Oregon- Volcanoes and Mapping Techniques
Cochise College                                                                                        
Geology Home Page 
Geology Exploration Using Google Earth  
Roger Weller, geology instructor 
wellerr@cochise.edu )

last edited:  9/26/16            15 views

     Oregon has a large number of volcanoes in addition to the major volcanoes of the Cascade
Mountains.  The volcanoes in the following view were mapped using a volcano icon from a list
of icons provided with Google Earth.

     This map includes both uneroded and eroded volcanic features.  Oregon probably has had
even greater numbers of volcanoes in the past but many have simply been eroded away or
covered by later deposits.

Oregon volcanoes

     The northern grouping of Oregon volcanoes follows the main line of the Cascade mountains.

a closer view of the northern portion of the distribution of volcanoes in Oregon

The southern grouping of Oregon volcanoes follows the main line of the Cascade mountains.

a closer view of the southern portion of the distribution of volcanoes in Oregon

The central distribution of Oregon volcanoes follows roughly a south-east trend

a close view of the central portion of the distribution of volcanoes in Oregon

Circular features in Oregon were also mapped using the measuring tool that accompanies Google Earth. 
The line segments in this view were given a green color.  The source of these circular patterns is still not
fully explained at present but is probably due to igneous and tectonic activity.

    The feature indicated by "Indian" is an archaeological site with large pictographs.

distribution of circular features in Oregon

     Different types of features can easily be included on the same Google Earth view.  The features are all
stored on kml files and can added to or be depleted.  Many circles are found along the Cascade Mountains
line along with the volcanoes.  The large number of circula features in the northeastern section does not
correlate with volcanoes but is an area of abundant hot springs.

volcanoes and circular features in Oregon

In the following view, North is to the right.  The map was turned sideways to better fit the diagonal
shape of the view.  Only the major volcanoes of the Cascades are marked with icons.  The small circular
features, most which are actually small volcanoes, closely follow the main line of the Cascade Mountains.

volcanoes and circular features along the Cascade Mountains

Extensive mapping of both linear features and drainage patterns was done for most of Oregon. 
Heavy vegetation cover East of the Cascades Mountains prevent the mapping of features in this area. 
Thousands of lines were used to create this map.  The significance of the project can only be appreciated
by zooming in closer on specific areas.

linears and drainage patterns in Oregon

 Three large circular features stand out in the following view.  The circles were determined primarily by
alignment of linear features and by the termination of linear features.  The largest two circular features
have diameters of 28 kilometers and 26 kilometers.

a close view of linear and circular features

Here is another view of large circular features indicated by linears stuctures.  The diameters of the
three largest circles are 53 kilometers, 35 kilometers, and 34 kilometers.

a close view of linear and circular features

Again, various types of features can be combined in a single map: linear features, circles and volcanoes. 
Together, these features nicely identify a large double ring structure.

a close view with linears, circles and volcanoes

An additional feature that can be added to these maps is color.  Most of eastern Oregon is a dull gray
color.  Occasionally there are brightly colored patches of red, orange, and yellow iron oxides produced by
the oxidation of iron minerals.  In the southeast corner of Oregon there is a large circular fearure that
extends into suurounding states.  This double-ringed circular features is nicely marked by colored patches
of iron oxides.  Also in this view are two smaller circular features emphasized by strongly colored patches
of iron oxides.

view of the southeast corner of Oregon

The following shows the distribution of hot springs in Oregon.

hot springs


     By combing both hot spings and volcanoes, one can areas of both correlation and no correlation.

volcanoes and hot springs

While searching for circular patterns in Oregon, I came across several strange spiral patterns.  This
view contains just two of the features. Research confirmed that these are archaeological artifacts that
have not been dated, very large pictographs. The area is next to Fluke lake where there are many much
smaller carvings of a similar pattern on rocks.  The size of these features is impressive.
Fluke lake pictographs

Just credit photos to Google Earth/R.Weller/Cochise College.