The Naked Scientists

The Naked Scientists Forum

Author Topic: duck and cover.  (Read 4736 times)

paul.fr

  • Guest
duck and cover.
« on: 21/08/2007 10:41:40 »
i seem to remember watching a video about what to do in the event of a volcano erupting, and the threat of lava on the people in it's path. The advice was to "duck and cover".

Even a simpleton such as I, knows this will not work (it doesn't does it?). So the question is, how do you protect villages and people at risk from a lava flow?

I have seen news clips where they appear to "blow up" the lava! whats that all about?


 

another_someone

  • Guest
duck and cover.
« Reply #1 on: 21/08/2007 13:25:27 »
One of the problems in Pompeii was that when Vesuvius erupted, all the residents went for shelter in their basements, the heavy toxic gasses emitted by Vesuvius then, being heaver than air, quickly filled up the basements as poisoned the population.

I think one probably has to look at each volcanic eruption differently, because different volcanoes, and even different volcanic events for the same volcano, behave differently.

Clearly, many volcanic events are associated with localised earthquakes, for which you need to be take account of falling masonry; while others will sent explosively rocks flying through the air (for this, and this alone, duck and cover might work), while others will just slowly ooze lava, while others just vent lots of toxic gas, and others may cause landslides from the earthquakes.  For most of these cases, your only real protection is simply to get out of the area.  In general, if you can't get far enough away, then I would imagine if you can at least reach high ground (not on the volcano itself), it might help protect from the lava and some of the heaver gasses (and preferably upwind).
 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
duck and cover.
« Reply #2 on: 22/08/2007 01:34:48 »
There are some efforts being made to find ways to channelize flows by use of explosives - not too effective - by digging channels around the place to be protected at a lower elevation than the elevated area and by placing huge obstacles, such as enormous boulder fields to re-direct flow. None are too successful.

Only the smallest and lightest of volcanic material can be gotten away from by duck and cove. The ejecta travels at too high a velocity otherwise. Scoria and pumice are ejecta that - if small enough - can protect against by duck and cover.
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
duck and cover.
« Reply #3 on: 22/08/2007 10:50:16 »
There's not much that would protect you from a pyroclastic flow short of a nuclear-proof bunker.
 

another_someone

  • Guest
duck and cover.
« Reply #4 on: 22/08/2007 13:29:28 »
There's not much that would protect you from a pyroclastic flow short of a nuclear-proof bunker.

What about concrete blocks faced with ablative surfaces like the Shuttle's (it would need to be thicker, and would not have an airflow to carry away material so it will have to boil off more vigorously - then again, making it a think solid foam would also give some space to boil and better thermal insulation).
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
duck and cover.
« Reply #5 on: 22/08/2007 14:36:14 »
There's not much that would protect you from a pyroclastic flow short of a nuclear-proof bunker.

What about concrete blocks faced with ablative surfaces like the Shuttle's (it would need to be thicker, and would not have an airflow to carry away material so it will have to boil off more vigorously - then again, making it a think solid foam would also give some space to boil and better thermal insulation).

Not many people have access to such material.
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1338
  • Thanked: 5 times
    • View Profile
duck and cover.
« Reply #6 on: 22/08/2007 16:48:31 »
In the 1902 pyroclastic (nuee ardente or glowing cloud) eruption of Mt. Pelee, nearly 28,000 people perished in St. Pierre on the island of Martinique.  One of the few survivors was a convict, who was in solitary confinement in the dungeon of the local jail.  He was reportedly burned with damage to his lungs, but survived the eruption due to the thick walls of the dungeon.
 

The Naked Scientists Forum

duck and cover.
« Reply #6 on: 22/08/2007 16:48:31 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums