquake on a vertically-inclined fault, there won't be more than a few cm of uplift or subsidence of any parts of the earth's surface.
The domino-style faulting that occurs in the Basin and Range of the US, basically from Owens Valley to Salt Lake City, is an expression of 'normal faulting' (rather than strike-slip faulting). Normal faults are inclined from the horizontal, and the block of crust above the fault slides down the fault, like down a ramp. After a lot earthquakes (hundreds to thousands of M6+ earthquakes) the blocks have rotated on a horizontal axis quite a bit, so that they are no longer upright [4]. Furthermore, and quite importantly, as a result of this faulting, the crust (or at least the upper crust where the faulting happened) is both thinner from top to bottom than it was previously, and wider than it was previously--we say that the crust got 'extended' because it is horizontally lengthened/widened. You are absolutely right that Death Valley is forming in this kind of environment.
There are two main reasons for crustal thinning and extension. One reason is that the boundary of that part of the crust moved away, so the crust stretched or extended to fill the gap. The other is that the crust was too thick and high, so it spread out. The continents are kind of like rafts of granite floating on more dense, hot, ductile rock below (the mantle). The density contrast between the lighter crust and the mantle is sort of like icebergs floating in sea water, so most of the continents are below the surface of the ocean basins. When a big mountain range is built that gets high, it also has to have a thick root to support its surface elevation, like the undewater part of an iceberg. However, the crust isn't always strong enough to support a big mountain range for a long time, and so it will break apart under the force of gravity and spread out laterally, reducing the gravitational potential energy contrast between the (formerly) high mountains and the surrounding lower elevation crust.
It is thought that in the western US, both processes (the moving boundary condition, and the gravitational collapse and spreading of the crust) have been the cause of the crustal extension that produced the domino-style block faulting. The big collapse was probably during the Miocene, say about 15 million years ago, which produced a lot of the faults and smaller mountain ranges that we see today. Many geologists think that California was one or two hundred kilometers closer to Colorado, and the area that is now Nevada and western Utah was narrower and much higher--say a mean elevation of over 10,000 feet. This has been nicknamed the 'Nevadaplano' in reference to the Altiplano of Bolivia and Peru, which is an analogous geologic feature. I think that there is also a slight component of extension between the North American and Pacific plates at this latitude, i.e. the Pacific plate is mostly sliding by North America on the San Andreas and parallel faults, but it might also be moving away from North America (i.e. Kansas) at a few mm per year.
[1]: https://earthquake.usgs.gov/earthquakes/eventpage/ci38457511...
[2]: https://en.wikipedia.org/wiki/Focal_mechanism
[3]: http://seismo.berkeley.edu/~rallen/eps122/lectures/L12.pdf
In the meantime, I wonder if there are any good photos of them? I wouldn't know what to search for.
These hikes aren't nearly as hot as the valley, and probably manageable even in the summer. Much of Death Valley's heat comes from the air being more compressed the lower you go, so if you're 6000 ft up it's not that bad at all. Although, be careful.
Here's some pictures I found online: https://www.americansouthwest.net/california/death_valley/wi... . Note that the rock below you has clearly toppled over to almost a 45 degree angle. All the mountains in the distance are like that also.
A few hours later I was on a different ridge and a bunch of fighter jets flew through a canyon _below_ me. Death Valley is awesome. (although that may have been right outside of it?)