The recent earthquake in Alaska and the California fires have brought something to mind for me. EARTHQUAKES!!! Fires!!! Disasters!!! I don't know if you've noticed, but the recent trembler around Anchorage resulted in lots of broken up roads, disrupted power and fuel supplies, some cracks in some buildings and NO FATALITIES. There are many places in the world where a quake like this centered in a metropolitan area would have (and too often has) resulted in thousands and thousands of fatalities. I would like to point out that the difference is due to a couple of things. 1. Building codes, even though in many areas around Anchorage the codes were not enforced until fairly recently, there was an awareness of 'How it
should be done'. 2. Almost purely stick built buildings or log construction around Anchorage, partly due to a short building season and lack of good
local alternatives.
Of
course, the devils in the details, you can build a crappy house or a sturdy house with relatively minor tweeks and attention to detail, but different styles have advantages and problems.
On this site we tend to look down on modern stick building practices, but they stand up well to earthquakes. Kind of like Goldilocks's porridge, there's JUUUUST
enough flex.
Types of construction that I think will handle earthquakes well are:
modern stick built
log cabin style
post and beam with infill
strawbale
Adobe tends to become a death trap in an earthquake. The walls collapse and roof falls in. There may be ways to make it work though. I read years ago (when the US and Iran were still friendly) an anecote about a US officer stationed there for some reason who was appalled by the death toll of a big earthquake (the local building style was adobe with arched roofs which disintegrated in a major earthquake). He noticed that the potters kiln was the only thing still standing in old abandoned villages. He got a couple of drums of
gasoline and hired the local potter to close up the necessary doors and windows to make a new adobe house draw well. They fired it (for a couple of days I think) and found that the interior few inches had fused making it a giant ceramic bowl. When an earthquake hit, many houses collapsed and the entire village sheltered in his new building. During the night another big quake hit and several more homes collapsed, but no fatalities because everyone was in the new style house.
brick and unreinforced stone can have similar problems because there is simply no give or flex and the materials are brittle.
(a lot of that depends on the particular style. I've notice that major earthquake locations than use stone traditionally seem to use the stone as infill between post and beam, breaking up the stone wall into smaller units between support members would reduce the damage from a failure.)
Wattle and daub is basically post and beam with wattle and daub infill, it should be pretty safe although I'll bet there may need some patching of the daub afterwards.
Cob. I realize that fibers are driven into each cob with a cobbers thumb, making it a fairly monolithic structure. I think for big earthquakes I would still want some sort of post and beam with wattle and daub infill.
load bearing Strawbale - It should be fine, as long as everything is tied together well with rods.
Fire:
I don't think anyone will claim that most modern stick built houses deal well with fire. But there are things that can be done.
I was looking at a historical youtube video where they asked about wooden european castles. We know they were not uncommon, why don't you see any in the paintings, etc. It was pointed out that the Japanese used
wood extensively in their castles (generally above where a man could reach), but that they covered it with a thick layer of lime or stucco or something to make it fireproof (a really good idea if you are building with the idea that an invading army might come calling). The youtuber then went on to point out that many of the castles, etc in medieval and renaisanse
art might have a wooden substructure, because wood or stone, they were often coated with a thick coat of lime or stucco, etc. This brings me to my point. A flammable structure can be rendered pretty much impervious to wild fires, etc. with a thick layer of lime or stucco. A wild fire is hot in an area until it burns the local fuel. If you have mostly brush or smaller stuff near your house, the fire will be hot but relatively short lived. A layer of lime or stucco would protect the wood for that long. Attention would need to be paid to the rafters and beams that support the overhanging roof.
Adobe, brick, stone, are fire proof.
Overall, I would say that post and beam with a fire proof/resistant infill is generally the safest, and is probably why we find that kind of construction all over the world. It uses wood, but fairly sparingly, for support and fills in with cheaper, less flamable materials. If the wood is protected it can be pretty fireproof and it is also resistant to major damage in an earthquake.
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