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					Hidden in the Hills

 Lauren Steinfurth

  Geology 302.01

Professor B. Wyatt

   9 April 2009
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    The hill’s that trace along highway seventeen in the Santa

Cruz Mountains conceal many hidden secrets. Living in the area

for nearly my entire life I had not the slightest clue that the

fault that has caused so much trauma and damage in many of our

California earthquakes was located in my own backyard. I

recently visited a portion of the San Andreas Fault located

between Santa Cruz, California, and Los Gatos, California in an

area that overlooks the Lexington Reservoir. The pacific plate

located beneath our feet is a right-lateral strike-slip fault,

which creates noticeable and significant changes in the

components it is disrupting when it shifts.

    While adventuring through the chaparral environment, I

focused on finding incomparable and obvious key features as to

what I thought the effects of being on or close to a strike-slip

fault would entail. Being in such a natural environment

everything seemed to be in its original place and nothing drew

my attention leading all signs to fault evidence. I spent nearly

four hours looking for the destinations with noted observations

but had a hard time locating them. As I continued I started

picking up on what the common eye would see as minuscule. On the

contrary these observations that were made could tell anyone

knowledgeable to the subject that the current surroundings held
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observations that would disclose all evidence of being among the

San Andreas Fault line.

     The first stop that I made was along a mountainside just

shy of Alma Bridge Road. During the 1985 earthquake many fires

broke out, creating serious threat and damage to the hills and

its residents. I observed patches of chaparral forest intermixed

with patches of dry clay, rock and dirt covered land. Today this

leaves serious threat for fires because of the conditions left

by the 1985 Earthquake left it in. This is a good sign that

trances the fault for the land to vary in such conditions and

source of life.

     Continuing on my search for evidence and understanding of

earthquake traces and plate motion, my second stop was near

Mountain Charlie Road. It is a notable stop on my journey

because it is a remnant of a late 18th century trail that

connected mission Santa Clara and mission Santa Cruz; it is

thought to once be an Indian path. Although this is an important

trivial piece of our local history this did not provide

information leading to plate or earthquake movement, however

observing the land near Mountain Charlie Road I noticed

something unusual. The earth along the road changes steadily in

regards to the dirt. It would intermittently change from dry
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clay-like substance to nutrient rich soil to a sandy-dust-like

texture. After doing some more investigation the San Andreas

Fault mirrors the transitioning transformation of soil in the

vegetation, soil and bedrock. Although unnoticed to an untrained

eye, the constant change in soil along the highway provides

evidence of fault zone activity.

    The final destination on my outdoors adventure and

scientific study was a historic railroad tunnel, now abandoned

and sealed shut; this passageway was damaged in the 1906

earthquake. The Wrights Tunnel is tucked away and closed off

from the public mountain road and is wedged between the Santa

Cruz Mountains. This is a picturesque location seeming very much

in its own pristine element. When I was admiring the

surroundings I noticed a creek that pools at the base of the

tunnel and continues to stream hugging the crevices of the

mountainside. I also noticed the angle of the train tunnel in

relation to the surroundings and the tracks that once passed

through this serene land has been overgrown and taken over by a

lush green environment. Throughout the openings of the hillside

where the stream flows, land has eroded into deeper earth and

old train tracks protrude and reveal their age through open

soil. I had to wonder if the earthquake has infact caused this
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stream to form due to its movement and shifts in the earth

encouraging a waterway to break from its once solid concrete

form. It is said that the Wrights tunnel was severally damaged

during the 1906 earthquake however it is hard to tell because

the tunnel was so dark inside. While looking for my own evidence

I found areas where land looks like as if it were torn apart and

revealed multiple defining layers of soil. It is hard to say if

this is evidence of an earthquake or fault movement but it does

pose as a potential indicator.

    The observations I had made on this afternoon were

difficult to find and I am still left a little unsure on strong

evidence, however I do feel like I have a greater working

knowledge on the subject and what I should be looking for.

Although the things I saw were not direct evidence of the

movement of the current workings of the San Andreas Fault, they

hold truth to the effects these movements have left on our

environment. As the pacific plate continue its shift, our local

environment will continue to change, however it may be difficult

to notice firsthand with an untrained eye.

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