Contained earth (CE) is a structurally designed natural building material that combines containment, inexpensive reinforcement, and strongly cohesive earthen walls. CE is earthbag construction that can be calibrated for several seismic risk levels based on building soil strength and plan standards for adequate bracing. There is a recognized need for structural understanding of alternative building materials. Construction guidelines for CE are currently under development, based on the New Zealand's performance-based code for adobe and rammed earth. CE is differentiated from contained gravel (CG) or contained sand (CS) by the use of damp, tamped, cured cohesive fill. CE can be modular, built in poly-propylene rice bag material containers, or solid, built in mesh tubing that allows earthen fill to solidify between courses. CG, filled with pumice or ordinary gravel and/ or small stones, is often used as water-resistant base walls under CE, which also provides an effective capillary break. Soilbags used mostly in horizontal applications by civil engineers contain loose fill which includes both CG and CS. CG courses, like soilbags, may contribute base isolation and/or vibration damping qualities, although out-of-plane strength needs research. For clarity, earthbag built with a low cohesion fill, or filled with dry soil that does not solidify, is not CE but CS. Uncured CE also performs structurally like CS. Earthbag variations Builders used to working without engineers are proud of earthbag's unlimited variations. Few trainers discuss risk levels of building sites, or recommend accurate tests of soil strength, even though soil strength is a key factor of improved seismic performance for earthen walls. Need for or use of metal components are disputed, including rebar hammered into walls and barbed wire between courses, although static friction of smooth bag-to-bag surfaces of heavy modular CE walls is 0.4 with no adhesion. Engineering knowledge of earthbag has been growing. More is known about the performance of walls made with sand or dry or uncured soil than about the overwhelming majority of earthbag buildings which have used damp, cohesive soil fill. Reports based on tests of soilbags and loose or granular fill (or uncured fill) assumes that soil strength is less important to wall strength than bag fabric strength for. However, shear tests show clearly that stronger cured, cohesive fill increases contained earth wall strength substantially. Earthbag for high risk environments Earthbag developed gradually without structural analysis, first for small domes, then for vertical wall buildings of many shapes. Although