January 4, 2004


Richard Bennett pointed me to an article on earthquake science, and the San Andreas Fault.

....The San Andreas last slipped in the region [Coachella Valley, in Southern California] 191 years ago. That is 40 years beyond the average interval for the southern segment, based on estimates that stretch back 12 centuries.

Geologists arrived at the calculations through paleoseismology, a fairly new technique that dates prehistoric quakes. Scientists dig into the fault to look for layers of peat and sand.

The strata time-stamp cracks � give or take 50 years � that quakes opened to the sunlight and that flood sediments filled later.

It is one of the disciplines that has made strides since Northridge, although the fault responsible for that quake resists paleo-detective work because it never broke the surface. The San Andreas is a proven crust-buster.

"Over the past 10 years, we've put a lot of effort into the L.A. Basin," McGill said. "Now it's time to put more attention on the San Andreas."

She was climbing a low ridge where the October wildfires burned away enough brush to leave fault impressions bare.

Her camera raised, she paused at a gully that stopped halfway down a hillside, as if it had hit an invisible wall. McGill pointed to a spot about 20 feet away where the gully reappeared. Its lower leg had been shunted to the right in shifting of the San Andreas....

The scientists seem to think that Northern Calififornia is not due for a big quake, that we are still benefitting from the release of tension in 1906. Doesn't mean that it can't happen, just that the probability is lower. It's Southern California that's way overdue.

Seems to me that if there is any area where we should not be thrifty, it's funding earthquake research. If I ran the circus, I'd shut down that utterly stupid "space station," (which should be more aptly termed the "space dead-end") where we spend billions to let a couple of guys do some part-time science, and use that money to let thousands of scientists do useful work.

The article is also interesting stuff on damage mitigation�how San Bernadino is pumping out excess groundwater to reduce the threat of soil liquification during a quake. I'd guess that there is a lot more that should be done, but won't. And one problem is that a lot of what should be done will be in the form of Big Government bullying people with things like tougher building codes.

Charlene and I recently investigated the possibility of adding some french-doors to open onto our garden. We spent a lot of effort and money just to find out how much it would cost (more than we can afford). The engineer said we would have to re-build the whole wall, with various pieces of steel inserted, etc. It was infuriating. BUT, a wall that's mostly window, such as we were dreaming of, is a weak point, unless it has extra reinforcement.

There's no easy answer to problems that require pushing people to do things that may pay off in the long run. One type of government coercion tends to lead to others. Building departments get hijacked by anti-growth types, who don't want to issue any permits. Which leads to evasion. And government always attracts, like flies to a corpse, the kind of people who think government should be controlling everything.

Posted by John Weidner at January 4, 2004 9:20 AM
Weblog by John Weidner