The American Geophysical Union's blog network covers landslides, earthquakes, carbon dioxide, and other geoscience topics.
HN commenters link its Landslide Blog posts for context on tsunami threats, past landslides such as Blackhawk, and land subsidence from water use.
> Thermal is an issue that gets worse with distance.
I would respectfully disagree. The rail industry has figured out how to do Continuous Welded Rail (CWR) quite well, using the elasticity of steel.
http://blogs.agu.org/landslideblog/2011/03/08/distorted-railway-lines-in-the-christchurch-earthquake/
Similarly the tube for the Hyperloop doesn't HAVE to free-float against its foundations. It might be easier or harder depending on various factors to work on expansion joints or doing the tube equivalent of CWR. You'd probably work on both to figure out which is easier in the long run.
Considering that it's a 9-11ft diameter tube with about 1" wall thickness, it's going to be pretty stiff, especially relative to traditional rails. The moment of inertia means that it should be very resistance to bending or buckling under compression and under tension steel is usually very good.
Given that there are going to be plenty of turns that the track has to make, I would look at doing a combination of two things:
1. Working towards a CWR style solution
2. Allow some movement so that the corners can take up the slack as the tube expands
The turns are very gradual and sweeping. But you could imagine that there's a virtual intersection between two straight portions that you determine by drawing lines from the straight portions until they meet. The actual turn will take place far from here, but it's instructive. So as the tube expands, the actual curve is going to move ever so…
...a failure state of the dam system.
One thing I'm really impressed with is how many redundancies are built in to dams, and how their failures are intended to be gradual and not catastrophic and sudden with a full release of the reservoir contents.
ie, use the water to generate electricity. If that's not enough outflow, use the spillway. If the spillway isn't enough, the emergency spillway will drain more.
There's even another contingency (with more details), described here, that I haven't heard anywhere else:
http://blogs.agu.org/landslideblog/2017/02/14/oroville-dam-site/#comment-214014
> The emergency spillway is not auxiliary, and i don’t believe any competent geologist present during it’s construction would have considered its use as anything but a last ditch effort. It was designed as a fail-safe to prevent the loss of the main dam during the event of a half a million cfs inflow to the lake during a 200 to 1000 year event. The ogee weir extending from the main spillway gates was likely built to protect the main spillway gates. The bedrock was excavated deeper below the ogee weir to find more competent bedrock than the concrete wall extending northwards from the ogee weir, which was built to protect the ogee weir. The lack of concrete in the far NW corner of the parking lot where we saw considerable erosion and helicopters lowering bags of rocks into is not lack of foresight, but designed weakness built into a weak structure. The parking lot is built on highly…
This article skews towards trying to make a political point, but it does so at the cost of truthfulness. It lays an elaborate case before the reader, detailing the woeful state of NASA interplanetary science and the assumed perfidy of a stingy congress.
This is a narrative that has only the slimmest hold on reality. Congress has done reasonably well at keeping NASA funded, with some occasional road bumps here and there. And certainly at a lower level than what many of us who value planetary exploration particularly highly would like. But still not too bad all things considering.
The real cause for the pinch in planetary science is NASA itself. It has indulged in undisciplined budgetary behavior and project planning at the cost of diversity and robustness in its science missions.
The major cause of these problems is something that is not mentioned once, even in passing, in this entire article: the James Webb Space Telescope (JWST). As of right now JWST is more than $7 billion over budget and 8 years behind schedule. That $7 billion compares to: 1 Curiosity rover ($2.5 billion) plus 2 Dawn double asteroid rendezvous missions (2x $500 million, 4 total asteroidal bodies visited) plus 1 Cassini mission ($1.4 billion) plus 1 New Horizons mission ($650 million) plus 1 Kepler mission ($550 million) plus an entire extra billion dollars. That's an exciting panoply of opportunities, and imagine those figures in the context of similar classes of missions. Ion engine powered…
Terraced open pit mines and rice paddies require an enormous amount of maintenance. The terraces are not naturally stable. Rice paddies will quickly silt-up, then flood and collapse in heavy rain.
Open pit mines will fill with water. The sides will collapse. In the desert, they will fill with dust. Deserts often have flash-floods following thunderstorms. They might remain recognizable as hollows, but not much more.
The Bingham mine has had collapses in 2013 and 2021:
https://blogs.agu.org/landslideblog/2021/06/04/2021-bingham-canyon/
https://blogs.agu.org/landslideblog/2013/04/30/analysing-the-bingham-canyon-mine-landslide-part-1-the-landslide-source-area/
https://blogs.agu.org/landslideblog/2013/05/06/analysing-the-bingham-canyon-mine-landslide-part-2-the-landslide-track/
There was a similar collapse recently at the Çöpler Mine in Turkey...
https://eos.org/thelandslideblog/copler-mine-1
https://eos.org/thelandslideblog/copler-mine-2
https://eos.org/thelandslideblog/copler-mine-3
https://www.youtube.com/watch?v=SUD0hQjueI0
https://www.youtube.com/watch?v=SCRTwnz3_oo
The ground is warmer (and therefore drier) now in
May, and this is especially so in the Boreal Forest
of Canada where temps. have been rising much faster
than they have in the mid latitudes.
This year the fire season started very early, and
temperatures in the region have been at record levels
for days, with some areas reaching above 30 C.
From http://blogs.agu.org/wildwildscience/2016/05/05/roaring-inferno-alberta-climate-change-looks-like/
I think this has a lot to do with climate change. If the average temperatures are warmer and the air/ground is drier, it can increase the likelihood, frequency, and severity of wildfires. Colorado and California have been/will be going through the same thing.
A few factors contribute to that photo's impression. Aside from being a composite:
- There's no atmosphere on the moon. Which means there's no distance haze. Far objects are just as sharp as near ones.
- There are no reference points to indicate scale. This is fairly common in terrestrial photos of barren landscapes, especially Alpine, Arctic, or glacial photos. In this image of a Pakistani landslide, note the apparently diminuitive size of the earth moving equipment and background figures: http://blogs.agu.org/landslideblog/files/2012/04/12_04-Siachen-2.jpg