<p>See the image below. In the picture, the San Andreas Fault <em>dip</em> is nearly 90 degrees or exactly vertical; The <em>strike</em> is pointing North.</p>

<p>Most normal faults and reverse faults (such as the Sierra Madre) are not vertical, but rather dip in either direction. (In the picture the Sierra Madre appears to have a dip of about 45 degrees).</p>

<p>In real life, the dip of the San Andreas is not perfectly vertical, but is variable, depending on where in California you are.</p>

<p>Strike and dip can be measured using a Brutton Compass.</p>

<p><a href="https://i.sstatic.net/EdgcA.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/EdgcA.gif" alt="enter image description here"></a></p>

CC BY-SA 3.0
2017-07-03T16:29:39.940Z
So.....the dip of the fault plane will be different if I'm in, say, San Diego vs. Eureka?
Knob Scratcher
CC BY-SA 3.0
2017-07-05T22:35:20.283Z
Yeah, it's possible.
J.W. Powell
CC BY-SA 3.0
2017-06-30T19:43:01.003Z
2017-06-30T21:09:41.853Z
2017-06-30T21:09:41.853Z
J.W. Powell
<p>I was reading a book about tectonic plate boundaries, and I came across this paragraph:
<a href="https://i.sstatic.net/aSypf.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/aSypf.jpg" alt="enter image description here"></a></p>

<p>It says that when a plate edge slides with another plate edge it causes a vertical fault, as San Andreas fault. I thought that SAF is a horizontal fault i.e. strike-slip fault. So what does the book mean by vertical faults?</p>

CC BY-SA 3.0
2017-06-20T11:43:03.527Z
The fault plane is vertical. It is also a strike slip fault.
bon
CC BY-SA 3.0
2017-06-20T16:11:36.250Z
@bon, you mean it speaks about the fault plane not the direction of motion of the rocks? Do you mean that if it wrote "horizontal fault" some people would interpret this to be a thrust fault?
Asmaa
CC BY-SA 3.0
2017-06-21T00:34:35.770Z
The fault itself is more or less vertical; the motion is horizontal.
BillDOe
CC BY-SA 3.0
2017-06-21T11:29:35.017Z
@Asmaa Yes it refers to the orientation of the fault plane. That is how most people would interpret this I think. Vertical fault, referring to the direction of motion would be ambiguous between a reverse or a normal fault so not a very useful description.
bon
<transform-fault>
Is San Andreas fault horizontal or vertical?
Asmaa
# Is San Andreas fault horizontal or vertical?

(Asked by: username_0 on 2017-06-20)

I was reading a book about tectonic plate boundaries, and I came across this paragraph:
[![enter image description here](https://i.sstatic.net/aSypf.jpg)](https://i.sstatic.net/aSypf.jpg)

It says that when a plate edge slides with another plate edge it causes a vertical fault, as San Andreas fault. I thought that SAF is a horizontal fault i.e. strike-slip fault. So what does the book mean by vertical faults?

**Tags:** transform-fault

> **Comments:**
> **username_1**: The fault plane is vertical. It is also a strike slip fault.  
> **username_0**: @username_1, you mean it speaks about the fault plane not the direction of motion of the rocks? Do you mean that if it wrote "horizontal fault" some people would interpret this to be a thrust fault?  
> **username_2**: The fault itself is more or less vertical; the motion is horizontal.  
> **username_1**: @username_0 Yes it refers to the orientation of the fault plane. That is how most people would interpret this I think. Vertical fault, referring to the direction of motion would be ambiguous between a reverse or a normal fault so not a very useful description.  

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## 1 answers

### Answer by username_3 on 2017-06-30. Score: 2 | Accepted answer

See the image below. In the picture, the San Andreas Fault *dip* is nearly 90 degrees or exactly vertical; The *strike* is pointing North.

Most normal faults and reverse faults (such as the Sierra Madre) are not vertical, but rather dip in either direction. (In the picture the Sierra Madre appears to have a dip of about 45 degrees).

In real life, the dip of the San Andreas is not perfectly vertical, but is variable, depending on where in California you are.

Strike and dip can be measured using a Brutton Compass.

[![enter image description here](https://i.sstatic.net/EdgcA.gif)](https://i.sstatic.net/EdgcA.gif)

> **Comments:**
> **username_4**: So.....the dip of the fault plane will be different if I'm in, say, San Diego vs. Eureka?  
> **username_3**: Yeah, it's possible.  

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