Bacteria To Protect Against Quakes

Roland Piquepaille writes "If you live near the sea, chances are high that your home is built over sandy soil. And if an earthquake strikes, deep and sandy soils can turn to liquid with disastrous consequences for the buildings built above them. Now, US researchers have found a way to use bacteria to steady buildings against earthquakes by turning these sandy soils into rocks. 'Starting from a sand pile, you turn it back into sandstone,' the chief researcher explained. It is already possible to inject chemicals into the ground to reinforce it, but this technique can have toxic effects on soil and water. In contrast, the use of common bacteria to 'cement' sands has no harmful effects on the environment. So far this method is limited to labs and the researchers are working on scaling their technique. Here are more references and a picture showing how unstable ground can aggravate the consequences of an earthquake."

Re:Research needed!

[canUbeleiveIT]

Exactly.

FTA: In contrast, the use of common bacteria to 'cement' sands has no harmful effects on the environment.

That should read "...has no *known* harmful effects..." Introducing species has a long history of unintended consequences. For example:

• Introduction of mongooses to various islands, resulting in the decimation of native bird populations
• Introduction of the Nile Perch into Lake Victoria, resulting in the extinction of certain species of chichlids
  
• Introduction of African (killer bees) honey bees to N. America
• etc, etc

This is different

[Reverberant]

The bacteria process basically improves the shear response of the soil when it's under motion to prevent/reduce liquefaction. The problem in Boston is that buildings in Back Bay and along the Harbor are basically setting on water. Short of soil mixing under each of the foundation, there's not much that you can do to solve the problem you describe.

Re:Research needed!

[Anonymous Coward]

Hello, I wrote the original story about this on our blog, eggheadblog.ucdavis.edu -- the key point here is nutrients. The bacteria occur naturally in these soils, but without additional nutrients and oxygen, the bacteria don't grow enough to produce the calcite and stick everything together. So it can't run away and turn the world's beaches into concrete.