If you live in an earthquake zone, you may be wondering whether a house made of mud is going to hold. I've now experienced four sizeable earthquakes in this house. My earthbag house loves them. But not as much as I do.There is something incomparably sublime about sitting in the home you built feeling the floor shift and watching your hanging candles swing, and not hearing a single creak from the rafters, nor see a crack in the plaster. Especially, when you haven't used a drop of cement and your foundations are nothing but gravel. What? What? No concrete? No rebar? Just gravel?
So, I think I can fairly safely say the gravel foundation works, and that earthbag roundhouses are pretty invincible when the ground decides to start bopping.
What gives earthbag homes (especially round earthbag houses) their incredible strength is the locking in of the bags using barbed wire. There is no weak point on an earthbag wall, thus nowhere to crack. It's also a structure that can move with the earth (mine has) which means a quake just ripples through it.
NB: When subject to earthquake testing, earthbag structures have been known to damage the testing equipment rather than collapse. Just one of the reasons they're being built in Nepal now. (See Kiffmeyer and Hunter's book on the subject)
Here's the earthquake history of my little house to date:
7 Oct 2015: 5.2 earthquake in Kumluca/Demre
5 Sept 2014: 5.3 earthquake at sea, Cirali-Finike.
28 Dec 2013: 5.8 earthquake at sea, just off the coast of Antalya
10 June 2012: 6.1 earthquake Fethiye to Antalya.