In addition to my other idea, 'Kentucky Fried Person Stopper', I was thinking we could build moats into volcanoes to stop lava in its tracks. Various attempts have been made to divert lava flows [link], but this seems the most effective.

Simply surround the volcano as close as possible to the vent (to make it cheap as possible), and wait for an eruption. The lava should flow straight into the moat, where it will cool and solidify. It would be a large scale project, but would be worthwhile if effective.
-- sambwiches, Mar 11 2003

Vesuvius engineering link http://cnn.com/virt...ameset.exclude.html
Explosives? what are they, crazy? [sambwiches, Oct 21 2004]

halfBaked by South Park http://www.tvtome.c...thPark/season1.html
In the episode "Volcano", "The trench itself also works by diverting the lava into a nearby canyon that goes to Denver." [reap, Oct 21 2004]

Perhaps I should have said this in your previous idea, but:

A few years ago, I was in Italy and someone pointed out that, should Vesuvius erupt again soon (extremely likely), the Italian government felt that it would be impossible to evacuate any significant number of the people currently living nearby. Some estimate that several thousand people died in the eruption nearly two thousand years ago.

In 79 AD, people actually fled from Pompeii to Herculaneum, only to get nailed by the second eruption. We now have a much more extensive (if not perfect) knowledge of volcanic eruptions and other tectonic activities. I can't say whether pre-dug channels will be enough (let us not forget the gas component), but I'm all for thinking ahead.

I missed seeing Pompeii while I was in the area. I'm fairly sure I'll never get another chance. (+) from me.
-- brenna, Mar 11 2003


Yeah, its not viable to organise a large scale evacuation every time there might be an eruption. The effect this uncertainty would have on the region's business would be huge (picture them movie Dante's Peak). Nobody would want to do business in the area. Also, the logistical difficulties of moving thousands of people out of a region at zero notice would be huge.

These moats probably wouldn't stop all flows, or have any effect on pyroclastic flows or ashfall, but if we could stop or slow a lot of the lava it would allow authorities a valuable few extra hours to clear the area.
-- sambwiches, Mar 11 2003


Just noticed your link, reap. Maybe my idea was subconsciously based on the old South Park poster on my wall.
-- sambwiches, Mar 11 2003


Im not a volcanoligist, nor did I sleep in a Holiday Inn last night but I did think of a possible problem. By using your moat idea you would essentially be creating a mammoth "plug". It seems to me that the plug might create an even bigger problem. Lava flows releive the volcanic pressure slowly and, in a way, non violently. If the lava cant flow it seems to me that the pressure would build and could lead to another Mount St. Helens.
-- Anvil, May 16 2003


Regarding Mt St Helens and lava and stuff, well...

To put this in as near to layman’s terms as I can manage, there are 2 types of volcanoes, acidic (like Mount Saint Helens), and basic (like Mauna Loa (Hawaii) The former are explosive because they extrude evolved lavas, i.e. the magma has absorbed components of the crust on the way up, and probably started of as melted oceanic crust that had been shoved down a trench anyway. The contain volatiles like water and carbon dioxide that make the rock more viscous, and it is the exsolution of these gasses and increase in gas pressure that gives the volcanoes their explosive nature. The lavas that are produced by such volcanoes are not like the common picture of lava flowing in fiery rivers, it forms a sticky rhyolitic dome, often to be seen in the bottom of recently (in geological terms) erupted cones.

The Hawaiian type, (basic) volcanoes are the ones with the traditional glowing rivers and fountains of lava. These are far less dangerous to man, as the lava moves very slowly, but not so slow that you can load your house/farm on to the back of a truck and drive it out of the lava's path, so mitigation via trenching, or pouring water to cool and solidify the lava may be a good plan. Do not try to follow Tommy Lee Jones' example in the movie 'Volcano' and use concrete blocks and fire engines to hold back a lava flow. Lava is so dense that both these items would float on it. This is like trying to stop a flood with polystyrene blocks and rubber dinghies.
-- Zircon, May 16 2003


Better to divert it like Southpark so you don't have to dig a new trench each time.
-- J Vander, Nov 13 2006



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