Rammed Earth is : Compacted layers of mixed gravel, sand and clay that is hard like stone. Add insulation and you have insulated rammed earth or add some cement and you have stabilized rammed earth. For seismic zones, steel reinforcing is added according to engineering specifications.
Please do not confuse rammed earth with Cob or mud as some people do. Rammed earth is vastly superior in strength and will not liquefy when exposed to large amounts of water.
Quality built walls are not only beautiful, durable and sophisticated, but act as structural walls that have a very heavy load bearing capacity.