We've reported on disaster relief housing before. Prefab methods are ideally suited for quick, cheap housing in far flung, resource-starved areas. An organization named CalEarth (California Institute of Earth Art and Architecture) has developed a method of home building that requires little more than the earth present at a homesite. 

CalEarth's designs are based on a proprietary product called Superadobe Earthbags. The bags come in widths ranging from 12" to 26" and can be ordered up to a mile long. Combined with barbed-wire and earth from the site, the bags create super-strong structures:

"To build simple emergency and safe structures in our backyards, to give us maximum safety with minimum environmental impact, we must choose natural materials and, like nature itself, build with minimum materials to create maximum space, like a beehive or a sea shell. The strongest structures in nature which work in tune with gravity, friction, minimum exposure and maximum compression, are arches, domes and vault forms. And they can be easily learned and utilize the most available material on earth: Earth."

CalEarth has experimented with a number of designs and implementations using Superadobe, ranging from the Eco-Dome house, aka the "Moon Cocoon", to emergency shelters. Features of the Eco-Dome include:
• Built from local earth-filled Superadobe coils (soil-cement or lime-stabilized earth).
• Tree free.
• Can be repeated and joined together to form larger homes and courtyard houses.
• Can be built by a team of 3-5 persons.
• Designed with the sun, shade and wind in mind for passive cooling and heating.
• Solar energy and radiant heating may be incorporated.

(Hat tip: Inhabitat shared a bunch of photos and thoughts on the design last week.)