San Andreas Fault

From: F.c. Kuechmann
To: Laurie Appleton

Appleton, are you really as hopeless as you appear to be?

>KK>      The Pacific plate is moving northwest at a speed of
>KK> some inches per year, while the North American plate is
>KK> moving west, grinding against the Pacific plate at an
>KK> interesting junction known as the San Andreas Fault.  On the
>KK> other side of the pond, the Pacific plate is being forced
>KK> under the Asian plate at locations known as trenches, such
>KK> as the Marianas Trench -- the deepest place on Earth.

LA>    You really should NOT declare such wild conjectures in a
LA> way that suggest that it is a known fact! We know NO such
LA> thing of course, and no one seems to know how much real
LA> movement has been made by any continents.  If it was "some
LA> inches per year" as you so glibly state, then it should be
LA> possible by now to say exactly how much it has actually
LA> moved over the last 20 or 30 years, shouldn't it?
At several points, slippage rate is 24mm-34mm per year -- see data below. Since 25mm = 1 inch and 12 inches = 1 ft, a location that slips at a 25mm/yr rate will slip approximately 2 ft in 24 years.

You should be ashamed of yourself, displaying your ignorance in a most self-destructive fashion. Why are you creationists so determined to parade your ignorance and inability to use even the most basic library research materials? Is your self-esteem that pathetically low?

Slippage rates vary greatly along the San Andreas fault system, which extends from the Gulf of California to Point Arena [N of San Francisco] -- a distance of 700+ miles.

For a nice map showing San Andreas slippage at various points, consult the following document available from the state of California for a nominal charge --

Jennings, Charles W. (1994). Fault Activity Map of California and Adjacent Areas with Location and Ages of Recent Volcanic Eruptions. California Geologic Data Map Series, Map No. 6. California Division of Mines and Geology.
A table called CALIFORNIA FAULT PARAMETERS, SAN ANDREAS FAULT ZONE presents the preliminary values used by the California Department of Conservation's Division of Mines and Geology and the U.S. Geological Survey for estimating seismic hazard in the State of California. Some data from that table --
              Fault Name  Length   Slip Rate
                 (1)     (km) +/- (mm/yr) +/-

             San Andreas- 95  10  25.00   5.00

             San Andreas-107  11  24.00   6.00
             San Bernardino

             San Andreas 203  20  24.00   6.00

             San Andreas- 99  10  30.00   7.00

             San Andreas-145  15  34.00   3.00

             San Andreas- 62   6  34.00   5.00

             San Andreas- 37   4  34.00   5.00
During the 1906 earthquake in the San Francisco region, roads, fences, and rows of trees and bushes that crossed the fault were offset several yards, and the road across the head of Tomales Bay was offset almost 21 feet, the maximum offset recorded. In each case, the ground west of the fault moved relatively northward.

If your creationist employers [are they at the Creation Research Foundation there in beautiful downtown Brisbane, perhaps?] provide you with internet access, you might try the following URLs.

maps --

chart here --

LA> But you cannot put a real figure on it, can you

Real figures are pathetically easy to come by, Laurie. All you hafta do is look somewhere other than creationist comic books.

LA> therefore the whole thing is just so much romaticizing,
LA> isn't it and NOT science at all?
Therefore you seem to be totally incapable of even the simplest library research. It's your creationist ignorance that's so much romanticizing.
From: Paul Rogers
To: F.c. Kuechmann
FK> Slippage rates vary greatly along the San Andreas fault system,
FK> which extends from the Gulf of California to Point Arena [N of
FK> San Francisco] -- a distance of 700+ miles.
As a native born Angelino intimate knowledge of the San Andreas was something I grew up with. You are quite right, of course, that the San Andreas is not uniform. There is a big kink in it between, oh, around Cholame or Maricopa to around Joshua Tree, where it runs W-E rather than NW-SE.
FK> For a nice map showing San Andreas slippage at various points,
FK> consult the following document available from the state of
FK> California for a nominal charge --
I can contribute the following, from an earlier message I posted in another echo (Scientific American covered the Southern California seismo-geology in an article many years ago):

The western edge of the North American Plate has over-ridden the descending edge of the eastern Pacific Plate. There is no trench off the Pacific coast of North America as there is along the coast of South America or the entire western edge of the Pacific Plate. The Coast Range in California is the scraped-up sediments from the former trench. "Diatomaceous Earth", the skeletons of oceanic diatoms, is mined near Lompoc. The San Andreas mostly runs down the east side of the Coast Range south of Salinas down to Maricopa. Then it turns east.

However, the Transverse Range, mostly the San Gabriel and San Bernardino mountains, but also including the San Jacinto Mountains, is also on the western side of the San Andreas fault in Southern California. These are big mountains and, like icebergs, these mountains, San Gorgonio 11,499', San Jacinto 10,804', Mt San Antonio (Old Baldy Peak) 10,064', even Mt Pinos 8,831' and Frazier Mountain 8,013' far to the west nearer Maricopa, have deep roots in crustal plates. These are not mere scrapings of sediment, but metamorphic granite. These must have been part of the North American Plate.

The problem for LA isn't the San Andreas    \SAF                    not to
fault, per se, but the "kink", looking       \                      scale,
much like it might have been a "fracture      \    L       V        just an
zone" offset feature of mid-oceanic            \ _______________    idea
ridges, these mountains have created.              \ SGM \ SBM  \
As coastal regions of Southern and Baja       ______\_____\_     \
California move north-west sliding along         \  SFV \___\_____\ SAF
the southern end of the San Andreas from   ....M. \______\___\ SB  \
Yucca Valley south through the Salton            ..SM  \ LA  P\_____\
Sea, they collide at this corner,                  .    \   W  \     \
fragment and push up the Santa Monica         SMB   .  I \______\ SJM \SAF
Mountains.  LA is in much more danger               .     \     R\     \
from local faults, Newport-Inglewood               .    LB \ SAM  \     \
(Long Beach 1933), and Whittier (1989?),           .PV ...  \______\_____\
creating earthquakes like Sylmar                    ...   . N             \
(2/9/1971) and Northridge (1993?).                         .    ^^^^^     SS
Look at a map of Southern California                            |||||
sometime.  LA, Whittier, Pomona, San                             push
Bernardino, Riverside, Lancaster, Newport,
Victorville, Malibu, Santa Monica, Inglewood,
Long Beach, Palos Verdes, Santa Monica Bay, and
look at the mountains, the San Gabriel's, Santa Ana's, San Jacinto's,
San Bernardino's, and Santa Monica's. It's not difficult to see!
Slam! BAM! Thank you, M'am. Why do people live there?
It's curious that nobody has used seismic tomography to either find that descending plate or prove that it has melted away. It's obvious to anyone who has ever seen Ansel Adams's famous picture of the eastern scarp of the Sierra Nevada's at dawn that there must be one hell of a fault in the Owens Valley. We know that Yosemite's Half Dome and El Capitan are plutons. And there is continuing geologic activity in the Long Valley Caldera near Mammoth Lakes. (When the volcano that created the LVC exploded it sent THICK layers of ash as far east as St Louis and the Mississippi River!) Yes, the Coast Range has definitely been pushed up by the edge of the North American Plate scraping the top of the Pacific Plate, but the geology of California and the west coast is much more complex and fascinating than just that. (Mt Nebo in Roseburg, OR, is covered in "pillow lava" meaning it was an undersea volcano.)