On 6 Oct 2004 23:08:31 -0700, (Raymond
Yeung) wrote:

We actually lived in the area for close to 10 years. I know a lot of
people wouldn't even think about earthquake at all. Some think that FEMA
would bail them out should major disaster strike, so they won't even bother
with Earthquake insurance on a house worth half to one million.

There's a misconception the very few houses cost half to one
million. But the property might. As I used to tell people in Palo
Alto, no, youdidn't pay $600,000 for this house; you paid about
$120,000 for the house and about $480,000 for the ground it's
sitting on. That's why people are so willing to buy a really cute
house and lot for $500,000 and then tear the house down and build
a new one.

Earthquake
would strike here someday much like snow would fall on the North.
Incidentally, I learnt that earthquake magnitue is more of log scale -
every increment causes a 30 fold increase in released energy. A major
one is something of 7 or above. Think about the last one that's about 6,
and then multiply that by 30, and with epicenter right in the neighbourhood.

Anyway, here comes more questions/comments:

1. I still haven't heard anything about post-tension. Did some digging
on newsgroup. This technique seems like a routine on modern building.
But it sounds like people here think wood-frame 2-3 storeys are safer?

You can't really post-tension a wooden structure. post-tenisionig
is usually done by embedding reinforcing bars in concrete and
then tightenign giant nuts at the ends after the concrete sets.

2. The tile roof looks pretty, but are they safe? Which material is safest,
affordable and reasonably durable?

Tile rooves are a disaster waiting to happen. They are mostly
held in place by gravity.

3. Any other features to avoid/desire, e.g. chimney, number/size of windows?
Would Singles Family House be better than Townhouse (due to connected walls
etc, if something bad happens next door, it would likely affect us also)?

People have been killed or injured by falling brick chimneys. Not
only that, even a minor shaker can crack the brickwork, making
the chimney a fire hazard from the leakage of hot gasses to the
wooden structure. Always have a chimney inspected after even a
minor earthquake.

Also avoid "soft stories"; these were a major problem in the
Marina in 1989. A soft story is a level of the structure that has
little support, like the typical San Francisco house that has an
open space or garage in the ground level and the living area
above that. If ther is a soft story, make sure that shear
paneling has been installed and the house is bolted to the
foundation (there used to be instructions for this in the front
of Bay Area telephone books).

The walls of the house should be tied together at the corners. A
major damage of houses in an earthquake is due to the walls
falling away from the house.

by the way, lot's of earhquake pictures at
http://nisee.berkeley.edu/eqiis.html

************* DAVE HATUNEN ) *************
* Tucson Arizona, out where the cacti grow *
* My typos & mispellings are intentional copyright traps *